Implement facility based logger, debugging via REST API

This implements a new debug/trace infrastructure based on a slightly
hacked up logger. Instead of the traditional "if debug { ... }" I've
rewritten the logger to have no-op Debugln and Debugf, unless debugging
has been enabled for a given "facility". The "facility" is just a
string, typically a package name.

This will be slightly slower than before; but not that much as it's
mostly a function call that returns immediately. For the cases where it
matters (the Debugln takes a hex.Dump() of something for example, and
it's not in a very occasional "if err != nil" branch) there is an
l.ShouldDebug(facility) that is fast enough to be used like the old "if
debug".

The point of all this is that we can now toggle debugging for the
various packages on and off at runtime. There's a new method
/rest/system/debug that can be POSTed a set of facilities to enable and
disable debug for, or GET from to get a list of facilities with
descriptions and their current debug status.

Similarly a /rest/system/log?since=... can grab the latest log entries,
up to 250 of them (hardcoded constant in main.go) plus the initial few.

Not implemented in this commit (but planned) is a simple debug GUI
available on /debug that shows the current log in an easily pasteable
format and has checkboxes to enable the various debug facilities.

The debug instructions to a user then becomes "visit this URL, check
these boxes, reproduce your problem, copy and paste the log". The actual
log viewer on the hypothetical /debug URL can poll regularly for new log
entries and this bypass the 250 line limit.

The existing STTRACE=foo variable is still obeyed and just sets the
start state of the system.

Godeps/Godeps.json

@@ -13,10 +13,6 @@
 			"ImportPath": "github.com/calmh/du",
 			"Rev": "3c0690cca16228b97741327b1b6781397afbdb24"
 		},
-		{
-			"ImportPath": "github.com/calmh/logger",
-			"Rev": "c96f6a1a8c7b6bf2f4860c667867d90174799eb2"
-		},
 		{
 			"ImportPath": "github.com/calmh/luhn",
 			"Rev": "0c8388ff95fa92d4094011e5a04fc99dea3d1632"

Godeps/_workspace/src/github.com/calmh/logger/LICENSE

@@ -1,19 +0,0 @@
-Copyright (C) 2013 Jakob Borg
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the "Software"), to deal in
-the Software without restriction, including without limitation the rights to
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-of the Software, and to permit persons to whom the Software is furnished to do
-so, subject to the following conditions:
-
-- The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.

Godeps/_workspace/src/github.com/calmh/logger/README.md

@@ -1,15 +0,0 @@
-logger
-======
-
-A small wrapper around `log` to provide log levels.
-
-Documentation
--------------
-
-http://godoc.org/github.com/calmh/logger
-
-License
--------
-
-MIT
-

Godeps/_workspace/src/github.com/calmh/logger/logger.go

@@ -1,187 +0,0 @@
-// Copyright (C) 2014 Jakob Borg. All rights reserved. Use of this source code
-// is governed by an MIT-style license that can be found in the LICENSE file.
-
-// Package logger implements a standardized logger with callback functionality
-package logger
-
-import (
-	"fmt"
-	"io/ioutil"
-	"log"
-	"os"
-	"strings"
-	"sync"
-)
-
-type LogLevel int
-
-const (
-	LevelDebug LogLevel = iota
-	LevelVerbose
-	LevelInfo
-	LevelOK
-	LevelWarn
-	LevelFatal
-	NumLevels
-)
-
-// A MessageHandler is called with the log level and message text.
-type MessageHandler func(l LogLevel, msg string)
-
-type Logger struct {
-	logger   *log.Logger
-	handlers [NumLevels][]MessageHandler
-	mut      sync.Mutex
-}
-
-// The default logger logs to standard output with a time prefix.
-var DefaultLogger = New()
-
-func New() *Logger {
-	if os.Getenv("LOGGER_DISCARD") != "" {
-		// Hack to completely disable logging, for example when running benchmarks.
-		return &Logger{
-			logger: log.New(ioutil.Discard, "", 0),
-		}
-	}
-
-	return &Logger{
-		logger: log.New(os.Stdout, "", log.Ltime),
-	}
-}
-
-// AddHandler registers a new MessageHandler to receive messages with the
-// specified log level or above.
-func (l *Logger) AddHandler(level LogLevel, h MessageHandler) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	l.handlers[level] = append(l.handlers[level], h)
-}
-
-// See log.SetFlags
-func (l *Logger) SetFlags(flag int) {
-	l.logger.SetFlags(flag)
-}
-
-// See log.SetPrefix
-func (l *Logger) SetPrefix(prefix string) {
-	l.logger.SetPrefix(prefix)
-}
-
-func (l *Logger) callHandlers(level LogLevel, s string) {
-	for _, h := range l.handlers[level] {
-		h(level, strings.TrimSpace(s))
-	}
-}
-
-// Debugln logs a line with a DEBUG prefix.
-func (l *Logger) Debugln(vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintln(vals...)
-	l.logger.Output(2, "DEBUG: "+s)
-	l.callHandlers(LevelDebug, s)
-}
-
-// Debugf logs a formatted line with a DEBUG prefix.
-func (l *Logger) Debugf(format string, vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintf(format, vals...)
-	l.logger.Output(2, "DEBUG: "+s)
-	l.callHandlers(LevelDebug, s)
-}
-
-// Infoln logs a line with a VERBOSE prefix.
-func (l *Logger) Verboseln(vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintln(vals...)
-	l.logger.Output(2, "VERBOSE: "+s)
-	l.callHandlers(LevelVerbose, s)
-}
-
-// Infof logs a formatted line with a VERBOSE prefix.
-func (l *Logger) Verbosef(format string, vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintf(format, vals...)
-	l.logger.Output(2, "VERBOSE: "+s)
-	l.callHandlers(LevelVerbose, s)
-}
-
-// Infoln logs a line with an INFO prefix.
-func (l *Logger) Infoln(vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintln(vals...)
-	l.logger.Output(2, "INFO: "+s)
-	l.callHandlers(LevelInfo, s)
-}
-
-// Infof logs a formatted line with an INFO prefix.
-func (l *Logger) Infof(format string, vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintf(format, vals...)
-	l.logger.Output(2, "INFO: "+s)
-	l.callHandlers(LevelInfo, s)
-}
-
-// Okln logs a line with an OK prefix.
-func (l *Logger) Okln(vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintln(vals...)
-	l.logger.Output(2, "OK: "+s)
-	l.callHandlers(LevelOK, s)
-}
-
-// Okf logs a formatted line with an OK prefix.
-func (l *Logger) Okf(format string, vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintf(format, vals...)
-	l.logger.Output(2, "OK: "+s)
-	l.callHandlers(LevelOK, s)
-}
-
-// Warnln logs a formatted line with a WARNING prefix.
-func (l *Logger) Warnln(vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintln(vals...)
-	l.logger.Output(2, "WARNING: "+s)
-	l.callHandlers(LevelWarn, s)
-}
-
-// Warnf logs a formatted line with a WARNING prefix.
-func (l *Logger) Warnf(format string, vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintf(format, vals...)
-	l.logger.Output(2, "WARNING: "+s)
-	l.callHandlers(LevelWarn, s)
-}
-
-// Fatalln logs a line with a FATAL prefix and exits the process with exit
-// code 1.
-func (l *Logger) Fatalln(vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintln(vals...)
-	l.logger.Output(2, "FATAL: "+s)
-	l.callHandlers(LevelFatal, s)
-	os.Exit(1)
-}
-
-// Fatalf logs a formatted line with a FATAL prefix and exits the process with
-// exit code 1.
-func (l *Logger) Fatalf(format string, vals ...interface{}) {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-	s := fmt.Sprintf(format, vals...)
-	l.logger.Output(2, "FATAL: "+s)
-	l.callHandlers(LevelFatal, s)
-	os.Exit(1)
-}

Godeps/_workspace/src/github.com/calmh/logger/logger_test.go

@@ -1,58 +0,0 @@
-// Copyright (C) 2014 Jakob Borg. All rights reserved. Use of this source code
-// is governed by an MIT-style license that can be found in the LICENSE file.
-
-package logger
-
-import (
-	"strings"
-	"testing"
-)
-
-func TestAPI(t *testing.T) {
-	l := New()
-	l.SetFlags(0)
-	l.SetPrefix("testing")
-
-	debug := 0
-	l.AddHandler(LevelDebug, checkFunc(t, LevelDebug, "test 0", &debug))
-	info := 0
-	l.AddHandler(LevelInfo, checkFunc(t, LevelInfo, "test 1", &info))
-	warn := 0
-	l.AddHandler(LevelWarn, checkFunc(t, LevelWarn, "test 2", &warn))
-	ok := 0
-	l.AddHandler(LevelOK, checkFunc(t, LevelOK, "test 3", &ok))
-
-	l.Debugf("test %d", 0)
-	l.Debugln("test", 0)
-	l.Infof("test %d", 1)
-	l.Infoln("test", 1)
-	l.Warnf("test %d", 2)
-	l.Warnln("test", 2)
-	l.Okf("test %d", 3)
-	l.Okln("test", 3)
-
-	if debug != 2 {
-		t.Errorf("Debug handler called %d != 2 times", debug)
-	}
-	if info != 2 {
-		t.Errorf("Info handler called %d != 2 times", info)
-	}
-	if warn != 2 {
-		t.Errorf("Warn handler called %d != 2 times", warn)
-	}
-	if ok != 2 {
-		t.Errorf("Ok handler called %d != 2 times", ok)
-	}
-}
-
-func checkFunc(t *testing.T, expectl LogLevel, expectmsg string, counter *int) func(LogLevel, string) {
-	return func(l LogLevel, msg string) {
-		*counter++
-		if l != expectl {
-			t.Errorf("Incorrect message level %d != %d", l, expectl)
-		}
-		if !strings.HasSuffix(msg, expectmsg) {
-			t.Errorf("%q does not end with %q", msg, expectmsg)
-		}
-	}
-}

cmd/syncthing/debug.go

@@ -9,10 +9,24 @@ package main
 import (
 	"os"
 	"strings"
+
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debugNet    = strings.Contains(os.Getenv("STTRACE"), "net") || os.Getenv("STTRACE") == "all"
+	l     = logger.DefaultLogger.NewFacility("main", "Main package")
-	debugHTTP   = strings.Contains(os.Getenv("STTRACE"), "http") || os.Getenv("STTRACE") == "all"
+	httpl = logger.DefaultLogger.NewFacility("http", "REST API")
-	debugSuture = strings.Contains(os.Getenv("STTRACE"), "suture") || os.Getenv("STTRACE") == "all"
 )
+
+func init() {
+	l.SetDebug("main", strings.Contains(os.Getenv("STTRACE"), "main") || os.Getenv("STTRACE") == "all")
+	l.SetDebug("http", strings.Contains(os.Getenv("STTRACE"), "http") || os.Getenv("STTRACE") == "all")
+}
+
+func shouldDebugMain() bool {
+	return l.ShouldDebug("main")
+}
+
+func shouldDebugHTTP() bool {
+	return l.ShouldDebug("http")
+}

cmd/syncthing/gui.go

@@ -20,16 +20,17 @@ import (
 	"path/filepath"
 	"reflect"
 	"runtime"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
 
-	"github.com/calmh/logger"
 	"github.com/syncthing/syncthing/lib/auto"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/discover"
 	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/logger"
 	"github.com/syncthing/syncthing/lib/model"
 	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/protocol"
@@ -41,15 +42,8 @@ import (
 	"golang.org/x/crypto/bcrypt"
 )
 
-type guiError struct {
-	Time  time.Time `json:"time"`
-	Error string    `json:"error"`
-}
-
 var (
 	configInSync = true
-	guiErrors    = []guiError{}
-	guiErrorsMut = sync.NewMutex()
 	startTime    = time.Now()
 )
 
@@ -65,9 +59,12 @@ type apiSvc struct {
 	fss             *folderSummarySvc
 	stop            chan struct{}
 	systemConfigMut sync.Mutex
+
+	guiErrors *logger.Recorder
+	systemLog *logger.Recorder
 }
 
-func newAPISvc(id protocol.DeviceID, cfg *config.Wrapper, assetDir string, m *model.Model, eventSub *events.BufferedSubscription, discoverer *discover.CachingMux, relaySvc *relay.Svc) (*apiSvc, error) {
+func newAPISvc(id protocol.DeviceID, cfg *config.Wrapper, assetDir string, m *model.Model, eventSub *events.BufferedSubscription, discoverer *discover.CachingMux, relaySvc *relay.Svc, errors, systemLog *logger.Recorder) (*apiSvc, error) {
 	svc := &apiSvc{
 		id:              id,
 		cfg:             cfg,
@@ -77,6 +74,8 @@ func newAPISvc(id protocol.DeviceID, cfg *config.Wrapper, assetDir string, m *mo
 		discoverer:      discoverer,
 		relaySvc:        relaySvc,
 		systemConfigMut: sync.NewMutex(),
+		guiErrors:       errors,
+		systemLog:       systemLog,
 	}
 
 	var err error
@@ -138,8 +137,6 @@ func (s *apiSvc) getListener(cfg config.GUIConfiguration) (net.Listener, error)
 func (s *apiSvc) Serve() {
 	s.stop = make(chan struct{})
 
-	l.AddHandler(logger.LevelWarn, s.showGuiError)
-
 	// The GET handlers
 	getRestMux := http.NewServeMux()
 	getRestMux.HandleFunc("/rest/db/completion", s.getDBCompletion)              // device folder
@@ -164,6 +161,9 @@ func (s *apiSvc) Serve() {
 	getRestMux.HandleFunc("/rest/system/status", s.getSystemStatus)              // -
 	getRestMux.HandleFunc("/rest/system/upgrade", s.getSystemUpgrade)            // -
 	getRestMux.HandleFunc("/rest/system/version", s.getSystemVersion)            // -
+	getRestMux.HandleFunc("/rest/system/debug", s.getSystemDebug)                // -
+	getRestMux.HandleFunc("/rest/system/log", s.getSystemLog)                    // [since]
+	getRestMux.HandleFunc("/rest/system/log.txt", s.getSystemLogTxt)             // [since]
 
 	// The POST handlers
 	postRestMux := http.NewServeMux()
@@ -181,6 +181,7 @@ func (s *apiSvc) Serve() {
 	postRestMux.HandleFunc("/rest/system/upgrade", s.postSystemUpgrade)        // -
 	postRestMux.HandleFunc("/rest/system/pause", s.postSystemPause)            // device
 	postRestMux.HandleFunc("/rest/system/resume", s.postSystemResume)          // device
+	postRestMux.HandleFunc("/rest/system/debug", s.postSystemDebug)            // [enable] [disable]
 
 	// Debug endpoints, not for general use
 	getRestMux.HandleFunc("/rest/debug/peerCompletion", s.getPeerCompletion)
@@ -223,9 +224,7 @@ func (s *apiSvc) Serve() {
 		handler = redirectToHTTPSMiddleware(handler)
 	}
 
-	if debugHTTP {
 	handler = debugMiddleware(handler)
-	}
 
 	srv := http.Server{
 		Handler:     handler,
@@ -379,6 +378,36 @@ func (s *apiSvc) getSystemVersion(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
+func (s *apiSvc) getSystemDebug(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	names := l.Facilities()
+	enabled := l.FacilityDebugging()
+	sort.Strings(enabled)
+	json.NewEncoder(w).Encode(map[string]interface{}{
+		"facilities": names,
+		"enabled":    enabled,
+	})
+}
+
+func (s *apiSvc) postSystemDebug(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	q := r.URL.Query()
+	for _, f := range strings.Split(q.Get("enable"), ",") {
+		if f == "" {
+			continue
+		}
+		l.SetDebug(f, true)
+		l.Infof("Enabled debug data for %q", f)
+	}
+	for _, f := range strings.Split(q.Get("disable"), ",") {
+		if f == "" {
+			continue
+		}
+		l.SetDebug(f, false)
+		l.Infof("Disabled debug data for %q", f)
+	}
+}
+
 func (s *apiSvc) getDBBrowse(w http.ResponseWriter, r *http.Request) {
 	qs := r.URL.Query()
 	folder := qs.Get("folder")
@@ -684,30 +713,41 @@ func (s *apiSvc) getSystemStatus(w http.ResponseWriter, r *http.Request) {
 
 func (s *apiSvc) getSystemError(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/json; charset=utf-8")
-	guiErrorsMut.Lock()
+	json.NewEncoder(w).Encode(map[string][]logger.Line{
-	json.NewEncoder(w).Encode(map[string][]guiError{"errors": guiErrors})
+		"errors": s.guiErrors.Since(time.Time{}),
-	guiErrorsMut.Unlock()
+	})
 }
 
 func (s *apiSvc) postSystemError(w http.ResponseWriter, r *http.Request) {
 	bs, _ := ioutil.ReadAll(r.Body)
 	r.Body.Close()
-	s.showGuiError(0, string(bs))
+	l.Warnln(string(bs))
 }
 
 func (s *apiSvc) postSystemErrorClear(w http.ResponseWriter, r *http.Request) {
-	guiErrorsMut.Lock()
+	s.guiErrors.Clear()
-	guiErrors = []guiError{}
-	guiErrorsMut.Unlock()
 }
 
-func (s *apiSvc) showGuiError(l logger.LogLevel, err string) {
+func (s *apiSvc) getSystemLog(w http.ResponseWriter, r *http.Request) {
-	guiErrorsMut.Lock()
+	q := r.URL.Query()
-	guiErrors = append(guiErrors, guiError{time.Now(), err})
+	since, err := time.Parse(time.RFC3339, q.Get("since"))
-	if len(guiErrors) > 5 {
+	l.Debugln(err)
-		guiErrors = guiErrors[len(guiErrors)-5:]
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+
+	json.NewEncoder(w).Encode(map[string][]logger.Line{
+		"messages": s.systemLog.Since(since),
+	})
+}
+
+func (s *apiSvc) getSystemLogTxt(w http.ResponseWriter, r *http.Request) {
+	q := r.URL.Query()
+	since, err := time.Parse(time.RFC3339, q.Get("since"))
+	l.Debugln(err)
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+
+	for _, line := range s.systemLog.Since(since) {
+		fmt.Fprintf(w, "%s: %s\n", line.When.Format(time.RFC3339), line.Message)
 	}
-	guiErrorsMut.Unlock()
 }
 
 func (s *apiSvc) getSystemDiscovery(w http.ResponseWriter, r *http.Request) {

cmd/syncthing/gui_auth.go

@@ -42,9 +42,7 @@ func basicAuthAndSessionMiddleware(cookieName string, cfg config.GUIConfiguratio
 			}
 		}
 
-		if debugHTTP {
+		httpl.Debugln("Sessionless HTTP request with authentication; this is expensive.")
-			l.Debugln("Sessionless HTTP request with authentication; this is expensive.")
-		}
 
 		error := func() {
 			time.Sleep(time.Duration(rand.Intn(100)+100) * time.Millisecond)

cmd/syncthing/main.go

@@ -7,6 +7,7 @@
 package main
 
 import (
+	"bytes"
 	"crypto/tls"
 	"flag"
 	"fmt"
@@ -21,16 +22,17 @@ import (
 	"regexp"
 	"runtime"
 	"runtime/pprof"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
 
-	"github.com/calmh/logger"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/connections"
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/discover"
 	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/logger"
 	"github.com/syncthing/syncthing/lib/model"
 	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/protocol"
@@ -71,6 +73,9 @@ const (
 	tlsDefaultCommonName = "syncthing"
 	tlsRSABits           = 3072
 	pingEventInterval    = time.Minute
+	maxSystemErrors      = 5
+	initialSystemLog     = 10
+	maxSystemLog         = 250
 )
 
 // The discovery results are sorted by their source priority.
@@ -80,8 +85,6 @@ const (
 	globalDiscoveryPriority
 )
 
-var l = logger.DefaultLogger
-
 func init() {
 	if Version != "unknown-dev" {
 		// If not a generic dev build, version string should come from git describe
@@ -148,25 +151,11 @@ Development Settings
 The following environment variables modify syncthing's behavior in ways that
 are mostly useful for developers. Use with care.
 
- STGUIASSETS     Directory to load GUI assets from. Overrides compiled in assets.
+ STGUIASSETS     Directory to load GUI assets from. Overrides compiled in
+                 assets.
 
  STTRACE         A comma separated string of facilities to trace. The valid
-                 facility strings are:
+                 facility strings listed below.
-
-                 - "beacon"   (the beacon package)
-                 - "discover" (the discover package)
-                 - "events"   (the events package)
-                 - "files"    (the files package)
-                 - "http"     (the main package; HTTP requests)
-                 - "locks"    (the sync package; trace long held locks)
-                 - "net"      (the main package; connections & network messages)
-                 - "model"    (the model package)
-                 - "scanner"  (the scanner package)
-                 - "stats"    (the stats package)
-                 - "suture"   (the suture package; service management)
-                 - "upnp"     (the upnp package)
-                 - "xdr"      (the xdr package)
-                 - "all"      (all of the above)
 
  STPROFILER      Set to a listen address such as "127.0.0.1:9090" to start the
                  profiler with HTTP access.
@@ -189,7 +178,15 @@ are mostly useful for developers. Use with care.
 
  GOGC            Percentage of heap growth at which to trigger GC. Default is
                  100. Lower numbers keep peak memory usage down, at the price
-                 of CPU usage (ie. performance).`
+                 of CPU usage (ie. performance).
+
+
+Debugging Facilities
+--------------------
+
+The following are valid values for the STTRACE variable:
+
+%s`
 )
 
 // Command line and environment options
@@ -245,7 +242,8 @@ func main() {
 	flag.BoolVar(&verbose, "verbose", false, "Print verbose log output")
 	flag.BoolVar(&paused, "paused", false, "Start with all devices paused")
 
-	flag.Usage = usageFor(flag.CommandLine, usage, fmt.Sprintf(extraUsage, baseDirs["config"]))
+	longUsage := fmt.Sprintf(extraUsage, baseDirs["config"], debugFacilities())
+	flag.Usage = usageFor(flag.CommandLine, usage, longUsage)
 	flag.Parse()
 
 	if noConsole {
@@ -397,6 +395,28 @@ func main() {
 	}
 }
 
+func debugFacilities() string {
+	facilities := l.Facilities()
+
+	// Get a sorted list of names
+	var names []string
+	maxLen := 0
+	for name := range facilities {
+		names = append(names, name)
+		if len(name) > maxLen {
+			maxLen = len(name)
+		}
+	}
+	sort.Strings(names)
+
+	// Format the choices
+	b := new(bytes.Buffer)
+	for _, name := range names {
+		fmt.Fprintf(b, " %-*s - %s\n", maxLen, name, facilities[name])
+	}
+	return b.String()
+}
+
 func upgradeViaRest() error {
 	cfg, err := config.Load(locations[locConfigFile], protocol.LocalDeviceID)
 	if err != nil {
@@ -439,9 +459,7 @@ func syncthingMain() {
 	// We want any logging it does to go through our log system.
 	mainSvc := suture.New("main", suture.Spec{
 		Log: func(line string) {
-			if debugSuture {
 			l.Debugln(line)
-			}
 		},
 	})
 	mainSvc.ServeBackground()
@@ -458,6 +476,9 @@ func syncthingMain() {
 		mainSvc.Add(newVerboseSvc())
 	}
 
+	errors := logger.NewRecorder(l, logger.LevelWarn, maxSystemErrors, 0)
+	systemLog := logger.NewRecorder(l, logger.LevelDebug, maxSystemLog, initialSystemLog)
+
 	// Event subscription for the API; must start early to catch the early events.
 	apiSub := events.NewBufferedSubscription(events.Default.Subscribe(events.AllEvents), 1000)
 
@@ -733,7 +754,7 @@ func syncthingMain() {
 
 	// GUI
 
-	setupGUI(mainSvc, cfg, m, apiSub, cachedDiscovery, relaySvc)
+	setupGUI(mainSvc, cfg, m, apiSub, cachedDiscovery, relaySvc, errors, systemLog)
 
 	// Start connection management
 
@@ -883,7 +904,7 @@ func startAuditing(mainSvc *suture.Supervisor) {
 	l.Infoln("Audit log in", auditFile)
 }
 
-func setupGUI(mainSvc *suture.Supervisor, cfg *config.Wrapper, m *model.Model, apiSub *events.BufferedSubscription, discoverer *discover.CachingMux, relaySvc *relay.Svc) {
+func setupGUI(mainSvc *suture.Supervisor, cfg *config.Wrapper, m *model.Model, apiSub *events.BufferedSubscription, discoverer *discover.CachingMux, relaySvc *relay.Svc, errors, systemLog *logger.Recorder) {
 	guiCfg := cfg.GUI()
 
 	if !guiCfg.Enabled {
@@ -918,7 +939,7 @@ func setupGUI(mainSvc *suture.Supervisor, cfg *config.Wrapper, m *model.Model, a
 		urlShow := fmt.Sprintf("%s://%s/", proto, net.JoinHostPort(hostShow, strconv.Itoa(addr.Port)))
 		l.Infoln("Starting web GUI on", urlShow)
 
-		api, err := newAPISvc(myID, cfg, guiAssets, m, apiSub, discoverer, relaySvc)
+		api, err := newAPISvc(myID, cfg, guiAssets, m, apiSub, discoverer, relaySvc, errors, systemLog)
 		if err != nil {
 			l.Fatalln("Cannot start GUI:", err)
 		}

cmd/syncthing/upnpsvc.go

@@ -98,9 +98,7 @@ func (s *upnpSvc) tryIGDs(igds []upnp.IGD, prevExtPort int) int {
 			l.Infof("New UPnP port mapping: external port %d to local port %d.", extPort, s.localPort)
 			events.Default.Log(events.ExternalPortMappingChanged, map[string]int{"port": extPort})
 		}
-		if debugNet {
 		l.Debugf("Created/updated UPnP port mapping for external port %d on device %s.", extPort, igd.FriendlyIdentifier())
-		}
 		return extPort
 	}
 

lib/beacon/broadcast.go

@@ -33,9 +33,7 @@ func NewBroadcast(port int) *Broadcast {
 			FailureBackoff:   60 * time.Second,
 			// Only log restarts in debug mode.
 			Log: func(line string) {
-				if debug {
 				l.Debugln(line)
-				}
 			},
 		}),
 		port:   port,
@@ -81,17 +79,13 @@ type broadcastWriter struct {
 }
 
 func (w *broadcastWriter) Serve() {
-	if debug {
 	l.Debugln(w, "starting")
 	defer l.Debugln(w, "stopping")
-	}
 
 	var err error
 	w.conn, err = net.ListenUDP("udp4", nil)
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		w.setError(err)
 		return
 	}
@@ -100,9 +94,7 @@ func (w *broadcastWriter) Serve() {
 	for bs := range w.inbox {
 		addrs, err := net.InterfaceAddrs()
 		if err != nil {
-			if debug {
 			l.Debugln(err)
-			}
 			w.setError(err)
 			continue
 		}
@@ -120,9 +112,7 @@ func (w *broadcastWriter) Serve() {
 			dsts = append(dsts, net.IP{0xff, 0xff, 0xff, 0xff})
 		}
 
-		if debug {
 		l.Debugln("addresses:", dsts)
-		}
 
 		success := 0
 		for _, ip := range dsts {
@@ -135,34 +125,25 @@ func (w *broadcastWriter) Serve() {
 			if err, ok := err.(net.Error); ok && err.Timeout() {
 				// Write timeouts should not happen. We treat it as a fatal
 				// error on the socket.
-				if debug {
 				l.Debugln(err)
-				}
 				w.setError(err)
 				return
 			}
 
 			if err, ok := err.(net.Error); ok && err.Temporary() {
 				// A transient error. Lets hope for better luck in the future.
-				if debug {
 				l.Debugln(err)
-				}
 				continue
 			}
 
 			if err != nil {
 				// Some other error that we don't expect. Bail and retry.
-				if debug {
 				l.Debugln(err)
-				}
 				w.setError(err)
 				return
 			}
 
-			if debug {
 			l.Debugf("sent %d bytes to %s", len(bs), dst)
-			}
-
 			success++
 		}
 
@@ -188,17 +169,13 @@ type broadcastReader struct {
 }
 
 func (r *broadcastReader) Serve() {
-	if debug {
 	l.Debugln(r, "starting")
 	defer l.Debugln(r, "stopping")
-	}
 
 	var err error
 	r.conn, err = net.ListenUDP("udp4", &net.UDPAddr{Port: r.port})
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		r.setError(err)
 		return
 	}
@@ -208,29 +185,23 @@ func (r *broadcastReader) Serve() {
 	for {
 		n, addr, err := r.conn.ReadFrom(bs)
 		if err != nil {
-			if debug {
 			l.Debugln(err)
-			}
 			r.setError(err)
 			return
 		}
 
 		r.setError(nil)
 
-		if debug {
 		l.Debugf("recv %d bytes from %s", n, addr)
-		}
 
 		c := make([]byte, n)
 		copy(c, bs)
 		select {
 		case r.outbox <- recv{c, addr}:
 		default:
-			if debug {
 			l.Debugln("dropping message")
 		}
 	}
-	}
 
 }
 

lib/beacon/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "beacon") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("beacon", "Multicast and broadcast discovery")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("beacon", strings.Contains(os.Getenv("STTRACE"), "beacon") || os.Getenv("STTRACE") == "all")
+}

lib/beacon/multicast.go

@@ -35,9 +35,7 @@ func NewMulticast(addr string) *Multicast {
 			FailureBackoff:   60 * time.Second,
 			// Only log restarts in debug mode.
 			Log: func(line string) {
-				if debug {
 				l.Debugln(line)
-				}
 			},
 		}),
 		inbox:  make(chan []byte),
@@ -85,25 +83,19 @@ type multicastWriter struct {
 }
 
 func (w *multicastWriter) Serve() {
-	if debug {
 	l.Debugln(w, "starting")
 	defer l.Debugln(w, "stopping")
-	}
 
 	gaddr, err := net.ResolveUDPAddr("udp6", w.addr)
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		w.setError(err)
 		return
 	}
 
 	conn, err := net.ListenPacket("udp6", ":0")
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		w.setError(err)
 		return
 	}
@@ -117,9 +109,7 @@ func (w *multicastWriter) Serve() {
 	for bs := range w.inbox {
 		intfs, err := net.Interfaces()
 		if err != nil {
-			if debug {
 			l.Debugln(err)
-			}
 			w.setError(err)
 			return
 		}
@@ -132,16 +122,12 @@ func (w *multicastWriter) Serve() {
 			pconn.SetWriteDeadline(time.Time{})
 
 			if err != nil {
-				if debug {
 				l.Debugln(err, "on write to", gaddr, intf.Name)
-				}
 				w.setError(err)
 				continue
 			}
 
-			if debug {
 			l.Debugf("sent %d bytes to %v on %s", len(bs), gaddr, intf.Name)
-			}
 
 			success++
 		}
@@ -149,9 +135,7 @@ func (w *multicastWriter) Serve() {
 		if success > 0 {
 			w.setError(nil)
 		} else {
-			if debug {
 			l.Debugln(err)
-			}
 			w.setError(err)
 		}
 	}
@@ -173,34 +157,26 @@ type multicastReader struct {
 }
 
 func (r *multicastReader) Serve() {
-	if debug {
 	l.Debugln(r, "starting")
 	defer l.Debugln(r, "stopping")
-	}
 
 	gaddr, err := net.ResolveUDPAddr("udp6", r.addr)
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		r.setError(err)
 		return
 	}
 
 	conn, err := net.ListenPacket("udp6", r.addr)
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		r.setError(err)
 		return
 	}
 
 	intfs, err := net.Interfaces()
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		r.setError(err)
 		return
 	}
@@ -209,20 +185,16 @@ func (r *multicastReader) Serve() {
 	joined := 0
 	for _, intf := range intfs {
 		err := pconn.JoinGroup(&intf, &net.UDPAddr{IP: gaddr.IP})
-		if debug {
 		if err != nil {
 			l.Debugln("IPv6 join", intf.Name, "failed:", err)
 		} else {
 			l.Debugln("IPv6 join", intf.Name, "success")
 		}
-		}
 		joined++
 	}
 
 	if joined == 0 {
-		if debug {
 		l.Debugln("no multicast interfaces available")
-		}
 		r.setError(errors.New("no multicast interfaces available"))
 		return
 	}
@@ -231,26 +203,20 @@ func (r *multicastReader) Serve() {
 	for {
 		n, _, addr, err := pconn.ReadFrom(bs)
 		if err != nil {
-			if debug {
 			l.Debugln(err)
-			}
 			r.setError(err)
 			continue
 		}
-		if debug {
 		l.Debugf("recv %d bytes from %s", n, addr)
-		}
 
 		c := make([]byte, n)
 		copy(c, bs)
 		select {
 		case r.outbox <- recv{c, addr}:
 		default:
-			if debug {
 			l.Debugln("dropping message")
 		}
 	}
-	}
 }
 
 func (r *multicastReader) Stop() {

lib/config/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "config") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("config", "Configuration loading and saving")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("config", strings.Contains(os.Getenv("STTRACE"), "config") || os.Getenv("STTRACE") == "all")
+}

lib/config/wrapper.go

@@ -142,13 +142,9 @@ func (w *Wrapper) replaceLocked(to Configuration) CommitResponse {
 	from := w.cfg
 
 	for _, sub := range w.subs {
-		if debug {
 		l.Debugln(sub, "verifying configuration")
-		}
 		if err := sub.VerifyConfiguration(from, to); err != nil {
-			if debug {
 			l.Debugln(sub, "rejected config:", err)
-			}
 			return CommitResponse{
 				ValidationError: err,
 			}
@@ -157,14 +153,10 @@ func (w *Wrapper) replaceLocked(to Configuration) CommitResponse {
 
 	allOk := true
 	for _, sub := range w.subs {
-		if debug {
 		l.Debugln(sub, "committing configuration")
-		}
 		ok := sub.CommitConfiguration(from, to)
 		if !ok {
-			if debug {
 			l.Debugln(sub, "requires restart")
-			}
 			allOk = false
 		}
 	}

lib/connections/connections.go

@@ -121,9 +121,7 @@ func NewConnectionSvc(cfg *config.Wrapper, myID protocol.DeviceID, mdl Model, tl
 			continue
 		}
 
-		if debug {
+		l.Debugln("listening on", uri)
-			l.Debugln("listening on", uri.String())
-		}
 
 		svc.Add(serviceFunc(func() {
 			listener(uri, svc.tlsCfg, svc.conns)
@@ -178,9 +176,7 @@ next:
 		ct, ok := s.connType[remoteID]
 		s.mut.RUnlock()
 		if ok && !ct.IsDirect() && c.Type.IsDirect() {
-			if debug {
 			l.Debugln("Switching connections", remoteID)
-			}
 			s.model.Close(remoteID, fmt.Errorf("switching connections"))
 		} else if s.model.ConnectedTo(remoteID) {
 			// We should not already be connected to the other party. TODO: This
@@ -236,9 +232,7 @@ next:
 				protoConn := protocol.NewConnection(remoteID, rd, wr, s.model, name, deviceCfg.Compression)
 
 				l.Infof("Established secure connection to %s at %s", remoteID, name)
-				if debug {
 				l.Debugf("cipher suite: %04X in lan: %t", c.Conn.ConnectionState().CipherSuite, !limit)
-				}
 
 				s.model.AddConnection(model.Connection{
 					c.Conn,
@@ -311,18 +305,14 @@ func (s *connectionSvc) connect() {
 
 				dialer, ok := dialers[uri.Scheme]
 				if !ok {
-					l.Infoln("Unknown address schema", uri.String())
+					l.Infoln("Unknown address schema", uri)
 					continue
 				}
 
-				if debug {
+				l.Debugln("dial", deviceCfg.DeviceID, uri)
-					l.Debugln("dial", deviceCfg.DeviceID, uri.String())
-				}
 				conn, err := dialer(uri, s.tlsCfg)
 				if err != nil {
-					if debug {
+					l.Debugln("dial failed", deviceCfg.DeviceID, uri, err)
-						l.Debugln("dial failed", deviceCfg.DeviceID, uri.String(), err)
-					}
 					continue
 				}
 
@@ -347,11 +337,9 @@ func (s *connectionSvc) connect() {
 
 			reconIntv := time.Duration(s.cfg.Options().RelayReconnectIntervalM) * time.Minute
 			if last, ok := s.lastRelayCheck[deviceID]; ok && time.Since(last) < reconIntv {
-				if debug {
 				l.Debugln("Skipping connecting via relay to", deviceID, "last checked at", last)
-				}
 				continue nextDevice
-			} else if debug {
+			} else {
 				l.Debugln("Trying relay connections to", deviceID, relays)
 			}
 
@@ -366,21 +354,17 @@ func (s *connectionSvc) connect() {
 
 				inv, err := client.GetInvitationFromRelay(uri, deviceID, s.tlsCfg.Certificates)
 				if err != nil {
-					if debug {
 					l.Debugf("Failed to get invitation for %s from %s: %v", deviceID, uri, err)
-					}
 					continue
-				} else if debug {
+				} else {
 					l.Debugln("Succesfully retrieved relay invitation", inv, "from", uri)
 				}
 
 				conn, err := client.JoinSession(inv)
 				if err != nil {
-					if debug {
 					l.Debugf("Failed to join relay session %s: %v", inv, err)
-					}
 					continue
-				} else if debug {
+				} else {
 					l.Debugln("Sucessfully joined relay session", inv)
 				}
 

lib/connections/connections_tcp.go

@@ -33,17 +33,13 @@ func tcpDialer(uri *url.URL, tlsCfg *tls.Config) (*tls.Conn, error) {
 
 	raddr, err := net.ResolveTCPAddr("tcp", uri.Host)
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		return nil, err
 	}
 
 	conn, err := net.DialTCP("tcp", nil, raddr)
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		return nil, err
 	}
 
@@ -81,9 +77,7 @@ func tcpListener(uri *url.URL, tlsCfg *tls.Config, conns chan<- model.Intermedia
 			continue
 		}
 
-		if debug {
 		l.Debugln("connect from", conn.RemoteAddr())
-		}
 
 		err = osutil.SetTCPOptions(conn.(*net.TCPConn))
 		if err != nil {

lib/connections/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "connections") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("connections", "Connection handling")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("connections", strings.Contains(os.Getenv("STTRACE"), "connections") || os.Getenv("STTRACE") == "all")
+}

lib/db/debug.go

@@ -10,11 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug   = strings.Contains(os.Getenv("STTRACE"), "files") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("db", "The database layer")
-	debugDB = strings.Contains(os.Getenv("STTRACE"), "db") || os.Getenv("STTRACE") == "all"
-	l       = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("db", strings.Contains(os.Getenv("STTRACE"), "db") || os.Getenv("STTRACE") == "all")
+}

lib/db/leveldb.go

@@ -178,20 +178,14 @@ func ldbGenericReplace(db *leveldb.DB, folder, device []byte, fs []protocol.File
 	limit := deviceKey(folder, device, []byte{0xff, 0xff, 0xff, 0xff}) // after all folder/device files
 
 	batch := new(leveldb.Batch)
-	if debugDB {
 	l.Debugf("new batch %p", batch)
-	}
 	snap, err := db.GetSnapshot()
 	if err != nil {
 		panic(err)
 	}
-	if debugDB {
 	l.Debugf("created snapshot %p", snap)
-	}
 	defer func() {
-		if debugDB {
 		l.Debugf("close snapshot %p", snap)
-		}
 		snap.Release()
 	}()
 
@@ -220,15 +214,11 @@ func ldbGenericReplace(db *leveldb.DB, folder, device []byte, fs []protocol.File
 
 		cmp := bytes.Compare(newName, oldName)
 
-		if debugDB {
 		l.Debugf("generic replace; folder=%q device=%v moreFs=%v moreDb=%v cmp=%d newName=%q oldName=%q", folder, protocol.DeviceIDFromBytes(device), moreFs, moreDb, cmp, newName, oldName)
-		}
 
 		switch {
 		case moreFs && (!moreDb || cmp == -1):
-			if debugDB {
 			l.Debugln("generic replace; missing - insert")
-			}
 			// Database is missing this file. Insert it.
 			if lv := ldbInsert(batch, folder, device, fs[fsi]); lv > maxLocalVer {
 				maxLocalVer = lv
@@ -244,15 +234,11 @@ func ldbGenericReplace(db *leveldb.DB, folder, device []byte, fs []protocol.File
 			// File exists on both sides - compare versions. We might get an
 			// update with the same version and different flags if a device has
 			// marked a file as invalid, so handle that too.
-			if debugDB {
 			l.Debugln("generic replace; exists - compare")
-			}
 			var ef FileInfoTruncated
 			ef.UnmarshalXDR(dbi.Value())
 			if !fs[fsi].Version.Equal(ef.Version) || fs[fsi].Flags != ef.Flags {
-				if debugDB {
 				l.Debugln("generic replace; differs - insert")
-				}
 				if lv := ldbInsert(batch, folder, device, fs[fsi]); lv > maxLocalVer {
 					maxLocalVer = lv
 				}
@@ -261,7 +247,7 @@ func ldbGenericReplace(db *leveldb.DB, folder, device []byte, fs []protocol.File
 				} else {
 					ldbUpdateGlobal(snap, batch, folder, device, fs[fsi])
 				}
-			} else if debugDB {
+			} else {
 				l.Debugln("generic replace; equal - ignore")
 			}
 
@@ -269,9 +255,7 @@ func ldbGenericReplace(db *leveldb.DB, folder, device []byte, fs []protocol.File
 			moreDb = dbi.Next()
 
 		case moreDb && (!moreFs || cmp == 1):
-			if debugDB {
 			l.Debugln("generic replace; exists - remove")
-			}
 			if lv := deleteFn(snap, batch, folder, device, oldName, dbi); lv > maxLocalVer {
 				maxLocalVer = lv
 			}
@@ -281,9 +265,7 @@ func ldbGenericReplace(db *leveldb.DB, folder, device []byte, fs []protocol.File
 		// Write out and reuse the batch every few records, to avoid the batch
 		// growing too large and thus allocating unnecessarily much memory.
 		if batch.Len() > batchFlushSize {
-			if debugDB {
 			l.Debugf("db.Write %p", batch)
-			}
 
 			err = db.Write(batch, nil)
 			if err != nil {
@@ -294,9 +276,7 @@ func ldbGenericReplace(db *leveldb.DB, folder, device []byte, fs []protocol.File
 		}
 	}
 
-	if debugDB {
 	l.Debugf("db.Write %p", batch)
-	}
 	err = db.Write(batch, nil)
 	if err != nil {
 		panic(err)
@@ -309,13 +289,9 @@ func ldbReplace(db *leveldb.DB, folder, device []byte, fs []protocol.FileInfo) i
 	// TODO: Return the remaining maxLocalVer?
 	return ldbGenericReplace(db, folder, device, fs, func(db dbReader, batch dbWriter, folder, device, name []byte, dbi iterator.Iterator) int64 {
 		// Database has a file that we are missing. Remove it.
-		if debugDB {
 		l.Debugf("delete; folder=%q device=%v name=%q", folder, protocol.DeviceIDFromBytes(device), name)
-		}
 		ldbRemoveFromGlobal(db, batch, folder, device, name)
-		if debugDB {
 		l.Debugf("batch.Delete %p %x", batch, dbi.Key())
-		}
 		batch.Delete(dbi.Key())
 		return 0
 	})
@@ -325,20 +301,14 @@ func ldbUpdate(db *leveldb.DB, folder, device []byte, fs []protocol.FileInfo) in
 	runtime.GC()
 
 	batch := new(leveldb.Batch)
-	if debugDB {
 	l.Debugf("new batch %p", batch)
-	}
 	snap, err := db.GetSnapshot()
 	if err != nil {
 		panic(err)
 	}
-	if debugDB {
 	l.Debugf("created snapshot %p", snap)
-	}
 	defer func() {
-		if debugDB {
 		l.Debugf("close snapshot %p", snap)
-		}
 		snap.Release()
 	}()
 
@@ -347,9 +317,7 @@ func ldbUpdate(db *leveldb.DB, folder, device []byte, fs []protocol.FileInfo) in
 	for _, f := range fs {
 		name := []byte(f.Name)
 		fk = deviceKeyInto(fk[:cap(fk)], folder, device, name)
-		if debugDB {
 		l.Debugf("snap.Get %p %x", snap, fk)
-		}
 		bs, err := snap.Get(fk, nil)
 		if err == leveldb.ErrNotFound {
 			if lv := ldbInsert(batch, folder, device, f); lv > maxLocalVer {
@@ -384,9 +352,7 @@ func ldbUpdate(db *leveldb.DB, folder, device []byte, fs []protocol.FileInfo) in
 		// Write out and reuse the batch every few records, to avoid the batch
 		// growing too large and thus allocating unnecessarily much memory.
 		if batch.Len() > batchFlushSize {
-			if debugDB {
 			l.Debugf("db.Write %p", batch)
-			}
 
 			err = db.Write(batch, nil)
 			if err != nil {
@@ -397,9 +363,7 @@ func ldbUpdate(db *leveldb.DB, folder, device []byte, fs []protocol.FileInfo) in
 		}
 	}
 
-	if debugDB {
 	l.Debugf("db.Write %p", batch)
-	}
 	err = db.Write(batch, nil)
 	if err != nil {
 		panic(err)
@@ -409,9 +373,7 @@ func ldbUpdate(db *leveldb.DB, folder, device []byte, fs []protocol.FileInfo) in
 }
 
 func ldbInsert(batch dbWriter, folder, device []byte, file protocol.FileInfo) int64 {
-	if debugDB {
 	l.Debugf("insert; folder=%q device=%v %v", folder, protocol.DeviceIDFromBytes(device), file)
-	}
 
 	if file.LocalVersion == 0 {
 		file.LocalVersion = clock(0)
@@ -419,9 +381,7 @@ func ldbInsert(batch dbWriter, folder, device []byte, file protocol.FileInfo) in
 
 	name := []byte(file.Name)
 	nk := deviceKey(folder, device, name)
-	if debugDB {
 	l.Debugf("batch.Put %p %x", batch, nk)
-	}
 	batch.Put(nk, file.MustMarshalXDR())
 
 	return file.LocalVersion
@@ -431,9 +391,7 @@ func ldbInsert(batch dbWriter, folder, device []byte, file protocol.FileInfo) in
 // file. If the device is already present in the list, the version is updated.
 // If the file does not have an entry in the global list, it is created.
 func ldbUpdateGlobal(db dbReader, batch dbWriter, folder, device []byte, file protocol.FileInfo) bool {
-	if debugDB {
 	l.Debugf("update global; folder=%q device=%v file=%q version=%d", folder, protocol.DeviceIDFromBytes(device), file.Name, file.Version)
-	}
 	name := []byte(file.Name)
 	gk := globalKey(folder, name)
 	svl, err := db.Get(gk, nil)
@@ -499,10 +457,8 @@ func ldbUpdateGlobal(db dbReader, batch dbWriter, folder, device []byte, file pr
 	fl.versions = append(fl.versions, nv)
 
 done:
-	if debugDB {
 	l.Debugf("batch.Put %p %x", batch, gk)
 	l.Debugf("new global after update: %v", fl)
-	}
 	batch.Put(gk, fl.MustMarshalXDR())
 
 	return true
@@ -519,9 +475,7 @@ func insertVersion(vl []fileVersion, i int, v fileVersion) []fileVersion {
 // given file. If the version list is empty after this, the file entry is
 // removed entirely.
 func ldbRemoveFromGlobal(db dbReader, batch dbWriter, folder, device, file []byte) {
-	if debugDB {
 	l.Debugf("remove from global; folder=%q device=%v file=%q", folder, protocol.DeviceIDFromBytes(device), file)
-	}
 
 	gk := globalKey(folder, file)
 	svl, err := db.Get(gk, nil)
@@ -545,15 +499,11 @@ func ldbRemoveFromGlobal(db dbReader, batch dbWriter, folder, device, file []byt
 	}
 
 	if len(fl.versions) == 0 {
-		if debugDB {
 		l.Debugf("batch.Delete %p %x", batch, gk)
-		}
 		batch.Delete(gk)
 	} else {
-		if debugDB {
 		l.Debugf("batch.Put %p %x", batch, gk)
 		l.Debugf("new global after remove: %v", fl)
-		}
 		batch.Put(gk, fl.MustMarshalXDR())
 	}
 }
@@ -565,13 +515,9 @@ func ldbWithHave(db *leveldb.DB, folder, device []byte, truncate bool, fn Iterat
 	if err != nil {
 		panic(err)
 	}
-	if debugDB {
 	l.Debugf("created snapshot %p", snap)
-	}
 	defer func() {
-		if debugDB {
 		l.Debugf("close snapshot %p", snap)
-		}
 		snap.Release()
 	}()
 
@@ -598,13 +544,9 @@ func ldbWithAllFolderTruncated(db *leveldb.DB, folder []byte, fn func(device []b
 	if err != nil {
 		panic(err)
 	}
-	if debugDB {
 	l.Debugf("created snapshot %p", snap)
-	}
 	defer func() {
-		if debugDB {
 		l.Debugf("close snapshot %p", snap)
-		}
 		snap.Release()
 	}()
 
@@ -659,19 +601,13 @@ func ldbGetGlobal(db *leveldb.DB, folder, file []byte, truncate bool) (FileIntf,
 	if err != nil {
 		panic(err)
 	}
-	if debugDB {
 	l.Debugf("created snapshot %p", snap)
-	}
 	defer func() {
-		if debugDB {
 		l.Debugf("close snapshot %p", snap)
-		}
 		snap.Release()
 	}()
 
-	if debugDB {
 	l.Debugf("snap.Get %p %x", snap, k)
-	}
 	bs, err := snap.Get(k, nil)
 	if err == leveldb.ErrNotFound {
 		return nil, false
@@ -691,9 +627,7 @@ func ldbGetGlobal(db *leveldb.DB, folder, file []byte, truncate bool) (FileIntf,
 	}
 
 	k = deviceKey(folder, vl.versions[0].device, file)
-	if debugDB {
 	l.Debugf("snap.Get %p %x", snap, k)
-	}
 	bs, err = snap.Get(k, nil)
 	if err != nil {
 		panic(err)
@@ -713,13 +647,9 @@ func ldbWithGlobal(db *leveldb.DB, folder, prefix []byte, truncate bool, fn Iter
 	if err != nil {
 		panic(err)
 	}
-	if debugDB {
 	l.Debugf("created snapshot %p", snap)
-	}
 	defer func() {
-		if debugDB {
 		l.Debugf("close snapshot %p", snap)
-		}
 		snap.Release()
 	}()
 
@@ -739,9 +669,7 @@ func ldbWithGlobal(db *leveldb.DB, folder, prefix []byte, truncate bool, fn Iter
 		}
 		name := globalKeyName(dbi.Key())
 		fk = deviceKeyInto(fk[:cap(fk)], folder, vl.versions[0].device, name)
-		if debugDB {
 		l.Debugf("snap.Get %p %x", snap, fk)
-		}
 		bs, err := snap.Get(fk, nil)
 		if err != nil {
 			l.Debugf("folder: %q (%x)", folder, folder)
@@ -802,13 +730,9 @@ func ldbWithNeed(db *leveldb.DB, folder, device []byte, truncate bool, fn Iterat
 	if err != nil {
 		panic(err)
 	}
-	if debugDB {
 	l.Debugf("created snapshot %p", snap)
-	}
 	defer func() {
-		if debugDB {
 		l.Debugf("close snapshot %p", snap)
-		}
 		snap.Release()
 	}()
 
@@ -854,9 +778,7 @@ nextFile:
 					continue nextFile
 				}
 				fk = deviceKeyInto(fk[:cap(fk)], folder, vl.versions[i].device, name)
-				if debugDB {
 				l.Debugf("snap.Get %p %x", snap, fk)
-				}
 				bs, err := snap.Get(fk, nil)
 				if err != nil {
 					var id protocol.DeviceID
@@ -886,9 +808,7 @@ nextFile:
 					continue nextFile
 				}
 
-				if debugDB {
 				l.Debugf("need folder=%q device=%v name=%q need=%v have=%v haveV=%d globalV=%d", folder, protocol.DeviceIDFromBytes(device), name, need, have, haveVersion, vl.versions[0].version)
-				}
 
 				if cont := fn(gf); !cont {
 					return
@@ -908,13 +828,9 @@ func ldbListFolders(db *leveldb.DB) []string {
 	if err != nil {
 		panic(err)
 	}
-	if debugDB {
 	l.Debugf("created snapshot %p", snap)
-	}
 	defer func() {
-		if debugDB {
 		l.Debugf("close snapshot %p", snap)
-		}
 		snap.Release()
 	}()
 
@@ -945,13 +861,9 @@ func ldbDropFolder(db *leveldb.DB, folder []byte) {
 	if err != nil {
 		panic(err)
 	}
-	if debugDB {
 	l.Debugf("created snapshot %p", snap)
-	}
 	defer func() {
-		if debugDB {
 		l.Debugf("close snapshot %p", snap)
-		}
 		snap.Release()
 	}()
 
@@ -995,13 +907,9 @@ func ldbCheckGlobals(db *leveldb.DB, folder []byte) {
 	if err != nil {
 		panic(err)
 	}
-	if debugDB {
 	l.Debugf("created snapshot %p", snap)
-	}
 	defer func() {
-		if debugDB {
 		l.Debugf("close snapshot %p", snap)
-		}
 		snap.Release()
 	}()
 
@@ -1011,9 +919,7 @@ func ldbCheckGlobals(db *leveldb.DB, folder []byte) {
 	defer dbi.Release()
 
 	batch := new(leveldb.Batch)
-	if debugDB {
 	l.Debugf("new batch %p", batch)
-	}
 
 	var fk []byte
 	for dbi.Next() {
@@ -1033,9 +939,7 @@ func ldbCheckGlobals(db *leveldb.DB, folder []byte) {
 		var newVL versionList
 		for _, version := range vl.versions {
 			fk = deviceKeyInto(fk[:cap(fk)], folder, version.device, name)
-			if debugDB {
 			l.Debugf("snap.Get %p %x", snap, fk)
-			}
 			_, err := snap.Get(fk, nil)
 			if err == leveldb.ErrNotFound {
 				continue
@@ -1051,8 +955,6 @@ func ldbCheckGlobals(db *leveldb.DB, folder []byte) {
 			batch.Put(dbi.Key(), newVL.MustMarshalXDR())
 		}
 	}
-	if debugDB {
+	l.Debugf("db check completed for %q", folder)
-		l.Infoln("db check completed for %q", folder)
-	}
 	db.Write(batch, nil)
 }

lib/db/set.go

@@ -62,18 +62,14 @@ func NewFileSet(folder string, db *leveldb.DB) *FileSet {
 		}
 		return true
 	})
-	if debug {
 	l.Debugf("loaded localVersion for %q: %#v", folder, s.localVersion)
-	}
 	clock(s.localVersion[protocol.LocalDeviceID])
 
 	return &s
 }
 
 func (s *FileSet) Replace(device protocol.DeviceID, fs []protocol.FileInfo) {
-	if debug {
 	l.Debugf("%s Replace(%v, [%d])", s.folder, device, len(fs))
-	}
 	normalizeFilenames(fs)
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
@@ -89,9 +85,7 @@ func (s *FileSet) Replace(device protocol.DeviceID, fs []protocol.FileInfo) {
 }
 
 func (s *FileSet) Update(device protocol.DeviceID, fs []protocol.FileInfo) {
-	if debug {
 	l.Debugf("%s Update(%v, [%d])", s.folder, device, len(fs))
-	}
 	normalizeFilenames(fs)
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
@@ -114,51 +108,37 @@ func (s *FileSet) Update(device protocol.DeviceID, fs []protocol.FileInfo) {
 }
 
 func (s *FileSet) WithNeed(device protocol.DeviceID, fn Iterator) {
-	if debug {
 	l.Debugf("%s WithNeed(%v)", s.folder, device)
-	}
 	ldbWithNeed(s.db, []byte(s.folder), device[:], false, nativeFileIterator(fn))
 }
 
 func (s *FileSet) WithNeedTruncated(device protocol.DeviceID, fn Iterator) {
-	if debug {
 	l.Debugf("%s WithNeedTruncated(%v)", s.folder, device)
-	}
 	ldbWithNeed(s.db, []byte(s.folder), device[:], true, nativeFileIterator(fn))
 }
 
 func (s *FileSet) WithHave(device protocol.DeviceID, fn Iterator) {
-	if debug {
 	l.Debugf("%s WithHave(%v)", s.folder, device)
-	}
 	ldbWithHave(s.db, []byte(s.folder), device[:], false, nativeFileIterator(fn))
 }
 
 func (s *FileSet) WithHaveTruncated(device protocol.DeviceID, fn Iterator) {
-	if debug {
 	l.Debugf("%s WithHaveTruncated(%v)", s.folder, device)
-	}
 	ldbWithHave(s.db, []byte(s.folder), device[:], true, nativeFileIterator(fn))
 }
 
 func (s *FileSet) WithGlobal(fn Iterator) {
-	if debug {
 	l.Debugf("%s WithGlobal()", s.folder)
-	}
 	ldbWithGlobal(s.db, []byte(s.folder), nil, false, nativeFileIterator(fn))
 }
 
 func (s *FileSet) WithGlobalTruncated(fn Iterator) {
-	if debug {
 	l.Debugf("%s WithGlobalTruncated()", s.folder)
-	}
 	ldbWithGlobal(s.db, []byte(s.folder), nil, true, nativeFileIterator(fn))
 }
 
 func (s *FileSet) WithPrefixedGlobalTruncated(prefix string, fn Iterator) {
-	if debug {
 	l.Debugf("%s WithPrefixedGlobalTruncated()", s.folder, prefix)
-	}
 	ldbWithGlobal(s.db, []byte(s.folder), []byte(osutil.NormalizedFilename(prefix)), true, nativeFileIterator(fn))
 }
 

lib/db/virtualmtime.go

@@ -34,9 +34,7 @@ func NewVirtualMtimeRepo(ldb *leveldb.DB, folder string) *VirtualMtimeRepo {
 }
 
 func (r *VirtualMtimeRepo) UpdateMtime(path string, diskMtime, actualMtime time.Time) {
-	if debug {
 	l.Debugf("virtual mtime: storing values for path:%s disk:%v actual:%v", path, diskMtime, actualMtime)
-	}
 
 	diskBytes, _ := diskMtime.MarshalBinary()
 	actualBytes, _ := actualMtime.MarshalBinary()
@@ -63,15 +61,11 @@ func (r *VirtualMtimeRepo) GetMtime(path string, diskMtime time.Time) time.Time
 			panic(fmt.Sprintf("Can't unmarshal stored mtime at path %s: %v", path, err))
 		}
 
-		if debug {
 		l.Debugf("virtual mtime: return %v instead of %v for path: %s", mtime, diskMtime, path)
-		}
 		return mtime
 	}
 
-	if debug {
 	l.Debugf("virtual mtime: record exists, but mismatch inDisk: %v dbDisk: %v for path: %s", diskMtime, mtime, path)
-	}
 	return diskMtime
 }
 

lib/discover/cache.go

@@ -75,10 +75,8 @@ func (m *CachingMux) Lookup(deviceID protocol.DeviceID) (direct []string, relays
 
 			if cacheEntry.found && time.Since(cacheEntry.when) < finder.cacheTime {
 				// It's a positive, valid entry. Use it.
-				if debug {
+				l.Debugln("cached discovery entry for", deviceID, "at", finder)
-					l.Debugln("cached discovery entry for", deviceID, "at", finder.String())
 				l.Debugln("  cache:", cacheEntry)
-				}
 				for _, addr := range cacheEntry.Direct {
 					pdirect = append(pdirect, prioritizedAddress{finder.priority, addr})
 				}
@@ -89,9 +87,7 @@ func (m *CachingMux) Lookup(deviceID protocol.DeviceID) (direct []string, relays
 			if !cacheEntry.found && time.Since(cacheEntry.when) < finder.negCacheTime {
 				// It's a negative, valid entry. We should not make another
 				// attempt right now.
-				if debug {
+				l.Debugln("negative cache entry for", deviceID, "at", finder)
-					l.Debugln("negative cache entry for", deviceID, "at", finder.String())
-				}
 				continue
 			}
 
@@ -100,11 +96,9 @@ func (m *CachingMux) Lookup(deviceID protocol.DeviceID) (direct []string, relays
 
 		// Perform the actual lookup and cache the result.
 		if td, tr, err := finder.Lookup(deviceID); err == nil {
-			if debug {
+			l.Debugln("lookup for", deviceID, "at", finder)
-				l.Debugln("lookup for", deviceID, "at", finder.String())
 			l.Debugln("  direct:", td)
 			l.Debugln("  relays:", tr)
-			}
 			for _, addr := range td {
 				pdirect = append(pdirect, prioritizedAddress{finder.priority, addr})
 			}
@@ -121,11 +115,9 @@ func (m *CachingMux) Lookup(deviceID protocol.DeviceID) (direct []string, relays
 
 	direct = uniqueSortedAddrs(pdirect)
 	relays = uniqueSortedRelays(relays)
-	if debug {
 	l.Debugln("lookup results for", deviceID)
 	l.Debugln("  direct: ", direct)
 	l.Debugln("  relays: ", relays)
-	}
 
 	return direct, relays, nil
 }

lib/discover/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "discover") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("discover", "Remote device discovery")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("discover", strings.Contains(os.Getenv("STTRACE"), "discover") || os.Getenv("STTRACE") == "all")
+}

lib/discover/global.go

@@ -124,16 +124,12 @@ func (c *globalClient) Lookup(device protocol.DeviceID) (direct []string, relays
 
 	resp, err := c.queryClient.Get(qURL.String())
 	if err != nil {
-		if debug {
+		l.Debugln("globalClient.Lookup", qURL, err)
-			l.Debugln("globalClient.Lookup", qURL.String(), err)
-		}
 		return nil, nil, err
 	}
 	if resp.StatusCode != 200 {
 		resp.Body.Close()
-		if debug {
+		l.Debugln("globalClient.Lookup", qURL, resp.Status)
-			l.Debugln("globalClient.Lookup", qURL.String(), resp.Status)
-		}
 		return nil, nil, errors.New(resp.Status)
 	}
 
@@ -198,9 +194,7 @@ func (c *globalClient) sendAnnouncement(timer *time.Timer) {
 
 	if len(ann.Direct)+len(ann.Relays) == 0 {
 		c.setError(errors.New("nothing to announce"))
-		if debug {
 		l.Debugln("Nothing to announce")
-		}
 		timer.Reset(announceErrorRetryInterval)
 		return
 	}
@@ -208,37 +202,27 @@ func (c *globalClient) sendAnnouncement(timer *time.Timer) {
 	// The marshal doesn't fail, I promise.
 	postData, _ := json.Marshal(ann)
 
-	if debug {
 	l.Debugf("Announcement: %s", postData)
-	}
 
 	resp, err := c.announceClient.Post(c.server, "application/json", bytes.NewReader(postData))
 	if err != nil {
-		if debug {
 		l.Debugln("announce POST:", err)
-		}
 		c.setError(err)
 		timer.Reset(announceErrorRetryInterval)
 		return
 	}
-	if debug {
 	l.Debugln("announce POST:", resp.Status)
-	}
 	resp.Body.Close()
 
 	if resp.StatusCode < 200 || resp.StatusCode > 299 {
-		if debug {
 		l.Debugln("announce POST:", resp.Status)
-		}
 		c.setError(errors.New(resp.Status))
 
 		if h := resp.Header.Get("Retry-After"); h != "" {
 			// The server has a recommendation on when we should
 			// retry. Follow it.
 			if secs, err := strconv.Atoi(h); err == nil && secs > 0 {
-				if debug {
 				l.Debugln("announce Retry-After:", secs, err)
-				}
 				timer.Reset(time.Duration(secs) * time.Second)
 				return
 			}
@@ -254,9 +238,7 @@ func (c *globalClient) sendAnnouncement(timer *time.Timer) {
 		// The server has a recommendation on when we should
 		// reannounce. Follow it.
 		if secs, err := strconv.Atoi(h); err == nil && secs > 0 {
-			if debug {
 			l.Debugln("announce Reannounce-After:", secs, err)
-			}
 			timer.Reset(time.Duration(secs) * time.Second)
 			return
 		}

lib/discover/local.go

@@ -166,15 +166,11 @@ func (c *localClient) recvAnnouncements(b beacon.Interface) {
 		var pkt Announce
 		err := pkt.UnmarshalXDR(buf)
 		if err != nil && err != io.EOF {
-			if debug {
 			l.Debugf("discover: Failed to unmarshal local announcement from %s:\n%s", addr, hex.Dump(buf))
-			}
 			continue
 		}
 
-		if debug {
 		l.Debugf("discover: Received local announcement from %s for %s", addr, protocol.DeviceIDFromBytes(pkt.This.ID))
-		}
 
 		var newDevice bool
 		if bytes.Compare(pkt.This.ID, c.myID[:]) != 0 {

lib/events/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "events") || os.Getenv("STTRACE") == "all"
+	dl = logger.DefaultLogger.NewFacility("events", "Event generation and logging")
-	dl    = logger.DefaultLogger
 )
+
+func init() {
+	dl.SetDebug("events", strings.Contains(os.Getenv("STTRACE"), "events") || os.Getenv("STTRACE") == "all")
+}

lib/events/events.go

@@ -138,9 +138,7 @@ func NewLogger() *Logger {
 
 func (l *Logger) Log(t EventType, data interface{}) {
 	l.mutex.Lock()
-	if debug {
+	dl.Debugln("log", l.nextID, t, data)
-		dl.Debugln("log", l.nextID, t.String(), data)
-	}
 	l.nextID++
 	e := Event{
 		ID:   l.nextID,
@@ -162,9 +160,7 @@ func (l *Logger) Log(t EventType, data interface{}) {
 
 func (l *Logger) Subscribe(mask EventType) *Subscription {
 	l.mutex.Lock()
-	if debug {
 	dl.Debugln("subscribe", mask)
-	}
 	s := &Subscription{
 		mask:    mask,
 		events:  make(chan Event, BufferSize),
@@ -177,9 +173,7 @@ func (l *Logger) Subscribe(mask EventType) *Subscription {
 
 func (l *Logger) Unsubscribe(s *Subscription) {
 	l.mutex.Lock()
-	if debug {
 	dl.Debugln("unsubscribe")
-	}
 	for i, ss := range l.subs {
 		if s == ss {
 			last := len(l.subs) - 1
@@ -197,9 +191,7 @@ func (l *Logger) Unsubscribe(s *Subscription) {
 // out of the event channel is closed. Poll should not be called concurrently
 // from multiple goroutines for a single subscription.
 func (s *Subscription) Poll(timeout time.Duration) (Event, error) {
-	if debug {
 	dl.Debugln("poll", timeout)
-	}
 
 	if !s.timeout.Reset(timeout) {
 		select {

lib/logger/logger.go

@@ -11,8 +11,12 @@ import (
 	"os"
 	"strings"
 	"sync"
+	"time"
 )
 
+// This package uses stdlib sync as it may be used to debug syncthing/lib/sync
+// and that would cause an implosion of the universe.
+
 type LogLevel int
 
 const (
@@ -46,14 +50,16 @@ type Logger interface {
 	Fatalf(format string, vals ...interface{})
 	ShouldDebug(facility string) bool
 	SetDebug(facility string, enabled bool)
-	Facilities() (enabled, disabled []string)
+	Facilities() map[string]string
-	NewFacility(facility string) Logger
+	FacilityDebugging() []string
+	NewFacility(facility, description string) Logger
 }
 
 type logger struct {
 	logger     *log.Logger
 	handlers   [NumLevels][]MessageHandler
-	debug    map[string]bool
+	facilities map[string]string // facility name => description
+	debug      map[string]bool   // facility name => debugging enabled
 	mut        sync.Mutex
 }
 
@@ -226,24 +232,42 @@ func (l *logger) SetDebug(facility string, enabled bool) {
 	l.mut.Unlock()
 }
 
-// Facilities returns the currently known set of facilities, both those for
+// FacilityDebugging returns the set of facilities that have debugging
-// which debug is enabled and those for which it is disabled.
+// enabled.
-func (l *logger) Facilities() (enabled, disabled []string) {
+func (l *logger) FacilityDebugging() []string {
+	var enabled []string
 	l.mut.Lock()
 	for facility, isEnabled := range l.debug {
 		if isEnabled {
 			enabled = append(enabled, facility)
-		} else {
-			disabled = append(disabled, facility)
 		}
 	}
 	l.mut.Unlock()
-	return
+	return enabled
+}
+
+// Facilities returns the currently known set of facilities and their
+// descriptions.
+func (l *logger) Facilities() map[string]string {
+	l.mut.Lock()
+	res := make(map[string]string, len(l.facilities))
+	for facility, descr := range l.facilities {
+		res[facility] = descr
+	}
+	l.mut.Unlock()
+	return res
 }
 
 // NewFacility returns a new logger bound to the named facility.
-func (l *logger) NewFacility(facility string) Logger {
+func (l *logger) NewFacility(facility, description string) Logger {
 	l.mut.Lock()
+	if l.facilities == nil {
+		l.facilities = make(map[string]string)
+	}
+	if description != "" {
+		l.facilities[facility] = description
+	}
+
 	if l.debug == nil {
 		l.debug = make(map[string]bool)
 	}
@@ -279,3 +303,77 @@ func (l *facilityLogger) Debugf(format string, vals ...interface{}) {
 	}
 	l.logger.Debugf(format, vals...)
 }
+
+// A Recorder keeps a size limited record of log events.
+type Recorder struct {
+	lines   []Line
+	initial int
+	mut     sync.Mutex
+}
+
+// A Line represents a single log entry.
+type Line struct {
+	When    time.Time
+	Message string
+}
+
+func NewRecorder(l Logger, level LogLevel, size, initial int) *Recorder {
+	r := &Recorder{
+		lines:   make([]Line, 0, size),
+		initial: initial,
+	}
+	l.AddHandler(level, r.append)
+	return r
+}
+
+func (r *Recorder) Since(t time.Time) []Line {
+	r.mut.Lock()
+	defer r.mut.Unlock()
+
+	res := r.lines
+	for i := 0; i < len(res) && res[i].When.Before(t); i++ {
+		// nothing, just incrementing i
+	}
+	if len(res) == 0 {
+		return nil
+	}
+
+	// We must copy the result as r.lines can be mutated as soon as the lock
+	// is released.
+	cp := make([]Line, len(res))
+	copy(cp, res)
+	return cp
+}
+
+func (r *Recorder) Clear() {
+	r.mut.Lock()
+	r.lines = r.lines[:0]
+	r.mut.Unlock()
+}
+
+func (r *Recorder) append(l LogLevel, msg string) {
+	line := Line{
+		When:    time.Now(),
+		Message: msg,
+	}
+
+	r.mut.Lock()
+	defer r.mut.Unlock()
+
+	if len(r.lines) == cap(r.lines) {
+		if r.initial > 0 {
+			// Shift all lines one step to the left, keeping the "initial" first intact.
+			copy(r.lines[r.initial+1:], r.lines[r.initial+2:])
+		} else {
+			copy(r.lines, r.lines[1:])
+		}
+		// Add the new one at the end
+		r.lines[len(r.lines)-1] = line
+		return
+	}
+
+	r.lines = append(r.lines, line)
+	if len(r.lines) == r.initial {
+		r.lines = append(r.lines, Line{time.Now(), "..."})
+	}
+}

lib/logger/logger_test.go

@@ -4,8 +4,10 @@
 package logger
 
 import (
+	"fmt"
 	"strings"
 	"testing"
+	"time"
 )
 
 func TestAPI(t *testing.T) {
@@ -14,45 +16,42 @@ func TestAPI(t *testing.T) {
 	l.SetPrefix("testing")
 
 	debug := 0
-	l.AddHandler(LevelDebug, checkFunc(t, LevelDebug, "test 0", &debug))
+	l.AddHandler(LevelDebug, checkFunc(t, LevelDebug, &debug))
 	info := 0
-	l.AddHandler(LevelInfo, checkFunc(t, LevelInfo, "test 1", &info))
+	l.AddHandler(LevelInfo, checkFunc(t, LevelInfo, &info))
-	warn := 0
-	l.AddHandler(LevelWarn, checkFunc(t, LevelWarn, "test 2", &warn))
 	ok := 0
-	l.AddHandler(LevelOK, checkFunc(t, LevelOK, "test 3", &ok))
+	l.AddHandler(LevelOK, checkFunc(t, LevelOK, &ok))
+	warn := 0
+	l.AddHandler(LevelWarn, checkFunc(t, LevelWarn, &warn))
 
 	l.Debugf("test %d", 0)
 	l.Debugln("test", 0)
 	l.Infof("test %d", 1)
 	l.Infoln("test", 1)
-	l.Warnf("test %d", 2)
+	l.Okf("test %d", 2)
-	l.Warnln("test", 2)
+	l.Okln("test", 2)
-	l.Okf("test %d", 3)
+	l.Warnf("test %d", 3)
-	l.Okln("test", 3)
+	l.Warnln("test", 3)
 
-	if debug != 2 {
+	if debug != 8 {
-		t.Errorf("Debug handler called %d != 2 times", debug)
+		t.Errorf("Debug handler called %d != 8 times", debug)
 	}
-	if info != 2 {
+	if info != 6 {
-		t.Errorf("Info handler called %d != 2 times", info)
+		t.Errorf("Info handler called %d != 6 times", info)
+	}
+	if ok != 4 {
+		t.Errorf("Ok handler called %d != 4 times", ok)
 	}
 	if warn != 2 {
 		t.Errorf("Warn handler called %d != 2 times", warn)
 	}
-	if ok != 2 {
-		t.Errorf("Ok handler called %d != 2 times", ok)
-	}
 }
 
-func checkFunc(t *testing.T, expectl LogLevel, expectmsg string, counter *int) func(LogLevel, string) {
+func checkFunc(t *testing.T, expectl LogLevel, counter *int) func(LogLevel, string) {
 	return func(l LogLevel, msg string) {
 		*counter++
-		if l != expectl {
+		if l < expectl {
-			t.Errorf("Incorrect message level %d != %d", l, expectl)
+			t.Errorf("Incorrect message level %d < %d", l, expectl)
-		}
-		if !strings.HasSuffix(msg, expectmsg) {
-			t.Errorf("%q does not end with %q", msg, expectmsg)
 		}
 	}
 }
@@ -69,12 +68,12 @@ func TestFacilityDebugging(t *testing.T) {
 		}
 	})
 
+	f0 := l.NewFacility("f0", "foo#0")
+	f1 := l.NewFacility("f1", "foo#1")
+
 	l.SetDebug("f0", true)
 	l.SetDebug("f1", false)
 
-	f0 := l.NewFacility("f0")
-	f1 := l.NewFacility("f1")
-
 	f0.Debugln("Debug line from f0")
 	f1.Debugln("Debug line from f1")
 
@@ -82,3 +81,60 @@ func TestFacilityDebugging(t *testing.T) {
 		t.Fatalf("Incorrent number of messages, %d != 1", msgs)
 	}
 }
+
+func TestRecorder(t *testing.T) {
+	l := New()
+	l.SetFlags(0)
+
+	// Keep the last five warnings or higher, no special initial handling.
+	r0 := NewRecorder(l, LevelWarn, 5, 0)
+	// Keep the last ten infos or higher, with the first three being permanent.
+	r1 := NewRecorder(l, LevelInfo, 10, 3)
+
+	// Log a bunch of messages.
+	for i := 0; i < 15; i++ {
+		l.Debugf("Debug#%d", i)
+		l.Infof("Info#%d", i)
+		l.Warnf("Warn#%d", i)
+	}
+
+	// r0 should contain the last five warnings
+	lines := r0.Since(time.Time{})
+	if len(lines) != 5 {
+		t.Fatalf("Incorrect length %d != 5", len(lines))
+	}
+	for i := 0; i < 5; i++ {
+		expected := fmt.Sprintf("Warn#%d", i+10)
+		if lines[i].Message != expected {
+			t.Error("Incorrect warning in r0:", lines[i].Message, "!=", expected)
+		}
+	}
+
+	// r0 should contain:
+	// - The first three messages
+	// - A "..." marker
+	// - The last six messages
+	// (totalling ten)
+	lines = r1.Since(time.Time{})
+	if len(lines) != 10 {
+		t.Fatalf("Incorrect length %d != 10", len(lines))
+	}
+	expected := []string{
+		"Info#0",
+		"Warn#0",
+		"Info#1",
+		"...",
+		"Info#12",
+		"Warn#12",
+		"Info#13",
+		"Warn#13",
+		"Info#14",
+		"Warn#14",
+	}
+	for i := 0; i < 10; i++ {
+		if lines[i].Message != expected[i] {
+			t.Error("Incorrect warning in r0:", lines[i].Message, "!=", expected[i])
+		}
+	}
+
+}

lib/model/debug.go

@@ -10,10 +10,17 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "model") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("model", "The root hub")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("model", strings.Contains(os.Getenv("STTRACE"), "model") || os.Getenv("STTRACE") == "all")
+}
+
+func shouldDebug() bool {
+	return l.ShouldDebug("model")
+}

lib/model/model.go

@@ -107,9 +107,7 @@ func NewModel(cfg *config.Wrapper, id protocol.DeviceID, deviceName, clientName,
 	m := &Model{
 		Supervisor: suture.New("model", suture.Spec{
 			Log: func(line string) {
-				if debug {
 				l.Debugln(line)
-				}
 			},
 		}),
 		cfg:                cfg,
@@ -335,9 +333,7 @@ func (m *Model) Completion(device protocol.DeviceID, folder string) float64 {
 	})
 
 	res := 100 * (1 - float64(need)/float64(tot))
-	if debug {
 	l.Debugf("%v Completion(%s, %q): %f (%d / %d)", m, device, folder, res, need, tot)
-	}
 
 	return res
 }
@@ -412,9 +408,7 @@ func (m *Model) NeedSize(folder string) (nfiles int, bytes int64) {
 		})
 	}
 	bytes -= m.progressEmitter.BytesCompleted(folder)
-	if debug {
 	l.Debugf("%v NeedSize(%q): %d %d", m, folder, nfiles, bytes)
-	}
 	return
 }
 
@@ -493,9 +487,7 @@ func (m *Model) Index(deviceID protocol.DeviceID, folder string, fs []protocol.F
 		return
 	}
 
-	if debug {
 	l.Debugf("IDX(in): %s %q: %d files", deviceID, folder, len(fs))
-	}
 
 	if !m.folderSharedWith(folder, deviceID) {
 		events.Default.Log(events.FolderRejected, map[string]string{
@@ -541,9 +533,7 @@ func (m *Model) IndexUpdate(deviceID protocol.DeviceID, folder string, fs []prot
 		return
 	}
 
-	if debug {
 	l.Debugf("%v IDXUP(in): %s / %q: %d files", m, deviceID, folder, len(fs))
-	}
 
 	if !m.folderSharedWith(folder, deviceID) {
 		l.Infof("Update for unexpected folder ID %q sent from device %q; ensure that the folder exists and that this device is selected under \"Share With\" in the folder configuration.", folder, deviceID)
@@ -766,16 +756,12 @@ func (m *Model) Request(deviceID protocol.DeviceID, folder, name string, offset
 		}
 
 		if lf.IsInvalid() || lf.IsDeleted() {
-			if debug {
 			l.Debugf("%v REQ(in): %s: %q / %q o=%d s=%d; invalid: %v", m, deviceID, folder, name, offset, len(buf), lf)
-			}
 			return protocol.ErrInvalid
 		}
 
 		if offset > lf.Size() {
-			if debug {
 			l.Debugf("%v REQ(in; nonexistent): %s: %q o=%d s=%d", m, deviceID, name, offset, len(buf))
-			}
 			return protocol.ErrNoSuchFile
 		}
 
@@ -806,7 +792,7 @@ func (m *Model) Request(deviceID protocol.DeviceID, folder, name string, offset
 		m.rvmut.Unlock()
 	}
 
-	if debug && deviceID != protocol.LocalDeviceID {
+	if deviceID != protocol.LocalDeviceID {
 		l.Debugf("%v REQ(in): %s: %q / %q o=%d s=%d", m, deviceID, folder, name, offset, len(buf))
 	}
 	m.fmut.RLock()
@@ -1033,9 +1019,8 @@ func sendIndexes(conn protocol.Connection, folder string, fs *db.FileSet, ignore
 	name := conn.Name()
 	var err error
 
-	if debug {
 	l.Debugf("sendIndexes for %s-%s/%q starting", deviceID, name, folder)
-	}
+	defer l.Debugf("sendIndexes for %s-%s/%q exiting: %v", deviceID, name, folder, err)
 
 	minLocalVer, err := sendIndexTo(true, 0, conn, folder, fs, ignores)
 
@@ -1060,9 +1045,6 @@ func sendIndexes(conn protocol.Connection, folder string, fs *db.FileSet, ignore
 		time.Sleep(250 * time.Millisecond)
 	}
 
-	if debug {
-		l.Debugf("sendIndexes for %s-%s/%q exiting: %v", deviceID, name, folder, err)
-	}
 }
 
 func sendIndexTo(initial bool, minLocalVer int64, conn protocol.Connection, folder string, fs *db.FileSet, ignores *ignore.Matcher) (int64, error) {
@@ -1084,9 +1066,7 @@ func sendIndexTo(initial bool, minLocalVer int64, conn protocol.Connection, fold
 		}
 
 		if ignores.Match(f.Name) || symlinkInvalid(folder, f) {
-			if debug {
 			l.Debugln("not sending update for ignored/unsupported symlink", f)
-			}
 			return true
 		}
 
@@ -1095,18 +1075,14 @@ func sendIndexTo(initial bool, minLocalVer int64, conn protocol.Connection, fold
 				if err = conn.Index(folder, batch, 0, nil); err != nil {
 					return false
 				}
-				if debug {
 				l.Debugf("sendIndexes for %s-%s/%q: %d files (<%d bytes) (initial index)", deviceID, name, folder, len(batch), currentBatchSize)
-				}
 				initial = false
 			} else {
 				if err = conn.IndexUpdate(folder, batch, 0, nil); err != nil {
 					return false
 				}
-				if debug {
 				l.Debugf("sendIndexes for %s-%s/%q: %d files (<%d bytes) (batched update)", deviceID, name, folder, len(batch), currentBatchSize)
 			}
-			}
 
 			batch = make([]protocol.FileInfo, 0, indexBatchSize)
 			currentBatchSize = 0
@@ -1119,12 +1095,12 @@ func sendIndexTo(initial bool, minLocalVer int64, conn protocol.Connection, fold
 
 	if initial && err == nil {
 		err = conn.Index(folder, batch, 0, nil)
-		if debug && err == nil {
+		if err == nil {
 			l.Debugf("sendIndexes for %s-%s/%q: %d files (small initial index)", deviceID, name, folder, len(batch))
 		}
 	} else if len(batch) > 0 && err == nil {
 		err = conn.IndexUpdate(folder, batch, 0, nil)
-		if debug && err == nil {
+		if err == nil {
 			l.Debugf("sendIndexes for %s-%s/%q: %d files (last batch)", deviceID, name, folder, len(batch))
 		}
 	}
@@ -1160,9 +1136,7 @@ func (m *Model) requestGlobal(deviceID protocol.DeviceID, folder, name string, o
 		return nil, fmt.Errorf("requestGlobal: no such device: %s", deviceID)
 	}
 
-	if debug {
 	l.Debugf("%v REQ(out): %s: %q / %q o=%d s=%d h=%x f=%x op=%s", m, deviceID, folder, name, offset, size, hash, flags, options)
-	}
 
 	return nc.Request(folder, name, offset, size, hash, flags, options)
 }
@@ -1403,9 +1377,7 @@ nextSub:
 
 			if ignores.Match(f.Name) || symlinkInvalid(folder, f) {
 				// File has been ignored or an unsupported symlink. Set invalid bit.
-				if debug {
 				l.Debugln("setting invalid bit on ignored", f)
-				}
 				nf := protocol.FileInfo{
 					Name:     f.Name,
 					Flags:    f.Flags | protocol.FlagInvalid,
@@ -1820,9 +1792,7 @@ func (m *Model) CommitConfiguration(from, to config.Configuration) bool {
 	for folderID, cfg := range toFolders {
 		if _, ok := fromFolders[folderID]; !ok {
 			// A folder was added.
-			if debug {
 			l.Debugln(m, "adding folder", folderID)
-			}
 			m.AddFolder(cfg)
 			if cfg.ReadOnly {
 				m.StartFolderRO(folderID)
@@ -1846,9 +1816,7 @@ func (m *Model) CommitConfiguration(from, to config.Configuration) bool {
 		toCfg, ok := toFolders[folderID]
 		if !ok {
 			// A folder was removed. Requires restart.
-			if debug {
 			l.Debugln(m, "requires restart, removing folder", folderID)
-			}
 			return false
 		}
 
@@ -1860,9 +1828,7 @@ func (m *Model) CommitConfiguration(from, to config.Configuration) bool {
 		for dev := range fromDevs {
 			if _, ok := toDevs[dev]; !ok {
 				// A device was removed. Requires restart.
-				if debug {
 				l.Debugln(m, "requires restart, removing device", dev, "from folder", folderID)
-				}
 				return false
 			}
 		}
@@ -1895,9 +1861,7 @@ func (m *Model) CommitConfiguration(from, to config.Configuration) bool {
 		fromCfg.Devices = nil
 		toCfg.Devices = nil
 		if !reflect.DeepEqual(fromCfg, toCfg) {
-			if debug {
 			l.Debugln(m, "requires restart, folder", folderID, "configuration differs")
-			}
 			return false
 		}
 	}
@@ -1906,18 +1870,14 @@ func (m *Model) CommitConfiguration(from, to config.Configuration) bool {
 	toDevs := mapDeviceCfgs(from.Devices)
 	for _, dev := range from.Devices {
 		if _, ok := toDevs[dev.DeviceID]; !ok {
-			if debug {
 			l.Debugln(m, "requires restart, device", dev.DeviceID, "was removed")
-			}
 			return false
 		}
 	}
 
 	// All of the generic options require restart
 	if !reflect.DeepEqual(from.Options, to.Options) {
-		if debug {
 		l.Debugln(m, "requires restart, options differ")
-		}
 		return false
 	}
 
@@ -1957,21 +1917,15 @@ func mapDeviceCfgs(devices []config.DeviceConfiguration) map[protocol.DeviceID]s
 func filterIndex(folder string, fs []protocol.FileInfo, dropDeletes bool) []protocol.FileInfo {
 	for i := 0; i < len(fs); {
 		if fs[i].Flags&^protocol.FlagsAll != 0 {
-			if debug {
 			l.Debugln("dropping update for file with unknown bits set", fs[i])
-			}
 			fs[i] = fs[len(fs)-1]
 			fs = fs[:len(fs)-1]
 		} else if fs[i].IsDeleted() && dropDeletes {
-			if debug {
 			l.Debugln("dropping update for undesired delete", fs[i])
-			}
 			fs[i] = fs[len(fs)-1]
 			fs = fs[:len(fs)-1]
 		} else if symlinkInvalid(folder, fs[i]) {
-			if debug {
 			l.Debugln("dropping update for unsupported symlink", fs[i])
-			}
 			fs[i] = fs[len(fs)-1]
 			fs = fs[:len(fs)-1]
 		} else {

lib/model/progressemitter.go

@@ -51,15 +51,11 @@ func (t *ProgressEmitter) Serve() {
 	for {
 		select {
 		case <-t.stop:
-			if debug {
 			l.Debugln("progress emitter: stopping")
-			}
 			return
 		case <-t.timer.C:
 			t.mut.Lock()
-			if debug {
 			l.Debugln("progress emitter: timer - looking after", len(t.registry))
-			}
 			output := make(map[string]map[string]*pullerProgress)
 			for _, puller := range t.registry {
 				if output[puller.folder] == nil {
@@ -70,10 +66,8 @@ func (t *ProgressEmitter) Serve() {
 			if !reflect.DeepEqual(t.last, output) {
 				events.Default.Log(events.DownloadProgress, output)
 				t.last = output
-				if debug {
 				l.Debugf("progress emitter: emitting %#v", output)
-				}
+			} else {
-			} else if debug {
 				l.Debugln("progress emitter: nothing new")
 			}
 			if len(t.registry) != 0 {
@@ -95,9 +89,7 @@ func (t *ProgressEmitter) CommitConfiguration(from, to config.Configuration) boo
 	defer t.mut.Unlock()
 
 	t.interval = time.Duration(to.Options.ProgressUpdateIntervalS) * time.Second
-	if debug {
 	l.Debugln("progress emitter: updated interval", t.interval)
-	}
 
 	return true
 }
@@ -112,9 +104,7 @@ func (t *ProgressEmitter) Stop() {
 func (t *ProgressEmitter) Register(s *sharedPullerState) {
 	t.mut.Lock()
 	defer t.mut.Unlock()
-	if debug {
 	l.Debugln("progress emitter: registering", s.folder, s.file.Name)
-	}
 	if len(t.registry) == 0 {
 		t.timer.Reset(t.interval)
 	}
@@ -125,9 +115,7 @@ func (t *ProgressEmitter) Register(s *sharedPullerState) {
 func (t *ProgressEmitter) Deregister(s *sharedPullerState) {
 	t.mut.Lock()
 	defer t.mut.Unlock()
-	if debug {
 	l.Debugln("progress emitter: deregistering", s.folder, s.file.Name)
-	}
 	delete(t.registry, filepath.Join(s.folder, s.file.Name))
 }
 
@@ -141,9 +129,7 @@ func (t *ProgressEmitter) BytesCompleted(folder string) (bytes int64) {
 			bytes += s.Progress().BytesDone
 		}
 	}
-	if debug {
 	l.Debugf("progress emitter: bytes completed for %s: %d", folder, bytes)
-	}
 	return
 }
 

lib/model/rofolder.go

@@ -48,10 +48,8 @@ func newROFolder(model *Model, folder string, interval time.Duration) *roFolder
 }
 
 func (s *roFolder) Serve() {
-	if debug {
 	l.Debugln(s, "starting")
 	defer l.Debugln(s, "exiting")
-	}
 
 	defer func() {
 		s.timer.Stop()
@@ -79,9 +77,7 @@ func (s *roFolder) Serve() {
 				continue
 			}
 
-			if debug {
 			l.Debugln(s, "rescan")
-			}
 
 			if err := s.model.internalScanFolderSubs(s.folder, nil); err != nil {
 				// Potentially sets the error twice, once in the scanner just
@@ -111,9 +107,7 @@ func (s *roFolder) Serve() {
 				continue
 			}
 
-			if debug {
 			l.Debugln(s, "forced rescan")
-			}
 
 			if err := s.model.internalScanFolderSubs(s.folder, req.subs); err != nil {
 				// Potentially sets the error twice, once in the scanner just

lib/model/rwfolder.go

@@ -157,10 +157,8 @@ func (p *rwFolder) ignorePermissions(file protocol.FileInfo) bool {
 // Serve will run scans and pulls. It will return when Stop()ed or on a
 // critical error.
 func (p *rwFolder) Serve() {
-	if debug {
 	l.Debugln(p, "starting")
 	defer l.Debugln(p, "exiting")
-	}
 
 	defer func() {
 		p.pullTimer.Stop()
@@ -182,9 +180,7 @@ func (p *rwFolder) Serve() {
 		sleepNanos := (p.scanIntv.Nanoseconds()*3 + rand.Int63n(2*p.scanIntv.Nanoseconds())) / 4
 		intv := time.Duration(sleepNanos) * time.Nanosecond
 
-		if debug {
 		l.Debugln(p, "next rescan in", intv)
-		}
 		p.scanTimer.Reset(intv)
 	}
 
@@ -199,15 +195,11 @@ func (p *rwFolder) Serve() {
 		case <-p.remoteIndex:
 			prevVer = 0
 			p.pullTimer.Reset(shortPullIntv)
-			if debug {
 			l.Debugln(p, "remote index updated, rescheduling pull")
-			}
 
 		case <-p.pullTimer.C:
 			if !initialScanCompleted {
-				if debug {
 				l.Debugln(p, "skip (initial)")
-				}
 				p.pullTimer.Reset(nextPullIntv)
 				continue
 			}
@@ -225,9 +217,7 @@ func (p *rwFolder) Serve() {
 			if newHash := curIgnores.Hash(); newHash != prevIgnoreHash {
 				// The ignore patterns have changed. We need to re-evaluate if
 				// there are files we need now that were ignored before.
-				if debug {
 				l.Debugln(p, "ignore patterns have changed, resetting prevVer")
-				}
 				prevVer = 0
 				prevIgnoreHash = newHash
 			}
@@ -235,16 +225,12 @@ func (p *rwFolder) Serve() {
 			// RemoteLocalVersion() is a fast call, doesn't touch the database.
 			curVer, ok := p.model.RemoteLocalVersion(p.folder)
 			if !ok || curVer == prevVer {
-				if debug {
 				l.Debugln(p, "skip (curVer == prevVer)", prevVer, ok)
-				}
 				p.pullTimer.Reset(nextPullIntv)
 				continue
 			}
 
-			if debug {
 			l.Debugln(p, "pulling", prevVer, curVer)
-			}
 
 			p.setState(FolderSyncing)
 			p.clearErrors()
@@ -254,9 +240,7 @@ func (p *rwFolder) Serve() {
 				tries++
 
 				changed := p.pullerIteration(curIgnores)
-				if debug {
 				l.Debugln(p, "changed", changed)
-				}
 
 				if changed == 0 {
 					// No files were changed by the puller, so we are in
@@ -276,9 +260,7 @@ func (p *rwFolder) Serve() {
 						curVer = lv
 					}
 					prevVer = curVer
-					if debug {
 					l.Debugln(p, "next pull in", nextPullIntv)
-					}
 					p.pullTimer.Reset(nextPullIntv)
 					break
 				}
@@ -289,9 +271,7 @@ func (p *rwFolder) Serve() {
 					// errors preventing us. Flag this with a warning and
 					// wait a bit longer before retrying.
 					l.Infof("Folder %q isn't making progress. Pausing puller for %v.", p.folder, pauseIntv)
-					if debug {
 					l.Debugln(p, "next pull in", pauseIntv)
-					}
 
 					if folderErrors := p.currentErrors(); len(folderErrors) > 0 {
 						events.Default.Log(events.FolderErrors, map[string]interface{}{
@@ -316,9 +296,7 @@ func (p *rwFolder) Serve() {
 				continue
 			}
 
-			if debug {
 			l.Debugln(p, "rescan")
-			}
 
 			if err := p.model.internalScanFolderSubs(p.folder, nil); err != nil {
 				// Potentially sets the error twice, once in the scanner just
@@ -345,9 +323,7 @@ func (p *rwFolder) Serve() {
 				continue
 			}
 
-			if debug {
 			l.Debugln(p, "forced rescan")
-			}
 
 			if err := p.model.internalScanFolderSubs(p.folder, req.subs); err != nil {
 				// Potentially sets the error twice, once in the scanner just
@@ -409,9 +385,7 @@ func (p *rwFolder) pullerIteration(ignores *ignore.Matcher) int {
 	pullWg := sync.NewWaitGroup()
 	doneWg := sync.NewWaitGroup()
 
-	if debug {
 	l.Debugln(p, "c", p.copiers, "p", p.pullers)
-	}
 
 	p.dbUpdates = make(chan dbUpdateJob)
 	updateWg.Add(1)
@@ -474,9 +448,7 @@ func (p *rwFolder) pullerIteration(ignores *ignore.Matcher) int {
 			return true
 		}
 
-		if debug {
 		l.Debugln(p, "handling", file.Name)
-		}
 
 		switch {
 		case file.IsDeleted():
@@ -498,9 +470,7 @@ func (p *rwFolder) pullerIteration(ignores *ignore.Matcher) int {
 			}
 		case file.IsDirectory() && !file.IsSymlink():
 			// A new or changed directory
-			if debug {
 			l.Debugln("Creating directory", file.Name)
-			}
 			p.handleDir(file)
 		default:
 			// A new or changed file or symlink. This is the only case where we
@@ -591,17 +561,13 @@ nextFile:
 	doneWg.Wait()
 
 	for _, file := range fileDeletions {
-		if debug {
 		l.Debugln("Deleting file", file.Name)
-		}
 		p.deleteFile(file)
 	}
 
 	for i := range dirDeletions {
 		dir := dirDeletions[len(dirDeletions)-i-1]
-		if debug {
 		l.Debugln("Deleting dir", dir.Name)
-		}
 		p.deleteDir(dir)
 	}
 
@@ -638,7 +604,7 @@ func (p *rwFolder) handleDir(file protocol.FileInfo) {
 		mode = 0777
 	}
 
-	if debug {
+	if shouldDebug() {
 		curFile, _ := p.model.CurrentFolderFile(p.folder, file.Name)
 		l.Debugf("need dir\n\t%v\n\t%v", file, curFile)
 	}
@@ -836,9 +802,7 @@ func (p *rwFolder) renameFile(source, target protocol.FileInfo) {
 		})
 	}()
 
-	if debug {
 	l.Debugln(p, "taking rename shortcut", source.Name, "->", target.Name)
-	}
 
 	from := filepath.Join(p.dir, source.Name)
 	to := filepath.Join(p.dir, target.Name)
@@ -926,9 +890,7 @@ func (p *rwFolder) handleFile(file protocol.FileInfo, copyChan chan<- copyBlocks
 		// We are supposed to copy the entire file, and then fetch nothing. We
 		// are only updating metadata, so we don't actually *need* to make the
 		// copy.
-		if debug {
 		l.Debugln(p, "taking shortcut on", file.Name)
-		}
 
 		events.Default.Log(events.ItemStarted, map[string]string{
 			"folder": p.folder,
@@ -1033,9 +995,7 @@ func (p *rwFolder) handleFile(file protocol.FileInfo, copyChan chan<- copyBlocks
 		mut:         sync.NewMutex(),
 	}
 
-	if debug {
 	l.Debugf("%v need file %s; copy %d, reused %v", p, file.Name, len(blocks), reused)
-	}
 
 	cs := copyBlocksState{
 		sharedPullerState: &s,
@@ -1135,14 +1095,12 @@ func (p *rwFolder) copierRoutine(in <-chan copyBlocksState, pullChan chan<- pull
 				hash, err := scanner.VerifyBuffer(buf, block)
 				if err != nil {
 					if hash != nil {
-						if debug {
 						l.Debugf("Finder block mismatch in %s:%s:%d expected %q got %q", folder, file, index, block.Hash, hash)
-						}
 						err = p.model.finder.Fix(folder, file, index, block.Hash, hash)
 						if err != nil {
 							l.Warnln("finder fix:", err)
 						}
-					} else if debug {
+					} else {
 						l.Debugln("Finder failed to verify buffer", err)
 					}
 					return false
@@ -1217,9 +1175,7 @@ func (p *rwFolder) pullerRoutine(in <-chan pullBlockState, out chan<- *sharedPul
 			buf, lastError := p.model.requestGlobal(selected, p.folder, state.file.Name, state.block.Offset, int(state.block.Size), state.block.Hash, 0, nil)
 			activity.done(selected)
 			if lastError != nil {
-				if debug {
 				l.Debugln("request:", p.folder, state.file.Name, state.block.Offset, state.block.Size, "returned error:", lastError)
-				}
 				continue
 			}
 
@@ -1227,9 +1183,7 @@ func (p *rwFolder) pullerRoutine(in <-chan pullBlockState, out chan<- *sharedPul
 			// try pulling it from another device.
 			_, lastError = scanner.VerifyBuffer(buf, state.block)
 			if lastError != nil {
-				if debug {
 				l.Debugln("request:", p.folder, state.file.Name, state.block.Offset, state.block.Size, "hash mismatch")
-				}
 				continue
 			}
 
@@ -1339,9 +1293,7 @@ func (p *rwFolder) performFinish(state *sharedPullerState) error {
 func (p *rwFolder) finisherRoutine(in <-chan *sharedPullerState) {
 	for state := range in {
 		if closed, err := state.finalClose(); closed {
-			if debug {
 			l.Debugln(p, "closing", state.file.Name)
-			}
 
 			p.queue.Done(state.file.Name)
 

lib/model/sharedpullerstate.go

@@ -193,9 +193,7 @@ func (s *sharedPullerState) failed() error {
 func (s *sharedPullerState) copyDone() {
 	s.mut.Lock()
 	s.copyNeeded--
-	if debug {
 	l.Debugln("sharedPullerState", s.folder, s.file.Name, "copyNeeded ->", s.copyNeeded)
-	}
 	s.mut.Unlock()
 }
 
@@ -211,18 +209,14 @@ func (s *sharedPullerState) pullStarted() {
 	s.copyNeeded--
 	s.pullTotal++
 	s.pullNeeded++
-	if debug {
 	l.Debugln("sharedPullerState", s.folder, s.file.Name, "pullNeeded start ->", s.pullNeeded)
-	}
 	s.mut.Unlock()
 }
 
 func (s *sharedPullerState) pullDone() {
 	s.mut.Lock()
 	s.pullNeeded--
-	if debug {
 	l.Debugln("sharedPullerState", s.folder, s.file.Name, "pullNeeded done ->", s.pullNeeded)
-	}
 	s.mut.Unlock()
 }
 

lib/protocol/debug.go

@@ -6,10 +6,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "protocol") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("protocol", "The BEP protocol")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("protocol", strings.Contains(os.Getenv("STTRACE"), "protocol") || os.Getenv("STTRACE") == "all")
+}

lib/protocol/protocol.go

@@ -369,9 +369,7 @@ func (c *rawConnection) readMessage() (hdr header, msg encodable, err error) {
 	hdr = decodeHeader(binary.BigEndian.Uint32(c.rdbuf0[0:4]))
 	msglen := int(binary.BigEndian.Uint32(c.rdbuf0[4:8]))
 
-	if debug {
 	l.Debugf("read header %v (msglen=%d)", hdr, msglen)
-	}
 
 	if msglen > MaxMessageLen {
 		err = fmt.Errorf("message length %d exceeds maximum %d", msglen, MaxMessageLen)
@@ -393,9 +391,7 @@ func (c *rawConnection) readMessage() (hdr header, msg encodable, err error) {
 		return
 	}
 
-	if debug {
 	l.Debugf("read %d bytes", len(c.rdbuf0))
-	}
 
 	msgBuf := c.rdbuf0
 	if hdr.compression && msglen > 0 {
@@ -405,18 +401,14 @@ func (c *rawConnection) readMessage() (hdr header, msg encodable, err error) {
 			return
 		}
 		msgBuf = c.rdbuf1
-		if debug {
 		l.Debugf("decompressed to %d bytes", len(msgBuf))
 	}
-	}
 
-	if debug {
 	if len(msgBuf) > 1024 {
 		l.Debugf("message data:\n%s", hex.Dump(msgBuf[:1024]))
 	} else {
 		l.Debugf("message data:\n%s", hex.Dump(msgBuf))
 	}
-	}
 
 	// We check each returned error for the XDRError.IsEOF() method.
 	// IsEOF()==true here means that the message contained fewer fields than
@@ -477,16 +469,12 @@ func (c *rawConnection) readMessage() (hdr header, msg encodable, err error) {
 }
 
 func (c *rawConnection) handleIndex(im IndexMessage) {
-	if debug {
 	l.Debugf("Index(%v, %v, %d file, flags %x, opts: %s)", c.id, im.Folder, len(im.Files), im.Flags, im.Options)
-	}
 	c.receiver.Index(c.id, im.Folder, filterIndexMessageFiles(im.Files), im.Flags, im.Options)
 }
 
 func (c *rawConnection) handleIndexUpdate(im IndexMessage) {
-	if debug {
 	l.Debugf("queueing IndexUpdate(%v, %v, %d files, flags %x, opts: %s)", c.id, im.Folder, len(im.Files), im.Flags, im.Options)
-	}
 	c.receiver.IndexUpdate(c.id, im.Folder, filterIndexMessageFiles(im.Files), im.Flags, im.Options)
 }
 
@@ -636,9 +624,7 @@ func (c *rawConnection) writerLoop() {
 					binary.BigEndian.PutUint32(msgBuf[4:8], uint32(len(tempBuf)))
 					msgBuf = msgBuf[0 : len(tempBuf)+8]
 
-					if debug {
 					l.Debugf("write compressed message; %v (len=%d)", hm.hdr, len(tempBuf))
-					}
 				} else {
 					// No point in compressing very short messages
 					hm.hdr.compression = false
@@ -652,14 +638,10 @@ func (c *rawConnection) writerLoop() {
 					msgBuf = msgBuf[0 : len(uncBuf)+8]
 					copy(msgBuf[8:], uncBuf)
 
-					if debug {
 					l.Debugf("write uncompressed message; %v (len=%d)", hm.hdr, len(uncBuf))
 				}
-				}
 			} else {
-				if debug {
 				l.Debugf("write empty message; %v", hm.hdr)
-				}
 				binary.BigEndian.PutUint32(msgBuf[4:8], 0)
 				msgBuf = msgBuf[:8]
 			}
@@ -669,10 +651,8 @@ func (c *rawConnection) writerLoop() {
 			if err == nil {
 				var n int
 				n, err = c.cw.Write(msgBuf)
-				if debug {
 				l.Debugf("wrote %d bytes on the wire", n)
 			}
-			}
 			if err != nil {
 				c.close(err)
 				return
@@ -725,15 +705,11 @@ func (c *rawConnection) pingSender() {
 		case <-ticker:
 			d := time.Since(c.cw.Last())
 			if d < PingSendInterval/2 {
-				if debug {
 				l.Debugln(c.id, "ping skipped after wr", d)
-				}
 				continue
 			}
 
-			if debug {
 			l.Debugln(c.id, "ping -> after", d)
-			}
 			c.ping()
 
 		case <-c.closed:
@@ -753,15 +729,11 @@ func (c *rawConnection) pingReceiver() {
 		case <-ticker:
 			d := time.Since(c.cr.Last())
 			if d > ReceiveTimeout {
-				if debug {
 				l.Debugln(c.id, "ping timeout", d)
-				}
 				c.close(ErrTimeout)
 			}
 
-			if debug {
 			l.Debugln(c.id, "last read within", d)
-			}
 
 		case <-c.closed:
 			return

lib/rc/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "rc") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("rc", "Remote control package")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("rc", strings.Contains(os.Getenv("STTRACE"), "rc") || os.Getenv("STTRACE") == "all")
+}

lib/rc/rc.go

@@ -351,9 +351,7 @@ func (p *Process) Model(folder string) (Model, error) {
 		return Model{}, err
 	}
 
-	if debug {
 	l.Debugf("%+v", res)
-	}
 
 	return res, nil
 }
@@ -506,9 +504,7 @@ func (p *Process) eventLoop() {
 				m[p.id.String()] = version
 				p.localVersion[folder] = m
 				p.done[folder] = false
-				if debug {
 				l.Debugf("LocalIndexUpdated %v %v done=false\n\t%+v", p.id, folder, m)
-				}
 				p.eventMut.Unlock()
 
 			case "RemoteIndexUpdated":
@@ -524,9 +520,7 @@ func (p *Process) eventLoop() {
 				m[device] = version
 				p.localVersion[folder] = m
 				p.done[folder] = false
-				if debug {
 				l.Debugf("RemoteIndexUpdated %v %v done=false\n\t%+v", p.id, folder, m)
-				}
 				p.eventMut.Unlock()
 
 			case "FolderSummary":
@@ -537,9 +531,7 @@ func (p *Process) eventLoop() {
 				done := need == 0
 				p.eventMut.Lock()
 				p.done[folder] = done
-				if debug {
 				l.Debugf("Foldersummary %v %v\n\t%+v", p.id, folder, p.done)
-				}
 				p.eventMut.Unlock()
 			}
 		}

lib/relay/client/client.go

@@ -66,15 +66,11 @@ func (c *ProtocolClient) Serve() {
 	defer close(c.stopped)
 
 	if err := c.connect(); err != nil {
-		if debug {
 		l.Debugln("Relay connect:", err)
-		}
 		return
 	}
 
-	if debug {
 	l.Debugln(c, "connected", c.conn.RemoteAddr())
-	}
 
 	if err := c.join(); err != nil {
 		c.conn.Close()
@@ -87,9 +83,7 @@ func (c *ProtocolClient) Serve() {
 		return
 	}
 
-	if debug {
 	l.Debugln(c, "joined", c.conn.RemoteAddr(), "via", c.conn.LocalAddr())
-	}
 
 	defer c.cleanup()
 	c.mut.Lock()
@@ -107,9 +101,7 @@ func (c *ProtocolClient) Serve() {
 		select {
 		case message := <-messages:
 			timeout.Reset(c.timeout)
-			if debug {
 			log.Printf("%s received message %T", c, message)
-			}
 
 			switch msg := message.(type) {
 			case protocol.Ping:
@@ -118,9 +110,7 @@ func (c *ProtocolClient) Serve() {
 					return
 
 				}
-				if debug {
 				l.Debugln(c, "sent pong")
-				}
 
 			case protocol.SessionInvitation:
 				ip := net.IP(msg.Address)
@@ -135,9 +125,7 @@ func (c *ProtocolClient) Serve() {
 			}
 
 		case <-c.stop:
-			if debug {
 			l.Debugln(c, "stopping")
-			}
 			return
 
 		case err := <-errors:
@@ -145,9 +133,7 @@ func (c *ProtocolClient) Serve() {
 			return
 
 		case <-timeout.C:
-			if debug {
 			l.Debugln(c, "timed out")
-			}
 			return
 		}
 	}
@@ -220,9 +206,7 @@ func (c *ProtocolClient) cleanup() {
 		c.Invitations = make(chan protocol.SessionInvitation)
 	}
 
-	if debug {
 	l.Debugln(c, "cleaning up")
-	}
 
 	c.mut.Lock()
 	c.connected = false

lib/relay/client/debug.go

@@ -6,10 +6,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "relay") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("relay", "")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("relay", strings.Contains(os.Getenv("STTRACE"), "relay") || os.Getenv("STTRACE") == "all")
+}

lib/relay/client/methods.go

@@ -49,9 +49,7 @@ func GetInvitationFromRelay(uri *url.URL, id syncthingprotocol.DeviceID, certs [
 	case protocol.Response:
 		return protocol.SessionInvitation{}, fmt.Errorf("Incorrect response code %d: %s", msg.Code, msg.Message)
 	case protocol.SessionInvitation:
-		if debug {
 		l.Debugln("Received invitation", msg, "via", conn.LocalAddr())
-		}
 		ip := net.IP(msg.Address)
 		if len(ip) == 0 || ip.IsUnspecified() {
 			msg.Address = conn.RemoteAddr().(*net.TCPAddr).IP[:]

lib/relay/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "relay") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("relay", "Relay connection handling")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("relay", strings.Contains(os.Getenv("STTRACE"), "relay") || os.Getenv("STTRACE") == "all")
+}

lib/relay/relay.go

@@ -47,9 +47,7 @@ func NewSvc(cfg *config.Wrapper, tlsCfg *tls.Config) *Svc {
 	svc := &Svc{
 		Supervisor: suture.New("Svc", suture.Spec{
 			Log: func(log string) {
-				if debug {
 				l.Debugln(log)
-				}
 			},
 			FailureBackoff:   5 * time.Minute,
 			FailureDecay:     float64((10 * time.Minute) / time.Second),
@@ -102,9 +100,7 @@ func (s *Svc) CommitConfiguration(from, to config.Configuration) bool {
 	for _, addr := range to.Options.RelayServers {
 		uri, err := url.Parse(addr)
 		if err != nil {
-			if debug {
 			l.Debugln("Failed to parse relay address", addr, err)
-			}
 			continue
 		}
 		existing[uri.String()] = uri
@@ -120,15 +116,11 @@ func (s *Svc) CommitConfiguration(from, to config.Configuration) bool {
 		// Trim off the `dynamic+` prefix
 		uri.Scheme = uri.Scheme[8:]
 
-		if debug {
 		l.Debugln("Looking up dynamic relays from", uri)
-		}
 
 		data, err := http.Get(uri.String())
 		if err != nil {
-			if debug {
 			l.Debugln("Failed to lookup dynamic relays", err)
-			}
 			continue
 		}
 
@@ -136,9 +128,7 @@ func (s *Svc) CommitConfiguration(from, to config.Configuration) bool {
 		err = json.NewDecoder(data.Body).Decode(&ann)
 		data.Body.Close()
 		if err != nil {
-			if debug {
 			l.Debugln("Failed to lookup dynamic relays", err)
-			}
 			continue
 		}
 
@@ -146,26 +136,20 @@ func (s *Svc) CommitConfiguration(from, to config.Configuration) bool {
 		for _, relayAnn := range ann.Relays {
 			ruri, err := url.Parse(relayAnn.URL)
 			if err != nil {
-				if debug {
 				l.Debugln("Failed to parse dynamic relay address", relayAnn.URL, err)
-				}
 				continue
 			}
-			if debug {
 			l.Debugln("Found", ruri, "via", uri)
-			}
 			dynRelayAddrs = append(dynRelayAddrs, ruri.String())
 		}
 
 		if len(dynRelayAddrs) > 0 {
 			dynRelayAddrs = relayAddressesSortedByLatency(dynRelayAddrs)
 			closestRelay := dynRelayAddrs[0]
-			if debug {
 			l.Debugln("Picking", closestRelay, "as closest dynamic relay from", uri)
-			}
 			ruri, _ := url.Parse(closestRelay)
 			existing[closestRelay] = ruri
-		} else if debug {
+		} else {
 			l.Debugln("No dynamic relay found on", uri)
 		}
 	}
@@ -175,9 +159,7 @@ func (s *Svc) CommitConfiguration(from, to config.Configuration) bool {
 	for key, uri := range existing {
 		_, ok := s.tokens[key]
 		if !ok {
-			if debug {
 			l.Debugln("Connecting to relay", uri)
-			}
 			c := client.NewProtocolClient(uri, s.tlsCfg.Certificates, s.invitations)
 			s.tokens[key] = s.Add(c)
 			s.clients[key] = c
@@ -190,11 +172,9 @@ func (s *Svc) CommitConfiguration(from, to config.Configuration) bool {
 			err := s.Remove(token)
 			delete(s.tokens, key)
 			delete(s.clients, key)
-			if debug {
 			l.Debugln("Disconnecting from relay", key, err)
 		}
 	}
-	}
 
 	s.mut.Unlock()
 
@@ -262,14 +242,10 @@ func (r *invitationReceiver) Serve() {
 	for {
 		select {
 		case inv := <-r.invitations:
-			if debug {
 			l.Debugln("Received relay invitation", inv)
-			}
 			conn, err := client.JoinSession(inv)
 			if err != nil {
-				if debug {
 				l.Debugf("Failed to join relay session %s: %v", inv, err)
-				}
 				continue
 			}
 

lib/scanner/blockqueue.go

@@ -42,9 +42,7 @@ func newParallelHasher(dir string, blockSize, workers int, outbox, inbox chan pr
 func HashFile(path string, blockSize int, sizeHint int64, counter *int64) ([]protocol.BlockInfo, error) {
 	fd, err := os.Open(path)
 	if err != nil {
-		if debug {
 		l.Debugln("open:", err)
-		}
 		return []protocol.BlockInfo{}, err
 	}
 	defer fd.Close()
@@ -52,9 +50,7 @@ func HashFile(path string, blockSize int, sizeHint int64, counter *int64) ([]pro
 	if sizeHint == 0 {
 		fi, err := fd.Stat()
 		if err != nil {
-			if debug {
 			l.Debugln("stat:", err)
-			}
 			return []protocol.BlockInfo{}, err
 		}
 		sizeHint = fi.Size()
@@ -71,9 +67,7 @@ func hashFiles(dir string, blockSize int, outbox, inbox chan protocol.FileInfo,
 
 		blocks, err := HashFile(filepath.Join(dir, f.Name), blockSize, f.CachedSize, counter)
 		if err != nil {
-			if debug {
 			l.Debugln("hash error:", f.Name, err)
-			}
 			continue
 		}
 

lib/scanner/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "scanner") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("scanner", "File change detection and hashing")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("scanner", strings.Contains(os.Getenv("STTRACE"), "scanner") || os.Getenv("STTRACE") == "all")
+}

lib/scanner/walk.go

@@ -94,9 +94,7 @@ type IgnoreMatcher interface {
 // Walk returns the list of files found in the local folder by scanning the
 // file system. Files are blockwise hashed.
 func (w *Walker) Walk() (chan protocol.FileInfo, error) {
-	if debug {
 	l.Debugln("Walk", w.Dir, w.Subs, w.BlockSize, w.Matcher)
-	}
 
 	err := checkDir(w.Dir)
 	if err != nil {
@@ -159,16 +157,12 @@ func (w *Walker) Walk() (chan protocol.FileInfo, error) {
 			for {
 				select {
 				case <-done:
-					if debug {
 					l.Debugln("Walk progress done", w.Dir, w.Subs, w.BlockSize, w.Matcher)
-					}
 					ticker.Stop()
 					return
 				case <-ticker.C:
 					current := atomic.LoadInt64(&progress)
-					if debug {
 					l.Debugf("Walk %s %s current progress %d/%d (%d%%)", w.Dir, w.Subs, current, total, current*100/total)
-					}
 					events.Default.Log(events.FolderScanProgress, map[string]interface{}{
 						"folder":  w.Folder,
 						"current": current,
@@ -179,9 +173,7 @@ func (w *Walker) Walk() (chan protocol.FileInfo, error) {
 		}()
 
 		for _, file := range filesToHash {
-			if debug {
 			l.Debugln("real to hash:", file.Name)
-			}
 			realToHashChan <- file
 		}
 		close(realToHashChan)
@@ -202,17 +194,13 @@ func (w *Walker) walkAndHashFiles(fchan, dchan chan protocol.FileInfo) filepath.
 		}
 
 		if err != nil {
-			if debug {
 			l.Debugln("error:", p, info, err)
-			}
 			return skip
 		}
 
 		rn, err := filepath.Rel(w.Dir, p)
 		if err != nil {
-			if debug {
 			l.Debugln("rel error:", p, err)
-			}
 			return skip
 		}
 
@@ -227,24 +215,18 @@ func (w *Walker) walkAndHashFiles(fchan, dchan chan protocol.FileInfo) filepath.
 
 		if w.TempNamer != nil && w.TempNamer.IsTemporary(rn) {
 			// A temporary file
-			if debug {
 			l.Debugln("temporary:", rn)
-			}
 			if info.Mode().IsRegular() && mtime.Add(w.TempLifetime).Before(now) {
 				os.Remove(p)
-				if debug {
 				l.Debugln("removing temporary:", rn, mtime)
 			}
-			}
 			return nil
 		}
 
 		if sn := filepath.Base(rn); sn == ".stignore" || sn == ".stfolder" ||
 			strings.HasPrefix(rn, ".stversions") || (w.Matcher != nil && w.Matcher.Match(rn)) {
 			// An ignored file
-			if debug {
 			l.Debugln("ignored:", rn)
-			}
 			return skip
 		}
 
@@ -313,17 +295,13 @@ func (w *Walker) walkAndHashFiles(fchan, dchan chan protocol.FileInfo) filepath.
 
 			target, targetType, err := symlinks.Read(p)
 			if err != nil {
-				if debug {
 				l.Debugln("readlink error:", p, err)
-				}
 				return skip
 			}
 
 			blocks, err := Blocks(strings.NewReader(target), w.BlockSize, 0, nil)
 			if err != nil {
-				if debug {
 				l.Debugln("hash link error:", p, err)
-				}
 				return skip
 			}
 
@@ -349,9 +327,7 @@ func (w *Walker) walkAndHashFiles(fchan, dchan chan protocol.FileInfo) filepath.
 				Blocks:   blocks,
 			}
 
-			if debug {
 			l.Debugln("symlink changedb:", p, f)
-			}
 
 			dchan <- f
 
@@ -386,9 +362,7 @@ func (w *Walker) walkAndHashFiles(fchan, dchan chan protocol.FileInfo) filepath.
 				Flags:    flags,
 				Modified: mtime.Unix(),
 			}
-			if debug {
 			l.Debugln("dir:", p, f)
-			}
 			dchan <- f
 			return nil
 		}
@@ -416,10 +390,8 @@ func (w *Walker) walkAndHashFiles(fchan, dchan chan protocol.FileInfo) filepath.
 					return nil
 				}
 
-				if debug {
 				l.Debugln("rescan:", cf, mtime.Unix(), info.Mode()&os.ModePerm)
 			}
-			}
 
 			var flags = curMode & uint32(maskModePerm)
 			if w.IgnorePerms {
@@ -433,9 +405,7 @@ func (w *Walker) walkAndHashFiles(fchan, dchan chan protocol.FileInfo) filepath.
 				Modified:   mtime.Unix(),
 				CachedSize: info.Size(),
 			}
-			if debug {
 			l.Debugln("to hash:", p, f)
-			}
 			fchan <- f
 		}
 
@@ -448,7 +418,7 @@ func checkDir(dir string) error {
 		return err
 	} else if !info.IsDir() {
 		return errors.New(dir + ": not a directory")
-	} else if debug {
+	} else {
 		l.Debugln("checkDir", dir, info)
 	}
 	return nil

lib/stats/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "stats") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("stats", "Persistent device and folder statistics")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("stats", strings.Contains(os.Getenv("STTRACE"), "stats") || os.Getenv("STTRACE") == "all")
+}

lib/stats/device.go

@@ -37,16 +37,12 @@ func (s *DeviceStatisticsReference) GetLastSeen() time.Time {
 		// time.Time{} from s.ns
 		return time.Unix(0, 0)
 	}
-	if debug {
 	l.Debugln("stats.DeviceStatisticsReference.GetLastSeen:", s.device, t)
-	}
 	return t
 }
 
 func (s *DeviceStatisticsReference) WasSeen() {
-	if debug {
 	l.Debugln("stats.DeviceStatisticsReference.WasSeen:", s.device)
-	}
 	s.ns.PutTime("lastSeen", time.Now())
 }
 

lib/stats/folder.go

@@ -54,9 +54,7 @@ func (s *FolderStatisticsReference) GetLastFile() LastFile {
 }
 
 func (s *FolderStatisticsReference) ReceivedFile(file string, deleted bool) {
-	if debug {
 	l.Debugln("stats.FolderStatisticsReference.ReceivedFile:", s.folder, file)
-	}
 	s.ns.PutTime("lastFileAt", time.Now())
 	s.ns.PutString("lastFileName", file)
 	s.ns.PutBool("lastFileDeleted", deleted)

lib/sync/debug.go

@@ -12,20 +12,28 @@ import (
 	"strings"
 	"time"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug     = strings.Contains(os.Getenv("STTRACE"), "locks") || os.Getenv("STTRACE") == "all"
 	threshold = time.Duration(100 * time.Millisecond)
-	l         = logger.DefaultLogger
+	l         = logger.DefaultLogger.NewFacility("sync", "Mutexes")
+
+	// We make an exception in this package and have an actual "if debug { ...
+	// }" variable, as it may be rather performance critical and does
+	// nonstandard things (from a debug logging PoV).
+	debug = strings.Contains(os.Getenv("STTRACE"), "sync") || os.Getenv("STTRACE") == "all"
 )
 
 func init() {
-	if n, err := strconv.Atoi(os.Getenv("STLOCKTHRESHOLD")); debug && err == nil {
+	l.SetDebug("sync", strings.Contains(os.Getenv("STTRACE"), "sync") || os.Getenv("STTRACE") == "all")
+
+	if n, err := strconv.Atoi(os.Getenv("STLOCKTHRESHOLD")); err == nil {
 		threshold = time.Duration(n) * time.Millisecond
 	}
-	if debug {
 	l.Debugf("Enabling lock logging at %v threshold", threshold)
-	}
+}
+
+func shouldDebug() bool {
+	return l.ShouldDebug("sync")
 }

lib/sync/sync_test.go

@@ -12,7 +12,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 const (
@@ -23,6 +23,7 @@ const (
 
 func TestTypes(t *testing.T) {
 	debug = false
+	l.SetDebug("sync", false)
 
 	if _, ok := NewMutex().(*sync.Mutex); !ok {
 		t.Error("Wrong type")
@@ -37,6 +38,7 @@ func TestTypes(t *testing.T) {
 	}
 
 	debug = true
+	l.SetDebug("sync", true)
 
 	if _, ok := NewMutex().(*loggedMutex); !ok {
 		t.Error("Wrong type")
@@ -51,10 +53,12 @@ func TestTypes(t *testing.T) {
 	}
 
 	debug = false
+	l.SetDebug("sync", false)
 }
 
 func TestMutex(t *testing.T) {
 	debug = true
+	l.SetDebug("sync", true)
 	threshold = logThreshold
 
 	msgmut := sync.Mutex{}
@@ -84,10 +88,12 @@ func TestMutex(t *testing.T) {
 	}
 
 	debug = false
+	l.SetDebug("sync", false)
 }
 
 func TestRWMutex(t *testing.T) {
 	debug = true
+	l.SetDebug("sync", true)
 	threshold = logThreshold
 
 	msgmut := sync.Mutex{}
@@ -142,10 +148,12 @@ func TestRWMutex(t *testing.T) {
 	mut.RUnlock()
 
 	debug = false
+	l.SetDebug("sync", false)
 }
 
 func TestWaitGroup(t *testing.T) {
 	debug = true
+	l.SetDebug("sync", true)
 	threshold = logThreshold
 
 	msgmut := sync.Mutex{}
@@ -182,4 +190,5 @@ func TestWaitGroup(t *testing.T) {
 	}
 
 	debug = false
+	l.SetDebug("sync", false)
 }

lib/upgrade/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "upgrade") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("upgrade", "Binary upgrades")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("upgrade", strings.Contains(os.Getenv("STTRACE"), "upgrade") || os.Getenv("STTRACE") == "all")
+}

lib/upgrade/upgrade_supported.go

@@ -96,12 +96,8 @@ func SelectLatestRelease(version string, rels []Release) (Release, error) {
 			assetName := path.Base(asset.Name)
 			// Check for the architecture
 			expectedRelease := releaseName(rel.Tag)
-			if debug {
 			l.Debugf("expected release asset %q", expectedRelease)
-			}
-			if debug {
 			l.Debugln("considering release", assetName)
-			}
 			if strings.HasPrefix(assetName, expectedRelease) {
 				return rel, nil
 			}
@@ -113,14 +109,10 @@ func SelectLatestRelease(version string, rels []Release) (Release, error) {
 // Upgrade to the given release, saving the previous binary with a ".old" extension.
 func upgradeTo(binary string, rel Release) error {
 	expectedRelease := releaseName(rel.Tag)
-	if debug {
 	l.Debugf("expected release asset %q", expectedRelease)
-	}
 	for _, asset := range rel.Assets {
 		assetName := path.Base(asset.Name)
-		if debug {
 		l.Debugln("considering release", assetName)
-		}
 
 		if strings.HasPrefix(assetName, expectedRelease) {
 			return upgradeToURL(binary, asset.URL)
@@ -151,9 +143,7 @@ func upgradeToURL(binary string, url string) error {
 }
 
 func readRelease(dir, url string) (string, error) {
-	if debug {
 	l.Debugf("loading %q", url)
-	}
 
 	req, err := http.NewRequest("GET", url, nil)
 	if err != nil {
@@ -199,9 +189,7 @@ func readTarGz(dir string, r io.Reader) (string, error) {
 
 		shortName := path.Base(hdr.Name)
 
-		if debug {
 		l.Debugf("considering file %q", shortName)
-		}
 
 		err = archiveFileVisitor(dir, &tempName, &sig, shortName, tr)
 		if err != nil {
@@ -238,9 +226,7 @@ func readZip(dir string, r io.Reader) (string, error) {
 	for _, file := range archive.File {
 		shortName := path.Base(file.Name)
 
-		if debug {
 		l.Debugf("considering file %q", shortName)
-		}
 
 		inFile, err := file.Open()
 		if err != nil {
@@ -271,18 +257,14 @@ func archiveFileVisitor(dir string, tempFile *string, signature *[]byte, filenam
 	var err error
 	switch filename {
 	case "syncthing", "syncthing.exe":
-		if debug {
 		l.Debugln("reading binary")
-		}
 		*tempFile, err = writeBinary(dir, filedata)
 		if err != nil {
 			return err
 		}
 
 	case "syncthing.sig", "syncthing.exe.sig":
-		if debug {
 		l.Debugln("reading signature")
-		}
 		*signature, err = ioutil.ReadAll(filedata)
 		if err != nil {
 			return err
@@ -300,9 +282,7 @@ func verifyUpgrade(tempName string, sig []byte) error {
 		return fmt.Errorf("no signature found")
 	}
 
-	if debug {
 	l.Debugf("checking signature\n%s", sig)
-	}
 
 	fd, err := os.Open(tempName)
 	if err != nil {

lib/upnp/debug.go

@@ -10,10 +10,17 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "upnp") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("upnp", "UPnP discovery and port mapping")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("upnp", strings.Contains(os.Getenv("STTRACE"), "upnp") || os.Getenv("STTRACE") == "all")
+}
+
+func shouldDebug() bool {
+	return l.ShouldDebug("upnp")
+}

lib/upnp/upnp.go

@@ -129,7 +129,7 @@ nextResult:
 	for result := range resultChan {
 		for _, existingResult := range results {
 			if existingResult.uuid == result.uuid {
-				if debug {
+				if shouldDebug() {
 					l.Debugf("Skipping duplicate result %s with services:", result.uuid)
 					for _, svc := range result.services {
 						l.Debugf("* [%s] %s", svc.serviceID, svc.serviceURL)
@@ -140,7 +140,7 @@ nextResult:
 		}
 
 		results = append(results, result)
-		if debug {
+		if shouldDebug() {
 			l.Debugf("UPnP discovery result %s with services:", result.uuid)
 			for _, svc := range result.services {
 				l.Debugf("* [%s] %s", svc.serviceID, svc.serviceURL)
@@ -167,15 +167,11 @@ Mx: %d
 
 	search := []byte(strings.Replace(searchStr, "\n", "\r\n", -1))
 
-	if debug {
+	l.Debugln("Starting discovery of device type", deviceType, "on", intf.Name)
-		l.Debugln("Starting discovery of device type " + deviceType + " on " + intf.Name)
-	}
 
 	socket, err := net.ListenMulticastUDP("udp4", intf, &net.UDPAddr{IP: ssdp.IP})
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		return
 	}
 	defer socket.Close() // Make sure our socket gets closed
@@ -186,9 +182,7 @@ Mx: %d
 		return
 	}
 
-	if debug {
+	l.Debugln("Sending search request for device type", deviceType, "on", intf.Name)
-		l.Debugln("Sending search request for device type " + deviceType + " on " + intf.Name)
-	}
 
 	_, err = socket.WriteTo(search, ssdp)
 	if err != nil {
@@ -196,9 +190,7 @@ Mx: %d
 		return
 	}
 
-	if debug {
+	l.Debugln("Listening for UPnP response for device type", deviceType, "on", intf.Name)
-		l.Debugln("Listening for UPnP response for device type " + deviceType + " on " + intf.Name)
-	}
 
 	// Listen for responses until a timeout is reached
 	for {
@@ -217,15 +209,11 @@ Mx: %d
 		}
 		results <- igd
 	}
-	if debug {
+	l.Debugln("Discovery for device type", deviceType, "on", intf.Name, "finished.")
-		l.Debugln("Discovery for device type " + deviceType + " on " + intf.Name + " finished.")
-	}
 }
 
 func parseResponse(deviceType string, resp []byte) (IGD, error) {
-	if debug {
 	l.Debugln("Handling UPnP response:\n\n" + string(resp))
-	}
 
 	reader := bufio.NewReader(bytes.NewBuffer(resp))
 	request := &http.Request{}
@@ -368,7 +356,7 @@ func getIGDServices(rootURL string, device upnpDevice, wanDeviceURN string, wanC
 	devices := getChildDevices(device, wanDeviceURN)
 
 	if len(devices) < 1 {
-		l.Infoln("[" + rootURL + "] Malformed InternetGatewayDevice description: no WANDevices specified.")
+		l.Infoln(rootURL, "- malformed InternetGatewayDevice description: no WANDevices specified.")
 		return result
 	}
 
@@ -376,27 +364,23 @@ func getIGDServices(rootURL string, device upnpDevice, wanDeviceURN string, wanC
 		connections := getChildDevices(device, wanConnectionURN)
 
 		if len(connections) < 1 {
-			l.Infoln("[" + rootURL + "] Malformed " + wanDeviceURN + " description: no WANConnectionDevices specified.")
+			l.Infoln(rootURL, "- malformed ", wanDeviceURN, "description: no WANConnectionDevices specified.")
 		}
 
 		for _, connection := range connections {
 			for _, serviceURN := range serviceURNs {
 				services := getChildServices(connection, serviceURN)
 
-				if len(services) < 1 && debug {
+				l.Debugln(rootURL, "- no services of type", serviceURN, " found on connection.")
-					l.Debugln("[" + rootURL + "] No services of type " + serviceURN + " found on connection.")
-				}
 
 				for _, service := range services {
 					if len(service.ControlURL) == 0 {
-						l.Infoln("[" + rootURL + "] Malformed " + service.ServiceType + " description: no control URL.")
+						l.Infoln(rootURL+"- malformed", service.ServiceType, "description: no control URL.")
 					} else {
 						u, _ := url.Parse(rootURL)
 						replaceRawPath(u, service.ControlURL)
 
-						if debug {
+						l.Debugln(rootURL, "- found", service.ServiceType, "with URL", u)
-							l.Debugln("[" + rootURL + "] Found " + service.ServiceType + " with URL " + u.String())
-						}
 
 						service := IGDService{serviceID: service.ServiceID, serviceURL: u.String(), serviceURN: service.ServiceType}
 
@@ -456,24 +440,18 @@ func soapRequest(url, service, function, message string) ([]byte, error) {
 	req.Header.Set("Cache-Control", "no-cache")
 	req.Header.Set("Pragma", "no-cache")
 
-	if debug {
 	l.Debugln("SOAP Request URL: " + url)
 	l.Debugln("SOAP Action: " + req.Header.Get("SOAPAction"))
 	l.Debugln("SOAP Request:\n\n" + body)
-	}
 
 	r, err := http.DefaultClient.Do(req)
 	if err != nil {
-		if debug {
 		l.Debugln(err)
-		}
 		return resp, err
 	}
 
 	resp, _ = ioutil.ReadAll(r.Body)
-	if debug {
+	l.Debugf("SOAP Response: %s\n\n%s\n\n", r.Status, resp)
-		l.Debugf("SOAP Response: %v\n\n%v\n\n", r.StatusCode, string(resp))
-	}
 
 	r.Body.Close()
 

lib/versioner/debug.go

@@ -10,10 +10,13 @@ import (
 	"os"
 	"strings"
 
-	"github.com/calmh/logger"
+	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	debug = strings.Contains(os.Getenv("STTRACE"), "versioner") || os.Getenv("STTRACE") == "all"
+	l = logger.DefaultLogger.NewFacility("versioner", "File versioning")
-	l     = logger.DefaultLogger
 )
+
+func init() {
+	l.SetDebug("versioner", strings.Contains(os.Getenv("STTRACE"), "versioner") || os.Getenv("STTRACE") == "all")
+}

lib/versioner/external.go

@@ -34,9 +34,7 @@ func NewExternal(folderID, folderPath string, params map[string]string) Versione
 		folderPath: folderPath,
 	}
 
-	if debug {
 	l.Debugf("instantiated %#v", s)
-	}
 	return s
 }
 
@@ -45,17 +43,13 @@ func NewExternal(folderID, folderPath string, params map[string]string) Versione
 func (v External) Archive(filePath string) error {
 	_, err := osutil.Lstat(filePath)
 	if os.IsNotExist(err) {
-		if debug {
 		l.Debugln("not archiving nonexistent file", filePath)
-		}
 		return nil
 	} else if err != nil {
 		return err
 	}
 
-	if debug {
 	l.Debugln("archiving", filePath)
-	}
 
 	inFolderPath, err := filepath.Rel(v.folderPath, filePath)
 	if err != nil {

lib/versioner/simple.go

@@ -35,9 +35,7 @@ func NewSimple(folderID, folderPath string, params map[string]string) Versioner
 		folderPath: folderPath,
 	}
 
-	if debug {
 	l.Debugf("instantiated %#v", s)
-	}
 	return s
 }
 
@@ -46,9 +44,7 @@ func NewSimple(folderID, folderPath string, params map[string]string) Versioner
 func (v Simple) Archive(filePath string) error {
 	fileInfo, err := osutil.Lstat(filePath)
 	if os.IsNotExist(err) {
-		if debug {
 		l.Debugln("not archiving nonexistent file", filePath)
-		}
 		return nil
 	} else if err != nil {
 		return err
@@ -58,9 +54,7 @@ func (v Simple) Archive(filePath string) error {
 	_, err = os.Stat(versionsDir)
 	if err != nil {
 		if os.IsNotExist(err) {
-			if debug {
 			l.Debugln("creating versions dir", versionsDir)
-			}
 			osutil.MkdirAll(versionsDir, 0755)
 			osutil.HideFile(versionsDir)
 		} else {
@@ -68,9 +62,7 @@ func (v Simple) Archive(filePath string) error {
 		}
 	}
 
-	if debug {
 	l.Debugln("archiving", filePath)
-	}
 
 	file := filepath.Base(filePath)
 	inFolderPath, err := filepath.Rel(v.folderPath, filepath.Dir(filePath))
@@ -86,9 +78,7 @@ func (v Simple) Archive(filePath string) error {
 
 	ver := taggedFilename(file, fileInfo.ModTime().Format(TimeFormat))
 	dst := filepath.Join(dir, ver)
-	if debug {
 	l.Debugln("moving to", dst)
-	}
 	err = osutil.Rename(filePath, dst)
 	if err != nil {
 		return err
@@ -114,9 +104,7 @@ func (v Simple) Archive(filePath string) error {
 
 	if len(versions) > v.keep {
 		for _, toRemove := range versions[:len(versions)-v.keep] {
-			if debug {
 			l.Debugln("cleaning out", toRemove)
-			}
 			err = os.Remove(toRemove)
 			if err != nil {
 				l.Warnln("removing old version:", err)

lib/versioner/staggered.go

@@ -47,14 +47,10 @@ func NewStaggered(folderID, folderPath string, params map[string]string) Version
 	// Use custom path if set, otherwise .stversions in folderPath
 	var versionsDir string
 	if params["versionsPath"] == "" {
-		if debug {
 		l.Debugln("using default dir .stversions")
-		}
 		versionsDir = filepath.Join(folderPath, ".stversions")
 	} else {
-		if debug {
 		l.Debugln("using dir", params["versionsPath"])
-		}
 		versionsDir = params["versionsPath"]
 	}
 
@@ -71,9 +67,7 @@ func NewStaggered(folderID, folderPath string, params map[string]string) Version
 		mutex: sync.NewMutex(),
 	}
 
-	if debug {
 	l.Debugf("instantiated %#v", s)
-	}
 
 	go func() {
 		s.clean()
@@ -86,14 +80,10 @@ func NewStaggered(folderID, folderPath string, params map[string]string) Version
 }
 
 func (v Staggered) clean() {
-	if debug {
 	l.Debugln("Versioner clean: Waiting for lock on", v.versionsPath)
-	}
 	v.mutex.Lock()
 	defer v.mutex.Unlock()
-	if debug {
 	l.Debugln("Versioner clean: Cleaning", v.versionsPath)
-	}
 
 	if _, err := os.Stat(v.versionsPath); os.IsNotExist(err) {
 		// There is no need to clean a nonexistent dir.
@@ -144,30 +134,22 @@ func (v Staggered) clean() {
 		}
 
 		if path == v.versionsPath {
-			if debug {
 			l.Debugln("Cleaner: versions dir is empty, don't delete", path)
-			}
 			continue
 		}
 
-		if debug {
 		l.Debugln("Cleaner: deleting empty directory", path)
-		}
 		err = os.Remove(path)
 		if err != nil {
 			l.Warnln("Versioner: can't remove directory", path, err)
 		}
 	}
 
-	if debug {
 	l.Debugln("Cleaner: Finished cleaning", v.versionsPath)
-	}
 }
 
 func (v Staggered) expire(versions []string) {
-	if debug {
 	l.Debugln("Versioner: Expiring versions", versions)
-	}
 	var prevAge int64
 	firstFile := true
 	for _, file := range versions {
@@ -185,18 +167,14 @@ func (v Staggered) expire(versions []string) {
 		loc, _ := time.LoadLocation("Local")
 		versionTime, err := time.ParseInLocation(TimeFormat, filenameTag(file), loc)
 		if err != nil {
-			if debug {
 			l.Debugf("Versioner: file name %q is invalid: %v", file, err)
-			}
 			continue
 		}
 		age := int64(time.Since(versionTime).Seconds())
 
 		// If the file is older than the max age of the last interval, remove it
 		if lastIntv := v.interval[len(v.interval)-1]; lastIntv.end > 0 && age > lastIntv.end {
-			if debug {
 			l.Debugln("Versioner: File over maximum age -> delete ", file)
-			}
 			err = os.Remove(file)
 			if err != nil {
 				l.Warnf("Versioner: can't remove %q: %v", file, err)
@@ -220,9 +198,7 @@ func (v Staggered) expire(versions []string) {
 		}
 
 		if prevAge-age < usedInterval.step {
-			if debug {
 			l.Debugln("too many files in step -> delete", file)
-			}
 			err = os.Remove(file)
 			if err != nil {
 				l.Warnf("Versioner: can't remove %q: %v", file, err)
@@ -237,17 +213,13 @@ func (v Staggered) expire(versions []string) {
 // Archive moves the named file away to a version archive. If this function
 // returns nil, the named file does not exist any more (has been archived).
 func (v Staggered) Archive(filePath string) error {
-	if debug {
 	l.Debugln("Waiting for lock on ", v.versionsPath)
-	}
 	v.mutex.Lock()
 	defer v.mutex.Unlock()
 
 	_, err := osutil.Lstat(filePath)
 	if os.IsNotExist(err) {
-		if debug {
 		l.Debugln("not archiving nonexistent file", filePath)
-		}
 		return nil
 	} else if err != nil {
 		return err
@@ -255,9 +227,7 @@ func (v Staggered) Archive(filePath string) error {
 
 	if _, err := os.Stat(v.versionsPath); err != nil {
 		if os.IsNotExist(err) {
-			if debug {
 			l.Debugln("creating versions dir", v.versionsPath)
-			}
 			osutil.MkdirAll(v.versionsPath, 0755)
 			osutil.HideFile(v.versionsPath)
 		} else {
@@ -265,9 +235,7 @@ func (v Staggered) Archive(filePath string) error {
 		}
 	}
 
-	if debug {
 	l.Debugln("archiving", filePath)
-	}
 
 	file := filepath.Base(filePath)
 	inFolderPath, err := filepath.Rel(v.folderPath, filepath.Dir(filePath))
@@ -283,9 +251,7 @@ func (v Staggered) Archive(filePath string) error {
 
 	ver := taggedFilename(file, time.Now().Format(TimeFormat))
 	dst := filepath.Join(dir, ver)
-	if debug {
 	l.Debugln("moving to", dst)
-	}
 	err = osutil.Rename(filePath, dst)
 	if err != nil {
 		return err

lib/versioner/trashcan.go

@@ -37,9 +37,7 @@ func NewTrashcan(folderID, folderPath string, params map[string]string) Versione
 		stop:         make(chan struct{}),
 	}
 
-	if debug {
 	l.Debugf("instantiated %#v", s)
-	}
 	return s
 }
 
@@ -48,9 +46,7 @@ func NewTrashcan(folderID, folderPath string, params map[string]string) Versione
 func (t *Trashcan) Archive(filePath string) error {
 	_, err := osutil.Lstat(filePath)
 	if os.IsNotExist(err) {
-		if debug {
 		l.Debugln("not archiving nonexistent file", filePath)
-		}
 		return nil
 	} else if err != nil {
 		return err
@@ -62,18 +58,14 @@ func (t *Trashcan) Archive(filePath string) error {
 			return err
 		}
 
-		if debug {
 		l.Debugln("creating versions dir", versionsDir)
-		}
 		if err := osutil.MkdirAll(versionsDir, 0777); err != nil {
 			return err
 		}
 		osutil.HideFile(versionsDir)
 	}
 
-	if debug {
 	l.Debugln("archiving", filePath)
-	}
 
 	relativePath, err := filepath.Rel(t.folderPath, filePath)
 	if err != nil {
@@ -85,9 +77,7 @@ func (t *Trashcan) Archive(filePath string) error {
 		return err
 	}
 
-	if debug {
 	l.Debugln("moving to", archivedPath)
-	}
 
 	if err := osutil.Rename(filePath, archivedPath); err != nil {
 		return err
@@ -102,10 +92,8 @@ func (t *Trashcan) Archive(filePath string) error {
 }
 
 func (t *Trashcan) Serve() {
-	if debug {
 	l.Debugln(t, "starting")
 	defer l.Debugln(t, "stopping")
-	}
 
 	// Do the first cleanup one minute after startup.
 	timer := time.NewTimer(time.Minute)