mirror of
https://github.com/octoleo/restic.git
synced 2024-12-24 20:00:21 +00:00
451 lines
15 KiB
Go
451 lines
15 KiB
Go
// Copyright 2016 Google Inc. All Rights Reserved.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
// +build linux,go1.7
|
|
|
|
package main
|
|
|
|
import (
|
|
"encoding/json"
|
|
"flag"
|
|
"fmt"
|
|
"io/ioutil"
|
|
"log"
|
|
"math/rand"
|
|
"os"
|
|
"sync"
|
|
"time"
|
|
|
|
"cloud.google.com/go/cmd/go-cloud-debug-agent/internal/breakpoints"
|
|
debuglet "cloud.google.com/go/cmd/go-cloud-debug-agent/internal/controller"
|
|
"cloud.google.com/go/cmd/go-cloud-debug-agent/internal/valuecollector"
|
|
"cloud.google.com/go/compute/metadata"
|
|
"golang.org/x/debug"
|
|
"golang.org/x/debug/local"
|
|
"golang.org/x/net/context"
|
|
"golang.org/x/oauth2"
|
|
"golang.org/x/oauth2/google"
|
|
cd "google.golang.org/api/clouddebugger/v2"
|
|
)
|
|
|
|
var (
|
|
appModule = flag.String("appmodule", "", "Optional application module name.")
|
|
appVersion = flag.String("appversion", "", "Optional application module version name.")
|
|
sourceContextFile = flag.String("sourcecontext", "", "File containing JSON-encoded source context.")
|
|
verbose = flag.Bool("v", false, "Output verbose log messages.")
|
|
projectNumber = flag.String("projectnumber", "", "Project number."+
|
|
" If this is not set, it is read from the GCP metadata server.")
|
|
projectID = flag.String("projectid", "", "Project ID."+
|
|
" If this is not set, it is read from the GCP metadata server.")
|
|
serviceAccountFile = flag.String("serviceaccountfile", "", "File containing JSON service account credentials.")
|
|
)
|
|
|
|
const (
|
|
maxCapturedStackFrames = 50
|
|
maxCapturedVariables = 1000
|
|
)
|
|
|
|
func main() {
|
|
flag.Usage = usage
|
|
flag.Parse()
|
|
args := flag.Args()
|
|
if len(args) == 0 {
|
|
// The user needs to supply the name of the executable to run.
|
|
flag.Usage()
|
|
return
|
|
}
|
|
if *projectNumber == "" {
|
|
var err error
|
|
*projectNumber, err = metadata.NumericProjectID()
|
|
if err != nil {
|
|
log.Print("Debuglet initialization: ", err)
|
|
}
|
|
}
|
|
if *projectID == "" {
|
|
var err error
|
|
*projectID, err = metadata.ProjectID()
|
|
if err != nil {
|
|
log.Print("Debuglet initialization: ", err)
|
|
}
|
|
}
|
|
sourceContexts, err := readSourceContextFile(*sourceContextFile)
|
|
if err != nil {
|
|
log.Print("Reading source context file: ", err)
|
|
}
|
|
var ts oauth2.TokenSource
|
|
ctx := context.Background()
|
|
if *serviceAccountFile != "" {
|
|
if ts, err = serviceAcctTokenSource(ctx, *serviceAccountFile, cd.CloudDebuggerScope); err != nil {
|
|
log.Fatalf("Error getting credentials from file %s: %v", *serviceAccountFile, err)
|
|
}
|
|
} else if ts, err = google.DefaultTokenSource(ctx, cd.CloudDebuggerScope); err != nil {
|
|
log.Print("Error getting application default credentials for Cloud Debugger:", err)
|
|
os.Exit(103)
|
|
}
|
|
c, err := debuglet.NewController(ctx, debuglet.Options{
|
|
ProjectNumber: *projectNumber,
|
|
ProjectID: *projectID,
|
|
AppModule: *appModule,
|
|
AppVersion: *appVersion,
|
|
SourceContexts: sourceContexts,
|
|
Verbose: *verbose,
|
|
TokenSource: ts,
|
|
})
|
|
if err != nil {
|
|
log.Fatal("Error connecting to Cloud Debugger: ", err)
|
|
}
|
|
prog, err := local.New(args[0])
|
|
if err != nil {
|
|
log.Fatal("Error loading program: ", err)
|
|
}
|
|
// Load the program, but don't actually start it running yet.
|
|
if _, err = prog.Run(args[1:]...); err != nil {
|
|
log.Fatal("Error loading program: ", err)
|
|
}
|
|
bs := breakpoints.NewBreakpointStore(prog)
|
|
|
|
// Seed the random number generator.
|
|
rand.Seed(time.Now().UnixNano())
|
|
|
|
// Now we want to do two things: run the user's program, and start sending
|
|
// List requests periodically to the Debuglet Controller to get breakpoints
|
|
// to set.
|
|
//
|
|
// We want to give the Debuglet Controller a chance to give us breakpoints
|
|
// before we start the program, otherwise we would miss any breakpoint
|
|
// triggers that occur during program startup -- for example, a breakpoint on
|
|
// the first line of main. But if the Debuglet Controller is not responding or
|
|
// is returning errors, we don't want to delay starting the program
|
|
// indefinitely.
|
|
//
|
|
// We pass a channel to breakpointListLoop, which will close it when the first
|
|
// List call finishes. Then we wait until either the channel is closed or a
|
|
// 5-second timer has finished before starting the program.
|
|
ch := make(chan bool)
|
|
// Start a goroutine that sends List requests to the Debuglet Controller, and
|
|
// sets any breakpoints it gets back.
|
|
go breakpointListLoop(ctx, c, bs, ch)
|
|
// Wait until 5 seconds have passed or breakpointListLoop has closed ch.
|
|
select {
|
|
case <-time.After(5 * time.Second):
|
|
case <-ch:
|
|
}
|
|
// Run the debuggee.
|
|
programLoop(ctx, c, bs, prog)
|
|
}
|
|
|
|
// usage prints a usage message to stderr and exits.
|
|
func usage() {
|
|
me := "a.out"
|
|
if len(os.Args) >= 1 {
|
|
me = os.Args[0]
|
|
}
|
|
fmt.Fprintf(os.Stderr, "Usage of %s:\n", me)
|
|
fmt.Fprintf(os.Stderr, "\t%s [flags...] -- <program name> args...\n", me)
|
|
fmt.Fprintf(os.Stderr, "Flags:\n")
|
|
flag.PrintDefaults()
|
|
fmt.Fprintf(os.Stderr,
|
|
"See https://cloud.google.com/tools/cloud-debugger/setting-up-on-compute-engine for more information.\n")
|
|
os.Exit(2)
|
|
}
|
|
|
|
// readSourceContextFile reads a JSON-encoded source context from the given file.
|
|
// It returns a non-empty slice on success.
|
|
func readSourceContextFile(filename string) ([]*cd.SourceContext, error) {
|
|
if filename == "" {
|
|
return nil, nil
|
|
}
|
|
scJSON, err := ioutil.ReadFile(filename)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("reading file %q: %v", filename, err)
|
|
}
|
|
var sc cd.SourceContext
|
|
if err = json.Unmarshal(scJSON, &sc); err != nil {
|
|
return nil, fmt.Errorf("parsing file %q: %v", filename, err)
|
|
}
|
|
return []*cd.SourceContext{&sc}, nil
|
|
}
|
|
|
|
// breakpointListLoop repeatedly calls the Debuglet Controller's List RPC, and
|
|
// passes the results to the BreakpointStore so it can set and unset breakpoints
|
|
// in the program.
|
|
//
|
|
// After the first List call finishes, ch is closed.
|
|
func breakpointListLoop(ctx context.Context, c *debuglet.Controller, bs *breakpoints.BreakpointStore, first chan bool) {
|
|
const (
|
|
avgTimeBetweenCalls = time.Second
|
|
errorDelay = 5 * time.Second
|
|
)
|
|
|
|
// randomDuration returns a random duration with expected value avg.
|
|
randomDuration := func(avg time.Duration) time.Duration {
|
|
return time.Duration(rand.Int63n(int64(2*avg + 1)))
|
|
}
|
|
|
|
var consecutiveFailures uint
|
|
|
|
for {
|
|
callStart := time.Now()
|
|
resp, err := c.List(ctx)
|
|
if err != nil && err != debuglet.ErrListUnchanged {
|
|
log.Printf("Debuglet controller server error: %v", err)
|
|
}
|
|
if err == nil {
|
|
bs.ProcessBreakpointList(resp.Breakpoints)
|
|
}
|
|
|
|
if first != nil {
|
|
// We've finished one call to List and set any breakpoints we received.
|
|
close(first)
|
|
first = nil
|
|
}
|
|
|
|
// Asynchronously send updates for any breakpoints that caused an error when
|
|
// the BreakpointStore tried to process them. We don't wait for the update
|
|
// to finish before the program can exit, as we do for normal updates.
|
|
errorBps := bs.ErrorBreakpoints()
|
|
for _, bp := range errorBps {
|
|
go func(bp *cd.Breakpoint) {
|
|
if err := c.Update(ctx, bp.Id, bp); err != nil {
|
|
log.Printf("Failed to send breakpoint update for %s: %s", bp.Id, err)
|
|
}
|
|
}(bp)
|
|
}
|
|
|
|
// Make the next call not too soon after the one we just did.
|
|
delay := randomDuration(avgTimeBetweenCalls)
|
|
|
|
// If the call returned an error other than ErrListUnchanged, wait longer.
|
|
if err != nil && err != debuglet.ErrListUnchanged {
|
|
// Wait twice as long after each consecutive failure, to a maximum of 16x.
|
|
delay += randomDuration(errorDelay * (1 << consecutiveFailures))
|
|
if consecutiveFailures < 4 {
|
|
consecutiveFailures++
|
|
}
|
|
} else {
|
|
consecutiveFailures = 0
|
|
}
|
|
|
|
// Sleep until we reach time callStart+delay. If we've already passed that
|
|
// time, time.Sleep will return immediately -- this should be the common
|
|
// case, since the server will delay responding to List for a while when
|
|
// there are no changes to report.
|
|
time.Sleep(callStart.Add(delay).Sub(time.Now()))
|
|
}
|
|
}
|
|
|
|
// programLoop runs the program being debugged to completion. When a breakpoint's
|
|
// conditions are satisfied, it sends an Update RPC to the Debuglet Controller.
|
|
// The function returns when the program exits and all Update RPCs have finished.
|
|
func programLoop(ctx context.Context, c *debuglet.Controller, bs *breakpoints.BreakpointStore, prog debug.Program) {
|
|
var wg sync.WaitGroup
|
|
for {
|
|
// Run the program until it hits a breakpoint or exits.
|
|
status, err := prog.Resume()
|
|
if err != nil {
|
|
break
|
|
}
|
|
|
|
// Get the breakpoints at this address whose conditions were satisfied,
|
|
// and remove the ones that aren't logpoints.
|
|
bps := bs.BreakpointsAtPC(status.PC)
|
|
bps = bpsWithConditionSatisfied(bps, prog)
|
|
for _, bp := range bps {
|
|
if bp.Action != "LOG" {
|
|
bs.RemoveBreakpoint(bp)
|
|
}
|
|
}
|
|
|
|
if len(bps) == 0 {
|
|
continue
|
|
}
|
|
|
|
// Evaluate expressions and get the stack.
|
|
vc := valuecollector.NewCollector(prog, maxCapturedVariables)
|
|
needStackFrames := false
|
|
for _, bp := range bps {
|
|
// If evaluating bp's condition didn't return an error, evaluate bp's
|
|
// expressions, and later get the stack frames.
|
|
if bp.Status == nil {
|
|
bp.EvaluatedExpressions = expressionValues(bp.Expressions, prog, vc)
|
|
needStackFrames = true
|
|
}
|
|
}
|
|
var (
|
|
stack []*cd.StackFrame
|
|
stackFramesStatusMessage *cd.StatusMessage
|
|
)
|
|
if needStackFrames {
|
|
stack, stackFramesStatusMessage = stackFrames(prog, vc)
|
|
}
|
|
|
|
// Read variable values from the program.
|
|
variableTable := vc.ReadValues()
|
|
|
|
// Start a goroutine to send updates to the Debuglet Controller or write
|
|
// to logs, concurrently with resuming the program.
|
|
// TODO: retry Update on failure.
|
|
for _, bp := range bps {
|
|
wg.Add(1)
|
|
switch bp.Action {
|
|
case "LOG":
|
|
go func(format string, evaluatedExpressions []*cd.Variable) {
|
|
s := valuecollector.LogString(format, evaluatedExpressions, variableTable)
|
|
log.Print(s)
|
|
wg.Done()
|
|
}(bp.LogMessageFormat, bp.EvaluatedExpressions)
|
|
bp.Status = nil
|
|
bp.EvaluatedExpressions = nil
|
|
default:
|
|
go func(bp *cd.Breakpoint) {
|
|
defer wg.Done()
|
|
bp.IsFinalState = true
|
|
if bp.Status == nil {
|
|
// If evaluating bp's condition didn't return an error, include the
|
|
// stack frames, variable table, and any status message produced when
|
|
// getting the stack frames.
|
|
bp.StackFrames = stack
|
|
bp.VariableTable = variableTable
|
|
bp.Status = stackFramesStatusMessage
|
|
}
|
|
if err := c.Update(ctx, bp.Id, bp); err != nil {
|
|
log.Printf("Failed to send breakpoint update for %s: %s", bp.Id, err)
|
|
}
|
|
}(bp)
|
|
}
|
|
}
|
|
}
|
|
|
|
// Wait for all updates to finish before returning.
|
|
wg.Wait()
|
|
}
|
|
|
|
// bpsWithConditionSatisfied returns the breakpoints whose conditions are true
|
|
// (or that do not have a condition.)
|
|
func bpsWithConditionSatisfied(bpsIn []*cd.Breakpoint, prog debug.Program) []*cd.Breakpoint {
|
|
var bpsOut []*cd.Breakpoint
|
|
for _, bp := range bpsIn {
|
|
cond, err := condTruth(bp.Condition, prog)
|
|
if err != nil {
|
|
bp.Status = errorStatusMessage(err.Error(), refersToBreakpointCondition)
|
|
// Include bp in the list to be updated when there's an error, so that
|
|
// the user gets a response.
|
|
bpsOut = append(bpsOut, bp)
|
|
} else if cond {
|
|
bpsOut = append(bpsOut, bp)
|
|
}
|
|
}
|
|
return bpsOut
|
|
}
|
|
|
|
// condTruth evaluates a condition.
|
|
func condTruth(condition string, prog debug.Program) (bool, error) {
|
|
if condition == "" {
|
|
// A condition wasn't set.
|
|
return true, nil
|
|
}
|
|
val, err := prog.Evaluate(condition)
|
|
if err != nil {
|
|
return false, err
|
|
}
|
|
if v, ok := val.(bool); !ok {
|
|
return false, fmt.Errorf("condition expression has type %T, should be bool", val)
|
|
} else {
|
|
return v, nil
|
|
}
|
|
}
|
|
|
|
// expressionValues evaluates a slice of expressions and returns a []*cd.Variable
|
|
// containing the results.
|
|
// If the result of an expression evaluation refers to values from the program's
|
|
// memory (e.g., the expression evaluates to a slice) a corresponding variable is
|
|
// added to the value collector, to be read later.
|
|
func expressionValues(expressions []string, prog debug.Program, vc *valuecollector.Collector) []*cd.Variable {
|
|
evaluatedExpressions := make([]*cd.Variable, len(expressions))
|
|
for i, exp := range expressions {
|
|
ee := &cd.Variable{Name: exp}
|
|
evaluatedExpressions[i] = ee
|
|
if val, err := prog.Evaluate(exp); err != nil {
|
|
ee.Status = errorStatusMessage(err.Error(), refersToBreakpointExpression)
|
|
} else {
|
|
vc.FillValue(val, ee)
|
|
}
|
|
}
|
|
return evaluatedExpressions
|
|
}
|
|
|
|
// stackFrames returns a stack trace for the program. It passes references to
|
|
// function parameters and local variables to the value collector, so it can read
|
|
// their values later.
|
|
func stackFrames(prog debug.Program, vc *valuecollector.Collector) ([]*cd.StackFrame, *cd.StatusMessage) {
|
|
frames, err := prog.Frames(maxCapturedStackFrames)
|
|
if err != nil {
|
|
return nil, errorStatusMessage("Error getting stack: "+err.Error(), refersToUnspecified)
|
|
}
|
|
stackFrames := make([]*cd.StackFrame, len(frames))
|
|
for i, f := range frames {
|
|
frame := &cd.StackFrame{}
|
|
frame.Function = f.Function
|
|
for _, v := range f.Params {
|
|
frame.Arguments = append(frame.Arguments, vc.AddVariable(debug.LocalVar(v)))
|
|
}
|
|
for _, v := range f.Vars {
|
|
frame.Locals = append(frame.Locals, vc.AddVariable(v))
|
|
}
|
|
frame.Location = &cd.SourceLocation{
|
|
Path: f.File,
|
|
Line: int64(f.Line),
|
|
}
|
|
stackFrames[i] = frame
|
|
}
|
|
return stackFrames, nil
|
|
}
|
|
|
|
// errorStatusMessage returns a *cd.StatusMessage indicating an error,
|
|
// with the given message and refersTo field.
|
|
func errorStatusMessage(msg string, refersTo int) *cd.StatusMessage {
|
|
return &cd.StatusMessage{
|
|
Description: &cd.FormatMessage{Format: "$0", Parameters: []string{msg}},
|
|
IsError: true,
|
|
RefersTo: refersToString[refersTo],
|
|
}
|
|
}
|
|
|
|
const (
|
|
// RefersTo values for cd.StatusMessage.
|
|
refersToUnspecified = iota
|
|
refersToBreakpointCondition
|
|
refersToBreakpointExpression
|
|
)
|
|
|
|
// refersToString contains the strings for each refersTo value.
|
|
// See the definition of StatusMessage in the v2/clouddebugger package.
|
|
var refersToString = map[int]string{
|
|
refersToUnspecified: "UNSPECIFIED",
|
|
refersToBreakpointCondition: "BREAKPOINT_CONDITION",
|
|
refersToBreakpointExpression: "BREAKPOINT_EXPRESSION",
|
|
}
|
|
|
|
func serviceAcctTokenSource(ctx context.Context, filename string, scope ...string) (oauth2.TokenSource, error) {
|
|
data, err := ioutil.ReadFile(filename)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("cannot read service account file: %v", err)
|
|
}
|
|
cfg, err := google.JWTConfigFromJSON(data, scope...)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("google.JWTConfigFromJSON: %v", err)
|
|
}
|
|
return cfg.TokenSource(ctx), nil
|
|
}
|