syncthing/cmd/infra/strelaypoolsrv/stats.go

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// Copyright (C) 2018 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
package main
import (
"encoding/json"
"net"
"net/http"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/syncthing/syncthing/lib/sync"
)
var (
statusClient = http.Client{
Timeout: 5 * time.Second,
}
apiRequestsTotal = makeCounter("api_requests_total", "Number of API requests.", "type", "result")
apiRequestsSeconds = makeSummary("api_requests_seconds", "Latency of API requests.", "type")
relayTestsTotal = makeCounter("tests_total", "Number of relay tests.", "result")
relayTestActionsSeconds = makeSummary("test_actions_seconds", "Latency of relay test actions.", "type")
locationLookupSeconds = makeSummary("location_lookup_seconds", "Latency of location lookups.").WithLabelValues()
metricsRequestsSeconds = makeSummary("metrics_requests_seconds", "Latency of metric requests.").WithLabelValues()
scrapeSeconds = makeSummary("relay_scrape_seconds", "Latency of metric scrapes from remote relays.", "result")
relayUptime = makeGauge("relay_uptime", "Uptime of relay", "relay")
relayPendingSessionKeys = makeGauge("relay_pending_session_keys", "Number of pending session keys (two keys per session, one per each side of the connection)", "relay")
relayActiveSessions = makeGauge("relay_active_sessions", "Number of sessions that are happening, a session contains two parties", "relay")
relayConnections = makeGauge("relay_connections", "Number of devices connected to the relay", "relay")
relayProxies = makeGauge("relay_proxies", "Number of active proxy routines sending data between peers (two proxies per session, one for each way)", "relay")
relayBytesProxied = makeGauge("relay_bytes_proxied", "Number of bytes proxied by the relay", "relay")
relayGoRoutines = makeGauge("relay_go_routines", "Number of Go routines in the process", "relay")
relaySessionRate = makeGauge("relay_session_rate", "Rate applied per session", "relay")
relayGlobalRate = makeGauge("relay_global_rate", "Global rate applied on the whole relay", "relay")
relayBuildInfo = makeGauge("relay_build_info", "Build information about a relay", "relay", "go_version", "go_os", "go_arch")
relayLocationInfo = makeGauge("relay_location_info", "Location information about a relay", "relay", "city", "country", "continent")
lastStats = make(map[string]stats)
)
func makeGauge(name string, help string, labels ...string) *prometheus.GaugeVec {
gauge := prometheus.NewGaugeVec(
prometheus.GaugeOpts{
Namespace: "syncthing",
Subsystem: "relaypoolsrv",
Name: name,
Help: help,
},
labels,
)
prometheus.MustRegister(gauge)
return gauge
}
func makeSummary(name string, help string, labels ...string) *prometheus.SummaryVec {
summary := prometheus.NewSummaryVec(
prometheus.SummaryOpts{
Namespace: "syncthing",
Subsystem: "relaypoolsrv",
Name: name,
Help: help,
Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
},
labels,
)
prometheus.MustRegister(summary)
return summary
}
func makeCounter(name string, help string, labels ...string) *prometheus.CounterVec {
counter := prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: "syncthing",
Subsystem: "relaypoolsrv",
Name: name,
Help: help,
},
labels,
)
prometheus.MustRegister(counter)
return counter
}
func statsRefresher(interval time.Duration) {
ticker := time.NewTicker(interval)
for range ticker.C {
refreshStats()
}
}
type statsFetchResult struct {
relay *relay
stats *stats
}
func refreshStats() {
mut.RLock()
relays := append(permanentRelays, knownRelays...)
mut.RUnlock()
now := time.Now()
wg := sync.NewWaitGroup()
results := make(chan statsFetchResult, len(relays))
for _, rel := range relays {
wg.Add(1)
go func(rel *relay) {
t0 := time.Now()
stats := fetchStats(rel)
duration := time.Since(t0).Seconds()
result := "success"
if stats == nil {
result = "failed"
}
scrapeSeconds.WithLabelValues(result).Observe(duration)
results <- statsFetchResult{
relay: rel,
stats: fetchStats(rel),
}
wg.Done()
}(rel)
}
wg.Wait()
close(results)
mut.Lock()
relayBuildInfo.Reset()
relayLocationInfo.Reset()
for result := range results {
result.relay.StatsRetrieved = now
result.relay.Stats = result.stats
if result.stats == nil {
deleteMetrics(result.relay.uri.Host)
} else {
updateMetrics(result.relay.uri.Host, *result.stats, result.relay.Location)
}
}
mut.Unlock()
}
func fetchStats(relay *relay) *stats {
statusAddr := relay.uri.Query().Get("statusAddr")
if statusAddr == "" {
statusAddr = ":22070"
}
statusHost, statusPort, err := net.SplitHostPort(statusAddr)
if err != nil {
return nil
}
if statusHost == "" {
if host, _, err := net.SplitHostPort(relay.uri.Host); err != nil {
return nil
} else {
statusHost = host
}
}
url := "http://" + net.JoinHostPort(statusHost, statusPort) + "/status"
response, err := statusClient.Get(url)
if err != nil {
return nil
}
var stats stats
if json.NewDecoder(response.Body).Decode(&stats); err != nil {
return nil
}
return &stats
}
func updateMetrics(host string, stats stats, location location) {
if stats.GoVersion != "" || stats.GoOS != "" || stats.GoArch != "" {
relayBuildInfo.WithLabelValues(host, stats.GoVersion, stats.GoOS, stats.GoArch).Add(1)
}
if location.City != "" || location.Country != "" || location.Continent != "" {
relayLocationInfo.WithLabelValues(host, location.City, location.Country, location.Continent).Add(1)
}
if lastStat, ok := lastStats[host]; ok {
stats = mergeStats(stats, lastStat)
}
relayUptime.WithLabelValues(host).Set(float64(stats.UptimeSeconds))
relayPendingSessionKeys.WithLabelValues(host).Set(float64(stats.PendingSessionKeys))
relayActiveSessions.WithLabelValues(host).Set(float64(stats.ActiveSessions))
relayConnections.WithLabelValues(host).Set(float64(stats.Connections))
relayProxies.WithLabelValues(host).Set(float64(stats.Proxies))
relayBytesProxied.WithLabelValues(host).Set(float64(stats.BytesProxied))
relayGoRoutines.WithLabelValues(host).Set(float64(stats.GoRoutines))
relaySessionRate.WithLabelValues(host).Set(float64(stats.Options.SessionRate))
relayGlobalRate.WithLabelValues(host).Set(float64(stats.Options.GlobalRate))
lastStats[host] = stats
}
func deleteMetrics(host string) {
relayUptime.DeleteLabelValues(host)
relayPendingSessionKeys.DeleteLabelValues(host)
relayActiveSessions.DeleteLabelValues(host)
relayConnections.DeleteLabelValues(host)
relayProxies.DeleteLabelValues(host)
relayBytesProxied.DeleteLabelValues(host)
relayGoRoutines.DeleteLabelValues(host)
relaySessionRate.DeleteLabelValues(host)
relayGlobalRate.DeleteLabelValues(host)
delete(lastStats, host)
}
// Due to some unexplainable behaviour, some of the numbers sometimes travel slightly backwards (by less than 1%)
// This happens between scrapes, which is 30s, so this can't be a race.
// This causes prometheus to assume a "rate reset", hence causes phenomenal spikes.
// One of the number that moves backwards is BytesProxied, which atomically increments a counter with numeric value
// returned by net.Conn.Read(). I don't think that can return a negative value, so I have no idea what's going on.
func mergeStats(new stats, old stats) stats {
new.UptimeSeconds = mergeValue(new.UptimeSeconds, old.UptimeSeconds)
new.PendingSessionKeys = mergeValue(new.PendingSessionKeys, old.PendingSessionKeys)
new.ActiveSessions = mergeValue(new.ActiveSessions, old.ActiveSessions)
new.Connections = mergeValue(new.Connections, old.Connections)
new.Proxies = mergeValue(new.Proxies, old.Proxies)
new.BytesProxied = mergeValue(new.BytesProxied, old.BytesProxied)
new.GoRoutines = mergeValue(new.GoRoutines, old.GoRoutines)
new.Options.SessionRate = mergeValue(new.Options.SessionRate, old.Options.SessionRate)
new.Options.GlobalRate = mergeValue(new.Options.GlobalRate, old.Options.GlobalRate)
return new
}
func mergeValue(new, old int) int {
if new >= old {
return new // normal increase
}
if float64(new) > 0.99*float64(old) {
return old // slight backward movement
}
return new // reset (relay restart)
}