Add basic telemetry

.golangci.yml

@@ -89,7 +89,10 @@ linters-settings:
   revive:
     ignore-generated-header: true
     severity: warning
-    enableAllRules: true
+    # TODO enable-all-rules: true
+    rules:
+      - name: exported
+        # TODO arguments: [checkPrivateReceivers]
   staticcheck:
     checks:
       - all

build/nfpm.yaml

@@ -4,7 +4,7 @@ arch: ${GOARCH}
 platform: linux
 version: ${VERSION}
 section: database
-maintainer: FerretDB packages <packages@ferretdb.com>
+maintainer: FerretDB packages <packages@ferretdb.io>
 description: >
   FerretDB (previously MangoDB) was founded to become the de-facto open-source substitute to MongoDB.
   FerretDB is an open-source proxy, converting the MongoDB 6.0+ wire protocol queries to SQL -

cmd/ferretdb/main.go

@@ -23,7 +23,10 @@ import (
 	"path/filepath"
 	"sort"
 	"strings"
+	"sync"
+	"time"
 
+	"github.com/AlekSi/pointer"
 	"github.com/alecthomas/kong"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/expfmt"
@@ -38,6 +41,7 @@ import (
 	"github.com/FerretDB/FerretDB/internal/util/debug"
 	"github.com/FerretDB/FerretDB/internal/util/logging"
 	"github.com/FerretDB/FerretDB/internal/util/state"
+	"github.com/FerretDB/FerretDB/internal/util/telemetry"
 	"github.com/FerretDB/FerretDB/internal/util/version"
 )
 
@@ -58,6 +62,9 @@ var cli struct {
 
 	MetricsUUID bool `default:"false" help:"Add instance UUID to all metrics."`
 
+	// TODO switch to string for 3 states
+	Telemetry bool `default:"false" help:"Enable basic telemetry. See https://beacon.ferretdb.io."`
+
 	Handler string `default:"pg" help:"${help_handler}"`
 
 	PostgreSQLURL string `name:"postgresql-url" default:"${default_postgresql_url}" help:"PostgreSQL URL for 'pg' handler."`
@@ -69,6 +76,12 @@ var cli struct {
 
 	Test struct {
 		RecordsDir string `default:""  help:"Testing flag: directory for record files."`
+		Telemetry  struct {
+			URL            string        `default:"https://beacon.ferretdb.io/" help:"Testing flag: telemetry URL."`
+			UndecidedDelay time.Duration `default:"1h"                          help:"Testing flag: delay for undecided state."`
+			ReportInterval time.Duration `default:"24h"                         help:"Testing flag: report interval."`
+			ReportTimeout  time.Duration `default:"5s"                          help:"Testing flag: report timeout."`
+		} `embed:"" prefix:"telemetry-"`
 	} `embed:"" prefix:"test-"`
 }
 
@@ -185,6 +198,19 @@ func setupLogger(stateProvider *state.Provider) *zap.Logger {
 	return l
 }
 
+// runTelemetryReporter runs telemetry reporter until ctx is canceled.
+func runTelemetryReporter(ctx context.Context, enabled bool, opts *telemetry.NewReporterOpts) {
+	// TODO probably move out of this function
+	opts.P.Update(func(s *state.State) { s.Telemetry = pointer.ToBool(enabled) })
+
+	r, err := telemetry.NewReporter(opts)
+	if err != nil {
+		opts.L.Fatal("Failed to create telemetry reporter.", zap.Error(err))
+	}
+
+	r.Run(ctx)
+}
+
 // run sets up environment based on provided flags and runs FerretDB.
 func run() {
 	if cli.Version {
@@ -212,7 +238,32 @@ func run() {
 		stop()
 	}()
 
-	go debug.RunHandler(ctx, cli.DebugAddr, metricsRegisterer, logger.Named("debug"))
+	var wg sync.WaitGroup
+
+	wg.Add(1)
+
+	go func() {
+		defer wg.Done()
+		debug.RunHandler(ctx, cli.DebugAddr, metricsRegisterer, logger.Named("debug"))
+	}()
+
+	wg.Add(1)
+
+	go func() {
+		defer wg.Done()
+		runTelemetryReporter(
+			ctx,
+			cli.Telemetry,
+			&telemetry.NewReporterOpts{
+				URL:            cli.Test.Telemetry.URL,
+				P:              stateProvider,
+				L:              logger.Named("telemetry"),
+				UndecidedDelay: cli.Test.Telemetry.UndecidedDelay,
+				ReportInterval: cli.Test.Telemetry.ReportInterval,
+				ReportTimeout:  cli.Test.Telemetry.ReportTimeout,
+			},
+		)
+	}()
 
 	cmdsList := maps.Keys(common.Commands)
 	sort.Strings(cmdsList)
@@ -257,6 +308,8 @@ func run() {
 		logger.Error("Listener stopped", zap.Error(err))
 	}
 
+	wg.Wait()
+
 	mfs, err := prometheus.DefaultGatherer.Gather()
 	if err != nil {
 		panic(err)

internal/clientconn/connmetrics/listener_metrics.go

@@ -28,7 +28,7 @@ type ListenerMetrics struct {
 	ConnMetrics      *ConnMetrics
 }
 
-// newListenerMetrics creates new listener metrics.
+// NewListenerMetrics creates new listener metrics.
 //
 // The cmds is the list of all expected commands that could be measured.
 // After providing them, they will be set with the zero values.

internal/util/state/metrics.go

@@ -59,8 +59,19 @@ func (mc *metricsCollector) Collect(ch chan<- prometheus.Metric) {
 		"debug":   strconv.FormatBool(v.Debug),
 	}
 
+	s := mc.p.Get()
+
+	switch {
+	case s.Telemetry == nil:
+		constLabels["telemetry"] = "undecided"
+	case *s.Telemetry:
+		constLabels["telemetry"] = "enabled"
+	default:
+		constLabels["telemetry"] = "disabled"
+	}
+
 	if mc.addUUIDToMetric {
-		constLabels["uuid"] = mc.p.Get().UUID
+		constLabels["uuid"] = s.UUID
 	}
 
 	ch <- prometheus.MustNewConstMetric(

internal/util/state/metrics_test.go

@@ -50,7 +50,7 @@ func TestMetrics(t *testing.T) {
 			`
 				# HELP ferretdb_up FerretDB instance state.
 				# TYPE ferretdb_up gauge
-				ferretdb_up{branch=%q,commit=%q,debug="%t",dirty="%t",uuid=%q,version=%q} 1
+				ferretdb_up{branch=%q,commit=%q,debug="%t",dirty="%t",telemetry="undecided",uuid=%q,version=%q} 1
 			`,
 			v.Branch, v.Commit, v.Debug, v.Dirty, uuid, v.Version,
 		)
@@ -69,7 +69,7 @@ func TestMetrics(t *testing.T) {
 			`
 				# HELP ferretdb_up FerretDB instance state.
 				# TYPE ferretdb_up gauge
-				ferretdb_up{branch=%q,commit=%q,debug="%t",dirty="%t",version=%q} 1
+				ferretdb_up{branch=%q,commit=%q,debug="%t",dirty="%t",telemetry="undecided",version=%q} 1
 			`,
 			v.Branch, v.Commit, v.Debug, v.Dirty, v.Version,
 		)

internal/util/state/state.go

@@ -18,17 +18,20 @@ package state
 import (
 	"time"
 
+	"github.com/AlekSi/pointer"
 	"github.com/google/uuid"
 
 	"github.com/FerretDB/FerretDB/internal/util/must"
 )
 
 // State represents FerretDB process state.
 type State struct {
-	UUID string `json:"uuid"`
+	UUID      string `json:"uuid"`
+	Telemetry *bool  `json:"telemetry,omitempty"` // nil for undecided
 
 	// never persisted
-	Start time.Time `json:"-"`
+	Start         time.Time `json:"-"`
+	LatestVersion string    `json:"-"`
 }
 
 // fill replaces all unset or invalid values with default.
@@ -44,8 +47,15 @@ func (s *State) fill() {
 
 // deepCopy returns a deep copy of the state.
 func (s *State) deepCopy() *State {
+	var telemetry *bool
+	if s.Telemetry != nil {
+		telemetry = pointer.ToBool(*s.Telemetry)
+	}
+
 	return &State{
-		UUID:  s.UUID,
-		Start: s.Start,
+		UUID:          s.UUID,
+		Telemetry:     telemetry,
+		Start:         s.Start,
+		LatestVersion: s.LatestVersion,
 	}
 }