Improve connection state logging for Jaeger exporter

Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>

exporter/jaegerexporter/exporter.go

@@ -17,10 +17,15 @@ package jaegerexporter
 import (
 	"context"
 	"fmt"
+	"sync"
+	"time"
 
 	jaegerproto "github.com/jaegertracing/jaeger/proto-gen/api_v2"
+	"go.opencensus.io/stats"
+	"go.opencensus.io/tag"
 	"go.uber.org/zap"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/metadata"
 
 	"go.opentelemetry.io/collector/component"
@@ -40,21 +45,30 @@ func newTraceExporter(cfg *Config, logger *zap.Logger) (component.TracesExporter
 		return nil, err
 	}
 
-	client, err := grpc.Dial(cfg.GRPCClientSettings.Endpoint, opts...)
+	conn, err := grpc.Dial(cfg.GRPCClientSettings.Endpoint, opts...)
 	if err != nil {
 		return nil, err
 	}
 
-	collectorServiceClient := jaegerproto.NewCollectorServiceClient(client)
+	collectorServiceClient := jaegerproto.NewCollectorServiceClient(conn)
 	s := &protoGRPCSender{
+		name:         cfg.NameVal,
 		logger:       logger,
 		client:       collectorServiceClient,
 		metadata:     metadata.New(cfg.GRPCClientSettings.Headers),
 		waitForReady: cfg.WaitForReady,
+
+		conn:                      conn,
+		connStateReporterInterval: time.Second,
+
+		stopCh: make(chan (struct{})),
 	}
+	s.AddStateChangeCallback(s.onStateChange)
 
 	exp, err := exporterhelper.NewTraceExporter(
 		cfg, logger, s.pushTraceData,
+		exporterhelper.WithStart(s.start),
+		exporterhelper.WithShutdown(s.shutdown),
 		exporterhelper.WithTimeout(cfg.TimeoutSettings),
 		exporterhelper.WithRetry(cfg.RetrySettings),
 		exporterhelper.WithQueue(cfg.QueueSettings),
@@ -66,10 +80,22 @@ func newTraceExporter(cfg *Config, logger *zap.Logger) (component.TracesExporter
 // protoGRPCSender forwards spans encoded in the jaeger proto
 // format, to a grpc server.
 type protoGRPCSender struct {
+	name         string
 	logger       *zap.Logger
 	client       jaegerproto.CollectorServiceClient
 	metadata     metadata.MD
 	waitForReady bool
+
+	conn                      stateReporter
+	connStateReporterInterval time.Duration
+	stateChangeCallbacks      []func(connectivity.State)
+
+	stopCh chan (struct{})
+	stopWg sync.WaitGroup
+}
+
+type stateReporter interface {
+	GetState() connectivity.State
 }
 
 func (s *protoGRPCSender) pushTraceData(
@@ -100,3 +126,52 @@ func (s *protoGRPCSender) pushTraceData(
 
 	return 0, nil
 }
+
+func (s *protoGRPCSender) shutdown(context.Context) error {
+	close(s.stopCh)
+	s.stopWg.Wait()
+	return nil
+}
+
+func (s *protoGRPCSender) start(context.Context, component.Host) error {
+	go s.startConnectionStatusReporter()
+	return nil
+}
+
+func (s *protoGRPCSender) startConnectionStatusReporter() {
+	connState := s.conn.GetState()
+	s.propagateStateChange(connState)
+
+	ticker := time.NewTicker(s.connStateReporterInterval)
+	for {
+		select {
+		case <-ticker.C:
+			s.stopWg.Add(1)
+			st := s.conn.GetState()
+			if connState != st {
+				// state has changed, report it
+				connState = st
+				s.propagateStateChange(st)
+			}
+			s.stopWg.Done()
+		case <-s.stopCh:
+			return
+		}
+	}
+}
+
+func (s *protoGRPCSender) propagateStateChange(st connectivity.State) {
+	for _, callback := range s.stateChangeCallbacks {
+		callback(st)
+	}
+}
+
+func (s *protoGRPCSender) onStateChange(st connectivity.State) {
+	mCtx, _ := tag.New(context.Background(), tag.Upsert(tag.MustNewKey("exporter_name"), s.name))
+	stats.Record(mCtx, mLastConnectionState.M(int64(st)))
+	s.logger.Info("State of the connection with the Jaeger Collector backend", zap.Stringer("state", st))
+}
+
+func (s *protoGRPCSender) AddStateChangeCallback(f func(connectivity.State)) {
+	s.stateChangeCallbacks = append(s.stateChangeCallbacks, f)
+}

exporter/jaegerexporter/exporter_test.go

@@ -20,16 +20,19 @@ import (
 	"path"
 	"sync"
 	"testing"
+	"time"
 
 	"github.com/jaegertracing/jaeger/model"
 	"github.com/jaegertracing/jaeger/proto-gen/api_v2"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/zap"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/credentials"
 
 	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/component/componenttest"
 	"go.opentelemetry.io/collector/config/configgrpc"
 	"go.opentelemetry.io/collector/config/configtls"
 	"go.opentelemetry.io/collector/consumer/pdata"
@@ -248,6 +251,56 @@ func TestMutualTLS(t *testing.T) {
 	assert.Equal(t, jTraceID, requestes[0].GetBatch().Spans[0].TraceID)
 }
 
+func TestConnectionStateChange(t *testing.T) {
+	var state connectivity.State
+
+	wg := sync.WaitGroup{}
+	sr := &mockStateReporter{
+		state: connectivity.Connecting,
+	}
+	sender := &protoGRPCSender{
+		logger:                    zap.NewNop(),
+		stopCh:                    make(chan (struct{})),
+		conn:                      sr,
+		connStateReporterInterval: 10 * time.Millisecond,
+	}
+
+	wg.Add(1)
+	sender.AddStateChangeCallback(func(c connectivity.State) {
+		state = c
+		wg.Done()
+	})
+
+	sender.start(context.Background(), componenttest.NewNopHost())
+	defer sender.shutdown(context.Background())
+	wg.Wait() // wait for the initial state to be propagated
+
+	// test
+	wg.Add(1)
+	sr.SetState(connectivity.Ready)
+
+	// verify
+	wg.Wait() // wait until we get the state change
+	assert.Equal(t, connectivity.Ready, state)
+}
+
+type mockStateReporter struct {
+	state connectivity.State
+	mu    sync.RWMutex
+}
+
+func (m *mockStateReporter) GetState() connectivity.State {
+	m.mu.RLock()
+	st := m.state
+	m.mu.RUnlock()
+	return st
+}
+func (m *mockStateReporter) SetState(st connectivity.State) {
+	m.mu.Lock()
+	m.state = st
+	m.mu.Unlock()
+}
+
 func initializeGRPCTestServer(t *testing.T, beforeServe func(server *grpc.Server), opts ...grpc.ServerOption) (*grpc.Server, net.Addr) {
 	server := grpc.NewServer(opts...)
 	lis, err := net.Listen("tcp", "localhost:0")

exporter/jaegerexporter/metrics.go

@@ -0,0 +1,39 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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.
+
+package jaegerexporter
+
+import (
+	"go.opencensus.io/stats"
+	"go.opencensus.io/stats/view"
+	"go.opencensus.io/tag"
+)
+
+var (
+	mLastConnectionState = stats.Int64("jaegerexporter_conn_state", "Last connection state: 0 = Idle, 1 = Connecting, 2 = Ready, 3 = TransientFailure, 4 = Shutdown", stats.UnitDimensionless)
+	vLastConnectionState = &view.View{
+		Name:        mLastConnectionState.Name(),
+		Measure:     mLastConnectionState,
+		Description: mLastConnectionState.Description(),
+		Aggregation: view.LastValue(),
+		TagKeys: []tag.Key{
+			tag.MustNewKey("exporter_name"),
+		},
+	}
+)
+
+// MetricViews return the metrics views according to given telemetry level.
+func MetricViews() []*view.View {
+	return []*view.View{vLastConnectionState}
+}

exporter/jaegerexporter/metrics_test.go

@@ -0,0 +1,32 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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.
+
+package jaegerexporter
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestProcessorMetrics(t *testing.T) {
+	expectedViewNames := []string{
+		"jaegerexporter_conn_state",
+	}
+
+	views := MetricViews()
+	for i, viewName := range expectedViewNames {
+		assert.Equal(t, viewName, views[i].Name)
+	}
+}

service/telemetry.go

@@ -25,6 +25,7 @@ import (
 	"go.uber.org/zap"
 
 	"go.opentelemetry.io/collector/config/configtelemetry"
+	"go.opentelemetry.io/collector/exporter/jaegerexporter"
 	"go.opentelemetry.io/collector/internal/collector/telemetry"
 	"go.opentelemetry.io/collector/obsreport"
 	"go.opentelemetry.io/collector/processor"
@@ -63,13 +64,15 @@ func (tel *appTelemetry) init(asyncErrorChannel chan<- error, ballastSizeBytes u
 	}
 
 	var views []*view.View
-	views = append(views, obsreport.Configure(level)...)
-	views = append(views, processor.MetricViews()...)
-	views = append(views, queuedprocessor.MetricViews()...)
 	views = append(views, batchprocessor.MetricViews()...)
+	views = append(views, fluentobserv.MetricViews()...)
+	views = append(views, jaegerexporter.MetricViews()...)
 	views = append(views, kafkareceiver.MetricViews()...)
+	views = append(views, obsreport.Configure(level)...)
 	views = append(views, processMetricsViews.Views()...)
-	views = append(views, fluentobserv.MetricViews()...)
+	views = append(views, processor.MetricViews()...)
+	views = append(views, queuedprocessor.MetricViews()...)
+
 	tel.views = views
 	if err = view.Register(views...); err != nil {
 		return err