Add debug logs

reporter.go

@@ -257,6 +257,7 @@ func (r *remoteReporter) Report(span *Span) {
 
 // Close implements Close() method of Reporter by waiting for the queue to be drained.
 func (r *remoteReporter) Close() {
+	r.logger.Debugf("closing reporter")
 	if swapped := atomic.CompareAndSwapInt64(&r.closed, 0, 1); !swapped {
 		r.logger.Error("Repeated attempt to close the reporter is ignored")
 		return
@@ -307,6 +308,7 @@ func (r *remoteReporter) processQueue() {
 					r.metrics.ReporterSuccess.Inc(int64(flushed))
 					// to reduce the number of gauge stats, we only emit queue length on flush
 					r.metrics.ReporterQueueLength.Update(atomic.LoadInt64(&r.queueLength))
+					r.logger.Debugf("flushed %d spans", flushed)
 				}
 				span.Release()
 			case reporterQueueItemClose:

reporter_test.go

@@ -92,14 +92,14 @@ func (s *reporterSuite) assertCounter(t *testing.T, name string, tags map[string
 	assert.Equal(t, expectedValue, getValue(), "expected counter: name=%s, tags=%+v", name, tags)
 }
 
-func (s *reporterSuite) assertLogs(t *testing.T, expectedLogs string) {
+func (s *reporterSuite) assertLogsContain(t *testing.T, expectedLogs string) {
 	for i := 0; i < 1000; i++ {
 		if s.logger.String() == expectedLogs {
 			break
 		}
 		time.Sleep(time.Millisecond)
 	}
-	assert.Equal(t, expectedLogs, s.logger.String(), "expected logs: %s", expectedLogs)
+	assert.Contains(t, s.logger.String(), expectedLogs, "expected logs: %s", expectedLogs)
 }
 
 func TestRemoteReporterAppend(t *testing.T) {
@@ -136,11 +136,12 @@ func TestRemoteReporterFailedFlushViaAppend(t *testing.T) {
 	s.tracer.StartSpan("sp1").Finish()
 	s.tracer.StartSpan("sp2").Finish()
 	s.sender.assertFlushedSpans(t, 2)
-	s.assertLogs(t, "ERROR: error reporting Jaeger span \"sp2\": flush error\n")
+	s.assertLogsContain(t, "ERROR: error reporting Jaeger span \"sp2\": flush error\n")
 	s.assertCounter(t, "jaeger.tracer.reporter_spans", map[string]string{"result": "err"}, 2)
 	s.assertCounter(t, "jaeger.tracer.reporter_spans", map[string]string{"result": "ok"}, 0)
 	s.close() // causes explicit flush that also fails with the same error
-	s.assertLogs(t, "ERROR: error reporting Jaeger span \"sp2\": flush error\nERROR: failed to flush Jaeger spans to server: flush error\n")
+	s.assertLogsContain(t, "ERROR: error reporting Jaeger span \"sp2\": flush error\n")
+	s.assertLogsContain(t, "ERROR: failed to flush Jaeger spans to server: flush error\n")
 }
 
 func TestRemoteReporterAppendWithPoolAllocator(t *testing.T) {
@@ -183,7 +184,7 @@ func TestRemoteReporterDoubleClose(t *testing.T) {
 	reporter := NewRemoteReporter(&fakeSender{}, ReporterOptions.QueueSize(1), ReporterOptions.Logger(logger))
 	reporter.Close()
 	reporter.Close()
-	assert.Equal(t, "ERROR: Repeated attempt to close the reporter is ignored\n", logger.String())
+	assert.Contains(t, logger.String(), "ERROR: Repeated attempt to close the reporter is ignored\n")
 }
 
 func TestRemoteReporterReportAfterClose(t *testing.T) {

sampler.go

@@ -17,6 +17,7 @@ package jaeger
 import (
 	"fmt"
 	"math"
+	"strings"
 	"sync"
 
 	"github.com/uber/jaeger-client-go/thrift-gen/sampling"
@@ -319,6 +320,10 @@ func (s *GuaranteedThroughputProbabilisticSampler) update(lowerBound, samplingRa
 	}
 }
 
+func (s GuaranteedThroughputProbabilisticSampler) String() string {
+	return fmt.Sprintf("GuaranteedThroughputProbabilisticSampler(lowerBound=%f, samplingRate=%f)", s.lowerBound, s.samplingRate)
+}
+
 // -----------------------
 
 // PerOperationSampler is a delegating sampler that applies GuaranteedThroughputProbabilisticSampler
@@ -456,6 +461,23 @@ func (s *PerOperationSampler) Close() {
 	s.defaultSampler.Close()
 }
 
+func (s PerOperationSampler) String() string {
+	var sb strings.Builder
+
+	fmt.Fprintf(&sb, "PerOperationSampler(defaultSampler=%v, ", s.defaultSampler)
+	fmt.Fprintf(&sb, "lowerBound=%f, ", s.lowerBound)
+	fmt.Fprintf(&sb, "maxOperations=%d, ", s.maxOperations)
+	fmt.Fprintf(&sb, "operationNameLateBinding=%t, ", s.operationNameLateBinding)
+	fmt.Fprintf(&sb, "currentOperationSize=%d,\n", len(s.samplers))
+	fmt.Fprintf(&sb, "samplers=[")
+	for operationName, sampler := range s.samplers {
+		fmt.Fprintf(&sb, "\n(operationName=%s, sampler=%v)", operationName, sampler)
+	}
+	fmt.Fprintf(&sb, "])")
+
+	return sb.String()
+}
+
 // Equal is not used.
 // TODO (breaking change) remove this in the future
 func (s *PerOperationSampler) Equal(other Sampler) bool {

sampler_remote.go

@@ -200,6 +200,7 @@ func (s *RemotelyControlledSampler) updateSamplerViaUpdaters(strategy interface{
 			return err
 		}
 		if sampler != nil {
+			s.logger.Debugf("sampler updated: %+v", sampler)
 			s.sampler = sampler
 			return nil
 		}

tracer.go

@@ -366,6 +366,7 @@ func (t *Tracer) Extract(
 
 // Close releases all resources used by the Tracer and flushes any remaining buffered spans.
 func (t *Tracer) Close() error {
+	t.logger.Debugf("closing tracer")
 	t.reporter.Close()
 	t.sampler.Close()
 	if mgr, ok := t.baggageRestrictionManager.(io.Closer); ok {