Opentracing support

vendor/github.com/uber/jaeger-client-go/reporter.go

@@ -0,0 +1,267 @@
+// Copyright (c) 2016 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package jaeger
+
+import (
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/opentracing/opentracing-go"
+
+	"github.com/uber/jaeger-client-go/log"
+)
+
+// Reporter is called by the tracer when a span is completed to report the span to the tracing collector.
+type Reporter interface {
+	// Report submits a new span to collectors, possibly asynchronously and/or with buffering.
+	Report(span *Span)
+
+	// Close does a clean shutdown of the reporter, flushing any traces that may be buffered in memory.
+	Close()
+}
+
+// ------------------------------
+
+type nullReporter struct{}
+
+// NewNullReporter creates a no-op reporter that ignores all reported spans.
+func NewNullReporter() Reporter {
+	return &nullReporter{}
+}
+
+// Report implements Report() method of Reporter by doing nothing.
+func (r *nullReporter) Report(span *Span) {
+	// no-op
+}
+
+// Close implements Close() method of Reporter by doing nothing.
+func (r *nullReporter) Close() {
+	// no-op
+}
+
+// ------------------------------
+
+type loggingReporter struct {
+	logger Logger
+}
+
+// NewLoggingReporter creates a reporter that logs all reported spans to provided logger.
+func NewLoggingReporter(logger Logger) Reporter {
+	return &loggingReporter{logger}
+}
+
+// Report implements Report() method of Reporter by logging the span to the logger.
+func (r *loggingReporter) Report(span *Span) {
+	r.logger.Infof("Reporting span %+v", span)
+}
+
+// Close implements Close() method of Reporter by doing nothing.
+func (r *loggingReporter) Close() {
+	// no-op
+}
+
+// ------------------------------
+
+// InMemoryReporter is used for testing, and simply collects spans in memory.
+type InMemoryReporter struct {
+	spans []opentracing.Span
+	lock  sync.Mutex
+}
+
+// NewInMemoryReporter creates a reporter that stores spans in memory.
+// NOTE: the Tracer should be created with options.PoolSpans = false.
+func NewInMemoryReporter() *InMemoryReporter {
+	return &InMemoryReporter{
+		spans: make([]opentracing.Span, 0, 10),
+	}
+}
+
+// Report implements Report() method of Reporter by storing the span in the buffer.
+func (r *InMemoryReporter) Report(span *Span) {
+	r.lock.Lock()
+	r.spans = append(r.spans, span)
+	r.lock.Unlock()
+}
+
+// Close implements Close() method of Reporter by doing nothing.
+func (r *InMemoryReporter) Close() {
+	// no-op
+}
+
+// SpansSubmitted returns the number of spans accumulated in the buffer.
+func (r *InMemoryReporter) SpansSubmitted() int {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+	return len(r.spans)
+}
+
+// GetSpans returns accumulated spans as a copy of the buffer.
+func (r *InMemoryReporter) GetSpans() []opentracing.Span {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+	copied := make([]opentracing.Span, len(r.spans))
+	copy(copied, r.spans)
+	return copied
+}
+
+// Reset clears all accumulated spans.
+func (r *InMemoryReporter) Reset() {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+	r.spans = nil
+}
+
+// ------------------------------
+
+type compositeReporter struct {
+	reporters []Reporter
+}
+
+// NewCompositeReporter creates a reporter that ignores all reported spans.
+func NewCompositeReporter(reporters ...Reporter) Reporter {
+	return &compositeReporter{reporters: reporters}
+}
+
+// Report implements Report() method of Reporter by delegating to each underlying reporter.
+func (r *compositeReporter) Report(span *Span) {
+	for _, reporter := range r.reporters {
+		reporter.Report(span)
+	}
+}
+
+// Close implements Close() method of Reporter by closing each underlying reporter.
+func (r *compositeReporter) Close() {
+	for _, reporter := range r.reporters {
+		reporter.Close()
+	}
+}
+
+// ------------------------------
+
+const (
+	defaultQueueSize           = 100
+	defaultBufferFlushInterval = 10 * time.Second
+)
+
+type remoteReporter struct {
+	// must be first in the struct because `sync/atomic` expects 64-bit alignment.
+	// Cf. https://github.com/uber/jaeger-client-go/issues/155, https://goo.gl/zW7dgq
+	queueLength int64
+
+	reporterOptions
+	sender       Transport
+	queue        chan *Span
+	queueDrained sync.WaitGroup
+	flushSignal  chan *sync.WaitGroup
+}
+
+// NewRemoteReporter creates a new reporter that sends spans out of process by means of Sender
+func NewRemoteReporter(sender Transport, opts ...ReporterOption) Reporter {
+	options := reporterOptions{}
+	for _, option := range opts {
+		option(&options)
+	}
+	if options.bufferFlushInterval <= 0 {
+		options.bufferFlushInterval = defaultBufferFlushInterval
+	}
+	if options.logger == nil {
+		options.logger = log.NullLogger
+	}
+	if options.metrics == nil {
+		options.metrics = NewNullMetrics()
+	}
+	if options.queueSize <= 0 {
+		options.queueSize = defaultQueueSize
+	}
+	reporter := &remoteReporter{
+		reporterOptions: options,
+		sender:          sender,
+		flushSignal:     make(chan *sync.WaitGroup),
+		queue:           make(chan *Span, options.queueSize),
+	}
+	go reporter.processQueue()
+	return reporter
+}
+
+// Report implements Report() method of Reporter.
+// It passes the span to a background go-routine for submission to Jaeger.
+func (r *remoteReporter) Report(span *Span) {
+	select {
+	case r.queue <- span:
+		atomic.AddInt64(&r.queueLength, 1)
+	default:
+		r.metrics.ReporterDropped.Inc(1)
+	}
+}
+
+// Close implements Close() method of Reporter by waiting for the queue to be drained.
+func (r *remoteReporter) Close() {
+	r.queueDrained.Add(1)
+	close(r.queue)
+	r.queueDrained.Wait()
+	r.sender.Close()
+}
+
+// processQueue reads spans from the queue, converts them to Thrift, and stores them in an internal buffer.
+// When the buffer length reaches batchSize, it is flushed by submitting the accumulated spans to Jaeger.
+// Buffer also gets flushed automatically every batchFlushInterval seconds, just in case the tracer stopped
+// reporting new spans.
+func (r *remoteReporter) processQueue() {
+	timer := time.NewTicker(r.bufferFlushInterval)
+	for {
+		select {
+		case span, ok := <-r.queue:
+			if ok {
+				atomic.AddInt64(&r.queueLength, -1)
+				if flushed, err := r.sender.Append(span); err != nil {
+					r.metrics.ReporterFailure.Inc(int64(flushed))
+					r.logger.Error(err.Error())
+				} else if flushed > 0 {
+					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))
+				}
+			} else {
+				// queue closed
+				timer.Stop()
+				r.flush()
+				r.queueDrained.Done()
+				return
+			}
+		case <-timer.C:
+			r.flush()
+		case wg := <-r.flushSignal: // for testing
+			r.flush()
+			wg.Done()
+		}
+	}
+}
+
+// flush causes the Sender to flush its accumulated spans and clear the buffer
+func (r *remoteReporter) flush() {
+	if flushed, err := r.sender.Flush(); err != nil {
+		r.metrics.ReporterFailure.Inc(int64(flushed))
+		r.logger.Error(err.Error())
+	} else if flushed > 0 {
+		r.metrics.ReporterSuccess.Inc(int64(flushed))
+	}
+}