// Copyright (c) 2017 Uber Technologies, Inc.
//
// 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 jaeger
import (
"fmt"
"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()
}
}
// ------------- REMOTE REPORTER -----------------
type reporterQueueItemType int
const (
defaultQueueSize = 100
defaultBufferFlushInterval = 1 * time.Second
reporterQueueItemSpan reporterQueueItemType = iota
reporterQueueItemClose
)
type reporterQueueItem struct {
itemType reporterQueueItemType
span *Span
close *sync.WaitGroup
}
type remoteReporter struct {
// These fields 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
closed int64 // 0 - not closed, 1 - closed
reporterOptions
sender Transport
queue chan reporterQueueItem
}
// NewRemoteReporter creates a new reporter that sends spans out of process by means of Sender.
// Calls to Report(Span) return immediately (side effect: if internal buffer is full the span is dropped).
// Periodically the transport buffer is flushed even if it hasn't reached max packet size.
// Calls to Close() block until all spans reported prior to the call to Close are flushed.
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,
queue: make(chan reporterQueueItem, 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 backend.
// If the internal queue is full, the span is dropped and metrics.ReporterDropped counter is incremented.
// If Report() is called after the reporter has been Close()-ed, the additional spans will not be
// sent to the backend, but the metrics.ReporterDropped counter may not reflect them correctly,
// because some of them may still be successfully added to the queue.
func (r *remoteReporter) Report(span *Span) {
select {
case r.queue <- reporterQueueItem{itemType: reporterQueueItemSpan, span: 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() {
if swapped := atomic.CompareAndSwapInt64(&r.closed, 0, 1); !swapped {
r.logger.Error("Repeated attempt to close the reporter is ignored")
return
}
r.sendCloseEvent()
r.sender.Close()
}
func (r *remoteReporter) sendCloseEvent() {
wg := &sync.WaitGroup{}
wg.Add(1)
item := reporterQueueItem{itemType: reporterQueueItemClose, close: wg}
r.queue <- item // if the queue is full we will block until there is space
atomic.AddInt64(&r.queueLength, 1)
wg.Wait()
}
// 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() {
// flush causes the Sender to flush its accumulated spans and clear the buffer
flush := func() {
if flushed, err := r.sender.Flush(); err != nil {
r.metrics.ReporterFailure.Inc(int64(flushed))
r.logger.Error(fmt.Sprintf("error when flushing the buffer: %s", err.Error()))
} else if flushed > 0 {
r.metrics.ReporterSuccess.Inc(int64(flushed))
}
}
timer := time.NewTicker(r.bufferFlushInterval)
for {
select {
case <-timer.C:
flush()
case item := <-r.queue:
atomic.AddInt64(&r.queueLength, -1)
switch item.itemType {
case reporterQueueItemSpan:
span := item.span
if flushed, err := r.sender.Append(span); err != nil {
r.metrics.ReporterFailure.Inc(int64(flushed))
r.logger.Error(fmt.Sprintf("error reporting span %q: %s", span.OperationName(), 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))
}
case reporterQueueItemClose:
timer.Stop()
flush()
item.close.Done()
return
}
}
}
}
