Add open tracing to pulsar go clinet (#518)

Here is the PR to add open tracing to the pulsar go client directly.
This is replicating what the java tracer does:
https://github.com/streamnative/pulsar-tracing
The usage is stipulated in the readme.md file

Co-authored-by: Marais Kruger <maraisk@cynet.com>

go.mod

@@ -16,8 +16,7 @@ require (
 	github.com/klauspost/compress v1.10.8
 	github.com/kr/pretty v0.2.0 // indirect
 	github.com/linkedin/goavro/v2 v2.9.8
-	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
-	github.com/modern-go/reflect2 v1.0.1 // indirect
+	github.com/opentracing/opentracing-go v1.2.0
 	github.com/pierrec/lz4 v2.0.5+incompatible
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.7.1

go.sum

@@ -125,6 +125,8 @@ github.com/onsi/ginkgo v1.14.0/go.mod h1:iSB4RoI2tjJc9BBv4NKIKWKya62Rps+oPG/Lv9k
 github.com/onsi/gomega v1.7.1/go.mod h1:XdKZgCCFLUoM/7CFJVPcG8C1xQ1AJ0vpAezJrB7JYyY=
 github.com/onsi/gomega v1.10.1 h1:o0+MgICZLuZ7xjH7Vx6zS/zcu93/BEp1VwkIW1mEXCE=
 github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
+github.com/opentracing/opentracing-go v1.2.0 h1:uEJPy/1a5RIPAJ0Ov+OIO8OxWu77jEv+1B0VhjKrZUs=
+github.com/opentracing/opentracing-go v1.2.0/go.mod h1:GxEUsuufX4nBwe+T+Wl9TAgYrxe9dPLANfrWvHYVTgc=
 github.com/pierrec/lz4 v2.0.5+incompatible h1:2xWsjqPFWcplujydGg4WmhC/6fZqK42wMM8aXeqhl0I=
 github.com/pierrec/lz4 v2.0.5+incompatible/go.mod h1:pdkljMzZIN41W+lC3N2tnIh5sFi+IEE17M5jbnwPHcY=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=

pulsar/internal/pulsartracing/consumer_interceptor.go

@@ -0,0 +1,58 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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 pulsartracing
+
+import (
+	"context"
+
+	"github.com/apache/pulsar-client-go/pulsar"
+	"github.com/opentracing/opentracing-go"
+)
+
+const fromPrefix = "From__"
+
+type ConsumerInterceptor struct {
+}
+
+func (t *ConsumerInterceptor) BeforeConsume(message pulsar.ConsumerMessage) {
+	buildAndInjectChildSpan(message).Finish()
+}
+
+func (t *ConsumerInterceptor) OnAcknowledge(consumer pulsar.Consumer, msgID pulsar.MessageID) {}
+
+func (t *ConsumerInterceptor) OnNegativeAcksSend(consumer pulsar.Consumer, msgIDs []pulsar.MessageID) {
+}
+
+func buildAndInjectChildSpan(message pulsar.ConsumerMessage) opentracing.Span {
+	tracer := opentracing.GlobalTracer()
+	parentContext := ExtractSpanContextFromConsumerMessage(message)
+
+	var span opentracing.Span
+
+	var startSpanOptions []opentracing.StartSpanOption
+	if parentContext != nil {
+		startSpanOptions = []opentracing.StartSpanOption{opentracing.FollowsFrom(parentContext)}
+	}
+
+	span = tracer.StartSpan(fromPrefix+message.Topic()+"__"+message.Subscription(), startSpanOptions...)
+
+	enrichConsumerSpan(&message, span)
+	InjectConsumerMessageSpanContext(opentracing.ContextWithSpan(context.Background(), span), message)
+
+	return span
+}

pulsar/internal/pulsartracing/consumer_interceptor_test.go

@@ -0,0 +1,89 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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 pulsartracing
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/apache/pulsar-client-go/pulsar"
+	"github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/mocktracer"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestConsumerBuildAndInjectChildSpan(t *testing.T) {
+	tracer := mocktracer.New()
+
+	opentracing.SetGlobalTracer(tracer)
+
+	message := pulsar.ConsumerMessage{
+		Consumer: &mockConsumer{},
+		Message: &mockConsumerMessage{
+			properties: map[string]string{},
+		},
+	}
+
+	span := buildAndInjectChildSpan(message)
+	assert.NotNil(t, span)
+	assert.True(t, len(message.Properties()) > 0)
+}
+
+type mockConsumer struct {
+}
+
+func (c *mockConsumer) Subscription() string {
+	return ""
+}
+
+func (c *mockConsumer) Unsubscribe() error {
+	return nil
+}
+
+func (c *mockConsumer) Receive(ctx context.Context) (message pulsar.Message, err error) {
+	return nil, nil
+}
+
+func (c *mockConsumer) Chan() <-chan pulsar.ConsumerMessage {
+	return nil
+}
+
+func (c *mockConsumer) Ack(msg pulsar.Message) {}
+
+func (c *mockConsumer) AckID(msgID pulsar.MessageID) {}
+
+func (c *mockConsumer) ReconsumeLater(msg pulsar.Message, delay time.Duration) {}
+
+func (c *mockConsumer) Nack(msg pulsar.Message) {}
+
+func (c *mockConsumer) NackID(msgID pulsar.MessageID) {}
+
+func (c *mockConsumer) Close() {}
+
+func (c *mockConsumer) Seek(msgID pulsar.MessageID) error {
+	return nil
+}
+
+func (c *mockConsumer) SeekByTime(time time.Time) error {
+	return nil
+}
+
+func (c *mockConsumer) Name() string {
+	return ""
+}

pulsar/internal/pulsartracing/message_carrier_adaptors.go

@@ -0,0 +1,84 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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 pulsartracing
+
+import (
+	"errors"
+
+	"github.com/apache/pulsar-client-go/pulsar"
+)
+
+// ProducerMessageExtractAdapter Implements TextMap Interface
+type ProducerMessageExtractAdapter struct {
+	message *pulsar.ProducerMessage
+}
+
+func (a *ProducerMessageExtractAdapter) ForeachKey(handler func(key, val string) error) error {
+	for k, v := range (*a.message).Properties {
+		if err := handler(k, v); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (a *ProducerMessageExtractAdapter) Set(key, val string) {}
+
+// ProducerMessageInjectAdapter Implements TextMap Interface
+type ProducerMessageInjectAdapter struct {
+	message *pulsar.ProducerMessage
+}
+
+func (a *ProducerMessageInjectAdapter) ForeachKey(handler func(key, val string) error) error {
+	return errors.New("iterator should never be used with Tracer.inject()")
+}
+
+func (a *ProducerMessageInjectAdapter) Set(key, val string) {
+	a.message.Properties[key] = val
+}
+
+// ConsumerMessageExtractAdapter Implements TextMap Interface
+type ConsumerMessageExtractAdapter struct {
+	message pulsar.ConsumerMessage
+}
+
+func (a *ConsumerMessageExtractAdapter) ForeachKey(handler func(key, val string) error) error {
+	for k, v := range a.message.Properties() {
+		if err := handler(k, v); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (a *ConsumerMessageExtractAdapter) Set(key, val string) {}
+
+// ConsumerMessageInjectAdapter Implements TextMap Interface
+type ConsumerMessageInjectAdapter struct {
+	message pulsar.ConsumerMessage
+}
+
+func (a *ConsumerMessageInjectAdapter) ForeachKey(handler func(key, val string) error) error {
+	return errors.New("iterator should never be used with tracer.inject()")
+}
+
+func (a *ConsumerMessageInjectAdapter) Set(key, val string) {
+	a.message.Properties()[key] = val
+}

pulsar/internal/pulsartracing/message_carrier_util.go

@@ -0,0 +1,89 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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 pulsartracing
+
+import (
+	"context"
+
+	"github.com/apache/pulsar-client-go/pulsar"
+	"github.com/opentracing/opentracing-go"
+	log "github.com/sirupsen/logrus"
+)
+
+func InjectProducerMessageSpanContext(ctx context.Context, message *pulsar.ProducerMessage) {
+	injectAdapter := &ProducerMessageInjectAdapter{message}
+
+	span := opentracing.SpanFromContext(ctx)
+
+	err := opentracing.GlobalTracer().Inject(span.Context(), opentracing.TextMap, injectAdapter)
+
+	if err != nil {
+		log.Error("could not inject span context into pulsar message", err)
+	}
+}
+
+func ExtractSpanContextFromProducerMessage(message *pulsar.ProducerMessage) opentracing.SpanContext {
+	extractAdapter := &ProducerMessageExtractAdapter{message}
+
+	spanContext, err := opentracing.GlobalTracer().Extract(opentracing.TextMap, extractAdapter)
+
+	if err != nil {
+		log.Error("could not extract span context from pulsar message", err)
+	}
+
+	return spanContext
+}
+
+func ExtractSpanContextFromConsumerMessage(message pulsar.ConsumerMessage) opentracing.SpanContext {
+	extractAdapter := &ConsumerMessageExtractAdapter{message}
+
+	spanContext, err := opentracing.GlobalTracer().Extract(opentracing.TextMap, extractAdapter)
+
+	if err != nil {
+		log.Error("could not extract span context from pulsar message", err)
+	}
+
+	return spanContext
+}
+
+func InjectConsumerMessageSpanContext(ctx context.Context, message pulsar.ConsumerMessage) {
+	injectAdapter := &ConsumerMessageInjectAdapter{message}
+	span := opentracing.SpanFromContext(ctx)
+
+	if span == nil {
+		log.Warn("no span could be extracted from context, nothing will be injected into the message properties")
+		return
+	}
+
+	err := opentracing.GlobalTracer().Inject(span.Context(), opentracing.TextMap, injectAdapter)
+
+	if err != nil {
+		log.Error("could not inject span context into pulsar message", err)
+	}
+}
+
+func CreateSpanFromMessage(cm *pulsar.ConsumerMessage, tracer opentracing.Tracer, label string) opentracing.Span {
+	parentSpan := ExtractSpanContextFromConsumerMessage(*cm)
+	var span opentracing.Span
+	if parentSpan != nil {
+		span = tracer.StartSpan(label, opentracing.ChildOf(parentSpan))
+	} else {
+		span = tracer.StartSpan(label)
+	}
+	return span
+}