Tracing

The tracing support is added using OpenTelemetry-cpp.

There are two types of spans:

1. Library generated spans:

   Send span ("amqp-message-send”) gets created just before sending a message and ends when that message gets settled.

   Receive span ("amqp-message-received") gets created just before receiving a message and ends as soon as the message is received.

2. Application generated spans:

   Users can also create their own spans and those spans will get linked with the library generated spans.

Usage:

1. Initialize the exporter

   opentelemetry::exporter::jaeger::JaegerExporterOptions opts;
   std::unique_ptr<opentelemetry::sdk::trace::SpanExporter> exporter = std::unique_ptr<opentelemetry::sdk::trace::SpanExporter>(
        new opentelemetry::exporter::jaeger::JaegerExporter(opts));

Above is an example of initializing a jaeger exporter. Apart from jaeger exporter, there are many other exporters supported by OpenTelelemetry.

2. Set the Tracer Provider

   auto processor = std::unique_ptr<opentelemetry::sdk::trace::SpanProcessor>(
        new opentelemetry::sdk::trace::SimpleSpanProcessor(std::move(exporter)));
   auto provider = opentelemetry::nostd::shared_ptr<opentelemetry::trace::TracerProvider>(
        new opentelemetry::sdk::trace::TracerProvider(std::move(processor));
   opentelemetry::trace::Provider::SetTracerProvider(provider);

3. Enable tracing in Proton C++

   proton::initOpenTelemetryTracer();

This will generates the library spans ("amqp-message-send" and "amqp-message-received").

In addition, users can create their own spans in the application. The tracing_client and tracing_server examples demonstrates how to do that with jaeger exporter.

Steps to run tracing examples:

A working example of distributed tracing using broker, tracing_server and tracing_client examples.

Start Jaeger, for example:

docker run -d –name jaeger \ -e COLLECTOR_ZIPKIN_HOST_PORT=:9411 \ -p 5775:5775/udp \ -p 6831:6831/udp \ -p 6832:6832/udp \ -p 5778:5778 \ -p 16686:16686 \ -p 14268:14268 \ -p 14250:14250 \ -p 9411:9411 \ jaegertracing/all-in-one:1.25

Build/Install Opentelemetry-cpp:

Note: Thrift is jaeger exporter dependency.

1. Clone opentelemetry-cpp
   https://github.com/open-telemetry/opentelemetry-cpp
2. cd opentelemetry-cpp
3. mkdir bld
4. cd bld
5. cmake .. -DBUILD_TESTING=OFF -DBUILD_SHARED_LIBS=ON -DCMAKE_POSITION_INDEPENDENT_CODE=ON -DWITH_JAEGER=ON
6. make
7. sudo make install

Demo with broker.

WORKDIR cpp/examples

1. broker.cpp
   In one window run:
   ./broker
   
2. tracing_server.cpp
   In another window run:
   ./tracing_server
3. tracing_client.cpp
   In the final window:
   ./tracing_client

Look in the Jaeger UI:

Browse to http://localhost:16686/. This should open up a console for the Jaeger tracing system.
Select the Service dropdown at the top of the Search options (if not already selected). Hit Find Traces.