jaeger-client-cpp

Jaeger SDK with OpenTracing API for C++ binding.

Contributing

Please see CONTRIBUTING.md.

Building

jaeger-client-cpp is built using CMake. It will automatically download needed dependencies using Hunter.

To build:

    mkdir build
    cd build
    cmake ..
    make

After building, the example program can be run with:

    ./app ../examples/config.yml

To run tests:

    make test

To install the library:

    make install

Generated files

This project uses Apache Thrift for wire-format protocol support code generation. It currently requires Thrift 0.11.0.

The code can be re-generated with

    $ git submodule update --init
    $ find idl/thrift/ -type f -name \*.thrift -exec thrift -gen cpp -out src/jaegertracing/thrift-gen {} \;
    $ git apply scripts/thrift-gen.patch

Updating Agent Host and Port

The default host and port for Jaeger Agent is 127.0.0.1:6831. When the application and Jaeger Agent are running in different containers on the same host, the application's notion of localhost/127.0.0.1 it restriced to its own container, so in this case it's usually necessary to override the Agent's host/port by updating your reporter configuration:

YAML configuration:

reporter:
  localAgentHostPort: jaeger-agent:6831

NOTE: It is not recommended to use a remote host for UDP connections.

Connecting directly to the Collector

In case the client should connect directly to the collector instead of going through an agent, it's necessary update the reporter configuration

reporter:
  endpoint: http://${collectorhost}:${collectorport}/api/traces

Note that if both localAgentHostPort and endpoint are specified, the endpoint will be used.

Updating Sampling Server URL

The default sampling collector URL is http://127.0.0.1:5778/sampling. Similar to UDP address above, you can use a different URL by updating the sampler configuration.

sampler:
  samplingServerURL: http://jaeger-agent.local:5778/sampling

Configuration via Environment

It's possible to populate the tracer configuration from the environement variables by calling jaegertracing::Config::fromEnv.

The following property names are currently available:

Property	Description
JAEGER_SERVICE_NAME	The service name
JAEGER_DISABLED (not recommended)	Instructs the Configuration to return a no-op tracer
JAEGER_AGENT_HOST	The hostname for communicating with agent via UDP
JAEGER_AGENT_PORT	The port for communicating with agent via UDP
JAEGER_ENDPOINT	The traces endpoint, in case the client should connect directly to the Collector, like http://jaeger-collector:14268/api/traces
JAEGER_PROPAGATION	The propagation format used by the tracer. Supported values are jaeger and w3c
JAEGER_REPORTER_LOG_SPANS	Whether the reporter should also log the spans
JAEGER_REPORTER_MAX_QUEUE_SIZE	The reporter's maximum queue size
JAEGER_REPORTER_FLUSH_INTERVAL	The reporter's flush interval (ms)
JAEGER_SAMPLER_TYPE	The sampler type
JAEGER_SAMPLER_PARAM	The sampler parameter (double)
JAEGER_SAMPLING_ENDPOINT	The url for the remote sampling conf when using sampler type remote. Default is http://127.0.0.1:5778/sampling
JAEGER_TAGS	A comma separated list of name = value tracer level tags, which get added to all reported spans. The value can also refer to an environment variable using the format ${envVarName:default}, where the :default is optional, and identifies a value to be used if the environment variable cannot be found

SelfRef

Jaeger Tracer supports an additional reference type call 'SelfRef'. It returns an opentracing::SpanReference which can be passed to Tracer::StartSpan to influence the SpanContext of the newly created span. Specifically, the new span inherits the traceID and spanID from the passed SELF reference. It can be used to pass externally generated IDs to the tracer, with the purpose of recording spans from data generated elsewhere (e.g. from logs), or by augmenting the data of the existing span (Jaeger backend will merge multiple instances of the spans with the same IDs). Must be the lone reference, can be used only for root spans.

Usage example:

  jaegertracing::SpanContext customCtx { {1, 2}, 3, 0, 0, jaegertracing::SpanContext::StrMap() }; // TraceId and SpanID must be != 0
  auto span = tracer->StartSpan("spanName", { jaegertracing::SelfRef(&customCtx) });

License

Apache 2.0 License.