xiaozongyang / jaeger-client-java

Jaeger Bindings for Java OpenTracing API

Jaeger's Tracing Instrumentation Library for Java

• Intended to be used with Jaeger backend, but can also be configured to send traces to Zipkin.
• Implements OpenTracing Java API.
• Supports Java 1.6 and above

Package rename to io.jaegertracing

The group ID com.uber.jaeger has been deprecated and moved to a different repository. Please switch to io.jaegertracing, as the old group ID will be maintained only for bug fixes.

Contributing and Developing

Please see CONTRIBUTING.md.

Core Modules

Click through for more detailed docs on specific modules.

• jaeger-client: the module that instrumented applications should usually include
• jaeger-core: the core implementation of the OpenTracing API
• jaeger-thrift: set of components that send data to the backend

Add-on Modules

• jaeger-zipkin: compatibility layer for using the Jaeger Tracer to Zipkin-compatible backends
• jaeger-micrometer: a metrics provider, to report internal Jaeger Client metrics to third-party backends, such as Prometheus
• jaeger-tracerresolver: an OpenTracing TracingResolver for the Jaeger Tracer.

Importing Dependencies

All artifacts are published to Maven Central. Snapshot artifacts are also published to Sonatype. Follow these instructions to add the snapshot repository to your build system.

Please use the latest version:

In the usual case, you just need to include the following dependency to your project:

<dependency>
    <groupId>io.jaegertracing</groupId>
    <artifactId>jaeger-client</artifactId>
    <version>$jaegerVersion</version>
</dependency>

This will bring a concrete sender, such as jaeger-thrift, as well as the jaeger-tracerresolver and jaeger-core.

Thrift version conflicts

The Jaeger Java Client uses org.apache.thrift:libthrift:0.11.0. By default, declaring a dependency on the jaeger-thrift module will bring a non-shaded version of Thrift (and others). A shaded version of the dependency is available with the classifier shadow.

Instantiating the Tracer

Please see jaeger-core/README.

Testing

When testing tracing instrumentation it is often useful to make sure that all spans are being captured, which is not the case in production configurations where heavy sampling is applied by default. The following configuration can be provided to affect which sampling is applied to the new traces:

sampler:
   type: const # can either be const, probabilistic, or ratelimiting
   param: 1  # can either be an integer, a double, or an integer

The valid values for type are:

• const: configures a sampler that always makes the same decision for new traces depending on the param: always no for param=0, always yes otherwise.
• probabilistic: configures a sampler that samples traces with probability equal to param (must be between 0.0 and 1.0)
• ratelimiting: configures a samlper that samples traces with a certain rate per second equal to param

Debug Traces (Forced Sampling)

Programmatically

The OpenTracing API defines a sampling.priority standard tag that can be used to affect the sampling of a span and its children:

import io.opentracing.tag.Tags;

Tags.SAMPLING_PRIORITY.set(span, 1);

Via HTTP Headers

Jaeger Tracer also understands a special HTTP Header jaeger-debug-id, which can be set in the incoming request, e.g.

curl -H "jaeger-debug-id: some-correlation-id" http://myhost.com

When Jaeger sees this header in the request that otherwise has no tracing context, it ensures that the new trace started for this request will be sampled in the "debug" mode (meaning it should survive all downsampling that might happen in the collection pipeline), and the root span will have a tag as if this statement was executed:

span.setTag("jaeger-debug-id", "some-correlation-id")

This allows using Jaeger UI to find the trace by this tag.

License

Apache 2.0 License.