This module provides core tracing functionality for custom instrumentation.
<dependency>
<groupId>com.uber.jaeger</groupId>
<artifactId>jaeger-core</artifactId>
<version>$jaegerVersion</version>
</dependency>For production usage, it is recommended to use com.uber.jaeger.Configuration with default parameters:
Configuration config = new Configuration("myServiceName", null, null);
config.setStatsFactory(...); // optional if you want to get metrics about tracer behavior
Tracer tracer = config.getTracer();The config objects lazily builds and configures Jaeger Tracer. Multiple calls to getTracer() return the same instance.
It is also possible to obtain a com.uber.jaeger.Configuration object configured using properties specified
as environment variables or system properties. A value specified as a system property will override a value
specified as an environment variable for the same property name.
Configuration config = Configuration.fromEnv();The property names are:
| Property | Required | Description |
|---|---|---|
| JAEGER_SERVICE_NAME | yes | The service name |
| JAEGER_AGENT_HOST | no | The hostname for communicating with agent via UDP |
| JAEGER_AGENT_PORT | no | The port for communicating with agent via UDP |
| JAEGER_ENDPOINT | no | The traces endpoint, in case the client should connect directly to the Collector, like http://jaeger-collector:14268/api/traces |
| JAEGER_AUTH_TOKEN | no | Authentication Token to send as "Bearer" to the endpoint |
| JAEGER_USER | no | Username to send as part of "Basic" authentication to the endpoint |
| JAEGER_PASSWORD | no | Password to send as part of "Basic" authentication to the endpoint |
| JAEGER_PROPAGATION | no | Comma separated list of formats to use for propagating the trace context. Defaults to the standard Jaeger format. Valid values are jaeger and b3 |
| JAEGER_REPORTER_LOG_SPANS | no | Whether the reporter should also log the spans |
| JAEGER_REPORTER_MAX_QUEUE_SIZE | no | The reporter's maximum queue size |
| JAEGER_REPORTER_FLUSH_INTERVAL | no | The reporter's flush interval (ms) |
| JAEGER_SAMPLER_TYPE | no | The sampler type |
| JAEGER_SAMPLER_PARAM | no | The sampler parameter (number) |
| JAEGER_SAMPLER_MANAGER_HOST_PORT | no | The host name and port when using the remote controlled sampler |
| JAEGER_TAGS | no | 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 |
| JAEGER_DISABLE_GLOBAL_TRACER | no | If set, disables registering the tracer with io.opentracing.GlobalTracer |
Setting JAEGER_AGENT_HOST/JAEGER_AGENT_PORT will make the client send traces to the agent via UdpSender.
If the JAEGER_ENDPOINT environment variable is also set, the traces are sent to the endpoint, effectively making
the JAEGER_AGENT_* vars ineffective.
When the JAEGER_ENDPOINT is set, the HttpSender is used when submitting traces to a remote
endpoint, usually served by a Jaeger Collector. If the endpoint is secured, a HTTP Basic Authentication
can be performed by setting the related environment vars. Similarly, if the endpoint expects an authentication
token, like a JWT, set the JAEGER_AUTH_TOKEN environment variable. If the Basic Authentication environment
variables and the Auth Token environment variable are set, Basic Authentication is used.
Jaeger's Java Client also provides an implementation of the
TracerResolver, allowing a Tracer to be
obtained in a vendor neutral manner. This TracerResolver implementation uses the configuration via
environment approach described above.
More information about using the TracerResolver can be found here.
The last two parameters to new Configuration() allow control over configuration of the Sampler and Reporter.
However, especially in unit tests, it's useful to have tracer that is not connected to tracing backend, but collects
spans in memory:
Reporter reporter = new InMemoryReporter();
Sampler sampler = new ConstSampler(true);
Tracer tracer = new Tracer.Builder(serviceName, reporter, sampler).build();See also: opentracing-java