Automatic Instrumentation

Supported Libraries and Frameworks

Disabled Instrumentations

Some instrumentations can produce too many spans and make traces very noisy. For this reason the following instrumentations are disabled by default:

• jdbc-datasource which creates spans whenever java.sql.DataSource#getConnection method is called.
• servlet-filter which creates spans around Servlet Filter methods.
• servlet-service which creates spans around Servlet methods.

To enable them, add otel.integration.<name>.enabled system property: -Dotel.integration.jdbc-datasource.enabled=true

Grizzly Instrumentation

Whenever you use Grizzly for Servlet-based applications, you get better experience from Servlet-specific support. As these two instrumentations conflict with each other, more generic instrumentation for Grizzly http server is disabled by default. If needed, you can enable it by add the following system property: -Dotel.integration.grizzly.enabled=true

Suppressing Instrumentation

Specific Libraries

You can suppress auto-instrumentation of specific libraries by using -Dotel.integration.[id].enabled=false where id is the instrumentation id.

Specific Classes

You can also exclude specific classes from being instrumented. This can be useful for a few reasons including:

• To completely silence spans from a given class/package.
• As a quick workaround for an instrumentation bug, when byte code in one specific class is problematic.

This option should not be used lightly, as it can leave some instrumentation partially applied, which could have unknown side-effects.

Logger MDC auto-instrumentation

The agent injects several pieces of information about the current span into each logging event’s MDC copy. As a result any services or tools that parse the application logs can correlate traces/spans with log statements.

• traceId (same as Span.current().getSpanContext().getTraceIdAsHexString())
• spanId (same as Span.current().getSpanContext().getSpanIdAsHexString())
• sampled (same as Span.current().getSpanContext().isSampled())

This information can be included in log statements produced by the logging library by specifying them in the pattern/format.

Example for Spring Boot configuration (which uses logback):

logging.pattern.console = %d{yyyy-MM-dd HH:mm:ss} - %logger{36} - %msg t:%X{traceId} s:%X{spanId} %n

Supported logging libraries

Configuration Options

Configuration parameters names are very likely to change until GA.

Exporters

The following configuration properties are common to all exporters:

OTLP exporter (both span and metric exporters)

In order to configure the service name for the OTLP exporter, you must add service.name key to the OpenTelemetry Resource (see below). For example: OTEL_RESOURCE_ATTRIBUTES=service.name=myservice.

Jaeger exporter

Currently only supports gRPC.

Zipkin exporter

Prometheus exporter

Logging exporter

The logging exporter simply prints the name of the span along with its attributes to stdout. It is used mainly for testing and debugging.

Propagator

The propagator controls which distributed tracing header format is used.

If this is set to a comma-delimited list of the values, the multi-propagator will be used. The multi-propagator will try to extract the context from incoming requests using each of the configured propagator formats (in order), stopping after the first successful context extraction. The multi-propagator will inject the context into outgoing requests using all the configured propagator formats.

OpenTelemetry Resource

The OpenTelemetry Resource is a representation of the entity producing telemetry.

Peer service name

The peer service name is the name of a remote service that is being connected to. It corresponds to service.name in the Resource for the local service.

Batch span processor

Trace config

Interval metric reader

Customizing the OpenTelemetry SDK

This is highly advanced behavior and still in the prototyping phase. It may change drastically or be removed completely. Use with caution

The OpenTelemetry API exposes SPI hooks for customizing its behavior, such as the Resource attached to spans or the Sampler.

Because the auto instrumentation runs in a separate classpath than the instrumented application, it is not possible for customization in the application to take advantage of this customization. In order to provide such customization, you can provide the path to a JAR file including an SPI implementation using the system property otel.initializer.jar. Note that this JAR will need to shade the OpenTelemetry API in the same way as the agent does. The simplest way to do this is to use the same shading configuration as the agent from here. In addition, you will have to specify the io.opentelemetry.javaagent.shaded.io.opentelemetry.api.trace.spi.TraceProvider to the name of the class that implements the SPI.

Manual Instrumentation

Starting with 0.6.0, and prior to version 1.0.0, opentelemetry-javaagent-all.jar only supports manual instrumentation using the opentelemetry-api version with the same version number as the Java agent you are using. Starting with 1.0.0, the Java agent will start supporting multiple (1.0.0+) versions of opentelemetry-api.

With auto-instrumentation it may be desirable to also add manual instrumentation. In this scenario, it is critical that both automatic and manual instrumentation stitch together properly. Two options exist to configure manual instrumentation with the appropriate span context:

• @WithSpan annotation: Simply annotate the functions or methods you wish to instrument
• getTracer: Traditional way to instrument with OpenTelemetry

Both options require a dependency on the opentelemetry-api library to get started.

Dependency

Maven

  <dependencies>
    <dependency>
      <groupId>io.opentelemetry</groupId>
      <artifactId>opentelemetry-api</artifactId>
      <version>0.10.0</version>
    </dependency>
  </dependencies>

Gradle

dependencies {
    compile('io.opentelemetry:opentelemetry-api:0.10.0')
}

Configure @WithSpan annotation

Add the trace annotation to your application’s code. Then, each time the application invokes the annotated method, it creates a span that denotes its duration and provides any thrown exceptions.

import io.opentelemetry.extensions.auto.annotations.WithSpan;

public class MyClass {
  @WithSpan
  public void MyLogic() {
      <...>
  }
}

Dependency

An additional dependency is required for this annotation:

Maven

  <dependencies>
    <dependency>
      <groupId>io.opentelemetry</groupId>
      <artifactId>opentelemetry-extension-auto-annotations</artifactId>
      <version>0.10.0</version>
    </dependency>
  </dependencies>

Groovy

dependencies {
    compile('io.opentelemetry:opentelemetry-extension-auto-annotations:0.10.0')
}

Suppressing @WithSpan instrumentation

This is useful in case you have code that is over-instrumented using @WithSpan, and you want to suppress some of them without modifying the code.

Configure the OpenTelemetry getTracer

See the Manual Instrumentation documentation for configuration information and examples.

Troubleshooting

To turn on the agent’s internal debug logging:

-Dio.opentelemetry.javaagent.slf4j.simpleLogger.defaultLogLevel=debug

Note these logs are extremely verbose. Enable debug logging only when needed. Debug logging negatively impacts the performance of your application.