Chapter 256. OpenTracing Component
Available as of Camel 2.19
Starting with Camel 2.21, it will be necessary to use an OpenTracing complaint tracer that is compatible with OpenTracing Java API version 0.31 or higher.
The camel-opentracing component is used for tracing and timing incoming and outgoing Camel messages using OpenTracing.
Events (spans) are captured for incoming and outgoing messages being sent to/from Camel.
See the OpenTracing website for a list of supported tracers.
256.1. Configuration
The configuration properties for the OpenTracing tracer are:
| Option | Default | Description |
|---|---|---|
| excludePatterns | Sets exclude pattern(s) that will disable tracing for Camel messages that matches the pattern. The content is a Set<String> where the key is a pattern. The pattern uses the rules from Intercept. | |
| encoding | false | Sets whether the header keys need to be encoded (connector specific) or not. The value is a boolean. Dashes need for instances to be encoded for JMS property keys. |
There are three ways in which an OpenTracing tracer can be configured to provide distributed tracing for a Camel application:
256.1.1. Explicit
Include the camel-opentracing component in your POM, along with any specific dependencies associated with the chosen OpenTracing compliant Tracer.
To explicitly configure OpenTracing support, instantiate the OpenTracingTracer and initialize the camel context. You can optionally specify a Tracer, or alternatively it can be implicitly discovered using the Registry or ServiceLoader.
OpenTracingTracer ottracer = new OpenTracingTracer(); // By default it uses a Noop Tracer, but you can override it with a specific OpenTracing implementation. ottracer.setTracer(...); // And then initialize the context ottracer.init(camelContext);
To use OpenTracingTracer in XML, all you need to do is to define the OpenTracing tracer beans. Camel will automatically discover and use them.
<bean id="tracer" class="..."/>
<bean id="ottracer" class="org.apache.camel.opentracing.OpenTracingTracer">
<property name="tracer" ref="tracer"/>
</bean>256.2. Spring Boot
If you are using Spring Boot then you can add the camel-opentracing-starter dependency, and turn on OpenTracing by annotating the main class with @CamelOpenTracing.
The Tracer will be implicitly obtained from the camel context’s Registry, or the ServiceLoader, unless a Tracer bean has been defined by the application.
256.3. Spring Boot Auto-Configuration
The component supports 2 options, which are listed below.
| Name | Description | Default | Type |
|---|---|---|---|
| camel.opentracing.encoding | Activate or deactivate dash encoding in headers (required by JMS) for messaging | Boolean | |
| camel.opentracing.exclude-patterns | Sets exclude pattern(s) that will disable tracing for Camel messages that matches the pattern. | Set |
256.4. Java Agent
The third approach is to use a Java Agent to automatically configure the OpenTracing support.
Include the camel-opentracing component in your POM, along with any specific dependencies associated with the chosen OpenTracing compliant Tracer.
The OpenTracing Java Agent is associated with the following dependency:
<dependency>
<groupId>io.opentracing.contrib</groupId>
<artifactId>opentracing-agent</artifactId>
</dependency>
The Tracer used will be implicitly loaded from the camel context Registry or using the ServiceLoader.
How this agent is used will be specific to how you execute your application. Service2 in the camel-example-opentracing downloads the agent into a local folder and then uses the exec-maven-plugin to launch the service with the -javaagent command line option.
256.5. Example
You can find an example demonstrating the three ways to configure OpenTracing here: camel-example-opentracing
