Chapter 108. OpenTelemetry

Add the following dependency to your pom.xml for this component:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-opentelemetry-starter</artifactId>
</dependency>

The configuration properties for the OpenTelemetry tracer are:

import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.api.trace.Tracer;

OpenTelemetryTracer otelTracer = new OpenTelemetryTracer();
// By default it uses the DefaultTracer, but you can override it with a specific OpenTelemetry Tracer implementation.
otelTracer.setTracer(...);
// And then initialize the context
otelTracer.init(camelContext);

Add the camel-opentelemetry-starter dependency, and then turn on the OpenTracing by annotating the main class with @CamelOpenTelemetry.

The OpenTelemetryTracer is implicitly obtained from the camel context’s Registry, unless a OpenTelemetryTracer bean has been defined by the application.

The camel-opentelemetry component starter allows you to trace not only the from/to Camel endpoints but also the Java Beans invoked from Camel processor/bean too. By default, Java beans invoked from Camel Processor or bean are categorized as another "span", that is, if user writes .to("bean:beanName?method=methodName"), it will be categorized under the same "span" with the from/to Camel endpoints.

To categorize the Java beans invoked from Camel processor/bean under the same "span", you can use the org.apache.camel.opentelemetry.OpenTelemetryTracingStrategy class with the setTracingStrategy() option.

import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.api.trace.Tracer;

@Configuration
public class CamelOtelConfiguration {
  public CamelOtelConfiguration(CamelContext camelContext, OpenTelemetryTracer tracer) {
    var strategy = new OpenTelemetryTracingStrategy(tracer);
    tracer.setTracingStrategy(strategy);
    camelContext.getCamelContextExtension().addInterceptStrategy(strategy);
  }
}

In case of too much data, you can filter the data by camel.opentelemetry.exclude-patterns property.

camel:
  opentelemetry:
    exclude-patterns:
      - ## Set some ID here to filter ##

Download the Java agent.

This package includes the instrumentation agent as well as instrumentations for all supported libraries and all available data exporters. The package provides a completely automatic, out-of-the-box experience.

Enable the instrumentation agent using the -javaagent flag to the JVM.

java -javaagent:path/to/opentelemetry-javaagent.jar \
     -jar myapp.jar

By default, the OpenTelemetry Java agent uses OTLP exporter configured to send data to OpenTelemetry collector at http://localhost:4317.

Configuration parameters are passed as Java system properties (-D flags) or as environment variables. See Configuring the agent and OpenTelemetry auto-configurationfor the full list of configuration items. For example:

java -javaagent:path/to/opentelemetry-javaagent.jar \
     -Dotel.service.name=your-service-name \
     -Dotel.traces.exporter=jaeger \
     -jar myapp.jar

To identify the origin of the Route, it is necessary to add the RouteID attribute to the span. The workaround is to use the Span decorator from Camel. For this, add a custom decorator for each component you want to enrich with the route id. For example, if you want to print the route id in the direct component, the implementation is as follows:

import org.apache.camel.Endpoint;
import org.apache.camel.Exchange;
import org.apache.camel.tracing.SpanAdapter;
import org.apache.camel.tracing.decorators.DirectSpanDecorator;

public class RouteIDSpanDecorator extends DirectSpanDecorator {

    @Override
    public void pre(SpanAdapter span, Exchange exchange, Endpoint endpoint) {
        super.pre(span, exchange, endpoint);
        span.setTag("camel.route.id", exchange.getFromRouteId());
    }
}

Add the file named org.apache.camel.tracing.SpanDecorator to src/main/resources/META-INF/services folder which contains the reference of the class . (for example, com.redhat.xxxx.RouteIDSpanDecorator). This allows the Camel tracing feature to load the custom Span decorator with the tag applied in the trace.

The component supports 2 options, which are listed below.

When MDC Logging is enabled for the active Camel context, the Trace ID and Span ID are added and removed from the MDC for each route, where the keys are trace_id and span_id, respectively.