Micrometer Observability

Since Camel 3.21

The Micrometer Observation component is used for performing observability of incoming and outgoing Camel messages using Micrometer Observation.

By configuring the ObservationRegistry you can add behaviour to your observations such as metrics (e.g., via Micrometer) or tracing (e.g., via OpenTelemetry or Brave) or any custom behaviour.

Events are captured for incoming and outgoing messages being sent to/from Camel.

Configuration

The configuration properties for the Micrometer Observations 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 required for instances to be encoded for JMS property keys.

Configuration

Include the camel-opentelemetry component in your POM, along with any specific dependencies associated with the chosen OpenTelemetry compliant Tracer.

To explicitly configure OpenTelemetry support, instantiate the OpenTelemetryTracer and initialize the camel context. You can optionally specify a Tracer, or alternatively it can be implicitly discovered using the Registry

ObservationRegistry observationRegistry = ObservationRegistry.create();
MicrometerObservationTracer micrometerObservationTracer = new MicrometerObservationTracer();

// This component comes from Micrometer Core - it's used for creation of metrics
MeterRegistry meterRegistry = new SimpleMeterRegistry();

// This component comes from Micrometer Tracing - it's an abstraction over tracers
io.micrometer.tracing.Tracer otelTracer = otelTracer();
// This component comes from Micrometer Tracing - an example of B3 header propagation via OpenTelemetry
OtelPropagator otelPropagator = new OtelPropagator(ContextPropagators.create(B3Propagator.injectingSingleHeader()), tracer);

// Configuration ObservationRegistry for metrics
observationRegistry.observationConfig().observationHandler(new DefaultMeterObservationHandler(meterRegistry));

// Configuration ObservationRegistry for tracing
observationRegistry.observationConfig().observationHandler(new ObservationHandler.FirstMatchingCompositeObservationHandler(new CamelPropagatingSenderTracingObservationHandler<>(otelTracer, otelPropagator), new CamelPropagatingReceiverTracingObservationHandler<>(otelTracer, otelPropagator), new CamelDefaultTracingObservationHandler(otelTracer)));

// Both components ObservationRegistry and MeterRegistry should be set manually, or they will be resolved from CamelContext if present
micrometerObservationTracer.setObservationRegistry(observationRegistry);
micrometerObservationTracer.setTracer(otelTracer);

// Initialize the MicrometerObservationTracer
micrometerObservationTracer.init(context);

Spring Boot

If you are using Spring Boot, then you can add the camel-observation-starter dependency, and turn on OpenTracing by annotating the main class with @CamelObservation.

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

Spring Boot Auto-Configuration

When using observation with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-observation-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 2 options, which are listed below.

Name Description Default Type

camel.observation.encoding

Activate or deactivate dash encoding in headers (required by JMS) for messaging.

Boolean

camel.observation.exclude-patterns

Sets exclude pattern(s) that will disable observability for Camel messages that matches the pattern. Multiple patterns can be separated by comma.

String

MDC Logging

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

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