Observability for Quarkus LangChain4j with Opik

Quarkus LangChain4j uses Quarkus OpenTelemetry configuration in application.properties.

When this guide applies

Use this if your app is Quarkus + LangChain4j and you want OTEL traces to land in Opik.

Opik OTLP endpoint modes

For full endpoint/header details, see Opik OpenTelemetry overview.

• Cloud endpoint: https://www.comet.com/opik/api/v1/private/otel
• Enterprise endpoint: https://<comet-deployment-url>/opik/api/v1/private/otel
• Self-hosted endpoint: http://localhost:5173/api/v1/private/otel

Example (application.properties)

Intent: Configure Quarkus OTEL trace exporter to target Opik directly.

Applies when: You are using Quarkus-native OTEL exporter settings.

Required fields:

• quarkus.otel.enabled=true
• quarkus.otel.traces.enabled=true
• quarkus.otel.exporter.otlp.traces.endpoint
• quarkus.otel.exporter.otlp.traces.protocol=http/protobuf

Optional fields:

• quarkus.otel.exporter.otlp.traces.headers (projectName strongly recommended)
• quarkus.application.name (for service.name attribution)

Minimal valid setup:

quarkus.otel.enabled=true
quarkus.otel.traces.enabled=true
quarkus.otel.exporter.otlp.traces.endpoint=https://www.comet.com/opik/api/v1/private/otel
quarkus.otel.exporter.otlp.traces.protocol=http/protobuf
quarkus.otel.exporter.otlp.traces.headers=Authorization=<your-api-key>,Comet-Workspace=<your-workspace>,projectName=<your-project-name>

Validation

1. Start your Quarkus app with OTEL enabled.
2. Trigger a LangChain4j-backed endpoint/action.
3. Confirm spans with your configured service.name and project headers arrive in Opik.

Source references

• Quarkus OpenTelemetry guide
• Quarkus LangChain4j docs
• Opik OpenTelemetry overview