The OpenTelemetry emitter generates OpenTelemetry Spans for queries.
The OpenTelemetry emitter processes ServiceMetricEvent
events for the query/time
metric. It extracts OpenTelemetry context from the query context. To link druid spans to parent traces, the query context should contain at least traceparent
key. See context propagation for more information. If no traceparent
key is provided, then spans are created without parentTraceId
and are not linked to the parent span. In addition, the emitter also adds other druid context entries to the span attributes.
To enable the OpenTelemetry emitter, add the extension and enable the emitter in common.runtime.properties
.
Load the plugin:
druid.extensions.loadList=[..., "opentelemetry-emitter"]
Then there are 2 options:
opentelemetry-emitter
druid.emitter=opentelemetry
opentelemetry-emitter
with other emittersdruid.emitter=composing druid.emitter.composing.emitters=[..., "opentelemetry"]
*More about Druid configuration here.
Create docker-compose.yaml
in your working dir:
version: "2" services: zipkin-all-in-one: image: openzipkin/zipkin:latest ports: - "9411:9411" otel-collector: image: otel/opentelemetry-collector:latest command: ["--config=otel-local-config.yaml", "${OTELCOL_ARGS}"] volumes: - ${PWD}/config.yaml:/otel-local-config.yaml ports: - "4317:4317"
Create config.yaml
file with configuration for otel-collector:
version: "2" receivers: receivers: otlp: protocols: grpc: exporters: zipkin: endpoint: "http://zipkin-all-in-one:9411/api/v2/spans" format: proto logging: processors: batch: service: pipelines: traces: receivers: [otlp] processors: [batch] exporters: [logging, zipkin]
*How to configure otel-collector you can read here.
Run otel-collector and zipkin.
docker compose up
Build Druid:
mvn clean install -Pdist tar -C /tmp -xf distribution/target/apache-druid-0.21.0-bin.tar.gz cd /tmp/apache-druid-0.21.0
Edit conf/druid/single-server/micro-quickstart/_common/common.runtime.properties
to enable the emitter ( see Configuration
section above).
Start the quickstart with the apppropriate environment variables for opentelemetry autoconfiguration:
OTEL_SERVICE_NAME="org.apache.druid" OTEL_EXPORTER_OTLP_ENDPOINT="http://localhost:4317" bin/start-micro-quickstart
*More about opentelemetry autoconfiguration here
Load sample data - example.
Create query.json
:
{ "query":"SELECT COUNT(*) as total FROM wiki WHERE countryName IS NOT NULL", "context":{ "traceparent":"00-54ef39243e3feb12072e0f8a74c1d55a-ad6d5b581d7c29c1-01" } }
Send query:
curl -XPOST -H'Content-Type: application/json' http://localhost:8888/druid/v2/sql/ -d @query.json
Then open http://localhost:9411/zipkin/
and you can see there your spans.