docker: add pulsar example (#3789)

Since there is no collector-pulsar module at present, compiling docker
will result in an error, so when this PR is merged, I will add
`zipkin-collector-pulsar` to the github actions in
#3788.

.github/workflows/test_readme.yml

@@ -181,3 +181,9 @@ jobs:
           build-bin/docker/docker_test_image openzipkin/zipkin-rabbitmq:test
         env:
           DOCKER_FILE: docker/test-images/zipkin-rabbitmq/Dockerfile
+      - name: docker/test-images/zipkin-pulsar/README.md
+        run: |
+          build-bin/docker/docker_build openzipkin/zipkin-pulsar:test &&
+          build-bin/docker/docker_test_image openzipkin/zipkin-pulsar:test
+        env:
+          DOCKER_FILE: docker/test-images/zipkin-pulsar/Dockerfile

docker/README.md

@@ -22,6 +22,7 @@ base layer `openzipkin/zipkin`, and setting up schema where relevant.
 * [ghcr.io/openzipkin/zipkin-eureka](test-images/zipkin-eureka/README.md) - runs Eureka
 * [ghcr.io/openzipkin/zipkin-kafka](test-images/zipkin-kafka/README.md) - runs both Kafka+ZooKeeper
 * [ghcr.io/openzipkin/zipkin-mysql](test-images/zipkin-mysql/README.md) - runs MySQL initialized with Zipkin's schema
+* [ghcr.io/openzipkin/zipkin-pulsar](test-images/zipkin-pulsar/README.md) - runs Pulsar
 * [ghcr.io/openzipkin/zipkin-rabbitmq](test-images/zipkin-rabbitmq/README.md) - runs RabbitMQ
 * [ghcr.io/openzipkin/zipkin-ui](test-images/zipkin-ui/README.md) - serves the (Lens) UI directly with NGINX
 

docker/test-images/zipkin-pulsar/Dockerfile

@@ -0,0 +1,36 @@
+#
+# Copyright The OpenZipkin Authors
+# SPDX-License-Identifier: Apache-2.0
+#
+
+# Use latest from https://hub.docker.com/r/apachepulsar/pulsar/tags
+ARG pulsar_version=4.0.2
+
+# We copy files from the context into a scratch container first to avoid a problem where docker and
+# docker compose don't share layer hashes /~https://github.com/docker/compose/issues/883 normally.
+# COPY --from= works around the issue.
+FROM scratch as scratch
+
+WORKDIR /docker-bin
+COPY build-bin/docker/docker-healthcheck /docker-bin/
+
+ARG pulsar_version
+
+FROM apachepulsar/pulsar:${pulsar_version} as zipkin-pulsar
+LABEL pulsar-version=$pulsar_version
+LABEL org.opencontainers.image.description="Apache Pulsar on Alpine Linux"
+
+# Add HEALTHCHECK and ENTRYPOINT scripts into the default search path
+COPY --from=scratch /docker-bin/* /usr/local/bin/
+# We use start period of 30s to avoid marking the container unhealthy on slow or contended CI hosts
+HEALTHCHECK --interval=1s --start-period=30s --timeout=5s CMD ["docker-healthcheck"]
+
+# Usually, we read env set from pid 1 to get docker-healthcheck parameters.
+# However, pulsar-server has to start as root even if permissions are dropped
+# later. So, we expose it in the Dockerfile instead.
+ENV HEALTHCHECK_PORT=8080
+ENV HEALTHCHECK_KIND=http
+ENV HEALTHCHECK_PATH=/admin/v2/clusters/standalone
+ENV PULSAR_LOG_ROOT_LEVEL=WARN
+EXPOSE 8080 6650
+CMD ["bin/pulsar", "standalone"]

docker/test-images/zipkin-pulsar/README.md

@@ -0,0 +1,10 @@
+## zipkin-pulsar Docker image
+
+The `zipkin-pulsar` testing image runs Pulsar for Pulsar collector integration.
+
+To build `openzipkin/zipkin-pulsar:test`, from the top-level of the repository, run:
+```bash
+$ DOCKER_FILE=docker/test-images/zipkin-pulsar/Dockerfile build-bin/docker/docker_build openzipkin/zipkin-pulsar:test
+```
+
+You can use the env variable `PULSAR_LOG_ROOT_LEVEL` to change the log level for Pulsar. Defaults to "WARN".