Add Quarkus Pub/Sub Sample

[dzou]

Adds a Quarkus Cloud Pub/Sub sample.

Fixes #30

Notes: I think it's possible to test this out (if you want) even if you don't have GraalVM installed. Quarkus offers the mvn package -P graal -Dquarkus.native.container-build=true command which conducts the build in a docker container and you should be able to run the resulting executable after ./target/quarkus-pubsub-sample-1.0.0-SNAPSHOT-runner.

[meltsufin]

Very cool!
Just some minor comments regarding getting the sample running more smoothly.

[meltsufin]

Was this file auto-generated by something?

[dzou]

Yup - this code was generated from the Quarkus equivalent of Initialzr.

[elefeint]

Looks awesome; did not test :)

[dzou]

@kostacasa - Hey sorry to bother you. I wanted to ask about your native image builds on Cloud Build. We've been able to get a quarkus sample app working with the Pub/Sub libraries locally (compilation + running), however when we try to build the quarkus app on Cloud Build we seem to get a new error.

I was just curious if you've seen this before and have handled it -- however, if not, no worries! (figure it was worth a shot asking). To me it seemed like it might be a Cloud Build-specific error.

Step #0: Detailed message:
Step #0: Error: Detected a started Thread in the image heap. Threads running in the image generator are no longer running at image run time.  Object has been initialized without the native-image initialization instrumentation and the stack trace can't be tracked. The object was probably created by a class initializer and is reachable from a static field. You can request class initialization at image run time by using the option --initialize-at-run-time=<class-name>. Or you can write your own initialization methods and call them explicitly from your main entry point.
Step #0: Trace: Object was reached by 
Step #0: 	reading field sun.net.www.http.KeepAliveCache.keepAliveTimer of
Step #0: 		constant sun.net.www.http.KeepAliveCache@2cc2b8b9 reached by 
Step #0: 	reading field sun.net.www.http.HttpClient.kac
Step #0: Error: No instances of java.net.PlainSocketImpl are allowed in the image heap as this class should be initialized at image runtime. Object has been initialized without the native-image initialization instrumentation and the stack trace can't be tracked.
Step #0: Trace: Object was reached by 
Step #0: 	reading field java.net.Socket.impl of
Step #0: 		constant java.net.Socket@226716c8 reached by 
Step #0: 	reading field sun.net.NetworkClient.serverSocket of
Step #0: 		constant sun.net.www.http.HttpClient@3c765f46 reached by 
Step #0: 	reading field sun.net.www.http.KeepAliveEntry.hc of
Step #0: 		constant sun.net.www.http.KeepAliveEntry@ff27720 reached by 
Step #0: 	indexing into array
Step #0: 		constant java.lang.Object[]@6ee171b2 reached by 
Step #0: 	reading field java.util.ArrayDeque.elements of
Step #0: 		constant sun.net.www.http.ClientVector@10200337 reached by 
Step #0: 	reading field java.util.HashMap$Node.value of
Step #0: 		constant java.util.HashMap$Node@3b7ed33b reached by 
Step #0: 	indexing into array
Step #0: 		constant java.util.HashMap$Node[]@1b761920 reached by 
Step #0: 	reading field java.util.HashMap.table of
Step #0: 		constant sun.net.www.http.KeepAliveCache@2cc2b8b9 reached by 
Step #0: 	reading field sun.net.www.http.HttpClient.kac

[kostacasa]

Hello! Interesting, have not seen that specific error unfortunately.

This is the Dockerfile we use for building native images:

## Stage 1 : build with maven builder image with native capabilities
FROM quay.io/quarkus/centos-quarkus-maven:20.1.0-java11 AS build
COPY pom.xml /usr/src/app/
COPY src /usr/src/app/src
COPY .m2 /usr/src/app/.m2
USER root
RUN chown -R quarkus /usr/src/app
USER quarkus
ENV JAVA_OPTIONS="-XshowSettings:vm"
ENV MAVEN_OPTS=-Xmx8G
RUN mvn -f /usr/src/app/pom.xml -Dmaven.repo.local=/usr/src/app/.m2/repository -Pnative deploy

## Stage 2 : create the docker final image
FROM registry.access.redhat.com/ubi8/ubi-minimal
WORKDIR /work/
COPY --from=build /usr/src/app/target/*-runner /work/application

# set up permissions for user `1001`
RUN chmod 775 /work /work/application \
  && chown -R 1001 /work \
  && chmod -R "g+rwX" /work \
  && chown -R 1001:root /work

EXPOSE 8080
USER 1001

CMD ["./application", "-Dquarkus.http.host=0.0.0.0"]

And our cloud build step is just a simple docker builder execution (we pull .m2 cache first).

    # Retrieve the cached .m2 directory from GCS
    -   name: 'gcr.io/cloud-builders/gsutil'
        entrypoint: bash
        args:
            - '-c'
            - |
                mkdir -p .m2/repository/
                cd .m2/repository/
                gsutil cp gs://m2_cache/$REPO_NAME.tar .
                if [ -f "$REPO_NAME.tar" ]; then
                    echo "Extracting archive"
                    tar -xf $REPO_NAME.tar
                    echo "Extracted"
                    rm $REPO_NAME.tar
                    ls
                fi
                true

    -   name: gcr.io/cloud-builders/docker
        args:
            - build
            - '--file=src/main/docker/Dockerfile.multistage'
            - '--tag=$_GCR_HOSTNAME/$PROJECT_ID/$REPO_NAME:$SHORT_SHA'
            - '--network=cloudbuild'
            - '.'

[dzou]

Ahh thanks so much, this is very helpful. I think what might be missing for us is maybe we should also try using the quay.io Quarkus images. Appreciate the tip @kostacasa

[meltsufin]

Works great! (I didn't try the compiled version though.)

Changes addressed!