chapter-6-quarkus-rest-debug

Chapter 6 - Quarkus REST application & Remote Debug

This is a simple Quarkus JAX-RS project using RESTEasy Reactive that we will use to perform live coding & debugging.

This project uses Quarkus, the Supersonic Subatomic Java Framework. If you want to learn more about Quarkus, please visit its website: https://quarkus.io/.

The Quarkus Kubernetes extension will populate the Kubernetes manifest needed to deploy the application on a kubernetes cluster while the Quarkus Container JIB extension will build a container image using Google JIB Tool.

Package the application

Package the application and build/push the container image to docker hub, quay.io, ... using the following command

./mvnw clean package

NOTE: Uncomment the quarkus.container-image* properties within the application.properties file and change the values according to the registry where you will push the image. Instead of changing the properties within the file, you can also define them as such:

./mvnw clean package \
    -Dquarkus.container-image.registry=localhost:5000 \
    -Dquarkus.container-image.group=quarkus \
    -Dquarkus.container-image.tag=1.0 \
    -Dquarkus.container-image.build=true \
    -Dquarkus.container-image.push=true \
    -Dquarkus.container-image.insecure=true \
    -Dquarkus.container-image.name=chapter-6-quarkus-rest-debug

Deploy the application on the Kubernetes platform

Deploy the application

kubectl create ns quarkus-demo-debug
kubectl apply -f ./target/kubernetes/kubernetes.yml -n quarkus-demo-debug

Access it using your browser pointing to the following url http://chapter-6-quarkus-rest-debug.127.0.0.1.nip.io/hello. You will see as response Hello RESTEasy.

WARNING: Change the domain name using the Ingress or OpenShift route address

Launch the application locally

• Launch locally your quarkus application containing the code that you would like to change remotely

./mvnw quarkus:remote-dev

• Do some code changes within the code.
• Check again the response using the URL of the endpoint ;-). This new request triggers the recompilation of the code as can be seen in the console output:

2021-06-02 09:56:25,322 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending dev/app/org/acme/GreeterResource.class

As soon as the code has been recompiled, it will be pushed to the remote application running as a linux container within a pod

Remote debugging

To remote debug the application, it is needed to expose on the cluster the remote port 5005. This could be achieved very easily if you create a Kubernetes Service using as type: NodePort where the target port maps a port exposed on the cluster (e.g: 5005 --> 31000).

• If the ports 31000 and 30000 are exposed on your cluster, then uncomment the following lines within the application.proerpties file

quarkus.kubernetes.service-type=NodePort
quarkus.kubernetes.ports.http.node-port=30000
quarkus.kubernetes.ports.remote.name=http
quarkus.kubernetes.ports.remote.host-port=5005
quarkus.kubernetes.ports.remote.container-port=5005
quarkus.kubernetes.ports.remote.node-port=31000

• To configure the java agent of the remote application, uncomment also the following line within the appliation.properties file

quarkus.kubernetes.env.vars.JAVA_TOOL_OPTIONS=-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=0.0.0.0:5005

• Next, re-deploy the application using rhe new manifests file

kubectl delete -f ./target/kubernetes/kubernetes.yml -n quarkus-demo-debug
kubectl apply -f ./target/kubernetes/kubernetes.yml -n quarkus-demo-debug

• Test again the url of the endpoint using your browser and the new address containing the NodePort such as http://127.0.0.1:30000/hello
• Next, using your IDE, launch a remote debugger

• Add a breakpoint within your code and call the service to debug it

Enjoy to remote debug !

Clean up

NAMESPACE=quarkus-demo-debug
kubectl delete -f ./target/kubernetes/kubernetes.yml -n $NAMESPACE
kubectl delete ns $NAMESPACE