CloudEvents Processing

This is a very simple showcase of how to use the CloudEvent Java SDK to process events in a Kubernetes cluster on top of Knative.

The following image illustrates the architecture of the showcase. Take a look at the kubernetes directory for more details about the objects created in the cluster.

Try it out locally

This image is available on Quay.io:

$ podman run --rm -it -p 8080:8080 quay.io/ricardozanini/ce-processing:1.0

Then just curl the 8080 port:

$ curl -X POST \
    -H "content-type: application/json"  \
    -H "ce-specversion: 1.0"  \
    -H "ce-source: curl-command"  \
    -H "ce-type: curl.demo"  \
    -H "ce-id: 123-abc"  \
    -d '{"name":"Zanini"}' \
http://localhost:8080

You should see the application logs like:

19:20:51.078 [vert.x-eventloop-thread-1] INFO  o.m.c.ce.CloudEventConsumerVerticle - Initializing Vertx Server
19:20:51.178 [vert.x-eventloop-thread-2] INFO  o.m.c.ce.CloudEventProducerVerticle - CE Publisher started, will publish events to 'http://localhost:8080/' endpoint
19:20:51.180 [vert.x-eventloop-thread-0] INFO  org.m88i.cloud.ce.MainVerticle - Successfully deployed MainVerticle
19:20:51.183 [vert.x-eventloop-thread-1] INFO  o.m.c.ce.CloudEventConsumerVerticle - Server started on port 8080
Jul 10, 2020 7:20:51 PM io.vertx.core.impl.launcher.commands.VertxIsolatedDeployer
INFO: Succeeded in deploying verticle
19:21:05.802 [vert.x-eventloop-thread-1] INFO  o.m.c.ce.CloudEventConsumerVerticle - Received event: 
☁ ️cloudevents.Event
Context Attributes,
	specversion: 1.0
	type: curl.demo
	source: curl-command
	id: 123-abc
	time: null
Extensions,
Data,
	{"name":"Zanini"}
19:21:05.822 [vert.x-eventloop-thread-2] INFO  o.m.c.ce.CloudEventProducerVerticle - Received internal message. Creating new CE request to http://localhost:8080/
19:21:05.869 [vert.x-eventloop-thread-1] INFO  o.m.c.ce.CloudEventConsumerVerticle - Received event: 
☁ ️cloudevents.Event
Context Attributes,
	specversion: 1.0
	type: success.ce.demo
	source: 69af641bcc77
	id: 67c4944f-7379-40d5-b2b9-ea2bd436353b
	time: null
Extensions,
Data,
	CE Processed ID: 123-abc
19:21:05.870 [vert.x-eventloop-thread-1] INFO  o.m.c.ce.CloudEventConsumerVerticle - Won't emit a follow up CloudEvent since CloudEvent{id='67c4944f-7379-40d5-b2b9-ea2bd436353b', source=69af641bcc77, type='success.ce.demo', datacontenttype='null', dataschema=null, subject='null', time=null, data=[67, 69, 32, 80, 114, 111, 99, 101, 115, 115, 101, 100, 32, 73, 68, 58, 32, 49, 50, 51, 45, 97, 98, 99], extensions={}} comes from a local source

Running with Knative Eventing

1. Install minikube and kubectl or have a Kubernetes cluster available
2. Setup Istio + Knative

# create the namespace
kubectl create namespace ce
# enable Knative Eventing injection
kubectl label namespace ce knative-eventing-injection=enabled
# deploy the application
kubectl apply -f kubernetes/ce-service-deploy.yaml -n ce
# deploy consumer and producers for the application
kubectl apply -f kubernetes/consumer-trigger.yaml -n ce
kubectl apply -f kubernetes/producer-sinkbinding.yaml -n ce
# deploy the event display
kubectl apply -f kubernetes/event-display.yaml -n ce
# deploy the event source
kubectl apply -f kubernetes/emitter.yaml -n ce

To see the showcase in action, try looking the logs of the deployed application:

kubectl logs -f ce-processing-<hash> -n ce

References

• Setting up Knative Eventing Resources
• Processing CloudEvents with Eclipse Vert.x
• CloudEvents Java SDK