http.kafka.oneway

http.kafka.oneway

Listens on http port 8080 or https port 9090 and will produce messages to the events topic in Kafka, synchronously.

Requirements

• bash, jq, nc
• Kubernetes (e.g. Docker Desktop with Kubernetes enabled)
• kubectl
• helm 3.0+
• kcat

Install kcat client

Requires Kafka client, such as kcat.

$ brew install kcat

Setup

The setup.sh script:

• installs Zilla and Kafka to the Kubernetes cluster with helm and waits for the pods to start up
• creates the events topic in Kafka.
• starts port forwarding

$ ./setup.sh
+ helm install zilla-http-kafka-oneway chart --namespace zilla-http-kafka-oneway --create-namespace --wait
NAME: zilla-http-kafka-oneway
LAST DEPLOYED: [...]
NAMESPACE: zilla-http-kafka-oneway
STATUS: deployed
REVISION: 1
TEST SUITE: None
++ kubectl get pods --namespace zilla-http-kafka-oneway --selector app.kubernetes.io/instance=kafka -o name
+ KAFKA_POD=pod/kafka-1234567890-abcde
+ kubectl exec --namespace zilla-http-kafka-oneway pod/kafka-1234567890-abcde -- /opt/bitnami/kafka/bin/kafka-topics.sh --bootstrap-server localhost:9092 --create --topic events --if-not-exists
Created topic events.
+ kubectl port-forward --namespace zilla-http-kafka-oneway service/zilla 8080 9090
+ nc -z localhost 8080
+ kubectl port-forward --namespace zilla-http-kafka-oneway service/kafka 9092 29092
+ sleep 1
+ nc -z localhost 8080
Connection to localhost port 8080 [tcp/http-alt] succeeded!
+ nc -z localhost 9092
Connection to localhost port 9092 [tcp/XmlIpcRegSvc] succeeded!

Verify behavior

Send a POST request with an event body.

$ curl -v \
       -X "POST" http://localhost:8080/events \
       -H "Content-Type: application/json" \
       -d "{\"greeting\":\"Hello, world\"}"
...
> POST /events HTTP/1.1
> Content-Type: application/json
...
< HTTP/1.1 204 No Content

Verify that the event has been produced to the events Kafka topic.

$ kcat -C -b localhost:9092 -t events -J -u | jq .
{
  "topic": "events",
  "partition": 0,
  "offset": 0,
  "tstype": "create",
  "ts": 1652465273281,
  "broker": 1001,
  "headers": [
    "content-type",
    "application/json"
  ],
  "payload": "{\"greeting\":\"Hello, world\"}"
}
% Reached end of topic events [0] at offset 1

Teardown

The teardown.sh script stops port forwarding, uninstalls Zilla and Kafka and deletes the namespace.

$ ./teardown.sh
+ pgrep kubectl
99999
99998
+ killall kubectl
+ helm uninstall zilla-http-kafka-oneway --namespace zilla-http-kafka-oneway
release "zilla-http-kafka-oneway" uninstalled
+ kubectl delete namespace zilla-http-kafka-oneway
namespace "zilla-http-kafka-oneway" deleted