Eventing Publisher Proxy

Overview

The Eventing Publisher Proxy receives legacy and Cloud Event publishing requests from the cluster workloads (microservice or Serverless functions) and redirects them to the Enterprise Messaging Service Cloud Event Gateway. It also fetches a list of subscriptions for a connected application.

Prerequisites

• Go
• Docker
• kubectl
• kustomize
• Access to a Kubernetes cluster (e.g. k3d / k8s)

Development

Build

make build

Run Tests

Run the unit and integration tests:

make generate-and-test

Linting

1. Fix common lint issues:

   make imports
   make fmt
   make lint

Build Container Images

Build and push your image to the location specified by IMG:

make docker-build docker-push IMG=<container-registry>/eventing-publisher-proxy:<tag> # If using docker, <container-registry> is your username.

For MacBook M1 devices, run:

make docker-buildx IMG=<container-registry>/eventing-publisher-proxy:<tag>

Deployment

You need a Kubernetes cluster to run against. You can use k3d to get a local cluster for testing, or run against a remote cluster.

Deploy Inside a Cluster

$ ko apply -f config/event-publisher-proxy/

Usage

Send Events

The following command supports CloudEvents:

curl -v -X POST \
    -H "Content-Type: application/cloudevents+json" \
    --data @<(<<EOF
    {
        "specversion": "1.0",
        "source": "/default/sap.kyma/kt1",
        "type": "sap.kyma.FreightOrder.Arrived.v1",
        "eventtypeversion": "v1",
        "id": "A234-1234-1234",
        "data" : "{\"foo\":\"bar\"}",
        "datacontenttype":"application/json"
    }
EOF
    ) \
    http://<hostname>/publish

This command supports legacy events:

curl -v -X POST \
    -H "Content-Type: application/json" \
    --data @<(<<EOF
    {
        "event-type": "order.created",
        "event-type-version": "v0",
        "event-time": "2020-04-02T21:37:00Z",
        "data" : "{\"foo\":\"legacy-mode-on\"}"
    }
EOF
    ) \
    http://<hostname>/application-name/v1/events

Get a list of subscriptions for a connected application

curl -v -X GET \
    -H "Content-Type: application/json" \
    http://hostname/:application-name/v1/events/subscribed

Environment Variables

Environment Variable	Default Value	Description
INGRESS_PORT	8080	The ingress port for the CloudEvents Gateway Proxy.
MAX_IDLE_CONNS	100	The maximum number of idle (keep-alive) connections across all hosts. Zero means no limit.
MAX_IDLE_CONNS_PER_HOST	2	The maximum idle (keep-alive) connections to keep per-host. Zero means the default value.
REQUEST_TIMEOUT	5s	The timeout for the outgoing requests to the Messaging server.
CLIENT_ID		The Client ID used to acquire Access Tokens from the Authentication server.
CLIENT_SECRET		The Client Secret used to acquire Access Tokens from the Authentication server.
TOKEN_ENDPOINT		The Authentication Server Endpoint to provide Access Tokens.
EMS_PUBLISH_URL		The Messaging Server Endpoint that accepts publishing CloudEvents to it.
BEB_NAMESPACE		The name of the namespace in BEB.
EVENT_TYPE_PREFIX		The prefix of the eventType as per the BEB event specification.

Flags

Flag	Default Value	Description
max-request-size	65536	The maximum size of the request.
metrics-addr	:9090	The address the metric endpoint binds to.