Event Publisher Proxy

Overview

The Event 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 modules
• ko
• lint
  • Install lint on the local environment:

curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | bash -s -- -b $GOPATH/bin

Development

• check code quality before a commit:

$ make code-check

Build

$ go mod vendor

Test

$ make test-local

Deploy inside a cluster

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

Send Events

This 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.
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