Azure EventHub Stream Proxy

A gRPC service to proxy (broadcast) stream of events from Azure EventHub to multiple clients.

How it works

A client calls Subscribe() on proxy. Once there are events in the EventHub, the proxy server streams events by calling ReceiveEvents() on each client.

Prerequisites

Bazel

This project is built using bazel in version >= 3.7.0. More information on Bazel: https://bazel.build/. More information on Bazelisk: https://github.com/bazelbuild/bazelisk.

Python

You need to use Python >= 3.8.

Configuring

Configuration is done using flags. Flags can be defined in flag_files/server_flags. To get detailed help on flags, run:

bazelisk run eventhub_stream_proxy:eventhub_stream_proxy -- --help

bazelisk run eventhub_stream_proxy:example_client -- --help

More information on flags: https://abseil.io/docs/python/guides/flags

Running

Server

bazelisk run eventhub_stream_proxy:eventhub_stream_proxy -- --flagfile=`pwd`/flag_files/server_flags

Example client(s)

bazelisk run eventhub_stream_proxy:example_client -- --eventhub_stream_proxy_address=localhost:50002

Integrating

Contract is defined in proto: proto/event.proto.

1. A client subscribes (EventSubscription::Subscribe) to a server to get the stream of events (Event).
2. A client implements EventReceiver to run each time new event is streamed.

More information on proto: https://developers.google.com/protocol-buffers/docs/proto3

Example

Please refer to eventhub_stream_proxy/example_client.py, where there is an example client implementation in Python. Since the service is written using gRPC, a client can be desinged using any framework supported by gRPC. More information on gRPC: https://grpc.io/

Running unit tests

bazelisk test ...:all

Building Docker image and pushing to the image registry

Append following rule to eventhub_stream_proxy/BUILD file:

container_push(
  name = "eventhub_stream_proxy_image_push",
  format = "Docker",
  image = ":eventhub_stream_proxy_image",
  registry = "YOUR_IMAGE_REGISTRY",
  repository = "YOUR_IMAGE_REPOSITORY",
  tag = "{BUILD_EMBED_LABEL}",
)

Replace YOUR_IMAGE_REGISTRY and YOUR_IMAGE_REPOSITORY with your values.

Then run the image push:

bazelisk run eventhub_stream_proxy:eventhub_stream_proxy_image_push --embed_label=1.2.3.4