Example - Publish and subscribe to messages

This example utilizes a publisher and a subscriber to show the bidirectional pubsub pattern. It creates a publisher and calls the publish_event method in the DaprClient. In the ssubscriber.py file it creates a subscriber object that can call the next_message method to get new messages from the stream. After processing the new message, it returns a status to the stream.

Note: Make sure to use the latest proto bindings

Pre-requisites

• Dapr CLI and initialized environment
• Install Python 3.10+

Install Dapr python-SDK

Run async example where users control reading messages off the stream

Run the following command in a terminal/command prompt:

# 1. Start Subscriber
dapr run --app-id python-subscriber --app-protocol grpc -- python3 subscriber.py --topic=TOPIC_B1

In another terminal/command prompt run:

# 2. Start Publisher
dapr run --app-id python-publisher --app-protocol grpc --dapr-grpc-port=3500 --enable-app-health-check -- python3 publisher.py --topic=TOPIC_B1

Run async example with a handler function

Run the following command in a terminal/command prompt:

# 1. Start Subscriber
dapr run --app-id python-subscriber --app-protocol grpc -- python3 subscriber-handler.py --topic=TOPIC_B2

In another terminal/command prompt run:

# 2. Start Publisher
dapr run --app-id python-publisher --app-protocol grpc --dapr-grpc-port=3500 --enable-app-health-check -- python3 publisher.py --topic=TOPIC_B2

Cleanup