pubsub-simple

Example - Publish and subscribe to messages

This example utilizes a publisher and a subscriber to show the pubsub pattern, it also shows PublishEvent, OnTopicEvent and GetTopicSubscriptions functionality. It creates a publisher and calls the publish_event method in the DaprClient. It will create a gRPC subscriber and bind the OnTopicEvent method, which gets triggered after a message is published to the subscribed topic.

Note: Make sure to use the latest proto bindings

Pre-requisites

• Dapr CLI and initialized environment
• Install Python 3.7+

Install Dapr python-SDK

pip3 install dapr dapr-ext-grpc

Run the example

Run the following command in a terminal/command prompt:

# 1. Start Subscriber (expose gRPC server receiver on port 50051)
dapr run --app-id python-subscriber --app-protocol grpc --app-port 50051 python3 subscriber.py

In another terminal/command prompt run:

# 2. Start Publisher
dapr run --app-id python-publisher --app-protocol grpc --dapr-grpc-port=3500 python3 publisher.py

Cleanup

dapr stop --app-id python-publisher
dapr stop --app-id python-subscriber