Streaming PubSub in the Dapr Python SDK

These examples demonstrate how to use the Dapr Python SDK to create a subscriber application that listens to a topic and receives messages from a publisher application. The subscriber application can be run in two modes: regular subscription and streaming subscription.

Running in self-hosted mode

Prerequisites for running locally

1. Install Dapr CLI and Runtime
Ensure that you have Dapr installed on your system:

dapr --version

If not installed, follow the Dapr installation guide

2. Install Python 3.8+
   Ensure that you have Python 3.8 or higher installed on your system. If not, download and install it from the official Python website.

3. Install Dependencies
   Install the required Python libraries for the subscriber applications:

pip3 install -r requirements.txt

4. Configure Components This example uses Redis as the pub/sub broker. Ensure Redis is installed and running locally. Also make sure the details of the default Redis component in the ../components directory match your local Redis installation. Refer to the Dapr pub/sub documentation for details.

Run the example: self-hosted mode

1. Run the publisher
   The publisher is written in Go, to make use of goroutines

export PUBSUB_NAME=mypubsub
export TOPIC_NAME=mytopic
cd publisher
dapr run --app-id python-publisher --app-protocol grpc --enable-app-health-check --resources-path=../components -- go run main.go

2. Run the subscriber with regular subscription

cd regular-pubsub
dapr run --app-id python-subscriber --app-protocol grpc --app-port 50051 --resources-path=../components -- python3 subscriber.py

3. Run the subscriber with streaming subscription

cd streaming-pubsub
dapr run --app-id python-subscriber --resources-path=../components -- python3 subscriber-handler.py

Running in Kubernetes

Prerequisites for running in Kubernetes

• A Kubernetes cluster

Run the example

Run the setup script:

./setup.sh

The script will set the context to kind-kind, but you can override this by running it with the desired context as the first argument:

./setup.sh mycontext