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Dapr pub/sub

In this quickstart, you'll create a publisher microservice and a subscriber microservice to demonstrate how Dapr enables a publish-subcribe pattern. The publisher generates messages for a specific topic, while the subscriber listen for messages in specific topics.

Check out the documentation about Dapr pubsub for more details.

Note: This example leverages the Dapr Client SDK. You can find an example using plain HTTP in the http folder.

This quickstart includes one publisher: Go client message generator checkout

And one subscriber: Go subscriber order-processor

Run all apps with multi-app run template file:

This section shows how to run both applications at once using multi-app run template files with dapr run -f .. This enables to you test the interactions between multiple applications.

Open a new terminal window and run the multi app run template:

dapr run -f .

The terminal console output should look similar to this:

== APP - checkout-sdk == Published data: {"orderId":1}
== APP - order-processor-sdk == Subscriber received: map[orderId:1]
== APP - checkout-sdk == Published data: {"orderId":2}
== APP - order-processor-sdk == Subscriber received: map[orderId:2]
== APP - checkout-sdk == Published data: {"orderId":3}
== APP - order-processor-sdk == Subscriber received: map[orderId:3]
== APP - checkout-sdk == Published data: {"orderId":4}
== APP - order-processor-sdk == Subscriber received: map[orderId:4]
== APP - checkout-sdk == Published data: {"orderId":5}
== APP - order-processor-sdk == Subscriber received: map[orderId:5]
== APP - checkout-sdk == Published data: {"orderId":6}
== APP - order-processor-sdk == Subscriber received: map[orderId:6]
== APP - checkout-sdk == Published data: {"orderId":7}
== APP - order-processor-sdk == Subscriber received: map[orderId:7]
== APP - checkout-sdk == Published data: {"orderId":8}
== APP - order-processor-sdk == Subscriber received: map[orderId:8]
== APP - checkout-sdk == Published data: {"orderId":9}
== APP - order-processor-sdk == Subscriber received: map[orderId:9]
== APP - checkout-sdk == Published data: {"orderId":10}
== APP - order-processor-sdk == Subscriber received: map[orderId:10]

Stop and clean up application processes

dapr stop -f .

Run a single app at a time with Dapr (Optional)

An alternative to running all or multiple applications at once is to run single apps one-at-a-time using multiple dapr run .. -- dotnet run commands. This next section covers how to do this.

Run Go message subscriber with Dapr

Run the Go subscriber app with Dapr in the order-processor folder:

cd ./order-processor
dapr run --app-port 6005 --app-id order-processor-sdk --app-protocol http --dapr-http-port 3501 --resources-path ../../../components -- go run .

Run Go message publisher with Dapr

1 Run the Go publisher app with Dapr in the checkout folder:

cd ./checkout
dapr run --app-id checkout-sdk --app-protocol http --dapr-http-port 3500 --resources-path ../../../components -- go run .

To stop:

dapr stop --app-id checkout-sdk
dapr stop --app-id order-processor-sdk

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