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spring-cloud-stream-solace-pubsub

License: MIT Buy Me A Coffee

A publish/subscribe demo using Solace PubSub+ and Spring Cloud Stream. A REST API publishes news events to topic ps/news/{type}/{country}/{city}, with consumer instances filtering by news type, country or city to showcase topic-based routing.

Proof-of-Concepts & Articles

On ivangfr.github.io, I have compiled my Proof-of-Concepts (PoCs) and articles. You can easily search for the technology you are interested in by using the filter. Who knows, perhaps I have already implemented a PoC or written an article about what you are looking for.

Additional Readings

Project Overview

flowchart TB
    subgraph users ["Users"]
        HTTP["REST Clients"]
        Browser["Browser"]
    end

    subgraph producer-service ["producer-service:9080 (Spring Boot)"]
        RestCtrl["NewsController /api/news"]
        NewsProducer["NewsEventProducer (StreamBridge)"]
    end

    subgraph solace ["Solace PubSub+"]
        Broker["Message Broker ps/news/*/*/*"]
        Manager["PubSub+ Manager http://localhost:8080"]
    end

    subgraph consumer-service ["consumer-service:9081 (Spring Boot)"]
        direction TB
        Consumer1["NewsEventConsumer instance-1\n(BR subscription)\nps/news/*/BR/>"]
        Consumer2["NewsEventConsumer instance-2\n(HEALTH subscription)\nps/news/HEALTH/>"]
    end

    HTTP -->|"POST /api/news"| RestCtrl
    HTTP -->|"POST /api/news/random"| RestCtrl
    Browser -->|"accesses"| Manager
    RestCtrl -->|"delegates"| NewsProducer
    NewsProducer -->|"publishes news events"| Broker
    Broker -->|"delivers to matching topics"| Consumer1
    Broker -->|"delivers to matching topics"| Consumer2
Loading

Applications

  • producer-service

    Spring Boot application that exposes a REST API to submit news events. It publishes news to the following destination with the format: ps/news/{type}/{country}/{city}

    Endpoints

    POST /api/news {"type": [SPORT|ECONOMY|HEALTH], "country": "...", "city": "...", "title": "..."}
POST /api/news/random {"number": ..., "delay": ...}

  • consumer-service

    Spring Boot application that consumes the news events published by producer-service.

Prerequisites

Start Environment

Open a terminal and inside the spring-cloud-stream-solace-pubsub root folder run:

docker compose up -d

Running Applications with Maven

  • producer-service

    • In a terminal, make sure you are in the spring-cloud-stream-solace-pubsub root folder.
    • Run the commands below: 
      ./mvnw clean spring-boot:run --projects producer-service

  • consumer-service-1

    • It subscribes to all news from Brazil.
    • Open a new terminal and navigate to the spring-cloud-stream-solace-pubsub root folder.
    • Run the commands below: 
      export NEWS_SUBSCRIPTION="ps/news/*/BR/>"
./mvnw clean spring-boot:run --projects consumer-service

  • consumer-service-2

    • It subscribes to all news related to HEALTH.
    • Open a new terminal and navigate to the spring-cloud-stream-solace-pubsub root folder.
    • Run the commands below: 
      export SERVER_PORT=9082
export NEWS_SUBSCRIPTION="ps/news/HEALTH/>"
./mvnw spring-boot:run --projects consumer-service

Running Applications as Docker containers

  • Build Docker Images

    • In a terminal, make sure you are inside the spring-cloud-stream-solace-pubsub root folder.
    • Run the following script to build the Docker images: 
      ./build-docker-images.sh

  • Environment Variables

    • producer-service

      Environment Variable Description
      SOLACE_HOST Specify host of the Solace PubSub+ message broker to use (default localhost)
      SOLACE_PORT Specify port of the Solace PubSub+ message broker to use (default 55556)

    • consumer-service

      Environment Variable Description
      SOLACE_HOST Specify host of the Solace PubSub+ message broker to use (default localhost)
      SOLACE_PORT Specify port of the Solace PubSub+ message broker to use (default 55556)

  • Run Docker Containers

    • producer-service

      Run the following command in a terminal:

      docker run --rm --name producer-service \
  -p 9080:9080 \
  -e SOLACE_HOST=solace -e SOLACE_PORT=55555 \
  --network=spring-cloud-stream-solace-pubsub_default \
  ivanfranchin/producer-service:1.0.0

    • consumer-service-1

      • It subscribes to all news from Brazil.
      • Open a new terminal and run the following command: 
        docker run --rm --name consumer-service-1 \
  -p 9081:9081 \
  -e SOLACE_HOST=solace -e SOLACE_PORT=55555 \
  -e NEWS_SUBSCRIPTION="ps/news/*/BR/>" \
  --network=spring-cloud-stream-solace-pubsub_default \
  ivanfranchin/consumer-service:1.0.0

    • consumer-service-2

      • It subscribes to all news related to HEALTH.
      • Open a new terminal and run the following command: 
        docker run --rm --name consumer-service-2 \
  -p 9082:9081 \
  -e SOLACE_HOST=solace -e SOLACE_PORT=55555 \
  -e NEWS_SUBSCRIPTION="ps/news/HEALTH/>" \
  --network=spring-cloud-stream-solace-pubsub_default \
  ivanfranchin/consumer-service:1.0.0

Playing around

In a terminal, submit the following POST requests to producer-service and check its logs and consumer-service logs.

Note: HTTPie is being used in the calls below

  • Sending news one by one

    • Just consumer-service-1 should consume:

      http :9080/api/news type="SPORT" country="BR" city="SaoPaulo" title="..."

    • Just consumer-service-2 should consume:

      http :9080/api/news type="HEALTH" country="PT" city="Porto" title="..."

    • Neither consumer-service-1 nor consumer-service-2 should consume:

      http :9080/api/news type="ECONOMY" country="DE" city="Berlin" title="..."

    • Both consumer-service-1 and consumer-service-2 should consume:

      http :9080/api/news type="HEALTH" country="BR" city="Brasilia" title="..."

  • Sending a number of news randomly with a specified delay in milliseconds:

    http :9080/api/news/random number=10 delayInMillis=1000 --stream

Useful Links

  • Solace

    Solace can be accessed at http://localhost:8080. Enter admin for both the username and password.

Shutdown

  • To stop applications, go to the terminals where they are running and press Ctrl+C.
  • To stop and remove docker compose containers, network and volumes, go to a terminal and, inside the spring-cloud-stream-solace-pubsub root folder, run the following command: 
    docker compose down -v

Running Tests

In a terminal, make sure you are inside the spring-cloud-stream-solace-pubsub root folder:

  • producer-service

    ./mvnw clean test --projects producer-service

  • consumer-service

    ./mvnw clean test --projects consumer-service

Cleanup

To remove the Docker images created by this project, go to a terminal and, inside the spring-cloud-stream-solace-pubsub root folder, run the following script:

./remove-docker-images.sh

Code Formatting

This project enforces consistent Java formatting using the Spotless Maven plugin with google-java-format (GOOGLE style).

  • Check formatting:

    ./mvnw spotless:check

  • Auto-fix formatting:

    ./mvnw spotless:apply

Formatting is enforced automatically during ./mvnw test.

Issues

The default Solace SMF port 55555 is not working, at least on my Mac machine. The problem is explained in this issue. For now, I've changed the mapping port from 55555 to 55556.

Support

If you find this useful, consider buying me a coffee:

Buy Me A Coffee

License

This project is licensed under the MIT License.

References

About

A publish/subscribe demo using Solace PubSub+ and Spring Cloud Stream. A REST API publishes news events to topic ps/news/{type}/{country}/{city}, with consumer instances filtering by news type, country or city to showcase topic-based routing.

Topics

dockerjavasolace-pubsubspring-bootspring-cloud-streamspring-webflux

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MIT license
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