Project Diagram

Applications

• news-producer

  Spring Boot Java Web application that exposes a REST API to manage news. It uses DynamoDB as database.

  It has the following endpoints:

     GET /api/news
     GET /api/news/{id}
    POST /api/news {"title": "..."}
    POST /api/news/randomly
  DELETE /api/news/{id}
  

• dynamodb-lambda-function

  Spring Cloud Function application that uses AWS Adapter to convert it to a form that can run in AWS Lambda.

  dynamodb-lambda-function listens to events emitted by an event-source created to monitor changes in DynamoDB news table. Once it receives an event, it processes it and publishes a news event to an SNS topic. Later, SNS publishes the news event to a SQS queue.

• news-consumer

  Spring Boot Java Web application that polls the news events that are queued in a SQS queue.

Prerequisites

• Java 25 or higher;
• A containerization tool (e.g., Docker, Podman, etc.)

Package dynamodb-lambda-function jar

• In a terminal, make sure you inside the springboot-aws-localstack-dynamodb-lambda-sns-sqs root folder:

• Run the following script:

  ./package-dynamodb-lambda-function-jar.sh
  

  When Maven packaging finishes, the jar file generated in dynamodb-lambda-function/target folder is copied to dynamodb-lambda-function/shared folder.

Start and Initialize LocalStack

• In a terminal, make sure you are in inside the springboot-aws-localstack-dynamodb-lambda-sns-sqs root folder:

• Start LocalStack Docker container:

  DEBUG=1 docker compose up -d
  

• [Optional] Debug logs are enabled so that we have more insights about what is happening. To monitor localstack Docker container logs, run the command below:

  docker logs localstack
  

• Initialize LocalStack by running the following script:

  ./init-localstack.sh
  

  The script will create:

  • create news-topic in SNS;
  • create news-consumer-queue in SQS;
  • subscribe news-consumer-queue to news-topic;
  • create news table in DynamoDB;
  • create ProcessDynamoDBEvent Lambda function;
  • create an event-source-mapping to connect DynamoDB to ProcessDynamoDBEvent Lambda function.

Running applications with Maven

• news-producer

  In a terminal and, inside the springboot-aws-localstack-dynamodb-lambda-sns-sqs root folder, run the following command:

  export AWS_REGION=eu-west-1 && export AWS_ACCESS_KEY_ID=key && export AWS_SECRET_ACCESS_KEY=secret && \
    ./mvnw clean spring-boot:run --projects news-producer
  

• news-consumer

  In another terminal and, inside the springboot-aws-localstack-dynamodb-lambda-sns-sqs root folder, run the command below:

  export AWS_REGION=eu-west-1 && export AWS_ACCESS_KEY_ID=key && export AWS_SECRET_ACCESS_KEY=secret && \
    ./mvnw clean spring-boot:run --projects news-consumer
  

Running applications as Docker container

• Build Docker images

  In a terminal and, inside the springboot-aws-localstack-dynamodb-lambda-sns-sqs root folder, run the following script:

  ./build-docker-images.sh
  

• Run Docker containers

  • news-producer

    In a terminal, run the following command:

    docker run --rm --name news-producer -p 9080:9080 \
      -e AWS_REGION=eu-west-1 -e AWS_ACCESS_KEY_ID=key -e AWS_SECRET_ACCESS_KEY=secret \
      --network=springboot-aws-localstack-dynamodb-lambda-sns-sqs_default \
      ivanfranchin/news-producer:1.0.0
    

  • news-consumer

    In a new terminal, run the command below:

    docker run --rm --name news-consumer -p 9081:9081 \
      -e AWS_REGION=eu-west-1 -e AWS_ACCESS_KEY_ID=key -e AWS_SECRET_ACCESS_KEY=secret \
      -e NEWS_PRODUCER_URL=http://news-producer:9080 \
      --network=springboot-aws-localstack-dynamodb-lambda-sns-sqs_default \
      ivanfranchin/news-consumer:1.0.0
    

Application URL

Playing around

• Creating news

  • In a terminal, run the following command:

    curl -i -X POST http://localhost:9080/api/news \
      -H 'Content-Type: application/json' \
      -d '{"title": "Palmeiras is three-time champion of the Copa Libertadores da América"}'
    

    or to create news randomly:

    curl -i -X POST http://localhost:9080/api/news/randomly
    

  • In news-consumer UI, the news should be displayed.

• Deleting news

  • In a terminal, run the following command:

    curl -i -X DELETE http://localhost:9080/api/news/<NEWS-ID>
    

  • In news-consumer UI, the news should be removed.

Demo

In the GIF below, we use news-producer Swagger UI to create one random news. Then, we delete the news created previously. Finally, we create more two more news randomly.

Shutdown

• To stop the applications, go to the terminal 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 springboot-aws-localstack-dynamodb-lambda-sns-sqs root folder, run the following command:

  docker compose down -v
  

Cleanup

To remove the Docker images created by this project, go to a terminal and, inside the springboot-aws-localstack-dynamodb-lambda-sns-sqs root folder, run the script below:

./remove-docker-images.sh