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Spring Boot SNS Lambda

Description​

In this example we will publish messages to an SNS topic, and Lambda from a Spring Boot application.

Prerequisites​

Run LocalStack​

version: '3.8'

services:
  localstack:
    image: localstack/localstack
    container_name: localstack_main
    ports:
      - "4566-4599:4566-4599"
    environment:
      - SERVICES=sns,s3,sqs,dynamodb,ses,lambda,logs,stepfunctions
      - DYNAMODB_SHARE_DB=1
      - DEBUG=1
      - DATA_DIR=/tmp/localstack/data
      - DOCKER_HOST=unix:///var/run/docker.sock
    volumes:
      - "${LOCALSTACK_VOLUME_DIR:-./volume}:/var/lib/localstack"
      - "/var/run/docker.sock:/var/run/docker.sock"

Create Topic​

awslocal sns create-topic --name localstack-topic --region us-east-1

Create a Subscription​

awslocal sns subscribe \
--region us-east-1 \
--protocol lambda \
--topic-arn arn:aws:sns:us-east-1:000000000000:localstack-topic \
--notification-endpoint arn:aws:lambda:us-east-1:000000000000:function:localstack-lambda-sns

Project Structure​

.
├── sns-lambda
│   ├── pom.xml
│   ├── src
│   │   ├── main
│   │   │   ├── java
│   │   │   │   └── com
│   │   │   │       └── example
│   │   │   │           ├── Main.java
│   │   │   │           └── SnsRequestHandler.java
│   │   │   └── resources
│   │   └── test
│   │       └── java
│   └── target
│       ├── classes
│       ├── original-sns-trigger-lambda-0.0.1.jar
│       ├── sns-trigger-lambda-0.0.1.jar
│       └── test-classes
|
└── spring-boot-sns-lambda
    ├── mvnw
    ├── mvnw.cmd
    ├── pom.xml
    ├── README.md
    ├── src
    │   ├── main
    │   │   ├── java
    │   │   │   └── com
    │   │   │       └── jreact
    │   │   │           └── sns
    │   │   │               ├── PersonRequest.java
    │   │   │               ├── SNSAppConfig.java
    │   │   │               └── SNSApp.java
    │   │   └── resources
    │   │       └── application.properties
    │   └── test
    │       └── java
    └── target

  • Lambda Function​

    https://github.com/ZbCiok/zjc-examples/tree/main/aws/aws/sns/spring-boot-sns-lambda/sns-lambda

    package com.example;

    import com.amazonaws.services.lambda.runtime.Context;
    import com.amazonaws.services.lambda.runtime.LambdaLogger;
    import com.amazonaws.services.lambda.runtime.RequestHandler;
    import com.amazonaws.services.lambda.runtime.events.SNSEvent;

    import java.util.List;
    import com.amazonaws.services.lambda.runtime.events.SNSEvent.SNSRecord;
    import lombok.extern.java.Log;

    import java.util.Iterator;

    @Log
    public class SnsRequestHandler implements RequestHandler<SNSEvent, Boolean> {
        LambdaLogger logger;
        private SNSEvent event;

        @Override
        public Boolean handleRequest(SNSEvent event, Context context) {
            log.info(">>> start handleRequest...");
            logger = context.getLogger();
            List<SNSRecord> records = event.getRecords();

            if (!records.isEmpty()) {
                Iterator<SNSRecord> recordsIter = records.iterator();
                while (recordsIter.hasNext()) {
                    processRecord(recordsIter.next());
                }
            }
            return Boolean.TRUE;
        }

        public void processRecord(SNSRecord record) {
            try {
                String message = record.getSNS().getMessage();
                logger.log(">>> message: " + message);
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }
    note

    SNSEvent​

    https://javadoc.io/doc/com.amazonaws/aws-lambda-java-events/3.7.0/com/amazonaws/services/lambda/runtime/events/SNSEvent.html

  • Run Lambda Function​

awslocal lambda create-function \
    --region us-east-1 \
    --function-name localstack-lambda-sns \
    --runtime java21 \
    --zip-file fileb://sns-trigger-lambda-0.0.1.jar \
    --handler com.example.SnsRequestHandler \
    --role arn:aws:iam::000000000000:role/example-lambda-noop-role \
    --timeout 120
mvn clean install
mvn spring-boot:run

  • Output (Docker Log):​


...
localstack_main  | 2024-10-07T15:06:10.577 DEBUG --- [ns:$LATEST_1] l.s.l.i.version_manager    : [localstack-lambda-sns-9977d26f-34e3-4fd8-b718-488404fe7eb3] INFO: >>> start handleRequest...
localstack_main  | 2024-10-07T15:06:10.577 DEBUG --- [ns:$LATEST_1] l.s.l.i.version_manager    : [localstack-lambda-sns-9977d26f-34e3-4fd8-b718-488404fe7eb3] >>> message: {"id":0,"firstName":"Jack","lastName":"Smith","age":30,"address":"Address02"}END RequestId: 9977d26f-34e3-4fd8-b718-488404fe7eb3
...
localstack_main  | 2024-10-07T15:06:10.602 DEBUG --- [ns:$LATEST_0] l.s.l.i.version_manager    : [localstack-lambda-sns-d762704c-0d15-4dee-9b45-543fb9193d6e] INFO: >>> start handleRequest...
localstack_main  | 2024-10-07T15:06:10.602 DEBUG --- [ns:$LATEST_0] l.s.l.i.version_manager    : [localstack-lambda-sns-d762704c-0d15-4dee-9b45-543fb9193d6e] >>> message: {"id":0,"firstName":"John","lastName":"Doe","age":26,"address":"Address01"}END RequestId: d762704c-0d15-4dee-9b45-543fb9193d6e
...
{"id":0,"firstName":"Jack","lastName":"Smith","age":30,"address":"Address02"}
{"id":0,"firstName":"John","lastName":"Doe","age":26,"address":"Address01"}