AWS Lambda Function with Spring Boot and Java 17

This project demonstrates a serverless AWS Lambda function built using Spring Boot 3.2 and Java 17. It leverages Spring Cloud Function to seamlessly integrate Spring Boot with AWS Lambda runtime.

Features

• ✅ Java 17
• ✅ Spring Boot 3.2.1
• ✅ Spring Cloud Function 4.1.0
• ✅ AWS Lambda Java Core & Events
• ✅ Maven build with Shade plugin
• ✅ Unit tests with JUnit 5

Project Structure

.
├── pom.xml                                          # Maven configuration
├── src
│   ├── main
│   │   ├── java/com/example/lambda
│   │   │   ├── LambdaApplication.java              # Spring Boot application
│   │   │   ├── LambdaHandler.java                  # AWS Lambda entry point
│   │   │   ├── Request.java                        # Request POJO
│   │   │   └── Response.java                       # Response POJO
│   │   └── resources
│   │       └── application.properties              # Spring configuration
│   └── test
│       └── java/com/example/lambda
│           ├── LambdaApplicationTests.java         # Context load test
│           └── ProcessRequestFunctionTests.java    # Function tests
└── README.md

Prerequisites

• Java 17 or higher
• Maven 3.6 or higher
• AWS CLI (for deployment)
• AWS Account with appropriate permissions

Building the Project

Build the project using Maven:

mvn clean package

This will create two JAR files in the target directory:

• aws-lambda-spring-boot-1.0.0.jar - Regular JAR
• aws-lambda-spring-boot-1.0.0-aws.jar - Shaded JAR with all dependencies (use this for AWS Lambda)

Running Tests

Run all tests:

mvn test

Local Testing

You can test the function locally using the AWS SAM CLI or by creating a simple test harness.

Example Test Input

{
  "name": "John Doe",
  "message": "Hello from Lambda"
}

Expected Output

{
  "message": "Hello John Doe! Your request has been processed successfully.",
  "status": "SUCCESS",
  "timestamp": 1706024897113
}

Deployment to AWS Lambda

Step 1: Create Lambda Function

Using AWS CLI:

aws lambda create-function \
  --function-name spring-boot-lambda \
  --runtime java17 \
  --role arn:aws:iam::YOUR_ACCOUNT_ID:role/lambda-execution-role \
  --handler com.example.lambda.LambdaHandler::handleRequest \
  --zip-file fileb://target/aws-lambda-spring-boot-1.0.0-aws.jar \
  --timeout 30 \
  --memory-size 512 \
  --environment Variables={SPRING_CLOUD_FUNCTION_DEFINITION=processRequest}

Step 2: Update Function Code

After making changes, update the function:

mvn clean package
aws lambda update-function-code \
  --function-name spring-boot-lambda \
  --zip-file fileb://target/aws-lambda-spring-boot-1.0.0-aws.jar

Step 3: Test the Function

aws lambda invoke \
  --function-name spring-boot-lambda \
  --payload '{"name":"John Doe","message":"Test"}' \
  response.json

cat response.json

Configuration

Lambda Handler

The Lambda handler is configured in LambdaHandler.java:

• Handler: com.example.lambda.LambdaHandler::handleRequest

Spring Cloud Function

The function is defined in LambdaApplication.java:

• Function Name: processRequest
• Input: Request object
• Output: Response object

Application Properties

Configuration in src/main/resources/application.properties:

spring.application.name=aws-lambda-spring-boot
spring.cloud.function.definition=processRequest

Customization

Adding New Functions

1. Create a new @Bean method in LambdaApplication.java:

@Bean
public Function<MyRequest, MyResponse> myFunction() {
    return request -> {
        // Your logic here
        return new MyResponse();
    };
}

2. Update application.properties:

spring.cloud.function.definition=myFunction

Environment Variables

Set environment variables in AWS Lambda console or via CLI:

aws lambda update-function-configuration \
  --function-name spring-boot-lambda \
  --environment Variables={SPRING_CLOUD_FUNCTION_DEFINITION=processRequest,LOG_LEVEL=DEBUG}

Performance Considerations

• Cold Start: Spring Boot Lambda functions may have longer cold start times. Consider using:

  • AWS Lambda SnapStart (for Java 11+)
  • Provisioned Concurrency
  • Reducing dependencies

• Memory: Allocate sufficient memory (512MB-1024MB recommended for Spring Boot)

• Timeout: Set appropriate timeout (30 seconds recommended minimum)

Troubleshooting

Common Issues

1. ClassNotFoundException: Ensure you're using the -aws.jar shaded artifact
2. Timeout: Increase Lambda timeout in function configuration
3. Out of Memory: Increase Lambda memory allocation

Viewing Logs

aws logs tail /aws/lambda/spring-boot-lambda --follow

License

This project is open source and available under the MIT License.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.