kudoh/lambda-snapstart-example

Lambda SnapStart with Micronaut and Serverless Framework

Install

Install Serverless Framework and Micronaut to your computer.

# Serverless Framework
npm install -g serverless

# Micronaut CLI
sdk install micronaut

# Create app
mn create-function-app com.mamezou.lambda-snapstart --features=aws-lambda --build=gradle --lang=java
cd lambda-snapstart/

Implementation

Add CRaC to use runtime hooks.

dependencies {
    // ...

    // add crac runtime hooks
    implementation group: 'io.github.crac', name: 'org-crac', version: '0.1.3'
}

Implements org.crac.Resource to your handler and add anything code to CRaC runtime hooks.

public class FunctionRequestHandler extends MicronautRequestHandler<APIGatewayProxyRequestEvent, APIGatewayProxyResponseEvent>
        implements Resource { // Interface追加

    @Inject
    ObjectMapper objectMapper;
    private static final SecureRandom random = new SecureRandom();
    private static int checkpointId;
    private static int restoreId;

    // Resource登録
    public FunctionRequestHandler() {
        Core.getGlobalContext().register(this);
    }

    @Override
    public APIGatewayProxyResponseEvent execute(APIGatewayProxyRequestEvent input) {
        APIGatewayProxyResponseEvent response = new APIGatewayProxyResponseEvent();
        try {
            System.out.printf("checkpointId:%d,restoreId:%d%n", checkpointId, restoreId);
            String json = objectMapper.writeValueAsString(Collections.singletonMap("message", "Hello World"));
            response.setStatusCode(200);
            response.setBody(json);
        } catch (JsonProcessingException e) {
            response.setStatusCode(500);
        }
        return response;
    }

    // CRaC Runtime Hooks追加
    @Override
    public void beforeCheckpoint(Context<? extends Resource> context) {
        checkpointId = random.nextInt();
        System.out.printf("BEFORE CHECKPOINT:%d%n", checkpointId);
    }

    @Override
    public void afterRestore(Context<? extends Resource> context) {
        restoreId = random.nextInt();
        System.out.printf("AFTER RESTORE:%d%n", restoreId);
    }
}

Build

Build with all-in-one jar by gradle task.

./gradlew shadowJar

Deploy to Lambda

see serverless.yml to enable Lambda SnapStart.

serverless deploy