aws-sdk-java-v2-lambda

# AWS SDK for Java 2.x - AWS Lambda ## Overview AWS Lambda is a compute service that runs code without managing servers. Use this skill to implement AWS Lambda operations using AWS SDK for Java 2.x in applications and services. ## When to Use - Invoking Lambda functions from Java applications - Deploying and updating Lambda functions via SDK - Managing function configurations and layers - Integrating Lambda with Spring Boot applications ## Quick Reference | Operation | SDK Method | Use Case | |-----------|------------|----------| | **Invoke** | `invoke()` | Synchronous/async function invocation | | **List Functions** | `listFunctions()` | Get all Lambda functions | | **Get Config** | `getFunction()` | Retrieve function configuration | | **Create Function** | `createFunction()` | Create new Lambda function | | **Update Code** | `updateFunctionCode()` | Deploy new function code | | **Update Config** | `updateFunctionConfiguration()` | Modify settings (timeout, memory, env vars) | | **Delete Function** | `deleteFunction()` | Remove Lambda function | ## Instructions ### 1. Add Dependencies Include Lambda SDK dependency in `pom.xml`: ```xml <dependency> <groupId>software.amazon.awssdk</groupId> <artifactId>lambda</artifactId> </dependency> ``` See [client-setup.md](references/client-setup.md) for complete setup. ### 2. Create Client Instantiate `LambdaClient` with proper configuration: ```java LambdaClient lambdaClient = LambdaClient.builder() .region(Region.US_EAST_1) .build(); ``` For async operations, use `LambdaAsyncClient`. ### 3. Invoke Lambda Function Synchronous invocation: ```java InvokeRequest request = InvokeRequest.builder() .functionName("my-function") .payload(SdkBytes.fromUtf8String(payload)) .build(); InvokeResponse response = lambdaClient.invoke(request); return response.payload().asUtf8String(); ``` See [invocation-patterns.md](references/invocation-patterns.md) for patterns. ### 4. Handle Responses Parse response payloads and check for errors: ```java if (response.functionError() != null) { throw new LambdaInvocationException("Lambda error: " + response.functionError()); } String result = response.payload().asUtf8String(); ``` ### 5. Manage Functions Create, update, or delete Lambda functions: ```java // Create CreateFunctionRequest createRequest = CreateFunctionRequest.builder() .functionName("my-function") .runtime(Runtime.JAVA17) .role(roleArn) .code(code) .build(); lambdaClient.createFunction(createRequest); // Verify function is active before proceeding GetFunctionRequest getRequest = GetFunctionRequest.builder() .functionName("my-function") .build(); GetFunctionResponse getResponse = lambdaClient.getFunction(getRequest); if (!"Active".equals(getResponse.configuration().state())) { throw new IllegalStateException("Function not active: " + getResponse.configuration().stateReason()); } // Update code UpdateFunctionCodeRequest updateCodeRequest = UpdateFunctionCodeRequest.builder() .functionName("my-function") .zipFile(SdkBytes.fromByteArray(zipBytes)) .build(); lambdaClient.updateFunctionCode(updateCodeRequest); // Wait for deployment to complete Waiter<GetFunctionConfigurationRequest> waiter = lambdaClient.waiter(); waiter.waitUntilFunctionUpdatedActive(GetFunctionConfigurationRequest.builder() .functionName("my-function") .build()); ``` See [function-management.md](references/function-management.md) for complete patterns. ### 6. Configure Environment Set environment variables and concurrency limits: ```java Environment env = Environment.builder() .variables(Map.of( "DB_URL", "jdbc:postgresql://db", "LOG_LEVEL", "INFO" )) .build(); UpdateFunctionConfigurationRequest configRequest = UpdateFunctionConfigurationRequest.builder() .functionName("my-function") .environment(env) .timeout(60) .memorySize(512) .build(); lambdaClient.updateFunctionConfiguration(configRequest); ``` ### 7. Integrate with Spring Boot Configure Lambda beans and services: ```java @Configuration public class LambdaConfiguration { @Bean public LambdaClient lambdaClient() { return LambdaClient.builder() .region(Region.US_EAST_1) .build(); } } @Service public class LambdaInvokerService { public <T, R> R invoke(String functionName, T request, Class<R> responseType) { // Implementation } } ``` See [spring-boot-integration.md](references/spring-boot-integration.md) for complete integration. ### 8. Test Locally Use mocks or LocalStack for development testing. See [testing.md](references/testing.md) for testing patterns. ## Examples ### Basic Invocation ```java public String invokeFunction(LambdaClient client, String functionName, String payload) { InvokeRequest request = InvokeRequest.builder() .functionName(functionName) .payload(SdkBytes.fromUtf8String(payload)) .build(); InvokeResponse response = client.invoke(request); if (response.functionError() != null) { throw new RuntimeException("Lambda error: " + response.functionError()); } return response.payload().asUtf8String(); } ``` ### Async Invocation ```java public void invokeAsync(LambdaClient client, String functionName, Map<String, Object> event) { String jsonPayload = new ObjectMapper().writeValueAsString(event); InvokeRequest request = InvokeRequest.builder() .functionName(functionName) .invocationType(InvocationType.EVENT) .payload(SdkBytes.fromUtf8String(jsonPayload)) .build(); client.invoke(request); } ``` ### Spring Boot Service ```java @Service public class LambdaService { private final LambdaClient lambdaClient; public UserResponse processUser(UserRequest request) { String payload = objectMapper.writeValueAsString(request); InvokeResponse response = lambdaClient.invoke( InvokeRequest.builder() .functionName("user-processor") .payload(SdkBytes.fromUtf8String(payload)) .build() ); return objectMapper.readValue( response.payload().asUtf8String(), UserResponse.class ); } } ``` See [examples.md](references/examples.md) for more examples. ## Best Practices - **Reuse clients**: Create `LambdaClient`/`LambdaAsyncClient` once; they are thread-safe - **Use async client**: For fire-and-forget invocations, use `LambdaAsyncClient` with `CompletableFuture` - **Verify deployments**: Always wait for function state to be `Active` after create/update operations - **Limit payload size**: Keep request/response payloads under 256KB for async, 6MB for sync invocations - **Configure timeouts**: Set client read timeout slightly higher than Lambda function timeout - **Use latest runtime**: Specify `Runtime.JAVA17` or newer for improved cold start performance ## Constraints and Warnings - **Payload Limit**: 6MB (sync), 256KB (async invocation) - **Timeout**: Max 900 seconds (15 minutes) per invocation - **Cold Starts**: JVM-based functions have longer cold starts; use GraalVM Native Image for improvement - **Deployment Size**: Function code + layers must not exceed 50MB (zipped) or 250MB (unzipped) - **Concurrency**: Default 1000 per region; use reserved concurrency to guarantee capacity - **Cost**: Monitor with CloudWatch metrics; set billing alerts to prevent runaway costs ## References - **[client-setup.md](references/client-setup.md)** — Client configuration and setup - **[invocation-patterns.md](references/invocation-patterns.md)** — Synchronous and async invocation patterns - **[function-management.md](references/function-management.md)** — Create, update, delete functions - **[spring-boot-integration.md](references/spring-boot-integration.md)** — Spring Boot configuration and services - **[testing.md](references/testing.md)** — Unit and integration testing patterns - **[examples.md](references/examples.md)** — Complete code examples and integration patterns - **[official-documentation.md](references/official-documentation.md)** — AWS Lambda concepts and API reference ## Related Skills - `aws-sdk-java-v2-core` — Core AWS SDK patterns and client configuration - `spring-boot-dependency-injection` — Spring dependency injection best practices - `unit-test-service-layer` — Service testing patterns with Mockito - `spring-boot-actuator` — Production monitoring and health checks ## External Resources - [Lambda Examples on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/lambda) - [Lambda API Reference](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/package-summary.html) - [AWS Lambda Developer Guide](https://docs.aws.amazon.com/lambda/latest/dg/welcome.html)