Package software.amazon.lambda.durable

Class DurableHandler<I,O>

java.lang.Object
software.amazon.lambda.durable.DurableHandler<I,O>
All Implemented Interfaces:
com.amazonaws.services.lambda.runtime.RequestStreamHandler
Direct Known Subclasses:
CallbackExample, ChildContextExample, CustomConfigExample, CustomPollingExample, ErrorHandlingExample, GenericInputOutputExample, GenericTypesExample, LoggingExample, ManyAsyncChildContextExample, ManyAsyncStepsExample, NoopExample, RetryExample, RetryInProcessExample, SimpleInvokeExample, SimpleStepExample, WaitAsyncExample, WaitAtLeastExample, WaitAtLeastInProcessExample, WaitExample
public abstract class DurableHandler<I,O> extends Object implements com.amazonaws.services.lambda.runtime.RequestStreamHandler

  • Constructor Details

    • DurableHandler

      protected DurableHandler()

  • Method Details

    • getConfiguration

      public DurableConfig getConfiguration()
      Gets the configuration used by this handler. This allows test frameworks and other tools to access the handler's configuration for testing purposes.

      DurableConfig is immutable.

      Returns:
      The DurableConfig instance used by this handler

    • createConfiguration

      protected DurableConfig createConfiguration()
      Template method for creating configuration. Override this method to provide custom DurableExecutionClient, SerDes, or other configuration.

      The LambdaDurableFunctionsClient is a wrapper that customers should use to inject their own configured LambdaClient. This allows full control over AWS SDK configuration including credentials, region, HTTP client, and retry policies.

      Basic example with custom region and credentials: 

      
 @Override
 protected DurableConfig createConfiguration() {
     // Create custom Lambda client with specific configuration
     var lambdaClient = LambdaClient.builder()
         .region(Region.US_WEST_2)
         .credentialsProvider(ProfileCredentialsProvider.create("my-profile"))
         .build();

     // Wrap the Lambda client with LambdaDurableFunctionsClient
     var durableClient = new LambdaDurableFunctionsClient(lambdaClient);

     return DurableConfig.builder()
         .withDurableExecutionClient(durableClient)
         .build();
 }

      Advanced example with AWS CRT HTTP Client for high-performance scenarios: 

      
 @Override
 protected DurableConfig createConfiguration() {
     // Configure AWS CRT HTTP Client for optimal performance
     var crtHttpClient = AwsCrtAsyncHttpClient.builder()
         .maxConcurrency(50)
         .connectionTimeout(Duration.ofSeconds(30))
         .connectionMaxIdleTime(Duration.ofSeconds(60))
         .build();

     // Create Lambda client with CRT HTTP client
     var lambdaClient = LambdaClient.builder()
         .region(Region.US_EAST_1)
         .credentialsProvider(EnvironmentVariableCredentialsProvider.create())
         .httpClient(crtHttpClient)
         .overrideConfiguration(ClientOverrideConfiguration.builder()
             .retryPolicy(RetryPolicy.builder()
                 .numRetries(5)
                 .build())
             .build())
         .build();

     // Wrap with LambdaDurableFunctionsClient
     var durableClient = new LambdaDurableFunctionsClient(lambdaClient);

     return DurableConfig.builder()
         .withDurableExecutionClient(durableClient)
         .withSerDes(customSerDes)  // Optional: custom SerDes for user data
         .withExecutorService(customExecutor)  // Optional: custom thread pool
         .build();
 }
      Returns:
      DurableConfig with desired configuration

    • handleRequest

      public final void handleRequest(InputStream inputStream, OutputStream outputStream, com.amazonaws.services.lambda.runtime.Context context) throws IOException
      Specified by:
      handleRequest in interface com.amazonaws.services.lambda.runtime.RequestStreamHandler
      Throws:
      IOException

    • handleRequest

      public abstract O handleRequest(I input, DurableContext context)
      Handle the durable execution.
      Parameters:
      input - User input
      context - Durable context for operations
      Returns:
      Result

    • createObjectMapper

      public static com.fasterxml.jackson.databind.ObjectMapper createObjectMapper()
      Creates ObjectMapper for DAR backend communication (internal use only). This is for INTERNAL use only - handles Lambda Durable Functions backend protocol.

      Customer-facing serialization uses SerDes from DurableConfig.

      Returns:
      Configured ObjectMapper for durable backend communication