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Module state

durable_execution_sdk

Module state 

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Execution state management for the AWS Durable Execution SDK.

This module provides the core state management types for durable executions, including checkpoint tracking, replay logic, and operation state management.

§Module Structure

  • checkpoint_result - Result types for checkpoint queries
  • replay_status - Replay state tracking
  • batcher - Checkpoint batching for efficient API calls
  • execution_state - Main execution state management

§Checkpoint Token Management

The SDK uses checkpoint tokens to ensure exactly-once checkpoint semantics:

  1. Initial Token: The first checkpoint uses the CheckpointToken from the DurableExecutionInvocationInput provided by Lambda.

  2. Token Updates: Each successful checkpoint returns a new token that MUST be used for the next checkpoint. The SDK automatically updates the token after each successful checkpoint.

  3. Token Consumption: Once a token is used for a checkpoint, it is consumed and cannot be reused. Attempting to reuse a consumed token results in an InvalidParameterValueException error.

  4. Error Handling: If a checkpoint fails with “Invalid checkpoint token”, the error is marked as retriable so Lambda can retry with a fresh token.

§Requirements

  • 2.9: THE Checkpointing_System SHALL use the CheckpointToken from invocation input for the first checkpoint
  • 2.10: THE Checkpointing_System SHALL use the returned CheckpointToken from each checkpoint response for subsequent checkpoints
  • 2.11: THE Checkpointing_System SHALL handle InvalidParameterValueException for invalid tokens by allowing propagation for retry

Structs§

BatchResult
Result of processing a batch of checkpoints.
CheckpointBatcher
The checkpoint batcher collects checkpoint requests and sends them in batches.
CheckpointBatcherConfig
Configuration for the checkpoint batcher.
CheckpointRequest
A request to checkpoint an operation.
CheckpointSender
Handle for sending checkpoint requests to the batcher.
CheckpointedResult
Result of checking for a checkpointed operation.
ExecutionState
Manages the execution state for a durable execution.

Enums§

ReplayStatus
Replay status indicating whether we’re replaying or executing new operations.

Functions§

create_checkpoint_queue
Creates a checkpoint queue with the given buffer size.