async-durable-execution 2.0.0a1

Community-maintained durable execution SDK for AWS Lambda in Python

Async Durable Execution for Python

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Build reliable, long-running AWS Lambda workflows with checkpointed steps, waits, callbacks, and parallel execution.

This package is distributed from a community-maintained fork of the original Apache-2.0 licensed AWS project and continues under Apache License 2.0 with upstream notices preserved.

This fork is specifically focused on making async Python work naturally with durable functions. The public API remains synchronous at the durable operation boundary, but the examples, helpers, and package direction here prioritize async def handlers, steps, child contexts, callback submitters, and condition checks.

✨ Key Features

• Async-first fork - This fork prioritizes making async def workflows feel natural with durable functions
• Automatic checkpointing - Resume execution after Lambda pauses or restarts
• Durable steps - Run work with retry strategies and deterministic replay
• Waits and callbacks - Pause for time or external signals without blocking Lambda
• Parallel and map operations - Fan out work with configurable completion criteria
• Child contexts - Structure complex workflows into isolated subflows
• Replay-safe logging - Use context.logger for structured, de-duplicated logs
• Local and cloud testing - Validate workflows with the testing SDK
• Async Python support - Use async def for handlers, steps, child contexts, callback submitters, and wait-for-condition checks

📦 Packages

Package	Description	Version
async-durable-execution	Execution SDK for Lambda durable functions
async-durable-execution-runner	Local/cloud test runner and pytest helpers
async-durable-execution-examples	Example durable functions and integration tests for local and cloud workflows	Shared repo version

🚀 Quick Start

This fork recommends writing new durable workflows with async callables by default.

Install the execution SDK:

pip install async-durable-execution

Create a durable Lambda handler:

import asyncio

from async_durable_execution import (
    DurableContext,
    StepContext,
    durable_execution,
    durable_step,
)
from async_durable_execution.config import Duration


@durable_step
async def validate_order(step_ctx: StepContext, order_id: str) -> dict:
    await asyncio.sleep(0)
    step_ctx.logger.info("Validating order", extra={"order_id": order_id})
    return {"order_id": order_id, "valid": True}


@durable_execution
async def handler(event: dict, context: DurableContext) -> dict:
    order_id = event["order_id"]
    context.logger.info("Starting workflow", extra={"order_id": order_id})

    validation = context.step(validate_order(order_id), name="validate_order")
    if not validation["valid"]:
        return {"status": "rejected", "order_id": order_id}

    # simulate approval (real world: use wait_for_callback)
    context.wait(duration=Duration.from_seconds(5), name="await_confirmation")

    return {"status": "approved", "order_id": order_id}

Async callables are supported anywhere the SDK accepts user code, including map() item functions, parallel() branches, child contexts, callback submitters, and wait-for-condition checks. The public Durable APIs stay synchronous, so async work is awaited transparently for you:

import asyncio

from async_durable_execution import (
    DurableContext,
    StepContext,
    durable_execution,
    durable_step,
)


@durable_step
async def fetch_order(step_ctx: StepContext, order_id: str) -> dict:
    await asyncio.sleep(0)
    step_ctx.logger.info("Fetched order", extra={"order_id": order_id})
    return {"order_id": order_id, "status": "ready"}


@durable_execution
async def handler(event: dict, context: DurableContext) -> dict:
    order = context.step(fetch_order(event["order_id"]), name="fetch_order")
    return {"order": order}

📚 Documentation

The complete documentation for the AWS Durable Execution SDK for Python lives on the AWS Documentation site:

• AWS Durable Execution Documentation - Concepts, getting started, core operations, advanced topics, and API reference
• AWS Lambda Durable Functions Guide - How durable functions work on Lambda

💬 Feedback & Support

• Bug report
• Feature request
• Documentation feedback
• Contributing guide

📄 License

See the LICENSE file for our project's licensing.