capo-swf: typed, async Python SDK for AWS SWF

capo-swf is a typed Python SDK for AWS SWF. It has an async client, AsyncSWFClient, for asyncio and trio, and a sync client, SWFClient, with the same methods. Requests and responses are typed with TypedDicts, so your editor and type checker know every field.

It is part of capo, a community-driven alternative to boto3 and aioboto3, built on its own HTTP stack instead of botocore and generated from the official AWS Smithy models. Documentation: https://capo-sdk.dev/services/swf/

Installation

pip install capo-swf

Usage

from capo_swf import AsyncSWFClient


async def main():
    async with AsyncSWFClient() as swf:
        # Example: call the count_closed_workflow_executions operation
        response = await swf.count_closed_workflow_executions()
        print(response["count"])

Pagination

Some operations in this SDK support pagination. If the operation supports pagination it will have an iter_ prefixed method that returns an async iterator.

from capo_swf import AsyncSWFClient


async def main():
    async with AsyncSWFClient() as swf:
        # Example: paginate over get_workflow_execution_history
        async for item in swf.iter_get_workflow_execution_history():
            print(item)

Error Handling

The SDK raises exceptions for errors returned by the API. Catch them to handle failures gracefully.

from capo_swf import AsyncSWFClient
from capo_swf.error import OperationNotPermittedFault


async def main():
    async with AsyncSWFClient() as swf:
        try:
            await swf.count_closed_workflow_executions()
        except OperationNotPermittedFault as e:
            print(f"Error: {e}")
            print(e.data)  # additional error data

Retrying

The SDK retries failed operations automatically. Retry behaviour follows the Smithy specification: errors are retried based on their is_retryable and is_throttling_error attributes. Throttling errors use a longer base delay. Network-level failures (connection errors and timeouts) are also retried. Non-retryable errors, such as client errors without the @retryable trait, are raised immediately without further attempts.

The number of attempts defaults to 3 and can be changed at the client level via retry_max_attempts, or per call via config_overrides.

from capo_swf import AsyncSWFClient


async def main():
    async with AsyncSWFClient() as swf:
        # Default: 3 attempts for every operation
        response = await swf.count_closed_workflow_executions()

        # Override per operation
        response = await swf.count_closed_workflow_executions(config_overrides={"retry_max_attempts": 5})

        # Disable retries for this call
        response = await swf.count_closed_workflow_executions(config_overrides={"retry_max_attempts": 1})