Type Annotations for Boto3 SWF

1.42.3 · active · verified Sat Apr 11

mypy-boto3-swf provides a set of type annotations (stubs) for the boto3 SWF (Simple Workflow Service) client. It enables static type checking with tools like MyPy for `boto3` interactions, enhancing code reliability and developer experience. The library is actively maintained, with new versions released frequently in sync with `boto3` updates and `mypy-boto3-builder` developments.

Warnings

breaking Python 3.8 support has been officially removed starting with `mypy-boto3-builder` version 8.12.0 (which generated `mypy-boto3-swf` 1.42.3). Projects using these stubs now require Python 3.9 or higher.
Fix: Upgrade your Python environment to 3.9 or newer.
breaking All `mypy-boto3` packages, including `mypy-boto3-swf`, migrated to PEP 561 compliant distributions with `mypy-boto3-builder` 8.12.0. This might affect how type checkers locate and use stubs in specific build or environment configurations.
Fix: Ensure your project's `pyproject.toml` or `setup.cfg` is correctly configured for PEP 561 stub packages, and update your type checker to a recent version.
gotcha `mypy-boto3-swf` provides *only* type annotations (stubs). It does not include the `boto3` runtime itself. For your code to run, you must install `boto3` as well.
Fix: Always ensure both `boto3` and `mypy-boto3-swf` are installed in your project (e.g., `pip install boto3 mypy-boto3-swf`).
breaking Older projects using the monolithic `mypy-boto3` package for all services should migrate to service-specific stub packages like `mypy-boto3-swf`. The builder changed to separate products in 8.9.0.
Fix: Replace `mypy-boto3` with `mypy-boto3-<service>` packages for specific AWS services you use, e.g., `pip install mypy-boto3-swf`.

Install

pip install boto3 mypy-boto3-swf Install `boto3` runtime and SWF stubs

Imports

SWFClient
```
from mypy_boto3_swf.client import SWFClient
```
Import for type-hinting the boto3 SWF client object.
ListDomainsResponseTypeDef
```
from mypy_boto3_swf.type_defs import ListDomainsResponseTypeDef
```
Import for type-hinting specific response objects or other TypeDefs.
boto3.client('swf')
```
import boto3; client: SWFClient = boto3.client('swf')
```
The actual client object comes from `boto3`; `mypy-boto3-swf` provides only the type definitions for it.

Quickstart

This example demonstrates how to initialize a type-hinted SWF client using `boto3.client` and then use it with `mypy-boto3-swf`'s stubs for static analysis. It shows how to import and apply `SWFClient` for the client object and `ListDomainsResponseTypeDef` for API call responses, ensuring type safety for your `boto3` interactions.

import boto3
from mypy_boto3_swf.client import SWFClient
from mypy_boto3_swf.type_defs import ListDomainsResponseTypeDef, DomainInfoTypeDef

# Create a typed SWF client
# Note: boto3 itself needs to be installed, mypy-boto3-swf only provides type stubs.
client: SWFClient = boto3.client("swf")

try:
    # List registered domains and type-hint the response
    response: ListDomainsResponseTypeDef = client.list_domains(
        registrationStatus="REGISTERED",
        maximumPageSize=5
    )
    print(f"Registered SWF Domains: {response.get('domainInfos', [])}")

    # Example of processing specific domain info with a TypeDef
    def process_domain_info(domain_info: DomainInfoTypeDef) -> None:
        print(f"Domain Name: {domain_info['name']}, Status: {domain_info['status']}")

    if 'domainInfos' in response and response['domainInfos']:
        process_domain_info(response['domainInfos'][0])

except Exception as e:
    print(f"Error listing domains: {e}")

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