Type annotations for boto3 MigrationHub

1.42.3 · active · verified Sat Apr 11

mypy-boto3-mgh provides type annotations for the boto3 MigrationHub service, enhancing static type checking for AWS SDK usage in Python. It is currently at version 1.42.3 and follows the release cadence of `mypy-boto3-builder`, which often aligns with `boto3` releases or significant internal changes, leading to frequent updates across many stub packages.

Warnings

breaking Beginning with `mypy-boto3-builder` version 8.12.0 (and consequently all generated stub packages, including `mypy-boto3-mgh` 1.42.3), Python 3.8 is no longer supported. Projects targeting Python 3.8 will fail to type-check or even install these stubs.
Fix: Upgrade your Python environment to 3.9 or newer.
breaking The `mypy-boto3-builder` (from version 8.9.0) introduced breaking changes to TypeDef naming conventions. Argument TypeDefs now use shorter names (e.g., `CreateDistributionRequestRequestTypeDef` -> `CreateDistributionRequestTypeDef`), and conflicting `Extra` postfixes are moved to the end (e.g., `CreateDistributionExtraRequestTypeDef` -> `CreateDistributionRequestExtraTypeDef`). This affects all generated service stubs.
Fix: Update your code to use the new TypeDef names. Refer to the specific service module's documentation for exact naming, or rely on IDE auto-completion.
gotcha While `mypy-boto3` aims for automatic type discovery, some IDEs (like VSCode) may require explicit type annotations for `boto3.client()`, `session.client()`, `.get_waiter()`, and `.get_paginator()` calls to provide full auto-completion and type checking. PyCharm users are sometimes recommended to use `mypy-boto3-lite` to avoid performance issues with `Literal` overloads.
Fix: Explicitly annotate the return type of `boto3.client('service')` calls, e.g., `client: MigrationHubClient = boto3.client('migrationhub')`. If using PyCharm and experiencing performance issues, consider `mypy-boto3-lite` or check for IDE updates.

Install

pip install mypy-boto3-mgh Install service stub
pip install boto3 Install boto3 runtime (required)
pip install mypy Install Mypy (optional, for type checking)

Imports

MigrationHubClient
```
from mypy_boto3_mgh.client import MigrationHubClient
```
Client types are located in the '.client' submodule for direct import.
MigrationHubServiceName
```
from mypy_boto3_mgh.literals import MigrationHubServiceName
```
Literal types for service names are useful for precise overloading.

Quickstart

This quickstart demonstrates how to obtain a type-hinted MigrationHub client using `boto3` and `mypy-boto3-mgh`. The `TYPE_CHECKING` block is a common pattern to avoid importing stubs in production environments.

import os
import boto3
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from mypy_boto3_mgh.client import MigrationHubClient

def get_migrationhub_client() -> "MigrationHubClient":
    """
    Retrieves a typed boto3 MigrationHub client.
    """
    # boto3 automatically picks up credentials from environment variables,
    # shared credential files, or IAM roles.
    # For a quickstart, we assume credentials are set up.
    session = boto3.Session(region_name=os.environ.get("AWS_REGION", "us-east-1"))
    client: "MigrationHubClient" = session.client("migrationhub")
    
    return client

if __name__ == "__main__":
    # This example requires AWS credentials configured in your environment
    # (e.g., AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_REGION)
    # or via ~/.aws/credentials.
    
    # Try to get a client
    mgh_client = get_migrationhub_client()
    print(f"Successfully obtained MigrationHub client: {mgh_client}")
    
    # You can now use mgh_client with full type hints, e.g.:
    # response = mgh_client.list_application_states()
    # print(response)

view raw JSON →