Type annotations for boto3 DatabaseMigrationService

Warnings

• breaking Python 3.8 support was removed starting with `mypy-boto3-builder` version 8.12.0. Ensure your project uses Python 3.9 or newer.
  Fix: Upgrade your Python environment to 3.9 or a later version.
• breaking TypeDef naming conventions changed in `mypy-boto3-builder` 8.9.0. Some packed method arguments now use shorter names (e.g., `RequestRequestTypeDef` -> `RequestTypeDef`), and conflicting `Extra` postfixes were moved (`ExtraRequestTypeDef` -> `RequestExtraTypeDef`). While this applies generally to generated service stubs, it may impact DMS TypeDefs if such patterns were used.
  Fix: Update your code to reflect the new TypeDef naming conventions if you were using explicitly imported TypeDefs that matched these patterns.
• gotcha PyCharm may experience slow performance or high CPU usage with `Literal` overloads, a common pattern in `mypy-boto3` stubs. It is recommended to use `boto3-stubs-lite` or disable PyCharm's internal type checker in favor of `mypy` or `pyright`.
  Fix: Consider installing `boto3-stubs-lite` (if available for DMS) or configure PyCharm to use external type checkers like Mypy/Pyright for `boto3` code.
• gotcha While many IDEs offer auto-discovery, explicitly annotating your `boto3.client('dms')` calls with `DatabaseMigrationServiceClient` provides the most robust type checking and autocompletion experience.
  Fix: Add explicit type annotations, as shown in the quickstart example: `client: DatabaseMigrationServiceClient = boto3.client("dms")`.
• gotcha `mypy-boto3-dms` is a stub-only package (PEP 561) and does not contain any runtime code. It must be installed in the same Python environment as `boto3` and `mypy` for type checkers to correctly find and utilize its type information.
  Fix: Ensure `mypy-boto3-dms` is installed via `pip` (or equivalent package manager) in the environment where your type checker runs. Avoid relying on `MYPYPATH` for stub-only packages.

Install

• pip install mypy-boto3-dms boto3 mypy Install with pip

Imports

• DatabaseMigrationServiceClient

  from mypy_boto3_dms.client import DatabaseMigrationServiceClient

  Primary client type for DMS.
• DescribeReplicationTasksResponseTypeDef

  from mypy_boto3_dms.type_defs import DescribeReplicationTasksResponseTypeDef

  Example TypeDef for API response structures.
• AssessmentReportTypeType

  from mypy_boto3_dms.literals import AssessmentReportTypeType

  Example Literal type for specific string values.

Quickstart

This quickstart demonstrates how to initialize a `boto3` DMS client with type annotations and perform a simple API call. The `TYPE_CHECKING` block ensures that type-only imports do not incur runtime overhead. Replace placeholder environment variables with actual AWS credentials for real use.

import boto3
from typing import TYPE_CHECKING
from os import environ

if TYPE_CHECKING:
    from mypy_boto3_dms.client import DatabaseMigrationServiceClient
    from mypy_boto3_dms.type_defs import DescribeReplicationTasksResponseTypeDef

def list_dms_replication_tasks() -> "DescribeReplicationTasksResponseTypeDef":
    """Lists DMS replication tasks with type hints."""
    # Explicitly type the client for enhanced IDE support and static analysis.
    client: DatabaseMigrationServiceClient = boto3.client(
        "dms",
        region_name=environ.get("AWS_REGION", "us-east-1"),
        aws_access_key_id=environ.get("AWS_ACCESS_KEY_ID", "TEST_ACCESS_KEY"),
        aws_secret_access_key=environ.get("AWS_SECRET_ACCESS_KEY", "TEST_SECRET_KEY"),
    )
    response = client.describe_replication_tasks()
    print("DMS Replication Tasks:", response.get("ReplicationTasks"))
    return response

if __name__ == "__main__":
    list_dms_replication_tasks()