boto-stubs.md

boto stubs

boto3-stubs are built by mypy_boto3_builder.

Install stubs per service, eg: for ec2

pip install boto3-stubs[ec2]

This will install the following packages:

• boto3-stubs - these files
• boto3
• mypy_boto3 - dynamically generates boto3.client/boto3.resource stubs
• mypy_boto3_ec2

Explicit type hints

Import the type stubs to use them as explicit type hints:

import boto3
from mypy_boto3_ec2 import Client

ec2_client:Client = boto3.client("ec2")

print(ec2_client.describe_instances())

Explicit type hints are needed in PyCharm. They are also needed to annotate function arguments or return values.

The disadvantage of using explicit type hints is it requires shipping the boto3-stubs package with your application, or using typing.TYPE_CHECKING to skip the imports in production code.

Use mypy_boto3 to generate boto3.client/boto3.resource stubs for implicit usage

Given boto3-stubs[ec2] is installed, then:

python -m mypy_boto3

Will generate the mypy_boto3.ec2 package containing client, service etc modules. This package in turn imports from mypy_boto3_ec2.

The generated modules enable usage of boto3.client and boto3.resource without explicit type hints:

import boto3

ec2_client = boto3.client("ec2")

print(ec2_client.describe_instances())

The advantage of implicit type hints is you don't need to import mypy_boto3_ec2 and therefore ship it with your application.

Reference

See also mypy_boto3/#4