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Typing

This typing utility provides static typing classes that can be used to ease the development by providing the IDE type hints.

Key features

  • Add static typing classes
  • Ease the development by leveraging your IDE's type hints
  • Avoid common typing mistakes in Python

Utilities Typing

Getting started

Tip

All examples shared in this documentation are available within the project repository.

We provide static typing for any context methods or properties implemented by Lambda context object.

LambdaContext

The LambdaContext typing is typically used in the handler method for the Lambda function.

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from aws_lambda_powertools.utilities.typing import LambdaContext


def handler(event: dict, context: LambdaContext) -> dict:
    # Insert business logic
    return event

Working with context methods and properties

Using LambdaContext typing makes it possible to access information and hints of all properties and methods implemented by Lambda context object.

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from time import sleep

import requests

from aws_lambda_powertools import Logger
from aws_lambda_powertools.utilities.typing import LambdaContext

logger = Logger()


def lambda_handler(event, context: LambdaContext) -> dict:
    limit_execution: int = 1000  # milliseconds

    # scrape website and exit before lambda timeout
    while context.get_remaining_time_in_millis() > limit_execution:
        comments: requests.Response = requests.get("https://jsonplaceholder.typicode.com/comments")
        # add logic here and save the results of the request to an S3 bucket, for example.

        logger.info(
            {
                "operation": "scrape_website",
                "request_id": context.aws_request_id,
                "remaining_time": context.get_remaining_time_in_millis(),
                "comments": comments.json()[:2],
            },
        )

        sleep(1)

    return {"message": "Success"}

Available properties and methods

Name Type Description
function_name property The name of the Lambda function
function_version property The version of the function
invoked_function_arn property The Amazon Resource Name (ARN) that's used to invoke the function
memory_limit_in_mb property The amount of memory that's allocated for the function
aws_request_id property The identifier of the invocation request
log_group_name property The log group for the function
log_stream_name property The log stream for the function instance
identity property Information about the Amazon Cognito identity that authorized the request
client_context property Client context that's provided to Lambda by the client application
tenant_id property The tenant_id used to invoke the function
get_remaining_time_in_millis method Returns the number of milliseconds left before the execution times out