https://github.com/amancevice/python-lambda-gateway

Simple HTTP server to invoke a Lambda function locally
https://github.com/amancevice/python-lambda-gateway

api-gateway asyncio cli lambda python zero-dependency

Last synced: about 2 months ago
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Simple HTTP server to invoke a Lambda function locally

• Host: GitHub
• URL: https://github.com/amancevice/python-lambda-gateway
• Owner: amancevice
• License: mit
• Created: 2020-04-27T16:31:15.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2024-03-10T15:19:32.000Z (10 months ago)
• Last Synced: 2024-10-10T04:07:55.146Z (2 months ago)
• Topics: api-gateway, asyncio, cli, lambda, python, zero-dependency
• Language: Python
• Size: 122 KB
• Stars: 15
• Watchers: 4
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Lambda Gateway

[![pypi](https://img.shields.io/pypi/v/lambda-gateway?color=yellow&logo=python&logoColor=eee&style=flat-square)](https://pypi.org/project/lambda-gateway/)

[![python](https://img.shields.io/pypi/pyversions/lambda-gateway?logo=python&logoColor=eee&style=flat-square)](https://pypi.org/project/lambda-gateway/)

[![pytest](https://img.shields.io/github/actions/workflow/status/amancevice/python-lambda-gateway/pytest.yml?logo=github&style=flat-square)](https://github.com/amancevice/python-lambda-gateway/actions/workflows/pytest.yml)

[![coverage](https://img.shields.io/codeclimate/coverage/amancevice/python-lambda-gateway?logo=code-climate&style=flat-square)](https://codeclimate.com/github/amancevice/python-lambda-gateway/test_coverage)

[![maintainability](https://img.shields.io/codeclimate/maintainability/amancevice/python-lambda-gateway?logo=code-climate&style=flat-square)](https://codeclimate.com/github/amancevice/python-lambda-gateway/maintainability)

Test AWS Lambda functions invoked as API Gateway proxy integrations locally.

This tool extends the native Python SimpleHTTPRequestHandler to proxy requests to a local Lambda function using the ThreadingHTTPServer.

This tool is was specifically implemented to use the standard Python library only. No additional pip installation is required.

After installing, navigate to the directory where your Lambda function is defined and invoke it with the CLI tool using the configured handler, eg:

```bash

lambda-gateway [-p PORT] [-t SECONDS] lambda_function.lambda_handler

# => Serving HTTP on :: port 8000 (http://[::]:8000/) ...

```

## Installation

Install with pip.

```bash

pip install lambda-gateway

```

## Usage

Create a Lambda function handler in Python 3

```python

# ./lambda_function.py

import json

def lambda_handler(event, context=None):

    # Get name from qs

    params = event.get('queryStringParameters') or {}

    name = params.get('name') or 'Pythonista'

    # Return response

    return {

        'body': json.dumps({'text': f'Hello, {name}! ~ Lambda Gateway'}),

        'statusCode': 200,

        'headers': {

            'Content-Type': 'application/json',

        },

    }

```

Start a local server with the signature of your Lambda handler as the argument.

_Note — the handler must be importable from the current working directory_

```bash

lambda-gateway [-B PATH] [-b ADDR] [-p PORT] [-t SECONDS] lambda_function.lambda_handler

# => Starting LambdaRequestHandler at http://localhost:8000/

```

Test the function with cURL.

```bash

curl http://localhost:8000/?name=Pythonista

# => {"text": "Hello, Pythonista! ~ Lambda Gateway"}

```

## Timeouts

API Gateway imposes a 30 second timeout on Lambda responses. This constraint is implemented in this project using Python's async/await syntax.

The timeout length can be adjusted using the `-t / --timeout` CLI option.

```bash

lambda-gateway -t 3 lambda_function.lambda_handler

```

## API Gateway Payloads

API Gateway supports [two versions](https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop-integrations-lambda.html) of proxied JSON payloads to Lambda integrations, `1.0` and `2.0`.

Versions `0.8+` of Lambda Gateway use `2.0` by default, but this can be changed at startup time using the `-V / --payload-version` option:

```bash

lambda-gateway -V1.0 lambda_function.lambda_handler

```