flask-lambda

Python module to make Flask compatible with AWS Lambda for creating RESTful applications.

Installation

pip install flask-lambda

Usage

This module works pretty much just like Flask. This allows you to run and develop this applicaiton locally just like you would in Flask. When ready deploy to Lambda, and configure the handler as:

my_python_file.app

Here is an example of what my_python_file.py would look like:

import json
from flask import request
from flask_lambda import FlaskLambda

app = FlaskLambda(__name__)


@app.route('/foo', methods=['GET', 'POST'])
def foo():
    data = {
        'form': request.form.copy(),
        'args': request.args.copy(),
        'json': request.json
    }
    return (
        json.dumps(data, indent=4, sort_keys=True),
        200,
        {'Content-Type': 'application/json'}
    )


if __name__ == '__main__':
    app.run(debug=True)

Flask-RESTful

Nothing special here, this module works without issue with Flask-RESTful as well.

API Gateway

Configure your API Gateway with a {proxy+} resource with an ANY method. Your "Method Response" should likely include an application/json "Response Body for 200" that uses the Empty model.

Deploying

Consider using python-mu.

Lambda Test Event

If you wish to use the "Test" functionality in Lambda for your function, you will need a "API Gateway AWS Proxy" event. Below is an event to test the above sample application:

{
  "body": "{\"test\":\"body\"}",
  "resource": "/{proxy+}",
  "requestContext": {
    "resourceId": "123456",
    "apiId": "1234567890",
    "resourcePath": "/{proxy+}",
    "httpMethod": "POST",
    "requestId": "c6af9ac6-7b61-11e6-9a41-93e8deadbeef",
    "accountId": "123456789012",
    "identity": {
      "apiKey": null,
      "userArn": null,
      "cognitoAuthenticationType": null,
      "caller": null,
      "userAgent": "Custom User Agent String",
      "user": null,
      "cognitoIdentityPoolId": null,
      "cognitoIdentityId": null,
      "cognitoAuthenticationProvider": null,
      "sourceIp": "127.0.0.1",
      "accountId": null
    },
    "stage": "prod"
  },
  "queryStringParameters": {
    "foo": "bar"
  },
  "headers": {
    "Via": "1.1 08f323deadbeefa7af34d5feb414ce27.cloudfront.net (CloudFront)",
    "Accept-Language": "en-US,en;q=0.8",
    "CloudFront-Is-Desktop-Viewer": "true",
    "CloudFront-Is-SmartTV-Viewer": "false",
    "CloudFront-Is-Mobile-Viewer": "false",
    "X-Forwarded-For": "127.0.0.1, 127.0.0.2",
    "CloudFront-Viewer-Country": "US",
    "Accept": "application/json",
    "Upgrade-Insecure-Requests": "1",
    "X-Forwarded-Port": "443",
    "Host": "1234567890.execute-api.us-east-1.amazonaws.com",
    "X-Forwarded-Proto": "https",
    "X-Amz-Cf-Id": "cDehVQoZnx43VYQb9j2-nvCh-9z396Uhbp027Y2JvkCPNLmGJHqlaA==",
    "CloudFront-Is-Tablet-Viewer": "false",
    "Cache-Control": "max-age=0",
    "User-Agent": "Custom User Agent String",
    "CloudFront-Forwarded-Proto": "https",
    "Accept-Encoding": "gzip, deflate, sdch",
    "Content-Type": "application/json"
  },
  "pathParameters": {
    "proxy": "foo"
  },
  "httpMethod": "POST",
  "stageVariables": {
    "baz": "qux"
  },
  "path": "/foo"
}

To update your test event, click "Actions" -> "Configure test event".

sivel / flask-lambda