AWS CloudFormation YAML Validator

This repo contains the source code for my first app that uses AWS's Python Serverless Microframework, chalice. The app is live at https://konekti.us/aws-cf-validator/.

chalice does not have a defined mechanism for distributing code. I've listed the steps you can follow to launch the app.

1. Install python 3.6 on your machine. My OS is Ubuntu 16.04. I used the J Fernyhough’s Personal Package Archive (PPA) as described in this blog post.
2. Create an AWS credentials file. Refer to the boto3 docs for instructions.
3. Use pip, pipenv or other python packaging tool to install the chalice and boto3 modules (e.g., pip install chalice boto3). I recommend using pipenv because it cleanly handles python versions and environments.
4. Execute the commands in the text below.

chalice new-project my-chalice-project
cd my-chalice-project
rm app.py
wget https://raw.githubusercontent.com/konekti/aws-cf-validator/master/app.py
chalice deploy

5. Note the REST API URL that chalice deploy prints. Add the string "validate" to the end. The URL for testing should resemble https://3d7dikellka.execute-api.us-east-1.amazonaws.com/api/validate/. I set the environment variable CFURL to prevent repetitive typing.
6. Download a valid CloudFormation YAML template such as this one.
7. Send a POST request using the data from the template. `curl -H "Content-Type: text/plain" --data-binary @vpc.yaml $CFURL. The response should be "{"validity": "true", "message": "valid"}".

In the case you get stuck, read the chalice README.