Python GitHub Webhooks

Simple Python WSGI application to handle GitHub webhooks.

Install

git clone git@github.com:carlos-jenkins/python-github-webhooks.git
cd python-github-webhooks

Dependencies

sudo pip install -r requirements.txt

Setup

You can configure what the application does by changing config.json:

{
    "github_ips_only": true,
    "enforce_secret": "",
    "return_scripts_info": true
}

github_ips_only:	Restrict application to be called only by GitHub IPs. IPs whitelist is obtained from GitHub Meta (endpoint). Default: true.
enforce_secret:	Enforce body signature with HTTP header X-Hub-Signature. See secret at GitHub WebHooks Documentation. Default: '' (do not enforce).
return_scripts_info:	Return a JSON with the stdout, stderr and exit code for each executed hook using the hook name as key. If this option is set you will be able to see the result of your hooks from within your GitHub hooks configuration page (see "Recent Deliveries"). Default: true.

Adding Hooks

This application will execute scripts in the hooks directory using the following order:

hooks/{event}-{name}-{branch}
hooks/{event}-{name}
hooks/{event}
hooks/all

The application will pass to the hooks the path to a JSON file holding the payload for the request as first argument. The event type will be passed as second argument. For example:

hooks/push-myrepo-master /tmp/sXFHji push

Hooks can be written in any scripting language as long as the file is executable and has a shebang. A simple example in Python could be:

#!/usr/bin/env python
# Python Example for Python GitHub Webhooks
# File: push-myrepo-master

import sys
import json

with open(sys.argv[1], 'r') as jsf:
  payload = json.loads(jsf.read())

### Do something with the payload
name = payload['repository']['name']
outfile = '/tmp/hook-{}.log'.format(name)

with open(outfile, 'w') as f:
    f.write(json.dumps(payload))

Not all events have an associated branch, so a branch-specific hook cannot fire for such events. For events that contain a pull_request object, the base branch (target for the pull request) is used, not the head branch.

Deploy

Apache

To deploy in Apache, just add a WSGIScriptAlias directive to your VirtualHost file:

<VirtualHost *:80>
    ServerAdmin you@my.site.com
    ServerName  my.site.com
    DocumentRoot /var/www/site.com/my/htdocs/

    # Handle Github webhook
    <Directory "/var/www/site.com/my/python-github-webhooks">
        Order deny,allow
        Allow from all
    </Directory>
    WSGIScriptAlias /webhooks /var/www/site.com/my/python-github-webhooks/webhooks.py

</VirtualHost>

You can now add that URL to your Github repository settings:

https://github.com/youruser/myrepo/settings/hooks

And add a Webhook to the WSGI script URL:

http://my.site.com/webhooks

Docker

To deploy in a Docker container you have to expose the port 5000, for example with the following command:

docker run -d --name webhooks -p 5000:5000 python-github-webhooks

You can also mount volume to setup the hooks/ directory, and the file config.json:

docker run -d --name webhooks \
  -v /path/to/my/hooks:/src/hooks \
  -v /path/to/my/config.json:/src/config.json \
  -p 5000:5000 python-github-webhooks

Debug

When running in Apache, the stderr of the hooks that return non-zero will be logged in Apache's error logs. For example:

sudo tail -f /var/log/apache2/error.log

Will log errors in your scripts if printed to stderr.

You can also launch the Flask web server in debug mode at port 5000.

python webhooks.py

This can help debug problem with the WSGI application itself.

License

Copyright (C) 2014-2015 Carlos Jenkins <carlos@jenkins.co.cr>

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.

Credits

This project is just the reinterpretation and merge of two approaches:

• github-webhook-wrapper.
• flask-github-webhook.

Thanks.