github-event-handler.py

#!/usr/bin/python

from __future__ import print_function

import argparse
import logging
import collections
import os
import json
import requests
import tempfile
import time
import sys


class StateFileStore(object):
    """Store some headers from github requests"""
    def __init__(self, org):
        self.headers = {}
        self.org = org
        self._state_filename = "gh-event-handler_%s.json" % org
        # FIXME(toabctl): it's stupid to use tempdir to store data!
        self._state_datadir = tempfile.gettempdir()
        if os.environ.has_key('XDG_CACHE_HOME'):
            self._state_datadir = os.environ['XDG_CACHE_HOME']

    def write(self):
        dest = os.path.join(self._state_datadir, self._state_filename)
        with open(dest, "w") as f:
            json.dump(self.headers, f)

    def read(self):
        src = os.path.join(self._state_datadir, self._state_filename)
        if os.path.exists(src):
            with open(src, "r") as f:
                self.headers = json.load(f)


def handle_events(events_list):
    """handle a list of events"""
    for e in events_list:
        logging.debug(
            "Received event '%s' for '%s' from '%s'" % (
                e["type"], e["repo"]["name"], e["actor"]["login"]))
        #if e["type"] == "PullRequestEvent":
        #    print(e["repo"]["name"], e["org"]["login"])
            #print(e.keys())
        #elif e["type"] == "PushEvent":
        #    print("Push detected")


def get_events(org, state):
    EventsInfo = collections.namedtuple("Events", ["event_list", "next_run"])

    # custom headers we want to set
    headers = {}
    if "etag" in state.headers.keys():
        headers["If-None-Match"] = state.headers["etag"]

    url = "https://api.github.com/orgs/%s/events" % org
    r = requests.get(url, headers=headers)

    if r.status_code == 304:
        # not modified (and does not count for the rate-limit), so
        # rerun shortly
        return EventsInfo([], 5)
    elif r.status_code == 200:
        # remember some specific headers
        state.headers = {k: r.headers[k] for k in (
            'etag', 'x-poll-interval')}

        # process events
        data = r.json()
        return EventsInfo(data, int(r.headers['x-poll-interval']))

    else:
        raise Exception(
            "'%s' while trying to access '%s'" % (
                r.status_code, url))


def handle_args():
    parser = argparse.ArgumentParser(description="process github events for a "
                                     "given organization")
    parser.add_argument("org", help="name of the github organization")
    parser.add_argument("--debug", action="store_true", help="debugging")
    return vars(parser.parse_args())


def setup_logging(debug=False):
    """basic logging setup"""
    root = logging.getLogger()
    if debug:
        root.setLevel(logging.DEBUG)
    else:
        root.setLevel(logging.INFO)
    ch = logging.StreamHandler(sys.stdout)
    formatter = logging.Formatter(
        '%(asctime)s - %(levelname)s - %(message)s')
    ch.setFormatter(formatter)
    root.addHandler(ch)


if __name__ == "__main__":
    args = handle_args()
    setup_logging(debug=args["debug"])

    # init state
    state = StateFileStore(args["org"])
    state.read()

    while True:
        events_info = get_events(args["org"], state)
        logging.debug("recieved %s events" % (
            len(events_info.event_list)))
        handle_events(events_info.event_list)
        # remember what we already did
        state.write()

        logging.debug("wait %ss before next run" % (events_info.next_run))
        time.sleep(events_info.next_run)