How Do You Look When Merging Fails ;-)

There was a Simpsons episode, I can’t recall correctly, but I think Bart recorded Lisa when her heart broke and he watched it in slow motion to stop exactly at that point.

I thought of this episode yesterday while playing around with my laptop’s webcam and a Python shell. Finally I wrote a little fun script that does almost the same: Just register it as a hg hook and it takes a picture of you exactly at the unique moment when merging fails and it sends it directly and without any further questions to Twitpic and Twitter:

#!/usr/bin/env python

import os
import sys
import tempfile
import time

from CVtypes import cv
from twitpic import TwitPicAPI

DEVICE = 0
TWITTER_USER = 'xxx'  # CHANGE THIS!
TWITTER_PWD = 'xxx'   # CHANGE THIS!
# This is the time in seconds you need to realize that the merge has
# failed. When setting this consider that it already takes about a second
# for the camera to take the picture. "0" means no delay ;-)
EMOTIONAL_SLUGGISHNESS_RATE = 0.0

def grab_image(fname):
  camera = cv.CreateCameraCapture(DEVICE)
  frame = cv.QueryFrame(camera)
  cv.SaveImage(fname, frame)

def how_do_you_look():
  failed = bool(os.environ.get('HG_ERROR', 0))
  if not failed:
    return  # hmpf, maybe next time...
  fd, fname = tempfile.mkstemp('.jpg')
  if EMOTIONAL_SLUGGISHNESS_RATE > 0:
    time.sleep(EMOTIONAL_SLUGGISHNESS_RATE)
  grab_image(fname)
  twit = TwitPicAPI(TWITTER_USER, TWITTER_PWD)
  retcode = twit.upload(fname, post_to_twitter=True,
                        message='Another merge failed.')
  os.remove(fname)

if __name__ == '__main__':
  how_do_you_look()

You’ll need the CVtypes OpenCV wrapper and this Twitpic Python module. I’ve patched the twitpic module to support messages. Have a look at this issue if it’s already supported, otherwise a diff that adds the message keyword is attached to the issue. To use it as a Mercurial hook just add to .hg/hgrc:

[hooks]
update =  /path/to/the/above/script.py

and make the script executable.

The results are pretty good :)

Have fun!

BTW, the way how to access the camera is inspired by this nice blog post about face recognition using OpenCV.

Edit (2009-05-12): It was Ralph, not Lisa. Thanks Florian!