Heroku app crashed after pushing small change. Very confused

Question

I am using Heroku with python and Flask. My app was working fine until I updated a few lines in my python application file. The app runs fine locally, but I now have the following error when I try to access my app:

"An error occurred in the application and your page could not be served. Please try again in a few moments. If you are the application owner, check your logs for details."

My logs look something like this:

2012-10-03T17:40:26+00:00 heroku[web.1]: Process exited with status 1
2012-10-03T17:40:26+00:00 heroku[web.1]: State changed from starting to crashed
2012-10-03T17:51:25+00:00 heroku[web.1]: State changed from crashed to starting
2012-10-03T17:51:26+00:00 heroku[web.1]: Starting process with command `python presentation.py`
2012-10-03T17:51:26+00:00 app[web.1]: ImportError: No module named site

I am also no longer able to run python through heroku:

Cinnas-MacBook-Pro:infinite-fortress-4866 cinna$ heroku run python
Running `python` attached to terminal... up, run.1
ImportError: No module named site

The next thing I have tried to do is check my environment variables:

Cinnas-MacBook-Pro:infinite-fortress-4866 cinna$ heroku config
=== infinite-fortress-4866 Config Vars
LANG:             en_US.UTF-8 
LD_LIBRARY_PATH:  /app/.heroku/vendor/lib
LIBRARY_PATH:     /app/.heroku/vendor/lib
PATH:             /app/.heroku/venv/bin:/bin:/usr/local/bin:/usr/bin
PYTHONHASHSEED:   random
PYTHONHOME:       /app/.heroku/venv/
PYTHONPATH:       /app/
PYTHONUNBUFFERED: true

However, when I try to look inside the library directories, I get something like this:

Cinnas-MacBook-Pro:infinite-fortress-4866 cinna$ heroku run ls /app/.heroku/vendor/lib
Running `ls /app/.heroku/vendor/lib` attached to terminal... up, run.1
ls: cannot access /app/.heroku/vendor/lib: No such file or directory

I am not sure where to proceed at this moment. I miss my app, please help!

Additional information:

The problems all started when I added the following lines to my app.py code:

 @app.route('/my_fb_graph',methods=['GET','POST'])
 def my_fb_graph():
 return render_template('my_fb_graph.html')

When I pushed the code and the app no longer worked. I then removed these lines of code, pushed the code again, and still got the same errors. The next thing I did was to completely remove the app.py file and try to a small test code which still did not work.

The root of the problem seems to be the error:

 2012-10-03T17:51:26+00:00 app[web.1]: ImportError: No module named site

Answer 1

I was able to fix the problem, but still dont know why it occurred in the first place!

After a lot of experimentation, I ended up setting up a completely new app on Heroku. I checked the environment variables in the new app and got the following:

 Cinnas-MacBook-Pro:thawing-temple-4323 cinna$ heroku config
 === thawing-temple-4323 Config Vars
 FACEBOOK_APP_ID:  ***
 FACEBOOK_SECRET:  ***
 PATH:             bin:/usr/local/bin:/usr/bin:/bin
 PYTHONUNBUFFERED: true

Checking my original app (the broken one), I realized that new environment variables were somehow added in my last push as indicated by my logs:

 2012-10-04T04:20:04+00:00 heroku[api]: Add PYTHONUNBUFFERED, PYTHONPATH, PYTHONHOME, LANG, LD_LIBRARY_PATH, PATH, PYTHONHASHSEED, LIBRARY_PATH config by ***@***

and by checking my environment variables:

 Cinnas-MacBook-Pro:infinite-fortress-4866 cinna$ heroku config
 === infinite-fortress-4866 Config Vars
 LANG:             en_US.UTF-8 
 LD_LIBRARY_PATH:  /app/.heroku/vendor/lib
 LIBRARY_PATH:     /app/.heroku/vendor/lib
 PATH:             /app/.heroku/venv/bin:/bin:/usr/local/bin:/usr/bin   
 PYTHONHASHSEED:   random
 PYTHONHOME:       /app/.heroku/venv/
 PYTHONPATH:       /app/
 PYTHONUNBUFFERED: true

I removed these new variables with the command:

 heroku config:remove PYTHONPATH PYTHONHOME LANG LD_LIBRARY_PATH PYTHONHASHSEED LIBRARY_PATH

and my app started to work again. I've been pushing more code, and this problem has not occurred again.

I am still really curious why/how these variables were added in the first place since all I did was do a git push.