Launching an app in heroku? What is procfile? 'web:' command?

Question

I was referring to this site as i am learning python/flask and trying to use heroku.

http://ryaneshea.com/lightweight-python-apps-with-flask-twitter-bootstrap-and-herok

Answer 1

the Procfile tells Heroku what commands should be run (https://devcenter.heroku.com/articles/procfile).

You are able to define difference process types, such as web (the only one which will autostart by default), workers, etc...

So basically a Procfile containing

web: python app.py

is telling Heroku to started a named process called web, and to run python app.py when it starts.

There is Python specific documentation for Heroku at https://devcenter.heroku.com/articles/getting-started-with-python#declare-process-types-with-procfile