Implement a better reloader about webpy

[anandology]

Justin has suggested a reloader that restarts the process on code changes.

http://groups.google.com/group/webpy/browse_thread/thread/10e255e2511741b2

caveat: doesn't work on windows

[aaronsw]

Reloading the whole process is slow; maybe just have some way to protect global state?

[thinxer]

http://webpy.org/cookbook/session_with_reloader

It seemed that web.config can be used to store global states. It would be better if web.py can handle session with reloader automatically.

[benhoyt]

FWIW, we store most of our global state in a file called caches.py, which we almost never change. Then other modules refer to caches.things, and if the other module changes and reloads, we're fine. It's only when we change caches.py itself that we have to (manually) restart the process.

I agree that restarting the whole process is slow. We aggressively cache things in Python objects on startup -- our server takes about 4GB of RAM and a few minutes to start up, so fast reload is very important to us. :-)

[despens]

If the reloader would work with sessions, that would be grand!

[gabrii]

It also desn't check canges on modules imported by unchanged modules.
If I have [main.py <- view.py <- render_functions.py] the changes of render_functions.py don't reaload until I modify view.py.

[jekiapp]

having same issue as @gabrii