WSGI middleware that automatically reloads the wrapped app if it changes

realapp.py

def app(env, start_response):
    start_response('200 ok', [])
    return 'hello\n'

reload-example.py

import sys
import os
import inspect

class ReloadApplicationMiddleware(object):
    def __init__(self, import_func):
        self.import_func = import_func
        self.app = import_func()
        self.files = self.get_module_mtimes()

    def get_module_mtimes(self):
        files = {}
        for module in sys.modules.itervalues():
            try:
                file = inspect.getsourcefile(module)
                files[file] = os.stat(file).st_mtime
            except TypeError:
                continue
        return files

    def shall_reload(self):
        for file, mtime in self.get_module_mtimes().iteritems():
            if not file in self.files or self.files[file] < mtime:
                self.files = self.get_module_mtimes()
                return True
        return False

    def __call__(self, *args, **kwargs):
        if self.shall_reload():
            print 'Reloading...'
            self.app = self.import_func()
        return self.app(*args, **kwargs)

def import_app():
   sys.modules.pop('realapp', None)
   import realapp
   return realapp.app

from bjoern import run
run(ReloadApplicationMiddleware(import_app), '0.0.0.0', 8080)