Enable applications to start the debugger

flask/cli.py

@@ -105,6 +105,15 @@ class DispatchingApp(object):
     of the Werkzeug debugger means that it shows up in the browser.
     """
 
+    @property
+    def debug(self):
+        try:
+            return self._app.debug
+        except AttributeError as e:
+            print('Application not created yet, can\'t determine debug '
+                  'status.')
+            return False
+
     def __init__(self, loader, use_eager_loading=False):
         self.loader = loader
         self._app = None
@@ -421,6 +430,10 @@ def run_command(info, host, port, reload, debugger, eager_loading,
         if info.debug is not None:
             print(' * Forcing debug %s' % (info.debug and 'on' or 'off'))
 
+    if app.debug:
+        debugger = True
+        print(' * Debug activated by application configuration.')
+
     run_simple(host, port, app, use_reloader=reload,
                use_debugger=debugger, threaded=with_threads)