Proof of Concept on Issue #297

Actually Add The Source

Delete Old Source

cement/ext/ext_reload_config.py

@@ -0,0 +1,70 @@
+"""Config Reloader Framework Extension"""
+
+import os
+import pyinotify
+import signal
+from ..core import backend, hook
+from ..utils.misc import minimal_logger
+from ..utils import shell
+
+LOG = minimal_logger(__name__)
+MASK = pyinotify.IN_CLOSE_WRITE
+NOTIFIER = None
+
+class ConfigEventHandler(pyinotify.ProcessEvent):
+    def __init__(self, app, watched_paths, **kw):
+        self.app = app
+        self.watched_paths = watched_paths
+        super(ConfigEventHandler, self).__init__()
+
+    def process_default(self, event):
+        if event.pathname in self.watched_paths:
+            self.app.log.debug('Config path modified: mask=%s, path=%s' % \
+                              (event.maskname, event.pathname))
+            self.app.log.info('Reloading configuration...')
+            for res in hook.run('pre_reload_config', self.app):
+                pass
+            self.app._setup_config_handler()
+            for res in hook.run('post_reload_config', self.app):
+                pass
+
+
+def spawn_watcher(app):
+    global NOTIFIER
+    watched_dirs = []
+    watched_paths = []
+
+    # watch manager
+    wm = pyinotify.WatchManager()
+    for path in app._meta.config_files:
+        if os.path.exists(path):
+            watched_paths.append(path)
+
+            this_dir = os.path.dirname(path)
+            if this_dir not in watched_dirs:
+                watched_dirs.append(this_dir)
+
+            wm.add_watch(this_dir, MASK, rec=True)
+
+    # event handler
+    eh = ConfigEventHandler(app, watched_paths)
+
+    # notifier
+    NOTIFIER = pyinotify.ThreadedNotifier(wm, eh)
+    NOTIFIER.start()
+
+def kill_watcher(app):
+    if NOTIFIER.isAlive():
+        NOTIFIER.stop()
+
+def signal_handler(signum, frame):
+    if signum in [signal.SIGTERM, signal.SIGINT]:
+        if NOTIFIER.isAlive():
+            NOTIFIER.stop()
+
+def load(app):
+    hook.define('pre_reload_config')
+    hook.define('post_reload_config')
+    hook.register('pre_run', spawn_watcher)
+    hook.register('pre_close', kill_watcher)
+    hook.register('signal', signal_handler)