Wrap lines over 80 characters
[ganeti-local] / daemons / ganeti-confd
index 9deb123..8cf896a 100755 (executable)
@@ -32,6 +32,7 @@ import logging
 import asyncore
 import socket
 import pyinotify
+import time
 
 from optparse import OptionParser
 
@@ -114,7 +115,6 @@ class ConfdInotifyEventHandler(pyinotify.ProcessEvent):
                 pyinotify.EventsCodes.IN_MODIFY
     self.file = file
     self.watch_handle = None
-    self.enable()
 
   def enable(self):
     """Watch the given file
@@ -123,7 +123,7 @@ class ConfdInotifyEventHandler(pyinotify.ProcessEvent):
     if self.watch_handle is None:
       result = self.watch_manager.add_watch(self.file, self.mask)
       if not self.file in result or result[self.file] <= 0:
-        raise errors.ConfdFatalError("Could not add inotify watcher")
+        raise errors.InotifyError("Could not add inotify watcher")
       else:
         self.watch_handle = result[self.file]
 
@@ -191,20 +191,29 @@ class ConfdConfigurationReloader(object):
   check, to verify that the reload hasn't failed.
 
   """
-  def __init__(self, reader):
+  def __init__(self, processor, mainloop):
     """Constructor for ConfdConfigurationReloader
 
-    @type reader: L{ssconf.SimpleConfigReader}
-    @param reader: ganeti-confd SimpleConfigReader
+    @type processor: L{confd.server.ConfdProcessor}
+    @param processor: ganeti-confd ConfdProcessor
+    @type mainloop: L{daemon.Mainloop}
+    @param mainloop: ganeti-confd mainloop
 
     """
-    self.reader = reader
+    self.processor = processor
+    self.mainloop = mainloop
+
+    self.polling = True
+    self.last_notification = 0
 
     # Asyncronous inotify handler for config changes
     self.wm = pyinotify.WatchManager()
     self.inotify_handler = ConfdInotifyEventHandler(self.wm, self.OnInotify)
     self.notifier = AsyncNotifier(self.wm, self.inotify_handler)
 
+    self.timer_handle = None
+    self._EnableTimer()
+
   def OnInotify(self, notifier_enabled):
     """Receive an inotify notification.
 
@@ -212,20 +221,111 @@ class ConfdConfigurationReloader(object):
     @param notifier_enabled: whether the notifier is still enabled
 
     """
-    if not notifier_enabled:
-      self.inotify_handler.enable()
+    current_time = time.time()
+    time_delta = current_time - self.last_notification
+    self.last_notification = current_time
+
+    if time_delta < constants.CONFD_CONFIG_RELOAD_RATELIMIT:
+      logging.debug("Moving from inotify mode to polling mode")
+      self.polling = True
+      if notifier_enabled:
+        self.inotify_handler.disable()
+
+    if not self.polling and not notifier_enabled:
+      try:
+        self.inotify_handler.enable()
+      except errors.InotifyError:
+        self.polling = True
 
     try:
-      reloaded = self.reader.Reload()
+      reloaded = self.processor.reader.Reload()
       if reloaded:
         logging.info("Reloaded ganeti config")
       else:
         logging.debug("Skipped double config reload")
     except errors.ConfigurationError:
-      # transform a ConfigurationError in a fatal error, that will cause confd
-      # to quit.
-      raise errors.ConfdFatalError(err)
+      self.DisableConfd()
+      self.inotify_handler.disable()
+      return
+
+    # Reset the timer. If we're polling it will go to the polling rate, if
+    # we're not it will delay it again to its base safe timeout.
+    self._ResetTimer()
+
+  def _DisableTimer(self):
+    if self.timer_handle is not None:
+      self.mainloop.scheduler.cancel(self.timer_handle)
+      self.timer_handle = None
+
+  def _EnableTimer(self):
+    if self.polling:
+      timeout = constants.CONFD_CONFIG_RELOAD_RATELIMIT
+    else:
+      timeout = constants.CONFD_CONFIG_RELOAD_TIMEOUT
+
+    if self.timer_handle is None:
+      self.timer_handle = self.mainloop.scheduler.enter(
+        timeout, 1, self.OnTimer, [])
+
+  def _ResetTimer(self):
+    self._DisableTimer()
+    self._EnableTimer()
+
+  def OnTimer(self):
+    """Function called when the timer fires
+
+    """
+    self.timer_handle = None
+    reloaded = False
+    was_disabled = False
+    try:
+      if self.processor.reader is None:
+        was_disabled = True
+        self.EnableConfd()
+        reloaded = True
+      else:
+        reloaded = self.processor.reader.Reload()
+    except errors.ConfigurationError:
+      self.DisableConfd(silent=was_disabled)
+      return
+
+    if self.polling and reloaded:
+      logging.info("Reloaded ganeti config")
+    elif reloaded:
+      # We have reloaded the config files, but received no inotify event.  If
+      # an event is pending though, we just happen to have timed out before
+      # receiving it, so this is not a problem, and we shouldn't alert
+      if not self.notifier.check_events() and not was_disabled:
+        logging.warning("Config file reload at timeout (inotify failure)")
+    elif self.polling:
+      # We're polling, but we haven't reloaded the config:
+      # Going back to inotify mode
+      logging.debug("Moving from polling mode to inotify mode")
+      self.polling = False
+      try:
+        self.inotify_handler.enable()
+      except errors.InotifyError:
+        self.polling = True
+    else:
+      logging.debug("Performed configuration check")
+
+    self._EnableTimer()
+
+  def DisableConfd(self, silent=False):
+    """Puts confd in non-serving mode
 
+    """
+    if not silent:
+      logging.warning("Confd is being disabled")
+    self.processor.Disable()
+    self.polling = False
+    self._ResetTimer()
+
+  def EnableConfd(self):
+    self.processor.Enable()
+    logging.warning("Confd is being enabled")
+    self.polling = True
+    self._ResetTimer()
 
 
 def CheckConfd(options, args):
@@ -238,8 +338,6 @@ def CheckConfd(options, args):
     print >> sys.stderr, "Need HMAC key %s to run" % constants.HMAC_CLUSTER_KEY
     sys.exit(constants.EXIT_FAILURE)
 
-  ssconf.CheckMasterCandidate(options.debug)
-
 
 def ExecConfd(options, args):
   """Main confd function, executed with PID file held
@@ -247,15 +345,19 @@ def ExecConfd(options, args):
   """
   mainloop = daemon.Mainloop()
 
-  # confd-level SimpleConfigReader
-  reader = ssconf.SimpleConfigReader()
-
   # Asyncronous confd UDP server
-  processor = ConfdProcessor(reader)
+  processor = ConfdProcessor()
+  try:
+    processor.Enable()
+  except errors.ConfigurationError:
+    # If enabling the processor has failed, we can still go on, but confd will
+    # be disabled
+    logging.warning("Confd is starting in disabled mode")
+    pass
   server = ConfdAsyncUDPServer(options.bind_address, options.port, processor)
 
   # Configuration reloader
-  reloader = ConfdConfigurationReloader(reader)
+  reloader = ConfdConfigurationReloader(processor, mainloop)
 
   mainloop.Run()