1 files changed, 149 insertions, 0 deletions
diff --git a/keystone-moon/keystone/openstack/common/threadgroup.py b/keystone-moon/keystone/openstack/common/threadgroup.py
new file mode 100644
index 00000000..fc0bcb53
--- /dev/null
+++ b/keystone-moon/keystone/openstack/common/threadgroup.py
@@ -0,0 +1,149 @@
+# Copyright 2012 Red Hat, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+import logging
+import threading
+
+import eventlet
+from eventlet import greenpool
+
+from keystone.openstack.common import loopingcall
+
+
+LOG = logging.getLogger(__name__)
+
+
+def _thread_done(gt, *args, **kwargs):
+    """Callback function to be passed to GreenThread.link() when we spawn()
+    Calls the :class:`ThreadGroup` to notify if.
+
+    """
+    kwargs['group'].thread_done(kwargs['thread'])
+
+
+class Thread(object):
+    """Wrapper around a greenthread, that holds a reference to the
+    :class:`ThreadGroup`. The Thread will notify the :class:`ThreadGroup` when
+    it has done so it can be removed from the threads list.
+    """
+    def __init__(self, thread, group):
+        self.thread = thread
+        self.thread.link(_thread_done, group=group, thread=self)
+
+    def stop(self):
+        self.thread.kill()
+
+    def wait(self):
+        return self.thread.wait()
+
+    def link(self, func, *args, **kwargs):
+        self.thread.link(func, *args, **kwargs)
+
+
+class ThreadGroup(object):
+    """The point of the ThreadGroup class is to:
+
+    * keep track of timers and greenthreads (making it easier to stop them
+      when need be).
+    * provide an easy API to add timers.
+    """
+    def __init__(self, thread_pool_size=10):
+        self.pool = greenpool.GreenPool(thread_pool_size)
+        self.threads = []
+        self.timers = []
+
+    def add_dynamic_timer(self, callback, initial_delay=None,
+                          periodic_interval_max=None, *args, **kwargs):
+        timer = loopingcall.DynamicLoopingCall(callback, *args, **kwargs)
+        timer.start(initial_delay=initial_delay,
+                    periodic_interval_max=periodic_interval_max)
+        self.timers.append(timer)
+
+    def add_timer(self, interval, callback, initial_delay=None,
+                  *args, **kwargs):
+        pulse = loopingcall.FixedIntervalLoopingCall(callback, *args, **kwargs)
+        pulse.start(interval=interval,
+                    initial_delay=initial_delay)
+        self.timers.append(pulse)
+
+    def add_thread(self, callback, *args, **kwargs):
+        gt = self.pool.spawn(callback, *args, **kwargs)
+        th = Thread(gt, self)
+        self.threads.append(th)
+        return th
+
+    def thread_done(self, thread):
+        self.threads.remove(thread)
+
+    def _stop_threads(self):
+        current = threading.current_thread()
+
+        # Iterate over a copy of self.threads so thread_done doesn't
+        # modify the list while we're iterating
+        for x in self.threads[:]:
+            if x is current:
+                # don't kill the current thread.
+                continue
+            try:
+                x.stop()
+            except eventlet.greenlet.GreenletExit:
+                pass
+            except Exception as ex:
+                LOG.exception(ex)
+
+    def stop_timers(self):
+        for x in self.timers:
+            try:
+                x.stop()
+            except Exception as ex:
+                LOG.exception(ex)
+        self.timers = []
+
+    def stop(self, graceful=False):
+        """stop function has the option of graceful=True/False.
+
+        * In case of graceful=True, wait for all threads to be finished.
+          Never kill threads.
+        * In case of graceful=False, kill threads immediately.
+        """
+        self.stop_timers()
+        if graceful:
+            # In case of graceful=True, wait for all threads to be
+            # finished, never kill threads
+            self.wait()
+        else:
+            # In case of graceful=False(Default), kill threads
+            # immediately
+            self._stop_threads()
+
+    def wait(self):
+        for x in self.timers:
+            try:
+                x.wait()
+            except eventlet.greenlet.GreenletExit:
+                pass
+            except Exception as ex:
+                LOG.exception(ex)
+        current = threading.current_thread()
+
+        # Iterate over a copy of self.threads so thread_done doesn't
+        # modify the list while we're iterating
+        for x in self.threads[:]:
+            if x is current:
+                continue
+            try:
+                x.wait()
+            except eventlet.greenlet.GreenletExit:
+                pass
+            except Exception as ex:
+                LOG.exception(ex)