coordination: add IPC driver

For now it only supports locking.

Change-Id: Iccbc1da162e70d0186131adc0ac9cfeb20f7a647

1 files changed, 85 insertions, 0 deletions

diff --git a/tooz/drivers/ipc.py b/tooz/drivers/ipc.py
new file mode 100644
index 0000000..748dac2
--- /dev/null
+++ b/tooz/drivers/ipc.py
@@ -0,0 +1,85 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright © 2014 eNovance
+#
+# Author: Julien Danjou <julien@danjou.info>
+#
+# 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 posix_ipc
+
+from tooz import coordination
+from tooz import locking
+from tooz.openstack.common import lockutils
+
+
+class IPCLock(locking.Lock):
+    _LOCK_PREFIX = b'_tooz_'
+
+    def __init__(self, name, timeout):
+        self.lock = lockutils.external_lock(
+            (self._LOCK_PREFIX + name).decode('ascii'))
+        self.timeout = timeout
+
+    def acquire(self, blocking=True):
+        timeout = self.timeout if blocking else 0
+        try:
+            return bool(self.lock.acquire(timeout=timeout))
+        # TODO(jd) This should be encapsulated in lockutils!
+        except posix_ipc.BusyError:
+            return False
+
+    def release(self):
+        return self.lock.release()
+
+
+class IPCDriver(coordination.CoordinationDriver):
+
+    def __init__(self, member_id, lock_timeout=30):
+        """Initialize the IPC driver.
+
+        :param lock_timeout: how many seconds to wait when trying to acquire
+                             a lock in blocking mode. None means forever, 0
+                             means don't wait, any other value means wait
+                             this amount of seconds. super(IPCDriver,
+                             self).__init__() self.lock_timeout =
+                             lock_timeout
+        """
+        super(IPCDriver, self).__init__()
+        self.lock_timeout = lock_timeout
+
+    def get_lock(self, name):
+        return IPCLock(name, self.lock_timeout)
+
+    @staticmethod
+    def watch_join_group(group_id, callback):
+        raise NotImplementedError
+
+    @staticmethod
+    def unwatch_join_group(group_id, callback):
+        raise NotImplementedError
+
+    @staticmethod
+    def watch_leave_group(group_id, callback):
+        raise NotImplementedError
+
+    @staticmethod
+    def unwatch_leave_group(group_id, callback):
+        raise NotImplementedError
+
+    @staticmethod
+    def watch_elected_as_leader(group_id, callback):
+        raise NotImplementedError
+
+    @staticmethod
+    def unwatch_elected_as_leader(group_id, callback):
+        raise NotImplementedError