1 files changed, 105 insertions, 0 deletions
diff --git a/keystone-moon/keystone/openstack/common/systemd.py b/keystone-moon/keystone/openstack/common/systemd.py
new file mode 100644
index 00000000..36243b34
--- /dev/null
+++ b/keystone-moon/keystone/openstack/common/systemd.py
@@ -0,0 +1,105 @@
+# Copyright 2012-2014 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.
+
+"""
+Helper module for systemd service readiness notification.
+"""
+
+import logging
+import os
+import socket
+import sys
+
+
+LOG = logging.getLogger(__name__)
+
+
+def _abstractify(socket_name):
+    if socket_name.startswith('@'):
+        # abstract namespace socket
+        socket_name = '\0%s' % socket_name[1:]
+    return socket_name
+
+
+def _sd_notify(unset_env, msg):
+    notify_socket = os.getenv('NOTIFY_SOCKET')
+    if notify_socket:
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
+        try:
+            sock.connect(_abstractify(notify_socket))
+            sock.sendall(msg)
+            if unset_env:
+                del os.environ['NOTIFY_SOCKET']
+        except EnvironmentError:
+            LOG.debug("Systemd notification failed", exc_info=True)
+        finally:
+            sock.close()
+
+
+def notify():
+    """Send notification to Systemd that service is ready.
+
+    For details see
+    http://www.freedesktop.org/software/systemd/man/sd_notify.html
+    """
+    _sd_notify(False, 'READY=1')
+
+
+def notify_once():
+    """Send notification once to Systemd that service is ready.
+
+    Systemd sets NOTIFY_SOCKET environment variable with the name of the
+    socket listening for notifications from services.
+    This method removes the NOTIFY_SOCKET environment variable to ensure
+    notification is sent only once.
+    """
+    _sd_notify(True, 'READY=1')
+
+
+def onready(notify_socket, timeout):
+    """Wait for systemd style notification on the socket.
+
+    :param notify_socket: local socket address
+    :type notify_socket:  string
+    :param timeout:       socket timeout
+    :type timeout:        float
+    :returns:             0 service ready
+                          1 service not ready
+                          2 timeout occurred
+    """
+    sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
+    sock.settimeout(timeout)
+    sock.bind(_abstractify(notify_socket))
+    try:
+        msg = sock.recv(512)
+    except socket.timeout:
+        return 2
+    finally:
+        sock.close()
+    if 'READY=1' in msg:
+        return 0
+    else:
+        return 1
+
+
+if __name__ == '__main__':
+    # simple CLI for testing
+    if len(sys.argv) == 1:
+        notify()
+    elif len(sys.argv) >= 2:
+        timeout = float(sys.argv[1])
+        notify_socket = os.getenv('NOTIFY_SOCKET')
+        if notify_socket:
+            retval = onready(notify_socket, timeout)
+            sys.exit(retval)