added util subpackage with auto_update_backups and update_backups

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk/qpid@911572 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 56 insertions, 0 deletions

diff --git a/python/qpid/messaging/util.py b/python/qpid/messaging/util.py
new file mode 100644
index 0000000000..12c02475f0
--- /dev/null
+++ b/python/qpid/messaging/util.py
@@ -0,0 +1,56 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+#
+
+"""
+Add-on utilities for the L{qpid.messaging} API.
+"""
+
+from logging import getLogger
+from threading import Thread
+
+log = getLogger("qpid.messaging.util")
+
+def auto_update_backups(conn):
+  ssn = conn.session("auto-update-backups")
+  rcv = ssn.receiver("amq.failover")
+  rcv.capacity = 10
+
+  def main():
+    while True:
+      msg = rcv.fetch()
+      update_backups(conn, msg)
+      ssn.acknowledge(msg, sync=False)
+
+  thread = Thread(name="auto-update-backups", target=main)
+  thread.setDaemon(True)
+  thread.start()
+
+
+def update_backups(conn, msg):
+  backups = []
+  urls = msg.properties["amq.failover"]
+  for u in urls:
+    if u.startswith("amqp:tcp:"):
+      parts = u.split(":")
+      host, port = parts[2:4]
+      backups.append((host, port))
+  conn.backups = backups
+  log.warn("updated backups for conn %s: %s", conn, backups)
+
+__all__ = ["auto_update_backups", "update_backups"]