Ansible launcher: add private gearman function

OpenStack's Zuul's gear server is spending most of its time dealing
with function registration (800 nodes, 20k functions each).
Alleviate the pain by adding a private gearman function to register
functions en masse.  In preliminary testing, this causes function
registration to take 27% of the current time.

Change-Id: I0d2342cadca5e3d6d6c1964a119e0d50b0bcc548

zuul/cmd/server.py

@@ -117,18 +117,18 @@ def start_gear_server(self):
         if child_pid == 0:
             os.close(pipe_write)
             self.setup_logging('gearman_server', 'log_config')
-            import gear
+            import zuul.lib.gearserver
             statsd_host = os.environ.get('STATSD_HOST')
             statsd_port = int(os.environ.get('STATSD_PORT', 8125))
             if self.config.has_option('gearman_server', 'listen_address'):
                 host = self.config.get('gearman_server', 'listen_address')
             else:
                 host = None
-            gear.Server(4730,
-                        host=host,
-                        statsd_host=statsd_host,
-                        statsd_port=statsd_port,
-                        statsd_prefix='zuul.geard')
+            zuul.lib.gearserver.GearServer(4730,
+                                           host=host,
+                                           statsd_host=statsd_host,
+                                           statsd_port=statsd_port,
+                                           statsd_prefix='zuul.geard')
 
             # Keep running until the parent dies:
             pipe_read = os.fdopen(pipe_read)

zuul/launcher/ansiblelaunchserver.py

@@ -51,6 +51,19 @@ def boolify(x):
     return bool(x)
 
 
+class GearWorker(gear.Worker):
+    MASS_DO = 101
+
+    def sendMassDo(self, functions):
+        data = b'\x00'.join([gear.convert_to_bytes(x) for x in functions])
+        self.broadcast_lock.acquire()
+        try:
+            p = gear.Packet(gear.constants.REQ, self.MASS_DO, data)
+            self.broadcast(p)
+        finally:
+            self.broadcast_lock.release()
+
+
 class Watchdog(object):
     def __init__(self, timeout, function, args):
         self.timeout = timeout
@@ -518,7 +531,7 @@ def run(self):
             port = self.config.get('gearman', 'port')
         else:
             port = 4730
-        self.worker = gear.Worker(self.name)
+        self.worker = GearWorker(self.name)
         self.worker.addServer(server, port)
         self.log.debug("Waiting for server")
         self.worker.waitForServer()
@@ -648,10 +661,7 @@ def register(self):
         new_functions = set()
         for job in self.jobs.values():
             new_functions |= self.generateFunctionNames(job)
-        for function in new_functions - self.registered_functions:
-            self.worker.registerFunction(function)
-        for function in self.registered_functions - new_functions:
-            self.worker.unRegisterFunction(function)
+        self.worker.sendMassDo(new_functions)
         self.registered_functions = new_functions
 
     def abortRunningJob(self):

zuul/lib/gearserver.py

@@ -0,0 +1,35 @@
+# Copyright 2016 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 gear
+
+MASS_DO = 101
+
+
+class GearServer(gear.Server):
+    def handlePacket(self, packet):
+        if packet.ptype == MASS_DO:
+            self.log.info("Received packet from %s: %s" % (packet.connection,
+                                                           packet))
+            self.handleMassDo(packet)
+        else:
+            return super(GearServer, self).handlePacket(packet)
+
+    def handleMassDo(self, packet):
+        packet.connection.functions = set()
+        for name in packet.data.split(b'\x00'):
+            self.log.debug("Adding function %s to %s" % (
+                name, packet.connection))
+            packet.connection.functions.add(name)
+            self.functions.add(name)