spawn multiple workers in services

the collector service only ever grabs one connection to the
database at a time. this causes a massive backlog on the message
queue. enable ability to spawn multiple workers for notification
and collector services.

Change-Id: Ie85c4a6eace52c771c3eb8425839d253f8dd74cd
Closes-Bug: #1291054

ceilometer/cli.py

@@ -84,8 +84,12 @@ def agent_compute():
 
 def agent_notification():
     service.prepare_service()
-    os_service.launch(notification.NotificationService(
-        cfg.CONF.host, 'ceilometer.agent.notification')).wait()
+    launcher = os_service.ProcessLauncher()
+    launcher.launch_service(
+        notification.NotificationService(cfg.CONF.host,
+                                         'ceilometer.agent.notification'),
+        workers=service.get_workers('notification'))
+    launcher.wait()
 
 
 def api():
@@ -96,8 +100,12 @@ def api():
 
 def collector_service():
     service.prepare_service()
-    os_service.launch(collector.CollectorService(
-        cfg.CONF.host, 'ceilometer.collector')).wait()
+    launcher = os_service.ProcessLauncher()
+    launcher.launch_service(
+        collector.CollectorService(cfg.CONF.host,
+                                   'ceilometer.collector'),
+        workers=service.get_workers('collector'))
+    launcher.wait()
 
 
 def storage_dbsync():

ceilometer/service.py

@@ -28,6 +28,7 @@ from ceilometer.openstack.common import gettextutils
 from ceilometer.openstack.common.gettextutils import _  # noqa
 from ceilometer.openstack.common import log
 from ceilometer.openstack.common import rpc
+from ceilometer import utils
 
 
 OPTS = [
@@ -40,6 +41,12 @@ OPTS = [
                     deprecated_group="collector",
                     default=['database'],
                     help='Dispatcher to process data.'),
+    cfg.IntOpt('collector_workers',
+               help='Number of workers for collector service. The default '
+               'will be equal to the number of CPUs available.'),
+    cfg.IntOpt('notification_workers',
+               help='Number of workers for notification service. The default '
+               'will be equal to the number of CPUs available.'),
 ]
 cfg.CONF.register_opts(OPTS)
 
@@ -88,6 +95,11 @@ cfg.CONF.register_cli_opts(CLI_OPTIONS, group="service_credentials")
 LOG = log.getLogger(__name__)
 
 
+class WorkerException(Exception):
+    """Exception for errors relating to service workers
+    """
+
+
 class DispatchedService(object):
 
     DISPATCHER_NAMESPACE = 'ceilometer.dispatcher'
@@ -106,6 +118,17 @@ class DispatchedService(object):
                         self.DISPATCHER_NAMESPACE)
 
 
+def get_workers(name):
+    workers = (cfg.CONF.get('%s_workers' % name) or
+               utils.cpu_count())
+    if workers and workers < 1:
+        msg = (_("%(worker_name)s value of %(workers)s is invalid, "
+                 "must be greater than 0") %
+               {'worker_name': '%s_workers' % name, 'workers': str(workers)})
+        raise WorkerException(msg)
+    return workers
+
+
 def prepare_service(argv=None):
     gettextutils.install('ceilometer', lazy=True)
     rpc.set_defaults(control_exchange='ceilometer')

ceilometer/utils.py

@@ -22,6 +22,7 @@ import calendar
 import copy
 import datetime
 import decimal
+import multiprocessing
 
 from ceilometer.openstack.common import timeutils
 from ceilometer.openstack.common import units
@@ -147,3 +148,10 @@ def update_nested(original_dict, updates):
         else:
             dict_to_update[key] = updates[key]
     return dict_to_update
+
+
+def cpu_count():
+    try:
+        return multiprocessing.cpu_count() or 1
+    except NotImplementedError:
+        return 1

etc/ceilometer/ceilometer.conf.sample

@@ -40,6 +40,14 @@
 # Dispatcher to process data. (multi valued)
 #dispatcher=database
 
+# Number of workers for collector service. The default will be
+# equal to the number of CPUs available. (integer value)
+#collector_workers=<None>
+
+# Number of workers for notification service. The default will
+# be equal to the number of CPUs available. (integer value)
+#notification_workers=<None>
+
 
 #
 # Options defined in ceilometer.api.app