server: make stats more efficient

Keep track of the three main queue stats we report, so that we don't
have to iterate over all the queued jobs to determine whether they
are running.

Also, drop the workers stat because it's not very useful and not
entirely trivial to calculate.

Change-Id: Id42a05e5626096d1100a9cb9e8166c8ec5103b41

gear/__init__.py

@@ -2714,6 +2714,9 @@ class Server(BaseClientServer):
         self.normal_queue = []
         self.low_queue = []
         self.jobs = {}
+        self.running_jobs = 0
+        self.waiting_jobs = 0
+        self.total_jobs = 0
         self.functions = set()
         self.max_handle = 0
         self.acl = acl
@@ -3039,6 +3042,11 @@ class Server(BaseClientServer):
             # A specific queue was supplied
             dequeue.remove(job)
         # If dequeue is false, no need to remove from any queue
+        self.total_jobs -= 1
+        if job.running:
+            self.running_jobs -= 1
+        else:
+            self.waiting_jobs -= 1
 
     def getQueue(self):
         """Returns a copy of all internal queues in a flattened form.
@@ -3278,32 +3286,9 @@ class Server(BaseClientServer):
         # prefix.queue.total
         # prefix.queue.running
         # prefix.queue.waiting
-        # prefix.workers
-        base_key = 'queue'
-        total = 0
-        running = 0
-        waiting = 0
-        for job in self.jobs.values():
-            total += 1
-            if job.running:
-                running += 1
-            else:
-                waiting += 1
-
-        key = '.'.join([base_key, 'total'])
-        self.statsd.gauge(key, total)
-
-        key = '.'.join([base_key, 'running'])
-        self.statsd.gauge(key, running)
-
-        key = '.'.join([base_key, 'waiting'])
-        self.statsd.gauge(key, waiting)
-
-        workers = 0
-        for connection in self.active_connections:
-            if connection.functions:
-                workers += 1
-        self.statsd.gauge('workers', workers)
+        self.statsd.gauge('queue.total', self.total_jobs)
+        self.statsd.gauge('queue.running', self.running_jobs)
+        self.statsd.gauge('queue.waiting', self.waiting_jobs)
 
     def _handleSubmitJob(self, packet, precedence, background=False):
         name = packet.getArgument(0)
@@ -3330,6 +3315,8 @@ class Server(BaseClientServer):
         p = Packet(constants.RES, constants.JOB_CREATED, handle)
         packet.connection.sendPacket(p)
         self.jobs[handle] = job
+        self.total_jobs += 1
+        self.waiting_jobs += 1
         if not background:
             packet.connection.related_jobs[handle] = job
         if precedence == PRECEDENCE_HIGH:
@@ -3369,6 +3356,8 @@ class Server(BaseClientServer):
                         connection.related_jobs[job.handle] = job
                         job.worker_connection = connection
                         job.running = True
+                        self.waiting_jobs -= 1
+                        self.running_jobs += 1
                         self._updateStats()
                     return job
         return None