Document methods.

rq/worker.py

@@ -29,6 +29,7 @@ class Worker(object):
 
 
     def validate_queues(self):
+        """Sanity check for the given queues."""
         if not iterable(self.queues):
             raise ValueError('Argument queues not iterable.')
         for queue in self.queues:
@@ -36,45 +37,110 @@ class Worker(object):
                 raise NoQueueError('Give each worker at least one Queue.')
 
     def queue_names(self):
+        """Returns the queue names of this worker's queues."""
         return map(lambda q: q.name, self.queues)
 
     def queue_keys(self):
+        """Returns the Redis keys representing this worker's queues."""
         return map(lambda q: q.key, self.queues)
 
 
     @property
     def name(self):
+        """Returns the name of the worker, under which it is registered to the
+        monitoring system.
+
+        By default, the name of the worker is constructed from the current
+        (short) host name and the current PID.
+        """
         if self._name is None:
             hostname = socket.gethostname()
             shortname, _, _ = hostname.partition('.')
             self._name = '%s.%s' % (shortname, self.pid)
         return self._name
 
+    @property
+    def key(self):
+        """Returns the worker's Redis hash key."""
+        return self.redis_worker_namespace_prefix + self.name
+
     @property
     def pid(self):
+        """The current process ID."""
         return os.getpid()
 
     def procline(self, message):
+        """Changes the current procname for the process.
+
+        This can be used to make `ps -ef` output more readable.
+        """
         self.log.debug(message)
         procname.setprocname('rq: %s' % (message,))
 
 
+    def register_birth(self):
+        """Registers its own birth."""
+        if conn.exists(self.key) and not conn.hexists(self.key, 'death'):
+            raise ValueError('There exists an active worker named \'%s\' alread.' % (self.name,))
+        with conn.pipeline() as p:
+            p.delete(self.key)
+            p.hset(self.key, 'birth', time.time())
+            p.execute()
+
+    def register_death(self):
+        """Registers its own birth."""
+        self.log.error('Registering death')
+        with conn.pipeline() as p:
+            # We cannot use self.state = 'dead' here, because that would
+            # rollback the pipeline
+            p.hset(self.key, 'state', 'dead')
+            p.hset(self.key, 'death', time.time())
+            p.expire(self.key, 60)
+            p.execute()
+
+    def set_state(self, new_state):
+        self._state = new_state
+        conn.hset(self.key, 'state', new_state)
+
+    def get_state(self):
+        return self._state
+
+    state = property(get_state, set_state)
+
     def _work(self, quit_when_done=False):
+        """This method starts the work loop.
+        """
         did_work = False
-        while True:
-            self.procline('Waiting on %s' % (', '.join(self.queue_names()),))
-            wait_for_job = not quit_when_done
-            job = Queue.dequeue_any(self.queues, wait_for_job)
-            if job is None:
-                break
-            did_work = True
-            self.fork_and_perform_job(job)
+        self.register_birth()
+        self.state = 'starting'
+        try:
+            while True:
+                self.procline('Waiting on %s' % (', '.join(self.queue_names()),))
+                wait_for_job = not quit_when_done
+                job = Queue.dequeue_any(self.queues, wait_for_job)
+                if job is None:
+                    break
+                self.state = 'busy'
+                self.fork_and_perform_job(job)
+                did_work = True
+                self.state = 'idle'
+        finally:
+            self.register_death()
         return did_work
 
     def work(self):
+        """Pop and perform all jobs on the current list of queues.  When all
+        queues are empty, block and wait for new jobs to arrive on any of the
+        queues.
+        """
         self._work(False)
 
     def work_burst(self):
+        """Pop and perform all jobs on the current list of queues.  When all
+        queues are empty, return.
+
+        The return value indicates whether any jobs were processed.
+        """
         return self._work(True)
 
     def fork_and_perform_job(self, job):