Queue commands on a connection - fixes #83

tornadoredis/client.py

@@ -244,6 +244,8 @@ def __init__(self, host='localhost', port=6379, unix_socket_path=None,
         self.password = password
         self.selected_db = selected_db or 0
         self._pipeline = None
+        self.executing = False
+        self.command_queue = deque()
 
     def __del__(self):
         try:
@@ -385,11 +387,20 @@ def format_reply(self, cmd_line, data):
         return res
     ####
 
+    @gen.engine
+    def queue_command(self, callback=None):
+        self.command_queue.append(callback)
+
     @gen.engine
     def execute_command(self, cmd, *args, **kwargs):
         result = None
         execute_pending = cmd not in ('AUTH', 'SELECT')
 
+        # You can only one run command down a connection at a time, otherwise you end up with parsing issues
+        if self.command_queue:
+            yield gen.Task(self.queue_command)
+        self.command_queue.appendleft(None)
+
         callback = kwargs.get('callback', None)
         if 'callback' in kwargs:
             del kwargs['callback']
@@ -447,6 +458,13 @@ def execute_command(self, cmd, *args, **kwargs):
         if execute_pending:
             self.connection.execute_pending_command()
 
+        #  Dequeue any pending commands
+        while self.command_queue:
+            cb = self.command_queue.popleft()
+            if cb is not None:
+                cb()
+                break
+
         if callback:
             callback(result)