never raise exceptions but return them

coherency with other methods

tests/test_pipeline.py

@@ -37,9 +37,6 @@ def test_empty_pipeline(self):
         c = Client()
         yield c.connect()
         p = Pipeline()
-        try:
-            yield c.call(p)
-            raise Exception("not raised ClientError")
-        except ClientError:
-            pass
+        res = yield c.call(p)
+        self.assertTrue(isinstance(res, ClientError))
         c.disconnect()

tests/test_pubsub.py

@@ -7,7 +7,6 @@
 
 from tornadis.pubsub import PubSubClient
 from tornadis.client import Client
-from tornadis.exceptions import ClientError
 from support import test_redis_or_raise_skiptest
 
 
@@ -91,9 +90,6 @@ def test_issue17(self):
     def test_empty_subscribe(self):
         c = PubSubClient()
         yield c.connect()
-        try:
-            yield c.pubsub_subscribe()
-            raise Exception("ClientError not raised")
-        except ClientError:
-            pass
+        res = yield c.pubsub_subscribe()
+        self.assertFalse(res)
         c.disconnect()

tornadis/client.py

@@ -211,17 +211,14 @@ def async_call(self, *args, **kwargs):
         - callback
             Function called (with the result as argument) when the result
             is available. If not set, the reply is silently discarded. In
-            case of connection errors, the callback is called with a
-            ConnectionError object as argument.
+            case of errors, the callback is called with a
+            TornadisException object as argument.
 
         Args:
             *args: full redis command as variable length argument list or
                 a Pipeline object (as a single argument).
             **kwargs: options as keyword parameters.
 
-        Raises:
-            ClientError: your Pipeline object is empty.
-
         Examples:
 
             >>> def cb(result):
@@ -254,7 +251,11 @@ def _call(self, *args, **kwargs):
             fn = self._pipelined_call
             pipeline = args[0]
             if pipeline.number_of_stacked_calls == 0:
-                raise ClientError("empty pipeline")
+                excep = ClientError("empty pipeline")
+                if callback:
+                    kwargs['callback'](excep)
+                else:
+                    return tornado.gen.maybe_future(excep)
             arguments = (pipeline,)
         else:
             if "__multiple_replies" in kwargs:

tornadis/pubsub.py

@@ -7,11 +7,15 @@
 import tornado.ioloop
 import tornado.gen
 from datetime import timedelta
+import logging
 
 from tornadis.client import Client
 from tornadis.exceptions import ConnectionError, ClientError
 
 
+LOG = logging.getLogger(__name__)
+
+
 class PubSubClient(Client):
     """High level specific object to interact with pubsub redis.
 
@@ -53,9 +57,6 @@ def pubsub_subscribe(self, *args):
         Returns:
             Future: Future with True as result if the subscribe is ok.
 
-        Raises:
-            ClientError: if you don't provide at least one channel
-
         Examples:
 
             >>> yield client.pubsub_subscribe("channel1", "channel2")
@@ -73,9 +74,6 @@ def pubsub_psubscribe(self, *args):
         Returns:
             Future: Future with True as result if the subscribe is ok.
 
-        Raises:
-            ClientError: if you don't provide at least one pattern
-
         Examples:
 
             >>> yield client.pubsub_psubscribe("channel*", "foo*")
@@ -85,7 +83,8 @@ def pubsub_psubscribe(self, *args):
     @tornado.gen.coroutine
     def _pubsub_subscribe(self, command, *args):
         if len(args) == 0:
-            raise ClientError("you must provide at least one argument")
+            LOG.warning("you must provide at least one argument")
+            raise tornado.gen.Return(False)
         results = yield Client.call(self, command, *args,
                                     __multiple_replies=len(args))
         for reply in results:
@@ -156,14 +155,13 @@ def pubsub_pop_message(self, deadline=None):
 
         Returns:
             Future with the popped message as result (or None if timeout
-                or ConnectionError object in case of connection errors).
-
-        Raises:
-            ClientError: when you are not subscribed to anything
+                or ConnectionError object in case of connection errors
+                or ClientError object if you are not subscribed)
         """
         if not self.subscribed:
-            raise ClientError("you must subscribe before using "
-                              "pubsub_pop_message")
+            excep = ClientError("you must subscribe before using "
+                                "pubsub_pop_message")
+            raise tornado.gen.Return(excep)
         reply = None
         try:
             reply = self._reply_list.pop(0)