Rewrite all logic regarding connection multiplexing.

bfxapi/websocket/_client/bfx_websocket_client.py

@@ -29,7 +29,6 @@ from bfxapi.websocket.exceptions import \
     InvalidCredentialError, \
     ReconnectionTimeoutError, \
     VersionMismatchError, \
-    ZeroConnectionsError, \
     UnknownChannelError, \
     UnknownSubscriptionError
 
@@ -246,27 +245,35 @@ class BfxWebSocketClient(Connection):
                         message[0] == 0 and message[1] != Connection._HEARTBEAT:
                     self.__handler.handle(message[1], message[2])
 
+    async def __new_bucket(self) -> BfxWebSocketBucket:
+        bucket = BfxWebSocketBucket( \
+            self._host, self.__event_emitter)
+
+        self.__buckets[bucket] = asyncio \
+            .create_task(bucket.start())
+
+        await bucket.wait()
+
+        return bucket
+
     @Connection.require_websocket_connection
     async def subscribe(self,
                         channel: str,
                         sub_id: Optional[str] = None,
                         **kwargs: Any) -> None:
-        if len(self.__buckets) == 0:
-            raise ZeroConnectionsError("Unable to subscribe: " \
-                "the number of connections must be greater than 0.")
-
         if not channel in ["ticker", "trades", "book", "candles", "status"]:
             raise UnknownChannelError("Available channels are: " + \
                 "ticker, trades, book, candles and status.")
 
-        _buckets = list(self.__buckets.keys())
+        for bucket in self.__buckets:
+            if not bucket.is_full:
+                return await bucket.subscribe( \
+                    channel, sub_id, **kwargs)
 
-        counters = [ bucket.count for bucket in _buckets ]
+        bucket = await self.__new_bucket()
 
-        index = counters.index(min(counters))
-
-        await _buckets[index] \
-            .subscribe(channel, sub_id, **kwargs)
+        return await bucket.subscribe( \
+            channel, sub_id, **kwargs)
 
     @Connection.require_websocket_connection
     async def unsubscribe(self, sub_id: str) -> None:

bfxapi/websocket/exceptions.py

@@ -11,11 +11,6 @@ class FullBucketError(BfxBaseException):
     Thrown when a user attempts a subscription but all buckets are full.
     """
 
-class ZeroConnectionsError(BfxBaseException):
-    """
-    This error indicates an attempt to subscribe to a public channel while the number of connections is 0.
-    """
-
 class ReconnectionTimeoutError(BfxBaseException):
     """
     This error indicates that the connection has been offline for too long without being able to reconnect.