Choose instance based on mode

Author: DifferentialOrange

tarantool/mesh_connection.py

@@ -152,7 +152,6 @@ def getnext(self):
         self.pos = (self.pos + 1) % len(self.addrs)
         return self.addrs[self.pos]
 
-
 class MeshConnection(Connection):
     '''
    Represents a connection to a cluster of Tarantool servers.
@@ -254,7 +253,8 @@ def __init__(self, host=None, port=None,
         self.last_nodes_refresh = 0
 
         self.pool = {}
-        self.ro = {}
+        self.pool_ro = {}
+        self.pool_rw = {}
 
         super(MeshConnection, self).__init__(
             host=host,
@@ -305,7 +305,37 @@ def connect(self):
                 continue
 
             # box.cfg was called at least once since we can connect.
-            self.ro[key] = conn.eval("return box.info.ro")
+            if conn.eval("return box.info.ro"):
+                self.pool_ro[key] = conn
+            else:
+                self.pool_rw[key] = conn
+
+    def _get_connection(self, mode):
+        if mode == Mode.RW:
+            if len(self.pool_rw) > 0:
+                return next(iter(self.pool_rw))[1]
+            else:
+                warn("can't find rw instance in pool, route request to default connection", ClusterDiscoveryWarning)
+                return self
+        elif mode == Mode.PREFER_RO:
+            if len(self.pool_ro) > 0:
+                return next(iter(self.pool_ro))[1]
+            elif len(self.pool_rw) > 0:
+                return next(iter(self.pool_rw))[1]
+            else:
+                warn("can't find rw/ro instance in pool, route request to default connection", ClusterDiscoveryWarning)
+                return self
+        elif mode == Mode.PREFER_RW:
+            if len(self.pool_rw) > 0:
+                return next(iter(self.pool_rw))[1]
+            elif len(self.pool_ro) > 0:
+                return next(iter(self.pool_ro))[1]
+            else:
+                warn("can't find rw/ro instance in pool, route request to default connection", ClusterDiscoveryWarning)
+                return self
+        else:
+            # warn("mode is not set", ClusterDiscoveryWarning)
+            return self
 
     def _opt_reconnect(self):
         '''
@@ -403,8 +433,9 @@ def _send_request(self, request):
 
         :rtype: `Response` instance
         '''
-        self._opt_refresh_instances()
-        return super(MeshConnection, self)._send_request(request)
+        conn = self._get_connection(request.mode)
+        conn._opt_refresh_instances()
+        return super(MeshConnection, conn)._send_request(request)
 
     def _build_insert_request(self, space_name, values):
         request = super(MeshConnection, self)._build_insert_request(space_name, values)