If only a single mongos is provided in the seedlist, fix issue where it would be assigned as single standalone server instead of mongos topology (Issue #130).

Author: christkv

HISTORY.md

@@ -1,3 +1,7 @@
+2.2.7
+----------------
+* If only a single mongos is provided in the seedlist, fix issue where it would be assigned as single standalone server instead of mongos topology (Issue #130).
+
 2.2.6 2016-08-16
 ----------------
 * Updated mongodb-core to 2.0.8.

lib/mongo_client.js

@@ -196,7 +196,22 @@ function createServer(options, callback) {
   // Set default options
   var servers = translateOptions(options);
   // Create Db instance
-  new Db(options.dbName, servers[0], options).open(callback);
+  new Db(options.dbName, servers[0], options).open(function(err, db) {
+    if(err) return callback(err);
+    // Check if we are really speaking to a mongos
+    var ismaster = db.serverConfig.lastIsMaster();
+
+    // Do we actually have a mongos
+    if(ismaster && ismaster.msg == 'isdbgrid') {
+      // Destroy the current connection
+      db.close();
+      // Create mongos connection instead
+      return createMongos(options, callback);
+    }
+
+    // Otherwise callback
+    callback(err, db);
+  });
 }
 
 function connectHandler(options, callback) {