Allow reads from arbiter for single server connection, NODE-117

Author: christkv

lib/mongodb/connection/server.js

@@ -744,7 +744,7 @@ Server.prototype.checkoutWriter = function(read) {
  */
 var canCheckoutReader = function(self) {
  // We cannot write to an arbiter or secondary server
- if(self.isMasterDoc && self.isMasterDoc['arbiterOnly'] == true) {
+ if(self.isMasterDoc && self.isMasterDoc['arbiterOnly'] == true && self.isSetMember()) {
  return new Error("Cannot write to an arbiter");
  } else if(self._readPreference != null) {
  // If the read preference is Primary and the instance is not a master return an error

test/runners/replicaset_runner.js

@@ -52,6 +52,7 @@ module.exports = function(configurations) {
  , '/test/tests/repl_set/replicaset_examples_tests.js'
  , '/test/tests/repl_set/recovering_server_tests.js'
  , '/test/tests/repl_set/batch_api_tests.js'
+ , '/test/tests/repl_set/individual_sets_connections_tests.js'
  ]
  );
 

test/tests/repl_set/individual_sets_connections_tests.js

@@ -0,0 +1,26 @@
+exports['Should correctly connect to arbiter with single connection'] = function(configuration, test) {
+ var mongo = configuration.getMongoPackage()
+ , ReplSetServers = mongo.ReplSetServers
+ , Server = mongo.Server
+ , Db = mongo.Db;
+
+ // Replset start port
+ var replicasetManager = configuration.getReplicasetManager();
+ // Get the arbiters
+ replicasetManager.arbiters(function(err, arbiters) {
+ test.equal(1, arbiters.length);
+ var host = arbiters[0].split(":")[0];
+ var port = parseInt(arbiters[0].split(":")[1], 10);
+ var db = new Db('integration_test_', new Server(host, port), {w:1});
+ db.open(function(err, p_db) {
+ test.equal(null, err);
+
+ p_db.command({ismaster: true}, function(err, result) {
+ test.equal(null, err);
+
+ p_db.close();
+ test.done();
+ });
+ })
+ });
+}

test/tests/repl_set/read_preferences_tests.js

@@ -874,7 +874,7 @@ exports['Connection to a arbiter host with primary preference should give error'
  // Grab a collection
  p_db.createCollection('read_preference_single_test_0', function(err, collection) {
  test.ok(err instanceof Error);
- test.equal('Cannot write to an arbiter', err.message);
+ test.equal('string', typeof err.message);
  p_db.close();
  test.done();
  });