CSHARP-600: added secondary ok commands.

Author: craiggwilson

Driver/MongoDefaults.cs

@@ -28,8 +28,9 @@ namespace MongoDB.Driver
     /// </summary>
     public static class MongoDefaults
     {
-        // public static fields
+        // private static fields
         private static bool __assignIdOnInsert = true;
+        private static Func<BsonDocument, bool> __canCommandBeSentToSecondary = CanCommandBeSendToSecondaryDefault;
         private static TimeSpan __connectTimeout = TimeSpan.FromSeconds(30);
         private static TimeSpan __maxConnectionIdleTime = TimeSpan.FromMinutes(10);
         private static TimeSpan __maxConnectionLifeTime = TimeSpan.FromMinutes(30);
@@ -38,6 +39,18 @@ public static class MongoDefaults
         private static int __minConnectionPoolSize = 0;
         private static SafeMode __safeMode = SafeMode.False;
         private static TimeSpan __secondaryAcceptableLatency = TimeSpan.FromMilliseconds(15);
+        private static HashSet<string> __secondaryOkCommands = new HashSet<string>(StringComparer.InvariantCultureIgnoreCase)
+        {
+            "group",
+            "aggregate",
+            "collStats",
+            "dbStats",
+            "count",
+            "distinct",
+            "geoNear",
+            "geoSearch",
+            "geoWalk"
+        };
         private static TimeSpan __socketTimeout = TimeSpan.Zero; // use operating system default (presumably infinite)
         private static int __tcpReceiveBufferSize = 64 * 1024; // 64KiB (note: larger than 2MiB fails on Mac using Mono)
         private static int __tcpSendBufferSize = 64 * 1024; // 64KiB (TODO: what is the optimum value for the buffers?)
@@ -55,6 +68,24 @@ public static bool AssignIdOnInsert
             set { __assignIdOnInsert = value; }
         }
 
+        /// <summary>
+        /// Gets or sets a delegate that informs the driver whether or not a command is allowed
+        /// to be sent to a secondary.
+        /// </summary>
+        public static Func<BsonDocument, bool> CanCommandBeSentToSecondary
+        {
+            get { return __canCommandBeSentToSecondary; }
+            set
+            {
+                if (value == null)
+                {
+                    throw new ArgumentNullException("value");
+                }
+
+                __canCommandBeSentToSecondary = value;
+            }
+        }
+
         /// <summary>
         /// Gets the actual wait queue size (either WaitQueueSize or WaitQueueMultiple x MaxConnectionPoolSize).
         /// </summary>
@@ -225,5 +256,38 @@ public static TimeSpan WaitQueueTimeout
             get { return __waitQueueTimeout; }
             set { __waitQueueTimeout = value; }
         }
+
+        // private static methods
+        private static bool CanCommandBeSendToSecondaryDefault(BsonDocument document)
+        {
+            if (document.ElementCount == 0)
+            {
+                return false;
+            }
+
+            var command = document.GetElement(0);
+
+            if (__secondaryOkCommands.Contains(command.Name))
+            {
+                return true;
+            }
+
+            if (!command.Value.IsBsonDocument)
+            {
+                return false;
+            }
+
+            if (command.Name.Equals("mapreduce", StringComparison.InvariantCultureIgnoreCase))
+            {
+                var options = command.Value.AsBsonDocument;
+                BsonValue outValue;
+                if (options.TryGetValue("out", out outValue) && outValue.IsBsonDocument)
+                {
+                    return outValue.AsBsonDocument.Contains("inline");
+                }
+            }
+
+            return false;
+        }
     }
-}
+}

DriverUnitTests/DriverUnitTests.csproj

@@ -189,6 +189,7 @@
     <Compile Include="Linq\MongoQueryProviderTests.cs" />
     <Compile Include="Linq\SkipAndTakeTests.cs" />
     <Compile Include="Linq\Utils\BsonSerializationInfoHelperTests.cs" />
+    <Compile Include="MongoDefaultsTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Samples\MagicDiscriminatorTests.cs" />
   </ItemGroup>

DriverUnitTests/MongoDefaultsTests.cs

@@ -0,0 +1,76 @@
+using MongoDB.Bson;
+using MongoDB.Driver;
+using NUnit.Framework;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace MongoDB.DriverUnitTests
+{
+    [TestFixture]
+    public class MongoDefaultsTests
+    {
+        [TestCase("group", true)]
+        [TestCase("aggregate", true)]
+        [TestCase("geoSearch", true)]
+        [TestCase("blah", false)]
+        [TestCase("foo", false)]
+        [TestCase("bar", false)]
+        [TestCase("mapreduce", false)]
+        public void TestCanSendCommandToSecondary(string command, bool expectedResult)
+        {
+            var doc = new BsonDocument(command, 1);
+            var result = MongoDefaults.CanCommandBeSentToSecondary(doc);
+
+            Assert.AreEqual(expectedResult, result);
+        }
+
+        [Test]
+        public void TestCanSendInlineMapReduceToSecondary()
+        {
+            var doc = new BsonDocument("mapreduce",
+                new BsonDocument
+                {
+                    { "map", "emit()" },
+                    { "reduce", "return 1" },
+                    { "out", new BsonDocument("inline", 1) }
+                });
+
+            var result = MongoDefaults.CanCommandBeSentToSecondary(doc);
+
+            Assert.IsTrue(result);
+        }
+
+        [Test]
+        public void TestCannotSendNonInlineMapReduceToSecondary()
+        {
+            var doc = new BsonDocument("mapreduce",
+                new BsonDocument
+                {
+                    { "map", "emit()" },
+                    { "reduce", "return 1" }
+                });
+
+            var result = MongoDefaults.CanCommandBeSentToSecondary(doc);
+
+            Assert.IsFalse(result);
+        }
+
+        [Test]
+        public void TestCannotSendNonInlineMapReduceToSecondary2()
+        {
+            var doc = new BsonDocument("mapreduce",
+                new BsonDocument
+                {
+                    { "map", "emit()" },
+                    { "reduce", "return 1" },
+                    { "out", new BsonDocument("merge", "foo") }
+                });
+
+            var result = MongoDefaults.CanCommandBeSentToSecondary(doc);
+
+            Assert.IsFalse(result);
+        }
+    }
+}