CSHARP-3676: SRV support for load balancer mode + SDAM. (#562)

CSHARP-3676: SRV support for load balancer mode + SDAM.

Author: DmitryLukyanov

build.cake

@@ -334,6 +334,38 @@ Task("TestGssapiNetStandard15").IsDependentOn("TestGssapi");
 Task("TestGssapiNetStandard20").IsDependentOn("TestGssapi");
 Task("TestGssapiNetStandard21").IsDependentOn("TestGssapi");
 
+Task("TestLoadBalanced")
+    .IsDependentOn("Build")
+    .DoesForEach(
+        GetFiles("./**/*.Tests.csproj"),
+        testProject =>
+     {
+        var settings = new DotNetCoreTestSettings
+        {
+            NoBuild = true,
+            NoRestore = true,
+            Configuration = configuration,
+            ArgumentCustomization = args => args.Append("-- RunConfiguration.TargetPlatform=x64"),
+            Filter = "Category=\"SupportLoadBalancing\""
+        };
+
+        switch (target.ToLowerInvariant())
+        {
+            case "testloadbalancednetstandard15": settings.Framework = "netcoreapp1.1"; break;
+            case "testloadbalancednetstandard20": settings.Framework = "netcoreapp2.1"; break;
+            case "testloadbalancednetstandard21": settings.Framework = "netcoreapp3.0"; break;
+        }
+
+        DotNetCoreTest(
+            testProject.FullPath,
+            settings
+        );
+     });
+ 
+Task("TestLoadBalancedNetStandard15").IsDependentOn("TestLoadBalanced");
+Task("TestLoadBalancedNetStandard20").IsDependentOn("TestLoadBalanced");
+Task("TestLoadBalancedNetStandard21").IsDependentOn("TestLoadBalanced");
+
 Task("Docs")
     .IsDependentOn("ApiDocs")
     .IsDependentOn("RefDocs");

evergreen/evergreen.yml

@@ -242,6 +242,37 @@ functions:
           DRIVERS_TOOLS="${DRIVERS_TOOLS}" \
           sh ${DRIVERS_TOOLS}/.evergreen/atlas_data_lake/run-mongohouse-local.sh
 
+  run-load-balancer:
+    - command: shell.exec
+      params:
+        script: |
+          DRIVERS_TOOLS=${DRIVERS_TOOLS} MONGODB_URI=${MONGODB_URI} bash ${DRIVERS_TOOLS}/.evergreen/run-load-balancer.sh start
+    - command: expansions.update
+      params:
+        file: lb-expansion.yml
+
+  run-load-balancer-tests:
+    - command: shell.exec
+      type: test
+      params:
+        working_dir: "mongo-csharp-driver"
+        script: |
+          ${PREPARE_SHELL}
+          SSL=${SSL} OS=${OS} evergreen/add-certs-if-needed.sh
+          AUTH="${AUTH}" SSL="${SSL}" \
+          FRAMEWORK=${FRAMEWORK} \
+          OS=${OS} \
+          SINGLE_MONGOS_LB_URI="${SINGLE_MONGOS_LB_URI}" \
+          MULTI_MONGOS_LB_URI="${MULTI_MONGOS_LB_URI}" \
+          evergreen/run-load-balancer-tests.sh
+
+  stop-load-balancer:
+    - command: shell.exec
+      params:
+        script: |
+          cd ${DRIVERS_TOOLS}/.evergreen
+          DRIVERS_TOOLS=${DRIVERS_TOOLS} MONGODB_URI=${MONGODB_URI} bash ${DRIVERS_TOOLS}/.evergreen/run-load-balancer.sh stop
+
   run-tests:
     - command: shell.exec
       type: test
@@ -678,6 +709,33 @@ tasks:
           vars:
             FRAMEWORK: netstandard21
 
+    - name: test-load-balancer-netstandard15
+      commands:
+        - func: bootstrap-mongo-orchestration
+        - func: run-load-balancer
+        - func: run-load-balancer-tests
+        - func: stop-load-balancer
+          vars:
+            FRAMEWORK: netstandard15
+
+    - name: test-load-balancer-netstandard20
+      commands:
+        - func: bootstrap-mongo-orchestration
+        - func: run-load-balancer
+        - func: run-load-balancer-tests
+        - func: stop-load-balancer
+          vars:
+            FRAMEWORK: netstandard20
+        
+    - name: test-load-balancer-netstandard21
+      commands:
+        - func: bootstrap-mongo-orchestration
+        - func: run-load-balancer
+        - func: run-load-balancer-tests
+        - func: stop-load-balancer
+          vars:
+            FRAMEWORK: netstandard21
+
     - name: atlas-connectivity-tests
       commands:
         - func: run-atlas-connectivity-tests
@@ -1327,6 +1385,22 @@ buildvariants:
   tasks:
     - name: plain-auth-tests
 
+- matrix_name: tests-load-balancer
+  matrix_spec: { version: ["5.0", "latest"], auth: "noauth", ssl: "nossl", topology: "sharded-cluster", os: "ubuntu-1804" }
+  display_name: "Load Balancer ${version} ${auth} ${ssl} ${os}"
+  tasks:
+    - name: "test-load-balancer-netstandard15"
+    - name: "test-load-balancer-netstandard20"
+    - name: "test-load-balancer-netstandard21"  
+    
+- matrix_name: tests-load-balancer-secure
+  matrix_spec: { version: ["5.0", "latest"], auth: "auth", ssl: "ssl", topology: "sharded-cluster", os: "ubuntu-1804" }
+  display_name: "Load Balancer ${version} ${auth} ${ssl} ${os}"
+  tasks:
+    - name: "test-load-balancer-netstandard15"
+    - name: "test-load-balancer-netstandard20"
+    - name: "test-load-balancer-netstandard21"
+
 - name: atlas-connectivity-tests
   display_name: "Atlas Connectivity Tests"
   run_on:

evergreen/run-load-balancer-tests.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+
+set -o xtrace  # Write all commands first to stderr
+set -o errexit # Exit the script with error if any of the commands fail
+
+# Supported/used environment variables:
+#   SSL                         Set to enable SSL. Values are "ssl" / "nossl" (default)
+#   OS                          Set to current operating system
+#   FRAMEWORK                   Set to .net framework
+#   SINGLE_MONGOS_LB_URI        Set the URI pointing to a load balancer configured with a single mongos server
+#   MULTI_MONGOS_LB_URI         Set the URI pointing to a load balancer configured with multiple mongos servers
+
+SSL=${SSL:-nossl}
+
+############################################
+#            Main Program                  #
+############################################
+
+if [[ ! "$OS" =~ Ubuntu|ubuntu ]]; then
+  echo "Unsupported OS:${OS}" 1>&2 # write to stderr
+  exit 1
+fi
+
+
+if [ "$SSL" != "nossl" ]; then 
+  SINGLE_MONGOS_LB_URI="${SINGLE_MONGOS_LB_URI}&ssl=true&tlsDisableCertificateRevocationCheck=true"
+  MULTI_MONGOS_LB_URI="${MULTI_MONGOS_LB_URI}&ssl=true&tlsDisableCertificateRevocationCheck=true" 
+fi
+
+echo "Running $AUTH tests (${FRAMEWORK}) over $SSL and connecting to SINGLE_MONGOS_LB_URI: $SINGLE_MONGOS_LB_URI or MULTI_MONGOS_LB_URI: $MULTI_MONGOS_LB_URI" 
+
+export MONGODB_URI=${SINGLE_MONGOS_LB_URI}
+export MONGODB_URI_WITH_MULTIPLE_MONGOSES=${MULTI_MONGOS_LB_URI}
+
+# show test output
+set -x
+
+./build.sh --target TestLoadBalanced${FRAMEWORK}

src/MongoDB.Driver.Core/Core/Bindings/CoreServerSessionPool.cs

@@ -95,16 +95,22 @@ public void ReleaseSession(ICoreServerSession session)
         private bool IsAboutToExpire(ICoreServerSession session)
         {
             var logicalSessionTimeout = _cluster.Description.LogicalSessionTimeout;
-            if (!session.LastUsedAt.HasValue || !logicalSessionTimeout.HasValue)
+            var clusterType = _cluster.Description.Type;
+
+            if (clusterType == ClusterType.LoadBalanced)
             {
-                return true;
+                return false;  // sessions never expire in load balancing mode
             }
-            else
+            else if (session.LastUsedAt.HasValue && logicalSessionTimeout.HasValue)
             {
                 var expiresAt = session.LastUsedAt.Value + logicalSessionTimeout.Value;
                 var timeRemaining = expiresAt - DateTime.UtcNow;
                 return timeRemaining < TimeSpan.FromMinutes(1);
             }
+            else
+            {
+                return true;
+            }
         }
 
         private bool IsAboutToExpireOrDirty(ICoreServerSession session)

src/MongoDB.Driver.Core/Core/Clusters/Cluster.cs

@@ -87,6 +87,7 @@ internal abstract class Cluster : ICluster
         protected Cluster(ClusterSettings settings, IClusterableServerFactory serverFactory, IEventSubscriber eventSubscriber)
         {
             _settings = Ensure.IsNotNull(settings, nameof(settings));
+            Ensure.That(!_settings.LoadBalanced, "LoadBalanced mode is not supported.");
             _serverFactory = Ensure.IsNotNull(serverFactory, nameof(serverFactory));
             Ensure.IsNotNull(eventSubscriber, nameof(eventSubscriber));
             _state = new InterlockedInt32(State.Initial);
@@ -155,7 +156,7 @@ public ICoreServerSession AcquireServerSession()
 
         protected IClusterableServer CreateServer(EndPoint endPoint)
         {
-            return _serverFactory.CreateServer(_clusterId, _clusterClock, endPoint);
+            return _serverFactory.CreateServer(_settings.GetInitialClusterType(), _clusterId, _clusterClock, endPoint);
         }
 
         public void Dispose()

src/MongoDB.Driver.Core/Core/Clusters/ClusterFactory.cs

@@ -40,6 +40,12 @@ public ICluster CreateCluster()
         {
             var settings = _settings;
 
+            bool createLoadBalancedCluster = settings.LoadBalanced;
+            if (createLoadBalancedCluster)
+            {
+                return CreateLoadBalancedCluster(settings);
+            }
+
             bool createSingleServerCluster;
 #pragma warning disable CS0618 // Type or member is obsolete
             if (settings.ConnectionModeSwitch == ConnectionModeSwitch.UseDirectConnection)
@@ -88,5 +94,10 @@ private SingleServerCluster CreateSingleServerCluster(ClusterSettings settings)
         {
             return new SingleServerCluster(settings, _serverFactory, _eventSubscriber);
         }
+
+        private LoadBalancedCluster CreateLoadBalancedCluster(ClusterSettings setting)
+        {
+            return new LoadBalancedCluster(setting, _serverFactory, _eventSubscriber);
+        }
     }
 }