Ignore read preference for standalone servers

JAVA-3306

Author: jyemin

driver-async/src/test/functional/com/mongodb/async/client/ReadConcernTest.java

@@ -18,11 +18,10 @@
 
 import com.mongodb.ClusterFixture;
 import com.mongodb.ReadConcern;
-import com.mongodb.ReadPreference;
 import com.mongodb.async.SingleResultCallback;
-import com.mongodb.internal.connection.TestCommandListener;
 import com.mongodb.event.CommandEvent;
 import com.mongodb.event.CommandStartedEvent;
+import com.mongodb.internal.connection.TestCommandListener;
 import org.bson.BsonDocument;
 import org.bson.BsonString;
 import org.junit.After;
@@ -34,7 +33,6 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 
-import static com.mongodb.ClusterFixture.isStandalone;
 import static com.mongodb.ClusterFixture.serverVersionAtLeast;
 import static com.mongodb.async.client.Fixture.getDefaultDatabaseName;
 import static com.mongodb.client.CommandMonitoringTestHelper.assertEventsEquality;
@@ -82,9 +80,6 @@ public void onResult(final Long result, final Throwable t) {
         if (serverVersionAtLeast(3, 6)) {
             commandDocument.put("$db", new BsonString(getDefaultDatabaseName()));
         }
-        if (isStandalone() && serverVersionAtLeast(3, 6)) {
-            commandDocument.put("$readPreference", ReadPreference.primaryPreferred().toDocument());
-        }
         assertEventsEquality(Arrays.<CommandEvent>asList(new CommandStartedEvent(1, null, getDefaultDatabaseName(),
                         "count", commandDocument)), events);
 

driver-core/src/main/com/mongodb/internal/connection/CommandMessage.java

@@ -48,6 +48,7 @@
 import static com.mongodb.connection.ClusterConnectionMode.MULTIPLE;
 import static com.mongodb.connection.ClusterConnectionMode.SINGLE;
 import static com.mongodb.connection.ServerType.SHARD_ROUTER;
+import static com.mongodb.connection.ServerType.STANDALONE;
 import static com.mongodb.internal.connection.BsonWriterHelper.writePayload;
 import static com.mongodb.internal.connection.ReadConcernHelper.getReadConcernDocument;
 import static com.mongodb.internal.operation.ServerVersionHelper.FOUR_DOT_TWO_WIRE_VERSION;
@@ -215,11 +216,13 @@ private int getOpQuerySlaveOkFlagBit() {
     }
 
     private boolean isSlaveOk() {
-        return (readPreference != null && readPreference.isSlaveOk()) || isDirectConnectionToNonShardRouter();
+        return (readPreference != null && readPreference.isSlaveOk()) || isDirectConnectionToReplicaSetMember();
     }
 
-    private boolean isDirectConnectionToNonShardRouter() {
-        return clusterConnectionMode == SINGLE && getSettings().getServerType() != SHARD_ROUTER;
+    private boolean isDirectConnectionToReplicaSetMember() {
+        return clusterConnectionMode == SINGLE
+                && getSettings().getServerType() != SHARD_ROUTER
+                && getSettings().getServerType() != STANDALONE;
     }
 
     private boolean useOpMsg() {
@@ -256,7 +259,7 @@ private List<BsonElement> getExtraElements(final SessionContext sessionContext)
         if (readPreference != null) {
             if (!readPreference.equals(primary())) {
                 extraElements.add(new BsonElement("$readPreference", readPreference.toDocument()));
-            } else if (isDirectConnectionToNonShardRouter()) {
+            } else if (isDirectConnectionToReplicaSetMember()) {
                 extraElements.add(new BsonElement("$readPreference", primaryPreferred().toDocument()));
             }
         }

driver-core/src/test/functional/com/mongodb/client/CommandMonitoringTestHelper.java

@@ -17,7 +17,6 @@
 package com.mongodb.client;
 
 import com.mongodb.ClusterFixture;
-import com.mongodb.ReadPreference;
 import com.mongodb.event.CommandEvent;
 import com.mongodb.event.CommandFailedEvent;
 import com.mongodb.event.CommandStartedEvent;
@@ -45,8 +44,6 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
-import static com.mongodb.ClusterFixture.isDiscoverableReplicaSet;
-import static com.mongodb.ClusterFixture.isSharded;
 import static java.util.Arrays.asList;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -89,9 +86,7 @@ public static List<CommandEvent> getExpectedEvents(final BsonArray expectedEvent
                     commandDocument.put("$db", new BsonString(actualDatabaseName));
                     if (operation != null && operation.containsKey("read_preference")) {
                         commandDocument.put("$readPreference", operation.getDocument("read_preference"));
-                    } else if (!isDiscoverableReplicaSet() && !isSharded() && !isWriteCommand(commandName)) {
-                        commandDocument.put("$readPreference", ReadPreference.primaryPreferred().toDocument());
-                    }
+                    } 
                 }
                 commandEvent = new CommandStartedEvent(1, null, actualDatabaseName, commandName,
                         commandDocument);

driver-sync/src/test/functional/com/mongodb/client/ReadConcernTest.java

@@ -18,11 +18,10 @@
 
 import com.mongodb.Block;
 import com.mongodb.ReadConcern;
-import com.mongodb.ReadPreference;
 import com.mongodb.connection.SocketSettings;
-import com.mongodb.internal.connection.TestCommandListener;
 import com.mongodb.event.CommandEvent;
 import com.mongodb.event.CommandStartedEvent;
+import com.mongodb.internal.connection.TestCommandListener;
 import org.bson.BsonDocument;
 import org.bson.BsonString;
 import org.junit.After;
@@ -33,7 +32,6 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
-import static com.mongodb.ClusterFixture.isStandalone;
 import static com.mongodb.ClusterFixture.serverVersionAtLeast;
 import static com.mongodb.client.CommandMonitoringTestHelper.assertEventsEquality;
 import static com.mongodb.client.Fixture.getDefaultDatabaseName;
@@ -81,9 +79,6 @@ public void shouldIncludeReadConcernInCommand() {
         if (serverVersionAtLeast(3, 6)) {
             commandDocument.put("$db", new BsonString(getDefaultDatabaseName()));
         }
-        if (isStandalone() && serverVersionAtLeast(3, 6)) {
-            commandDocument.put("$readPreference", ReadPreference.primaryPreferred().toDocument());
-        }
         assertEventsEquality(Arrays.<CommandEvent>asList(new CommandStartedEvent(1, null, getDefaultDatabaseName(),
                         "count", commandDocument)), events);
     }