Remove nio transport from 6.x (elastic#34756) (elastic#34879)

This commit removes the nio transport work from 6.x This work will never
be enabled outside of the test framework. Additionally, we get
sufficient testing on master/7.0 right now. So there is no need to have
it on 6.x.

This is motivated by the fact that this work has diverged significantly
from master. This makes backports difficult. Additionally, the nio
transport uses many connections increasing the timeouts due to resource
exhaustion in the build.

qa/smoke-test-client/src/test/java/org/elasticsearch/smoketest/ESSmokeClientTestCase.java

@@ -32,7 +32,6 @@
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.transport.MockTcpTransportPlugin;
 import org.elasticsearch.transport.client.PreBuiltTransportClient;
-import org.elasticsearch.transport.nio.NioTransportPlugin;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Before;
@@ -82,16 +81,9 @@ private static Client startClient(Path tempDir, TransportAddress... transportAdd
             .put("client.transport.ignore_cluster_name", true)
             .put(Environment.PATH_HOME_SETTING.getKey(), tempDir);
         final Collection<Class<? extends Plugin>> plugins;
-        boolean usNio = random().nextBoolean();
-        String transportKey;
-        Class<? extends Plugin> transportPlugin;
-        if (usNio) {
-            transportKey = NioTransportPlugin.NIO_TRANSPORT_NAME;
-            transportPlugin = NioTransportPlugin.class;
-        } else {
-            transportKey = MockTcpTransportPlugin.MOCK_TCP_TRANSPORT_NAME;
-            transportPlugin = MockTcpTransportPlugin.class;
-        }
+        String transportKey = MockTcpTransportPlugin.MOCK_TCP_TRANSPORT_NAME;
+        Class<? extends Plugin> transportPlugin = MockTcpTransportPlugin.class;
+
         if (random().nextBoolean()) {
             builder.put(NetworkModule.TRANSPORT_TYPE_KEY, transportKey);
             plugins = Collections.singleton(transportPlugin);

qa/smoke-test-http/src/test/java/org/elasticsearch/http/HttpSmokeTestCase.java

@@ -24,7 +24,6 @@
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.transport.MockTcpTransportPlugin;
 import org.elasticsearch.transport.Netty4Plugin;
-import org.elasticsearch.transport.nio.NioTransportPlugin;
 import org.junit.BeforeClass;
 
 import java.util.Arrays;
@@ -47,8 +46,6 @@ public static void setUpTransport() {
     private static String getTypeKey(Class<? extends Plugin> clazz) {
         if (clazz.equals(MockTcpTransportPlugin.class)) {
             return MockTcpTransportPlugin.MOCK_TCP_TRANSPORT_NAME;
-        } else if (clazz.equals(NioTransportPlugin.class)) {
-            return NioTransportPlugin.NIO_TRANSPORT_NAME;
         } else {
             assert clazz.equals(Netty4Plugin.class);
             return Netty4Plugin.NETTY_TRANSPORT_NAME;

test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java

@@ -112,7 +112,6 @@
 import org.elasticsearch.test.junit.listeners.ReproduceInfoPrinter;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.MockTcpTransportPlugin;
-import org.elasticsearch.transport.nio.NioTransportPlugin;
 import org.joda.time.DateTimeZone;
 import org.junit.After;
 import org.junit.AfterClass;
@@ -128,8 +127,8 @@
 import java.nio.file.DirectoryStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.time.ZoneId;
 import java.security.Security;
+import java.time.ZoneId;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -991,19 +990,12 @@ public static String randomGeohash(int minPrecision, int maxPrecision) {
         return geohashGenerator.ofStringLength(random(), minPrecision, maxPrecision);
     }
 
-    private static boolean useNio;
-
-    @BeforeClass
-    public static void setUseNio() throws Exception {
-        useNio = randomBoolean();
-    }
-
     public static String getTestTransportType() {
-        return useNio ? NioTransportPlugin.NIO_TRANSPORT_NAME : MockTcpTransportPlugin.MOCK_TCP_TRANSPORT_NAME;
+        return MockTcpTransportPlugin.MOCK_TCP_TRANSPORT_NAME;
     }
 
     public static Class<? extends Plugin> getTestTransportPlugin() {
-        return useNio ? NioTransportPlugin.class : MockTcpTransportPlugin.class;
+        return MockTcpTransportPlugin.class;
     }
 
     private static final GeohashGenerator geohashGenerator = new GeohashGenerator();

test/framework/src/main/java/org/elasticsearch/test/ExternalTestCluster.java

@@ -36,7 +36,6 @@
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.transport.MockTcpTransportPlugin;
 import org.elasticsearch.transport.MockTransportClient;
-import org.elasticsearch.transport.nio.NioTransportPlugin;
 
 import java.io.IOException;
 import java.net.InetSocketAddress;
@@ -84,12 +83,9 @@ public ExternalTestCluster(Path tempDir, Settings additionalSettings, Collection
         if (addMockTcpTransport) {
             String transport = getTestTransportType();
             clientSettingsBuilder.put(NetworkModule.TRANSPORT_TYPE_KEY, transport);
-            if (pluginClasses.contains(MockTcpTransportPlugin.class) == false &&
-                pluginClasses.contains(NioTransportPlugin.class) == false) {
+            if (pluginClasses.contains(MockTcpTransportPlugin.class) == false) {
                 pluginClasses = new ArrayList<>(pluginClasses);
-                if (transport.equals(NioTransportPlugin.NIO_TRANSPORT_NAME)) {
-                    pluginClasses.add(NioTransportPlugin.class);
-                } else {
+                if (transport.equals(MockTcpTransportPlugin.MOCK_TCP_TRANSPORT_NAME)) {
                     pluginClasses.add(MockTcpTransportPlugin.class);
                 }
             }

test/framework/src/main/java/org/elasticsearch/transport/MockTransportClient.java

@@ -23,7 +23,6 @@
 import org.elasticsearch.common.network.NetworkModule;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.plugins.Plugin;
-import org.elasticsearch.transport.nio.NioTransportPlugin;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -59,14 +58,6 @@ private static Collection<Class<? extends Plugin>> addMockTransportIfMissing(Set
                 plugins.add(MockTcpTransportPlugin.class);
                 return plugins;
             }
-        } else if (NioTransportPlugin.NIO_TRANSPORT_NAME.equals(transportType)) {
-            if (plugins.contains(NioTransportPlugin.class)) {
-                return plugins;
-            } else {
-                plugins = new ArrayList<>(plugins);
-                plugins.add(NioTransportPlugin.class);
-                return plugins;
-            }
         }
         return plugins;
     }