Deprecate tribe service

This commit deprecates the tribe service so that deprecation log
messages are delivered if a tribe node is configured.

Relates #24598

core/src/main/java/org/elasticsearch/tribe/TribeService.java

@@ -49,6 +49,8 @@ import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.io.stream.NamedWriteableAwareStreamInput;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.logging.DeprecationLogger;
+import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.network.NetworkModule;
 import org.elasticsearch.common.network.NetworkService;
 import org.elasticsearch.common.regex.Regex;
@@ -230,6 +232,10 @@ public class TribeService extends AbstractLifecycleComponent {
         this.blockIndicesMetadata = BLOCKS_METADATA_INDICES_SETTING.get(settings).toArray(Strings.EMPTY_ARRAY);
         this.blockIndicesRead = BLOCKS_READ_INDICES_SETTING.get(settings).toArray(Strings.EMPTY_ARRAY);
         this.blockIndicesWrite = BLOCKS_WRITE_INDICES_SETTING.get(settings).toArray(Strings.EMPTY_ARRAY);
+        if (!nodes.isEmpty()) {
+            new DeprecationLogger(Loggers.getLogger(TribeService.class))
+                .deprecated("tribe nodes are deprecated in favor of cross-cluster search and will be removed in Elasticsearch 7.0.0");
+        }
         this.onConflict = ON_CONFLICT_SETTING.get(settings);
     }
 

core/src/test/java/org/elasticsearch/tribe/TribeServiceTests.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.tribe;
 
+import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.cluster.NamedDiff;
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.common.io.stream.StreamInput;
@@ -27,11 +28,14 @@ import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.set.Sets;
 import org.elasticsearch.env.Environment;
-import org.elasticsearch.script.ScriptService;
+import org.elasticsearch.node.MockNode;
+import org.elasticsearch.node.Node;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.test.TestCustomMetaData;
+import org.elasticsearch.transport.MockTcpTransportPlugin;
 
 import java.io.IOException;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -180,6 +184,28 @@ public class TribeServiceTests extends ESTestCase {
         assertEquals(mergedCustom.getData(), "data2"+String.valueOf(n));
     }
 
+    public void testTribeNodeDeprecation() throws IOException {
+        final Path tempDir = createTempDir();
+        Settings.Builder settings = Settings.builder()
+            .put("node.name", "test-node")
+            .put("path.home", tempDir)
+            .put(NetworkModule.HTTP_ENABLED.getKey(), false)
+            .put(NetworkModule.TRANSPORT_TYPE_SETTING.getKey(), "mock-socket-network");
+
+        final boolean tribeServiceEnable = randomBoolean();
+        if (tribeServiceEnable) {
+            String clusterName = "single-node-cluster";
+            String tribeSetting = "tribe." + clusterName + ".";
+            settings.put(tribeSetting + ClusterName.CLUSTER_NAME_SETTING.getKey(), clusterName)
+                .put(tribeSetting + NetworkModule.TRANSPORT_TYPE_SETTING.getKey(), "mock-socket-network");
+        }
+        try (Node node = new MockNode(settings.build(),Collections.singleton(MockTcpTransportPlugin.class) )) {
+            if (tribeServiceEnable) {
+                assertWarnings("tribe nodes are deprecated in favor of cross-cluster search and will be removed in Elasticsearch 7.0.0");
+            }
+        }
+    }
+
     static class MergableCustomMetaData1 extends TestCustomMetaData
             implements TribeService.MergableCustomMetaData<MergableCustomMetaData1> {
         public static final String TYPE = "custom_md_1";

qa/evil-tests/src/test/java/org/elasticsearch/tribe/TribeUnitTests.java

@@ -99,6 +99,7 @@ public class TribeUnitTests extends ESTestCase {
             .put(Environment.PATH_CONF_SETTING.getKey(), pathConf)
             .build();
         assertTribeNodeSuccessfullyCreated(settings);
+        assertWarnings("tribe nodes are deprecated in favor of cross-cluster search and will be removed in Elasticsearch 7.0.0");
     }
 
     private static void assertTribeNodeSuccessfullyCreated(Settings extraSettings) throws Exception {