ES: Allow to configure multiple ElasticSearch servers

Add possibility to configure more than one ES servers in the
gerrit.config file.

We also permanently disable auto-discovery feature of JEST since
administrators can configure multiple ES servers it is no longer
required to relay on it. Especially that we would need to write
complicated code to ensure that we don't use not fully initialized JEST
client.

Change-Id: I8277150ee6210183cb41a10ef179d7800471844b

Documentation/config-gerrit.txt

@@ -2667,25 +2667,9 @@ Open and closed changes are indexed in a single index, separated
 into types 'open_changes' and 'closed_changes' respectively.
 
 The following settings are only used when the index type is
-`ELASTICSEARCH`.
+`ELASTICSEARCH`. To configure Elasticsearch servers look into
+link:#elasticsearch[Elasticsearch section]
 
-[[index.protocol]]index.protocol::
-+
-Elasticsearch server protocol [http|https].
-+
-Defaults to `http`.
-
-[[index.hostname]]index.hostname::
-+
-Elasticsearch server hostname.
-
-Defaults to `localhost`.
-
-[[index.port]]index.port::
-+
-Elasticsearch server port.
-+
-Defaults to `9200`.
 
 [[index.prefix]]index.prefix::
 +
@@ -2695,6 +2679,33 @@ change index named 'gerrit1_changes_0001'.
 +
 Not set by default.
 
+[[elasticsearch]]
+=== Section elasticsearch
+
+WARNING: The Elasticsearch support is incomplete. Online reindexing
+is not implemented yet.
+
+Each section correspond to the one Elasticsearch server.
+
+[[elasticsearch.name.protocol]]elasticsearch.name.protocol::
++
+Elasticsearch server protocol [http|https].
++
+Defaults to `http`.
+
+[[elasticsearch.name.hostname]]elasticsearch.name.hostname::
++
+Elasticsearch server hostname.
+
+Defaults to `localhost`.
+
+[[elasticsearch.name.port]]elasticsearch.name.port::
++
+Elasticsearch server port.
++
+Defaults to `9200`.
+
+
 [[ldap]]
 === Section ldap
 

gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java

@@ -63,7 +63,6 @@ abstract class AbstractElasticIndex<K, V> implements Index<K, V> {
   private final FillArgs fillArgs;
   private final SitePaths sitePaths;
 
-  protected final boolean refresh;
   protected final String indexName;
   protected final JestHttpClient client;
   protected final Gson gson;
@@ -87,7 +86,6 @@ abstract class AbstractElasticIndex<K, V> implements Index<K, V> {
             Strings.nullToEmpty(cfg.getString("index", null, "prefix")),
             indexName,
             schema.getVersion());
-    this.refresh = clientBuilder.refresh;
     this.client = clientBuilder.build();
   }
 
@@ -108,7 +106,7 @@ abstract class AbstractElasticIndex<K, V> implements Index<K, V> {
 
   @Override
   public void delete(K c) throws IOException {
-    Bulk bulk = addActions(new Bulk.Builder(), c).refresh(refresh).build();
+    Bulk bulk = addActions(new Bulk.Builder(), c).refresh(true).build();
     JestResult result = client.execute(bulk);
     if (!result.isSucceeded()) {
       throw new IOException(

gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticAccountIndex.java

@@ -96,7 +96,7 @@ public class ElasticAccountIndex extends AbstractElasticIndex<Account.Id, Accoun
             .defaultIndex(indexName)
             .defaultType(ACCOUNTS)
             .addAction(insert(ACCOUNTS, as))
-            .refresh(refresh)
+            .refresh(true)
             .build();
     JestResult result = client.execute(bulk);
     if (!result.isSucceeded()) {

gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java

@@ -137,7 +137,7 @@ class ElasticChangeIndex extends AbstractElasticIndex<Change.Id, ChangeData>
             .defaultType("changes")
             .addAction(insert(insertIndex, cd))
             .addAction(delete(deleteIndex, cd.getId()))
-            .refresh(refresh)
+            .refresh(true)
             .build();
     JestResult result = client.execute(bulk);
     if (!result.isSucceeded()) {

gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java

@@ -0,0 +1,71 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.elasticsearch;
+
+import com.google.common.base.MoreObjects;
+import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Set;
+import org.eclipse.jgit.lib.Config;
+
+@Singleton
+class ElasticConfiguration {
+  private static final String DEFAULT_HOST = "localhost";
+  private static final String DEFAULT_PORT = "9200";
+  private static final String DEFAULT_PROTOCOL = "http";
+
+  final List<String> urls;
+
+  @Inject
+  ElasticConfiguration(@GerritServerConfig Config cfg) {
+    Set<String> subsections = cfg.getSubsections("elasticsearch");
+    if (subsections.isEmpty()) {
+      this.urls = Arrays.asList(buildUrl(DEFAULT_PROTOCOL, DEFAULT_HOST, DEFAULT_PORT));
+    } else {
+      this.urls = new ArrayList<>(subsections.size());
+      for (String subsection : subsections) {
+        String port = getString(cfg, subsection, "port", DEFAULT_PORT);
+        String host = getString(cfg, subsection, "hostname", DEFAULT_HOST);
+        String protocol = getString(cfg, subsection, "protocol", DEFAULT_PROTOCOL);
+        this.urls.add(buildUrl(protocol, host, port));
+      }
+    }
+  }
+
+  private String getString(Config cfg, String subsection, String name, String defaultValue) {
+    return MoreObjects.firstNonNull(cfg.getString("elasticsearch", subsection, name), defaultValue);
+  }
+
+  private String buildUrl(String protocol, String hostname, String port) {
+    try {
+      return new URL(protocol, hostname, Integer.parseInt(port), "").toString();
+    } catch (MalformedURLException | NumberFormatException e) {
+      throw new RuntimeException(
+          "Cannot build url to Elasticsearch from values: protocol="
+              + protocol
+              + " hostname="
+              + hostname
+              + " port="
+              + port,
+          e);
+    }
+  }
+}

gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticGroupIndex.java

@@ -93,7 +93,7 @@ public class ElasticGroupIndex extends AbstractElasticIndex<AccountGroup.UUID, A
             .defaultIndex(indexName)
             .defaultType(GROUPS)
             .addAction(insert(GROUPS, group))
-            .refresh(refresh)
+            .refresh(true)
             .build();
     JestResult result = client.execute(bulk);
     if (!result.isSucceeded()) {

gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/JestClientBuilder.java

@@ -14,72 +14,30 @@
 
 package com.google.gerrit.elasticsearch;
 
-import com.google.common.base.MoreObjects;
-import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import io.searchbox.client.JestClientFactory;
 import io.searchbox.client.config.HttpClientConfig;
 import io.searchbox.client.http.JestHttpClient;
-import java.net.MalformedURLException;
-import java.net.URL;
 import java.util.concurrent.TimeUnit;
-import org.eclipse.jgit.lib.Config;
 
 @Singleton
 class JestClientBuilder {
-
-  private final String url;
-
-  final boolean refresh;
+  private final ElasticConfiguration cfg;
 
   @Inject
-  JestClientBuilder(@GerritServerConfig Config cfg) {
-    String protocol = MoreObjects.firstNonNull(cfg.getString("index", null, "protocol"), "http");
-    String hostname =
-        MoreObjects.firstNonNull(cfg.getString("index", null, "hostname"), "localhost");
-    String port = String.valueOf(cfg.getInt("index", null, "port", 9200));
-
-    // By default Elasticsearch has a 1s delay before changes are available in
-    // the index.  Setting refresh(true) on calls to the index makes the index
-    // refresh immediately.
-    //
-    // Discovery should be disabled during test mode to prevent spurious
-    // connection failures caused by the client starting up and being ready
-    // before the test node.
-    //
-    // This setting should only be set to true during testing, and is not
-    // documented.
-    this.refresh = cfg.getBoolean("index", "elasticsearch", "test", false);
-
-    this.url = buildUrl(protocol, hostname, port);
+  JestClientBuilder(ElasticConfiguration cfg) {
+    this.cfg = cfg;
   }
 
   JestHttpClient build() {
     JestClientFactory factory = new JestClientFactory();
     factory.setHttpClientConfig(
-        new HttpClientConfig.Builder(url)
+        new HttpClientConfig.Builder(cfg.urls)
             .multiThreaded(true)
-            // Temporary disable servers discovery.
-            // We can enable it again when we can wait for it to finish
             .discoveryEnabled(false)
             .discoveryFrequency(1L, TimeUnit.MINUTES)
             .build());
     return (JestHttpClient) factory.getObject();
   }
-
-  private String buildUrl(String protocol, String hostname, String port) {
-    try {
-      return new URL(protocol, hostname, Integer.parseInt(port), "").toString();
-    } catch (MalformedURLException | NumberFormatException e) {
-      throw new RuntimeException(
-          "Cannot build url to Elasticsearch from values: protocol="
-              + protocol
-              + " hostname="
-              + hostname
-              + " port="
-              + port,
-          e);
-    }
-  }
 }