Add ssh command to activate the latest index

In case the online indexer fails, this allows the admins to activate
the latest index.

Change-Id: I59ebf2bce02a599b87d0f7771fc806ff64a3ba64

Documentation/cmd-index-activate.txt

@@ -0,0 +1,32 @@
+= gerrit index activate
+
+== NAME
+gerrit index activate - Activate the latest index version available
+
+== SYNOPSIS
+--
+'ssh' -p @SSH_PORT@ @SSH_HOST@ 'gerrit index activate'
+--
+
+== DESCRIPTION
+Gerrit supports online index schema upgrades. When starting Gerrit for the first
+time after an upgrade that requires an index schema upgrade, the online indexer
+will be started. If the schema upgrade is a success, the new index will be
+activated and if it fails, a statement in the logs will be printed with the
+number of successfully/failed indexed changes.
+
+This command allows to activate the latest index even if there were some
+failures.
+
+== ACCESS
+Caller must be a member of the privileged 'Administrators' group.
+
+== SCRIPTING
+This command is intended to be used in scripts.
+
+GERRIT
+------
+Part of link:index.html[Gerrit Code Review]
+
+SEARCHBOX
+---------

Documentation/cmd-index.txt

@@ -117,6 +117,9 @@ link:cmd-gc.html[gerrit gc]::
 link:cmd-gsql.html[gerrit gsql]::
 	Administrative interface to active database.
 
+link:cmd-index-index.html[gerrit index activate]::
+	Activate the latest index version available.
+
 link:cmd-index-start.html[gerrit index start]::
 	Start the online indexer.
 

gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneVersionManager.java

@@ -182,6 +182,22 @@ public class LuceneVersionManager implements LifecycleListener {
     return false;
   }
 
+  /**
+   * Activate the latest index if the current index is not already the latest.
+   *
+   * @return true if index was activate, otherwise false.
+   * @throws ReindexerAlreadyRunningException
+   */
+  public synchronized boolean activateLatestIndex()
+      throws ReindexerAlreadyRunningException {
+    validateReindexerNotRunning();
+    if (!isCurrentIndexVersionLatest()) {
+      reindexer.activateIndex();
+      return true;
+    }
+    return false;
+  }
+
   private boolean isCurrentIndexVersionLatest() {
     return reindexer == null
         || reindexer.getVersion() == indexes.getSearchIndex().getSchema()

gerrit-lucene/src/main/java/com/google/gerrit/lucene/OnlineReindexer.java

@@ -43,6 +43,7 @@ public class OnlineReindexer {
   private final SiteIndexer batchIndexer;
   private final ProjectCache projectCache;
   private final int version;
+  private ChangeIndex index;
   private final AtomicBoolean running = new AtomicBoolean();
 
   @Inject
@@ -88,7 +89,7 @@ public class OnlineReindexer {
   }
 
   private void reindex() {
-    ChangeIndex index = checkNotNull(indexes.getWriteIndex(version),
+    index = checkNotNull(indexes.getWriteIndex(version),
         "not an active write schema version: %s", version);
     log.info("Starting online reindex from schema version {} to {}",
         version(indexes.getSearchIndex()), version(index));
@@ -100,9 +101,13 @@ public class OnlineReindexer {
           version(index), result.doneCount(), result.failedCount());
       return;
     }
+    log.info("Reindex to version {} complete", version(index));
+    activateIndex();
+  }
 
+  void activateIndex() {
     indexes.setSearchIndex(index);
-    log.info("Reindex complete, using schema version {}", version(index));
+    log.info("Using schema version {}", version(index));
     try {
       index.markReady(true);
     } catch (IOException e) {

gerrit-sshd/src/main/java/com/google/gerrit/sshd/commands/DefaultCommandModule.java

@@ -59,6 +59,7 @@ public class DefaultCommandModule extends CommandModule {
     command(gerrit, GarbageCollectionCommand.class);
 
     command(index).toProvider(new DispatchCommandProvider(index));
+    command(index, IndexActivateCommand.class);
     command(index, IndexStartCommand.class);
 
     command(gerrit, "plugin").toProvider(new DispatchCommandProvider(plugin));

gerrit-sshd/src/main/java/com/google/gerrit/sshd/commands/IndexActivateCommand.java

@@ -0,0 +1,49 @@
+// Copyright (C) 2015 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.sshd.commands;
+
+import static com.google.gerrit.sshd.CommandMetaData.Mode.MASTER;
+
+import com.google.gerrit.common.data.GlobalCapability;
+import com.google.gerrit.extensions.annotations.RequiresCapability;
+import com.google.gerrit.lucene.LuceneVersionManager;
+import com.google.gerrit.lucene.ReindexerAlreadyRunningException;
+import com.google.gerrit.sshd.CommandMetaData;
+import com.google.gerrit.sshd.SshCommand;
+import com.google.inject.Inject;
+
+@RequiresCapability(GlobalCapability.ADMINISTRATE_SERVER)
+@CommandMetaData(name = "activate",
+  description = "Activate the latest index version available",
+  runsAt = MASTER)
+public class IndexActivateCommand extends SshCommand {
+
+  @Inject
+  private LuceneVersionManager luceneVersionManager;
+
+  @Override
+  protected void run() throws UnloggedFailure {
+    try {
+      if (luceneVersionManager.activateLatestIndex()) {
+        stdout.println("Activated latest index version");
+      } else {
+        stdout.println("Not activating index, already using latest version");
+      }
+    } catch (ReindexerAlreadyRunningException e) {
+      throw new UnloggedFailure("Failed to activate latest index: "
+          + e.getMessage());
+    }
+  }
+}