Merge branch 'stable-2.14'

* stable-2.14:
  Index: Extract common parts into AbstractVersionManager
  ES: Adds configuration for the JEST client

Change-Id: Idcd918450d6ab51fb71f68d949f77e35494043ee

gerrit-server/src/main/java/com/google/gerrit/server/index/AbstractVersionManager.java

@@ -0,0 +1,223 @@
+// 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.server.index;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import com.google.gerrit.extensions.events.LifecycleListener;
+import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.server.config.SitePaths;
+import com.google.gerrit.server.index.IndexDefinition.IndexFactory;
+import com.google.inject.ProvisionException;
+import java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.lib.Config;
+
+public abstract class AbstractVersionManager implements LifecycleListener {
+  public static class Version<V> {
+    public final Schema<V> schema;
+    public final int version;
+    public final boolean ready;
+
+    public Version(Schema<V> schema, int version, boolean ready) {
+      checkArgument(schema == null || schema.getVersion() == version);
+      this.schema = schema;
+      this.version = version;
+      this.ready = ready;
+    }
+  }
+
+  protected final boolean onlineUpgrade;
+  protected final String runReindexMsg;
+  protected final SitePaths sitePaths;
+  protected final Map<String, IndexDefinition<?, ?, ?>> defs;
+  protected final Map<String, OnlineReindexer<?, ?, ?>> reindexers;
+
+  protected AbstractVersionManager(
+      @GerritServerConfig Config cfg,
+      SitePaths sitePaths,
+      Collection<IndexDefinition<?, ?, ?>> defs) {
+    this.sitePaths = sitePaths;
+    this.defs = Maps.newHashMapWithExpectedSize(defs.size());
+    for (IndexDefinition<?, ?, ?> def : defs) {
+      this.defs.put(def.getName(), def);
+    }
+
+    reindexers = Maps.newHashMapWithExpectedSize(defs.size());
+    onlineUpgrade = cfg.getBoolean("index", null, "onlineUpgrade", true);
+    runReindexMsg =
+        "No index versions ready; run java -jar "
+            + sitePaths.gerrit_war.toAbsolutePath()
+            + " reindex";
+  }
+
+  @Override
+  public void start() {
+    GerritIndexStatus cfg = createIndexStatus();
+    for (IndexDefinition<?, ?, ?> def : defs.values()) {
+      initIndex(def, cfg);
+    }
+  }
+
+  @Override
+  public void stop() {
+    // Do nothing; indexes are closed on demand by IndexCollection.
+  }
+
+  /**
+   * Start the online reindexer if the current index is not already the latest.
+   *
+   * @param name index name
+   * @param force start re-index
+   * @return true if started, otherwise false.
+   * @throws ReindexerAlreadyRunningException
+   */
+  public synchronized boolean startReindexer(String name, boolean force)
+      throws ReindexerAlreadyRunningException {
+    OnlineReindexer<?, ?, ?> reindexer = reindexers.get(name);
+    validateReindexerNotRunning(reindexer);
+    if (force || !isLatestIndexVersion(name, reindexer)) {
+      reindexer.start();
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Activate the latest index if the current index is not already the latest.
+   *
+   * @param name index name
+   * @return true if index was activated, otherwise false.
+   * @throws ReindexerAlreadyRunningException
+   */
+  public synchronized boolean activateLatestIndex(String name)
+      throws ReindexerAlreadyRunningException {
+    OnlineReindexer<?, ?, ?> reindexer = reindexers.get(name);
+    validateReindexerNotRunning(reindexer);
+    if (!isLatestIndexVersion(name, reindexer)) {
+      reindexer.activateIndex();
+      return true;
+    }
+    return false;
+  }
+
+  protected <K, V, I extends Index<K, V>> void initIndex(
+      IndexDefinition<K, V, I> def, GerritIndexStatus cfg) {
+    TreeMap<Integer, Version<V>> versions = scanVersions(def, cfg);
+    // Search from the most recent ready version.
+    // Write to the most recent ready version and the most recent version.
+    Version<V> search = null;
+    List<Version<V>> write = Lists.newArrayListWithCapacity(2);
+    for (Version<V> v : versions.descendingMap().values()) {
+      if (v.schema == null) {
+        continue;
+      }
+      if (write.isEmpty() && onlineUpgrade) {
+        write.add(v);
+      }
+      if (v.ready) {
+        search = v;
+        if (!write.contains(v)) {
+          write.add(v);
+        }
+        break;
+      }
+    }
+    if (search == null) {
+      throw new ProvisionException(runReindexMsg);
+    }
+
+    IndexFactory<K, V, I> factory = def.getIndexFactory();
+    I searchIndex = factory.create(search.schema);
+    IndexCollection<K, V, I> indexes = def.getIndexCollection();
+    indexes.setSearchIndex(searchIndex);
+    for (Version<V> v : write) {
+      if (v.version != search.version) {
+        indexes.addWriteIndex(factory.create(v.schema));
+      } else {
+        indexes.addWriteIndex(searchIndex);
+      }
+    }
+
+    markNotReady(def.getName(), versions.values(), write);
+
+    synchronized (this) {
+      if (!reindexers.containsKey(def.getName())) {
+        int latest = write.get(0).version;
+        OnlineReindexer<K, V, I> reindexer = new OnlineReindexer<>(def, latest);
+        reindexers.put(def.getName(), reindexer);
+        if (onlineUpgrade && latest != search.version) {
+          reindexer.start();
+        }
+      }
+    }
+  }
+
+  protected GerritIndexStatus createIndexStatus() {
+    try {
+      return new GerritIndexStatus(sitePaths);
+    } catch (ConfigInvalidException | IOException e) {
+      throw fail(e);
+    }
+  }
+
+  protected abstract <V> boolean isDirty(Collection<Version<V>> inUse, Version<V> v);
+
+  protected abstract <K, V, I extends Index<K, V>> TreeMap<Integer, Version<V>> scanVersions(
+      IndexDefinition<K, V, I> def, GerritIndexStatus cfg);
+
+  private boolean isLatestIndexVersion(String name, OnlineReindexer<?, ?, ?> reindexer) {
+    int readVersion = defs.get(name).getIndexCollection().getSearchIndex().getSchema().getVersion();
+    return reindexer == null || reindexer.getVersion() == readVersion;
+  }
+
+  private static void validateReindexerNotRunning(OnlineReindexer<?, ?, ?> reindexer)
+      throws ReindexerAlreadyRunningException {
+    if (reindexer != null && reindexer.isRunning()) {
+      throw new ReindexerAlreadyRunningException();
+    }
+  }
+
+  private <V> void markNotReady(
+      String name, Iterable<Version<V>> versions, Collection<Version<V>> inUse) {
+    GerritIndexStatus cfg = createIndexStatus();
+    boolean dirty = false;
+    for (Version<V> v : versions) {
+      if (isDirty(inUse, v)) {
+        cfg.setReady(name, v.version, false);
+        dirty = true;
+      }
+    }
+    if (dirty) {
+      try {
+        cfg.save();
+      } catch (IOException e) {
+        throw fail(e);
+      }
+    }
+  }
+
+  private ProvisionException fail(Throwable t) {
+    ProvisionException e = new ProvisionException("Error scanning indexes");
+    e.initCause(t);
+    return e;
+  }
+}