com.google.gerrit.server.index.change.ChangeIndexer Maven / Gradle / Ivy
// Copyright (C) 2013 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.change;
import static com.google.gerrit.server.git.QueueProvider.QueueType.BATCH;
import com.google.common.base.Objects;
import com.google.common.flogger.FluentLogger;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.ListeningExecutorService;
import com.google.gerrit.common.Nullable;
import com.google.gerrit.entities.Change;
import com.google.gerrit.entities.Project;
import com.google.gerrit.exceptions.StorageException;
import com.google.gerrit.extensions.events.ChangeIndexedListener;
import com.google.gerrit.index.Index;
import com.google.gerrit.server.config.GerritServerConfig;
import com.google.gerrit.server.index.IndexExecutor;
import com.google.gerrit.server.index.StalenessCheckResult;
import com.google.gerrit.server.index.options.IsFirstInsertForEntry;
import com.google.gerrit.server.logging.Metadata;
import com.google.gerrit.server.logging.TraceContext;
import com.google.gerrit.server.logging.TraceContext.TraceTimer;
import com.google.gerrit.server.notedb.ChangeNotes;
import com.google.gerrit.server.plugincontext.PluginSetContext;
import com.google.gerrit.server.project.NoSuchChangeException;
import com.google.gerrit.server.query.change.ChangeData;
import com.google.gerrit.server.util.RequestContext;
import com.google.gerrit.server.util.ThreadLocalRequestContext;
import com.google.inject.OutOfScopeException;
import com.google.inject.assistedinject.Assisted;
import com.google.inject.assistedinject.AssistedInject;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Future;
import org.eclipse.jgit.errors.RepositoryNotFoundException;
import org.eclipse.jgit.lib.Config;
/**
* Helper for (re)indexing a change document.
*
* Indexing is run in the background, as it may require substantial work to compute some of the
* fields and/or update the index.
*/
public class ChangeIndexer {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
public interface Factory {
ChangeIndexer create(ListeningExecutorService executor, ChangeIndex index);
ChangeIndexer create(ListeningExecutorService executor, ChangeIndexCollection indexes);
}
@Nullable private final ChangeIndexCollection indexes;
@Nullable private final ChangeIndex index;
private final ChangeData.Factory changeDataFactory;
private final ChangeNotes.Factory notesFactory;
private final ThreadLocalRequestContext context;
private final ListeningExecutorService batchExecutor;
private final ListeningExecutorService executor;
private final PluginSetContext indexedListeners;
private final StalenessChecker stalenessChecker;
private final boolean autoReindexIfStale;
private final IsFirstInsertForEntry isFirstInsertForEntry;
private final Map queuedIndexTasks = new ConcurrentHashMap<>();
private final Set queuedReindexIfStaleTasks =
Collections.newSetFromMap(new ConcurrentHashMap<>());
@AssistedInject
ChangeIndexer(
@GerritServerConfig Config cfg,
ChangeData.Factory changeDataFactory,
ChangeNotes.Factory notesFactory,
ThreadLocalRequestContext context,
PluginSetContext indexedListeners,
StalenessChecker stalenessChecker,
@IndexExecutor(BATCH) ListeningExecutorService batchExecutor,
@Assisted ListeningExecutorService executor,
@Assisted ChangeIndex index,
IsFirstInsertForEntry isFirstInsertForEntry) {
this.executor = executor;
this.changeDataFactory = changeDataFactory;
this.notesFactory = notesFactory;
this.context = context;
this.indexedListeners = indexedListeners;
this.stalenessChecker = stalenessChecker;
this.batchExecutor = batchExecutor;
this.autoReindexIfStale = autoReindexIfStale(cfg);
this.index = index;
this.indexes = null;
this.isFirstInsertForEntry = isFirstInsertForEntry;
}
@AssistedInject
ChangeIndexer(
@GerritServerConfig Config cfg,
ChangeData.Factory changeDataFactory,
ChangeNotes.Factory notesFactory,
ThreadLocalRequestContext context,
PluginSetContext indexedListeners,
StalenessChecker stalenessChecker,
@IndexExecutor(BATCH) ListeningExecutorService batchExecutor,
@Assisted ListeningExecutorService executor,
@Assisted ChangeIndexCollection indexes,
IsFirstInsertForEntry isFirstInsertForEntry) {
this.executor = executor;
this.changeDataFactory = changeDataFactory;
this.notesFactory = notesFactory;
this.context = context;
this.indexedListeners = indexedListeners;
this.stalenessChecker = stalenessChecker;
this.batchExecutor = batchExecutor;
this.autoReindexIfStale = autoReindexIfStale(cfg);
this.index = null;
this.indexes = indexes;
this.isFirstInsertForEntry = isFirstInsertForEntry;
}
private static boolean autoReindexIfStale(Config cfg) {
return cfg.getBoolean("index", null, "autoReindexIfStale", false);
}
/**
* Start indexing a change.
*
* @param changeId change to index.
* @return future for the indexing task.
*/
public ListenableFuture indexAsync(Project.NameKey project, Change.Id changeId) {
// If the change was already scheduled for indexing, we do not need to schedule it again. Change
// updates that happened after the change was scheduled for indexing will automatically be taken
// into account when the index task is executed (as it reads the current change state).
// To skip duplicate index requests, queuedIndexTasks keeps track of the scheduled index tasks.
// Here we check if the change has already been scheduled for indexing, and only if not we
// create a new index task for the change.
// By using computeIfAbsent we ensure that the lookup and the insertion of a new task happens
// atomically. Some attempted update operations on this map by other threads may be blocked
// while the computation is in progress (but not all as ConcurrentHashMap doesn't lock the
// entire table on write, but only segments of the table).
IndexTask task =
queuedIndexTasks.computeIfAbsent(
changeId,
id -> {
fireChangeScheduledForIndexingEvent(project.get(), id.get());
return new IndexTask(project, id);
});
// Submitting the task to the executor must not happen from within the computeIfAbsent callback,
// as this could result in the task being executed before the computeIfAbsent method has
// finished (e.g. if a direct executor is used, but also if starting the task asynchronously is
// faster than finishing the computeIfAbsent method). This could lead to failures and unexpected
// behavior:
// * The first thing that IndexTask does is to remove itself from queuedIndexTasks.
// This is done so that index requests which are received while an index task for the same
// change is in progress, are not dropped but added to the queue. This is important since
// the change state that is written to the index is read at the beginning of the index task
// and change updates that happen after this read will not be considered when updating the
// index.
// * Trying to remove the IndexTask from queuedIndexTasks at the beginning of the task doesn't
// work if the computeIfAbsent method hasn't finished yet. Either the queuedIndexTasks doesn't
// contain the new entry yet and the removal has no effect as it is done before the entry is
// added to the map, or the removal fails with {@link IllegalStateException} as recursive
// updates from within the computeIfAbsent callback are not allowed.
return task.submitIfNeeded();
}
/**
* Synchronously index a change, then check if the index is stale due to a race condition.
*
* @param cd change to index.
*/
public void index(ChangeData cd) {
fireChangeScheduledForIndexingEvent(cd.project().get(), cd.getId().get());
doIndex(cd);
}
private void doIndex(ChangeData cd) {
indexImpl(cd);
// Always double-check whether the change might be stale immediately after
// interactively indexing it. This fixes up the case where two writers write
// to the primary storage in one order, and the corresponding index writes
// happen in the opposite order:
// 1. Writer A writes to primary storage.
// 2. Writer B writes to primary storage.
// 3. Writer B updates index.
// 4. Writer A updates index.
//
// Without the extra reindexIfStale step, A has no way of knowing that it's
// about to overwrite the index document with stale data. It doesn't work to
// have A check for staleness before attempting its index update, because
// B's index update might not have happened when it does the check.
//
// With the extra reindexIfStale step after (3)/(4), we are able to detect
// and fix the staleness. It doesn't matter which order the two
// reindexIfStale calls actually execute in; we are guaranteed that at least
// one of them will execute after the second index write, (4).
autoReindexIfStale(cd);
}
private void indexImpl(ChangeData cd) {
logger.atFine().log("Reindex change %d in index.", cd.getId().get());
for (Index i : getWriteIndexes()) {
try (TraceTimer traceTimer =
TraceContext.newTimer(
"Reindexing change in index",
Metadata.builder()
.changeId(cd.getId().get())
.patchSetId(cd.currentPatchSet().number())
.indexVersion(i.getSchema().getVersion())
.build())) {
if (isFirstInsertForEntry.equals(IsFirstInsertForEntry.YES)) {
i.insert(cd);
} else {
i.replace(cd);
}
} catch (RuntimeException e) {
throw new StorageException(
String.format(
"Failed to reindex change %d in index version %d (current patch set = %d)",
cd.getId().get(), i.getSchema().getVersion(), cd.currentPatchSet().number()),
e);
}
}
fireChangeIndexedEvent(cd.project().get(), cd.getId().get());
}
private void fireChangeScheduledForIndexingEvent(String projectName, int id) {
indexedListeners.runEach(l -> l.onChangeScheduledForIndexing(projectName, id));
}
private void fireChangeIndexedEvent(String projectName, int id) {
indexedListeners.runEach(l -> l.onChangeIndexed(projectName, id));
}
private void fireChangeScheduledForDeletionFromIndexEvent(int id) {
indexedListeners.runEach(l -> l.onChangeScheduledForDeletionFromIndex(id));
}
private void fireChangeDeletedFromIndexEvent(int id) {
indexedListeners.runEach(l -> l.onChangeDeleted(id));
}
/**
* Synchronously index a change.
*
* @param change change to index.
*/
public void index(Change change) {
index(changeDataFactory.create(change));
}
/**
* Synchronously index a change.
*
* @param project the project to which the change belongs.
* @param changeId ID of the change to index.
*/
public void index(Project.NameKey project, Change.Id changeId) {
index(changeDataFactory.create(project, changeId));
}
/**
* Start deleting a change.
*
* @param id change to delete.
* @return future for the deleting task, the result of the future is always {@code null}
*/
public ListenableFuture deleteAsync(Project.NameKey project, Change.Id id) {
fireChangeScheduledForDeletionFromIndexEvent(id.get());
return submit(new DeleteTask(id, Optional.of(project)));
}
/**
* Synchronously delete a change.
*
* @param id change ID to delete.
*/
public void delete(Change.Id id) {
fireChangeScheduledForDeletionFromIndexEvent(id.get());
doDelete(id);
}
private void doDelete(Project.NameKey project, Change.Id id) {
new DeleteTask(id, Optional.of(project)).call();
}
private void doDelete(Change.Id id) {
new DeleteTask(id, Optional.empty()).call();
}
/**
* Asynchronously check if a change is stale, and reindex if it is.
*
* Always run on the batch executor, even if this indexer instance is configured to use a
* different executor.
*
* @param project the project to which the change belongs.
* @param id ID of the change to index.
* @return future for reindexing the change; returns true if the change was stale.
*/
public ListenableFuture reindexIfStale(Project.NameKey project, Change.Id id) {
ReindexIfStaleTask task = new ReindexIfStaleTask(project, id);
if (queuedReindexIfStaleTasks.add(task)) {
return submit(task, batchExecutor);
}
return Futures.immediateFuture(false);
}
private void autoReindexIfStale(ChangeData cd) {
autoReindexIfStale(cd.project(), cd.getId());
}
private void autoReindexIfStale(Project.NameKey project, Change.Id id) {
if (autoReindexIfStale) {
// Don't retry indefinitely; if this fails the change will be stale.
@SuppressWarnings("unused")
Future possiblyIgnoredError = reindexIfStale(project, id);
}
}
private Collection getWriteIndexes() {
return indexes != null ? indexes.getWriteIndexes() : Collections.singleton(index);
}
private ListenableFuture submit(Callable task) {
return submit(task, executor);
}
private static ListenableFuture submit(
Callable task, ListeningExecutorService executor) {
return Futures.nonCancellationPropagating(executor.submit(task));
}
private abstract class AbstractIndexTask implements Callable {
protected final Project.NameKey project;
protected final Change.Id id;
protected AbstractIndexTask(Project.NameKey project, Change.Id id) {
this.project = project;
this.id = id;
}
protected abstract T callImpl() throws Exception;
protected abstract void remove();
@Override
public abstract String toString();
@Override
public final T call() throws Exception {
try {
RequestContext newCtx =
() -> {
throw new OutOfScopeException("No user during ChangeIndexer");
};
RequestContext oldCtx = context.setContext(newCtx);
try {
return callImpl();
} finally {
context.setContext(oldCtx);
}
} catch (Exception e) {
logger.atSevere().withCause(e).log("Failed to execute %s", this);
throw e;
}
}
}
private class IndexTask extends AbstractIndexTask {
ListenableFuture future;
private IndexTask(Project.NameKey project, Change.Id id) {
super(project, id);
}
/**
* Submits this task to be executed, if it wasn't submitted yet.
*
* Submits this task to the executor if it hasn't been submitted yet. The future is cached so
* that it can be returned if this method is called again.
*
*
This method must be synchronized so that concurrent calls do not submit this task to the
* executor multiple times.
*
* @return future from which the result of the index task (the {@link ChangeData} instance) can
* be retrieved.
*/
private synchronized ListenableFuture submitIfNeeded() {
if (future == null) {
future = submit(this);
}
return future;
}
@Nullable
@Override
public ChangeData callImpl() throws Exception {
// Remove this task from queuedIndexTasks. This is done right at the beginning of this task so
// that index requests which are received for the same change while this index task is in
// progress, are not dropped but added to the queue. This is important since change updates
// that happen after reading the change notes below will not be considered when updating the
// index.
remove();
try {
ChangeNotes changeNotes = notesFactory.createChecked(project, id);
ChangeData changeData = changeDataFactory.create(changeNotes);
doIndex(changeData);
return changeData;
} catch (NoSuchChangeException e) {
doDelete(project, id);
}
return null;
}
@Override
public int hashCode() {
return Objects.hashCode(IndexTask.class, id.get());
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof IndexTask)) {
return false;
}
IndexTask other = (IndexTask) obj;
return id.get() == other.id.get();
}
@Override
public String toString() {
return "index-change-" + id;
}
@Override
protected void remove() {
queuedIndexTasks.remove(id);
}
}
// Not AbstractIndexTask as it doesn't need a request context.
private class DeleteTask implements Callable {
private final Change.Id id;
private final Optional project;
private DeleteTask(Change.Id id, Optional project) {
this.id = id;
this.project = project;
}
@Nullable
@Override
public ChangeData call() {
logger.atFine().log("Delete change %d from index.", id.get());
// Don't bother setting a RequestContext to provide the DB.
// Implementations should not need to access the DB in order to delete a
// change ID.
for (ChangeIndex i : getWriteIndexes()) {
try (TraceTimer traceTimer =
TraceContext.newTimer(
"Deleting change in index",
Metadata.builder()
.changeId(id.get())
.indexVersion(i.getSchema().getVersion())
.build())) {
// Some index implementation require ProjectKey to build a database key
// If delete(K) method is used, this will require changeId -> projectKey lookup (index
// query), which is expensive.
// Use changeData with ProjectKey and deleteByValue(V) method, if possible
project.ifPresentOrElse(
p -> i.deleteByValue(changeDataFactory.create(p, id)), () -> i.delete(id));
} catch (RuntimeException e) {
throw new StorageException(
String.format(
"Failed to delete change %d from index version %d",
id.get(), i.getSchema().getVersion()),
e);
}
}
fireChangeDeletedFromIndexEvent(id.get());
return null;
}
}
private class ReindexIfStaleTask extends AbstractIndexTask {
private ReindexIfStaleTask(Project.NameKey project, Change.Id id) {
super(project, id);
}
@Override
public Boolean callImpl() throws Exception {
remove();
try {
StalenessCheckResult stalenessCheckResult = stalenessChecker.check(id);
if (stalenessCheckResult.isStale()) {
logger.atInfo().log("Reindexing stale document %s", stalenessCheckResult);
indexImpl(changeDataFactory.create(project, id));
return true;
}
} catch (Exception e) {
if (!isCausedByRepositoryNotFoundException(e)) {
throw e;
}
logger.atFine().log(
"Change %s belongs to deleted project %s, aborting reindexing the change.",
id.get(), project.get());
}
return false;
}
@Override
public int hashCode() {
return Objects.hashCode(ReindexIfStaleTask.class, id.get());
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof ReindexIfStaleTask)) {
return false;
}
ReindexIfStaleTask other = (ReindexIfStaleTask) obj;
return id.get() == other.id.get();
}
@Override
public String toString() {
return "reindex-if-stale-change-" + id;
}
@Override
protected void remove() {
queuedReindexIfStaleTasks.remove(this);
}
}
private boolean isCausedByRepositoryNotFoundException(Throwable throwable) {
while (throwable != null) {
if (throwable instanceof RepositoryNotFoundException) {
return true;
}
throwable = throwable.getCause();
}
return false;
}
}