// Copyright (C) 2009 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.git;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;
import com.google.gerrit.reviewdb.client.Branch;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.server.CurrentUser;
import com.google.gerrit.server.RemotePeer;
import com.google.gerrit.server.config.GerritRequestModule;
import com.google.gerrit.server.ssh.SshInfo;
import com.google.gerrit.server.util.RequestContext;
import com.google.gerrit.server.util.RequestScopePropagator;
import com.google.inject.AbstractModule;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.OutOfScopeException;
import com.google.inject.Provider;
import com.google.inject.Provides;
import com.google.inject.Singleton;
import com.google.inject.servlet.RequestScoped;
import com.jcraft.jsch.HostKey;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.net.SocketAddress;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;
@Singleton
public class ChangeMergeQueue implements MergeQueue {
private static final Logger log =
LoggerFactory.getLogger(ChangeMergeQueue.class);
private final Map<Branch.NameKey, MergeEntry> active =
new HashMap<Branch.NameKey, MergeEntry>();
private final Map<Branch.NameKey, RecheckJob> recheck =
new HashMap<Branch.NameKey, RecheckJob>();
private final WorkQueue workQueue;
private final Provider<MergeOp.Factory> bgFactory;
private final PerThreadRequestScope.Scoper threadScoper;
@Inject
ChangeMergeQueue(final WorkQueue wq, Injector parent) {
workQueue = wq;
Injector child = parent.createChildInjector(new AbstractModule() {
@Override
protected void configure() {
bindScope(RequestScoped.class, PerThreadRequestScope.REQUEST);
bind(RequestScopePropagator.class)
.to(PerThreadRequestScope.Propagator.class);
bind(PerThreadRequestScope.Propagator.class);
install(new GerritRequestModule());
bind(SocketAddress.class).annotatedWith(RemotePeer.class).toProvider(
new Provider<SocketAddress>() {
@Override
public SocketAddress get() {
throw new OutOfScopeException("No remote peer on merge thread");
}
});
bind(SshInfo.class).toInstance(new SshInfo() {
@Override
public List<HostKey> getHostKeys() {
return Collections.emptyList();
}
});
}
@Provides
public PerThreadRequestScope.Scoper provideScoper(
final PerThreadRequestScope.Propagator propagator) {
final RequestContext requestContext = new RequestContext() {
@Override
public CurrentUser getCurrentUser() {
throw new OutOfScopeException("No user on merge thread");
}
};
return new PerThreadRequestScope.Scoper() {
@Override
public <T> Callable<T> scope(Callable<T> callable) {
return propagator.scope(requestContext, callable);
}
};
}
});
bgFactory = child.getProvider(MergeOp.Factory.class);
threadScoper = child.getInstance(PerThreadRequestScope.Scoper.class);
}
@Override
public void merge(MergeOp.Factory mof, Branch.NameKey branch) {
if (start(branch)) {
mergeImpl(mof, branch);
}
}
private synchronized boolean start(final Branch.NameKey branch) {
final MergeEntry e = active.get(branch);
if (e == null) {
// Let the caller attempt this merge, its the only one interested
// in processing this branch right now.
//
active.put(branch, new MergeEntry(branch));
return true;
} else {
// Request that the job queue handle this merge later.
//
e.needMerge = true;
return false;
}
}
@Override
public synchronized void schedule(final Branch.NameKey branch) {
MergeEntry e = active.get(branch);
if (e == null) {
e = new MergeEntry(branch);
active.put(branch, e);
}
e.needMerge = true;
scheduleJob(e);
}
@Override
public synchronized void recheckAfter(final Branch.NameKey branch,
final long delay, final TimeUnit delayUnit) {
final long now = System.currentTimeMillis();
final long at = now + MILLISECONDS.convert(delay, delayUnit);
RecheckJob e = recheck.get(branch);
if (e == null) {
e = new RecheckJob(branch);
workQueue.getDefaultQueue().schedule(e, now - at, MILLISECONDS);
recheck.put(branch, e);
}
e.recheckAt = Math.max(at, e.recheckAt);
}
private synchronized void finish(final Branch.NameKey branch) {
final MergeEntry e = active.get(branch);
if (e == null) {
// Not registered? Shouldn't happen but ignore it.
//
return;
}
if (!e.needMerge) {
// No additional merges are in progress, we can delete it.
//
active.remove(branch);
return;
}
scheduleJob(e);
}
private void scheduleJob(final MergeEntry e) {
if (!e.jobScheduled) {
// No job has been scheduled to execute this branch, but it needs
// to run a merge again.
//
e.jobScheduled = true;
workQueue.getDefaultQueue().schedule(e, 0, TimeUnit.SECONDS);
}
}
private synchronized void unschedule(final MergeEntry e) {
e.jobScheduled = false;
e.needMerge = false;
}
private void mergeImpl(MergeOp.Factory opFactory, Branch.NameKey branch) {
try {
opFactory.create(branch).merge();
} catch (Throwable e) {
log.error("Merge attempt for " + branch + " failed", e);
} finally {
finish(branch);
}
}
private void mergeImpl(final Branch.NameKey branch) {
try {
threadScoper.scope(new Callable<Void>(){
@Override
public Void call() throws Exception {
bgFactory.get().create(branch).merge();
return null;
}
}).call();
} catch (Throwable e) {
log.error("Merge attempt for " + branch + " failed", e);
} finally {
finish(branch);
}
}
private synchronized void recheck(final RecheckJob e) {
final long remainingDelay = e.recheckAt - System.currentTimeMillis();
if (MILLISECONDS.convert(10, SECONDS) < remainingDelay) {
// Woke up too early, the job deadline was pushed back.
// Reschedule for the new deadline. We allow for a small
// amount of fuzz due to multiple reschedule attempts in
// a short period of time being caused by MergeOp.
//
workQueue.getDefaultQueue().schedule(e, remainingDelay, MILLISECONDS);
} else {
// Schedule a merge attempt on this branch to see if we can
// actually complete it this time.
//
schedule(e.dest);
}
}
private class MergeEntry implements Runnable {
final Branch.NameKey dest;
boolean needMerge;
boolean jobScheduled;
MergeEntry(final Branch.NameKey d) {
dest = d;
}
public void run() {
unschedule(this);
mergeImpl(dest);
}
@Override
public String toString() {
final Project.NameKey project = dest.getParentKey();
return "submit " + project.get() + " " + dest.getShortName();
}
}
private class RecheckJob implements Runnable {
final Branch.NameKey dest;
long recheckAt;
RecheckJob(final Branch.NameKey d) {
dest = d;
}
@Override
public void run() {
recheck(this);
}
@Override
public String toString() {
final Project.NameKey project = dest.getParentKey();
return "recheck " + project.get() + " " + dest.getShortName();
}
}
}