com.google.devtools.build.lib.worker.WorkerFactory.java Source code

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Here is the source code for com.google.devtools.build.lib.worker.WorkerFactory.java

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// Copyright 2015 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.lib.worker;

import com.google.common.hash.HashCode;
import com.google.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.events.Reporter;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import java.util.TreeSet;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.commons.pool2.BaseKeyedPooledObjectFactory;
import org.apache.commons.pool2.PooledObject;
import org.apache.commons.pool2.impl.DefaultPooledObject;

/**
 * Factory used by the pool to create / destroy / validate worker processes.
 */
final class WorkerFactory extends BaseKeyedPooledObjectFactory<WorkerKey, Worker> {

    // It's fine to use an AtomicInteger here (which is 32-bit), because it is only incremented when
    // spawning a new worker, thus even under worst-case circumstances and buggy workers quitting
    // after each action, this should never overflow.
    private static final AtomicInteger pidCounter = new AtomicInteger();

    private WorkerOptions workerOptions;
    private final Path workerBaseDir;
    private Reporter reporter;

    public WorkerFactory(WorkerOptions workerOptions, Path workerBaseDir) {
        this.workerOptions = workerOptions;
        this.workerBaseDir = workerBaseDir;
    }

    public void setReporter(Reporter reporter) {
        this.reporter = reporter;
    }

    public void setOptions(WorkerOptions workerOptions) {
        this.workerOptions = workerOptions;
    }

    @Override
    public Worker create(WorkerKey key) throws Exception {
        int workerId = pidCounter.getAndIncrement();
        Path logFile = workerBaseDir.getRelative("worker-" + workerId + "-" + key.getMnemonic() + ".log");

        Worker worker;
        boolean sandboxed = workerOptions.workerSandboxing || key.mustBeSandboxed();
        if (sandboxed) {
            Path workDir = getSandboxedWorkerPath(key, workerId);
            worker = new SandboxedWorker(key, workerId, workDir, logFile);
        } else {
            worker = new Worker(key, workerId, key.getExecRoot(), logFile);
        }
        worker.prepareExecution(key);
        worker.createProcess();
        if (workerOptions.workerVerbose) {
            reporter.handle(Event.info(String.format("Created new %s %s worker (id %d), logging to %s",
                    sandboxed ? "sandboxed" : "non-sandboxed", key.getMnemonic(), workerId, logFile)));
        }
        return worker;
    }

    Path getSandboxedWorkerPath(WorkerKey key, int workerId) {
        String workspaceName = key.getExecRoot().getBaseName();
        return workerBaseDir.getRelative("worker-" + workerId + "-" + key.getMnemonic()).getRelative(workspaceName);
    }

    /**
     * Use the DefaultPooledObject implementation.
     */
    @Override
    public PooledObject<Worker> wrap(Worker worker) {
        return new DefaultPooledObject<>(worker);
    }

    /**
     * When a worker process is discarded, destroy its process, too.
     */
    @Override
    public void destroyObject(WorkerKey key, PooledObject<Worker> p) throws Exception {
        if (workerOptions.workerVerbose) {
            reporter.handle(Event.info(
                    String.format("Destroying %s worker (id %d)", key.getMnemonic(), p.getObject().getWorkerId())));
        }
        p.getObject().destroy();
    }

    /** The worker is considered to be valid when its files have not changed on disk. */
    @Override
    public boolean validateObject(WorkerKey key, PooledObject<Worker> p) {
        Worker worker = p.getObject();
        boolean hashMatches = key.getWorkerFilesCombinedHash().equals(worker.getWorkerFilesCombinedHash());

        if (reporter != null && !hashMatches) {
            StringBuilder msg = new StringBuilder();
            msg.append(String.format(
                    "%s worker (id %d) can no longer be used, because its files have changed on disk:",
                    key.getMnemonic(), worker.getWorkerId()));
            TreeSet<PathFragment> files = new TreeSet<>();
            files.addAll(key.getWorkerFilesWithHashes().keySet());
            files.addAll(worker.getWorkerFilesWithHashes().keySet());
            for (PathFragment file : files) {
                HashCode oldHash = key.getWorkerFilesWithHashes().get(file);
                HashCode newHash = worker.getWorkerFilesWithHashes().get(file);
                if (!oldHash.equals(newHash)) {
                    msg.append("\n").append(file.getPathString()).append(": ")
                            .append(oldHash != null ? oldHash : "<none>").append(" -> ")
                            .append(newHash != null ? newHash : "<none>");
                }
            }

            reporter.handle(Event.warn(msg.toString()));
        }

        return hashMatches;
    }
}