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.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.events.Reporter;
import com.google.devtools.build.lib.vfs.Path;
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 = workerBaseDir.getRelative("worker-" + workerId + "-" + key.getMnemonic());
            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;
    }

    /**
     * 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 and its process is
     * still alive.
     */
    @Override
    public boolean validateObject(WorkerKey key, PooledObject<Worker> p) {
        Worker worker = p.getObject();

        boolean hashMatches = key.getWorkerFilesHash().equals(worker.getWorkerFilesHash());
        boolean workerIsAlive = worker.isAlive();
        boolean workerIsStillValid = hashMatches && workerIsAlive;

        if (reporter != null && !workerIsStillValid) {
            StringBuilder msg = new StringBuilder();
            msg.append(key.getMnemonic());
            msg.append(" worker (id ");
            msg.append(p.getObject().getWorkerId());
            msg.append(") can no longer be used, because");

            if (!workerIsAlive) {
                msg.append(" its process terminated itself or got killed");
            }

            if (!hashMatches) {
                if (!workerIsAlive) {
                    msg.append(" and");
                }
                msg.append(" its files have changed on disk [");
                msg.append(worker.getWorkerFilesHash());
                msg.append(" -> ");
                msg.append(key.getWorkerFilesHash());
                msg.append("]");
            }

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

        return workerIsStillValid;
    }
}