org.apache.htrace.util.HTracedProcess.java Source code

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Here is the source code for org.apache.htrace.util.HTracedProcess.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.htrace.util;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.ProcessBuilder.Redirect;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.URL;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * To get instance of HTraced up and running, create an instance of this class.
 * Upon successful construction, htraced is running using <code>dataDir</code> as directory to
 * host data (leveldbs and logs).
 * TODO: We expect to find the htraced in a very particular place. Fragile. Will break if stuff
 * moves.
 */
public class HTracedProcess extends Process {
    private static final Log LOG = LogFactory.getLog(HTracedProcess.class);
    private final Process delegate;

    private final String httpAddr;

    /**
     * Data send back from the HTraced process on the notification port.
     */
    @JsonIgnoreProperties(ignoreUnknown = true)
    public static class StartupNotificationData {
        /**
         * The hostname:port pair which the HTraced process uses for HTTP requests.
         */
        @JsonProperty("HttpAddr")
        String httpAddr;

        /**
         * The process ID of the HTraced process.
         */
        @JsonProperty("ProcessId")
        long processId;
    }

    public HTracedProcess(final File binPath, final File dataDir, final String host) throws IOException {
        // Create a notifier socket bound to a random port.
        ServerSocket listener = new ServerSocket(0);
        boolean success = false;
        Process process = null;
        try {
            // Use a random port for the web address.  No 'scheme' yet.
            String webAddress = host + ":0";
            String logPath = new File(dataDir, "log.txt").getAbsolutePath();
            // Pass cmdline args to htraced to it uses our test dir for data.
            ProcessBuilder pb = new ProcessBuilder(binPath.toString(), "-Dlog.level=TRACE", "-Dlog.path=" + logPath,
                    "-Dweb.address=" + webAddress, "-Ddata.store.clear=true",
                    "-Dstartup.notification.address=localhost:" + listener.getLocalPort(),
                    "-Ddata.store.directories=" + dataDir.toString());
            pb.redirectErrorStream(true);
            // Inherit STDERR/STDOUT i/o; dumps on console for now.  Can add logs later.
            pb.inheritIO();
            pb.directory(dataDir);
            //assert pb.redirectInput() == Redirect.PIPE;
            //assert pb.redirectOutput().file() == dataDir;
            process = pb.start();
            assert process.getInputStream().read() == -1;
            StartupNotificationData data = readStartupNotification(listener);
            httpAddr = data.httpAddr;
            LOG.info("Started htraced process " + data.processId + " with http " + "address " + data.httpAddr
                    + ", logging to " + logPath);
            success = true;
        } finally {
            if (!success) {
                // Clean up after failure
                if (process != null) {
                    process.destroy();
                    process = null;
                }
            }
            delegate = process;
            listener.close();
        }
    }

    private static StartupNotificationData readStartupNotification(ServerSocket listener) throws IOException {
        Socket socket = listener.accept();
        try {
            InputStream in = socket.getInputStream();
            ObjectMapper objectMapper = new ObjectMapper();
            StartupNotificationData data = objectMapper.readValue(in, StartupNotificationData.class);
            return data;
        } finally {
            socket.close();
        }
    }

    public int hashCode() {
        return delegate.hashCode();
    }

    public OutputStream getOutputStream() {
        throw new UnsupportedOperationException("Unsupported until complaint; output on STDOUT");
    }

    public InputStream getInputStream() {
        throw new UnsupportedOperationException("Unsupported until complaint; output on STDOUT");
    }

    public boolean equals(Object obj) {
        return delegate.equals(obj);
    }

    public InputStream getErrorStream() {
        throw new UnsupportedOperationException("Unsupported until complaint; output on STDOUT");
    }

    public int waitFor() throws InterruptedException {
        return delegate.waitFor();
    }

    public int exitValue() {
        return delegate.exitValue();
    }

    public void destroy() {
        delegate.destroy();
    }

    public String toString() {
        return delegate.toString();
    }

    public String getHttpAddr() {
        return httpAddr;
    }

    /**
     * Ugly but how else to do file-math?
     * @param topLevel Presumes top-level of the htrace checkout.
     * @return Path to the htraced binary.
     */
    public static File getPathToHTraceBinaryFromTopLevel(final File topLevel) {
        return new File(new File(new File(new File(topLevel, "htrace-htraced"), "go"), "build"), "htraced");
    }
}