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18. Gradle编译其他应用代码流程（六) - 执行Task过程
一. 守护进程的作用
守护进程就是一个用来构建的其他进程。
从前几篇文章我们知道gradle编译的时候会加载各种所需要的Jar，加载这些Jar是需要时间的。
如果我们之前有守护进程编译过其他程序，而这个进程没有被kill掉，那么是可以重用这个守护进程的。
二. 选择守护进程编译
选择守护进程编译的策略是
如果守护进程存在，那么就使用守护进程编译。
否则，如果可以在当前进程编译，那么就在当前进程编译。
否则，启动新的守护进程来编译。
代码如下：
class BuildActionsFactory implements CommandLineAction {
public Runnable createAction(CommandLineParser parser, ParsedCommandLine commandLine) {
...
if (parameters.getDaemonParameters().isEnabled()) {
return runBuildWithDaemon(parameters.getStartParameter(), parameters.getDaemonParameters(), loggingServices);
}
if (canUseCurrentProcess(parameters.getDaemonParameters())) {
return runBuildInProcess(parameters.getStartParameter(), parameters.getDaemonParameters(), loggingServices);
}
return runBuildInSingleUseDaemon(parameters.getStartParameter(), parameters.getDaemonParameters(), loggingServices);
}
}三. 启动守护进程的入口
public class DefaultDaemonStarter implements DaemonStarter {
....
public DaemonStartupInfo startDaemon() {
String daemonUid = UUID.randomUUID().toString();
GradleInstallation gradleInstallation = CurrentGradleInstallation.get();
ModuleRegistry registry = new DefaultModuleRegistry(gradleInstallation);
ClassPath classpath;
List searchClassPath;
if (gradleInstallation == null) {
// When not running from a Gradle distro, need runtime impl for launcher plus the search path to look for other modules
classpath = new DefaultClassPath();
for (Module module : registry.getModule("gradle-launcher").getAllRequiredModules()) {
classpath = classpath.plus(module.getClasspath());
}
searchClassPath = registry.getAdditionalClassPath().getAsFiles();
} else {
// When running from a Gradle distro, only need launcher jar. The daemon can find everything from there.
classpath = registry.getModule("gradle-launcher").getImplementationClasspath();
searchClassPath = Collections.emptyList();
}
if (classpath.isEmpty()) {
throw new IllegalStateException("Unable to construct a bootstrap classpath when starting the daemon");
}
versionValidator.validate(daemonParameters);
List daemonArgs = new ArrayList();
daemonArgs.add(daemonParameters.getEffectiveJvm().getJavaExecutable().getAbsolutePath());
List daemonOpts = daemonParameters.getEffectiveJvmArgs();
daemonArgs.addAll(daemonOpts);
daemonArgs.add("-cp");
daemonArgs.add(CollectionUtils.join(File.pathSeparator, classpath.getAsFiles()));
if (Boolean.getBoolean("org.gradle.daemon.debug")) {
daemonArgs.add("-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005");
}
daemonArgs.add(GradleDaemon.class.getName());
// Version isn't used, except by a human looking at the output of jps.
daemonArgs.add(GradleVersion.current().getVersion());
// Serialize configuration to daemon via the process' stdin
ByteArrayOutputStream serializedConfig = new ByteArrayOutputStream();
FlushableEncoder encoder = new KryoBackedEncoder(new EncodedStream.EncodedOutput(serializedConfig));
try {
encoder.writeString(daemonParameters.getGradleUserHomeDir().getAbsolutePath());
encoder.writeString(daemonDir.getBaseDir().getAbsolutePath());
encoder.writeSmallInt(daemonParameters.getIdleTimeout());
encoder.writeSmallInt(daemonParameters.getPeriodicCheckInterval());
encoder.writeString(daemonUid);
encoder.writeSmallInt(daemonOpts.size());
for (String daemonOpt : daemonOpts) {
encoder.writeString(daemonOpt);
}
encoder.writeSmallInt(searchClassPath.size());
for (File file : searchClassPath) {
encoder.writeString(file.getAbsolutePath());
}
encoder.flush();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
ByteArrayInputStream stdInput = new ByteArrayInputStream(serializedConfig.toByteArray());
return startProcess(daemonArgs, daemonDir.getVersionedDir(), stdInput);
} 四. 守护进程执行入口
public class GradleDaemon {
public static void main(String[] args) {
new ProcessBootstrap().run("org.gradle.launcher.daemon.bootstrap.DaemonMain", args);
}
}
public class DaemonMain extends EntryPoint {
private static final Logger LOGGER = Logging.getLogger(DaemonMain.class);
private PrintStream originalOut;
private PrintStream originalErr;
@Override
protected void doAction(String[] args, ExecutionListener listener) {
...
KryoBackedDecoder decoder = new KryoBackedDecoder(new EncodedStream.EncodedInput(System.in));
try {
gradleHomeDir = new File(decoder.readString());
daemonBaseDir = new File(decoder.readString());
idleTimeoutMs = decoder.readSmallInt();
periodicCheckIntervalMs = decoder.readSmallInt();
daemonUid = decoder.readString();
int argCount = decoder.readSmallInt();
startupOpts = new ArrayList(argCount);
for (int i = 0; i < argCount; i++) {
startupOpts.add(decoder.readString());
}
int additionalClassPathLength = decoder.readSmallInt();
additionalClassPath = new ArrayList(additionalClassPathLength);
for (int i = 0; i < additionalClassPathLength; i++) {
additionalClassPath.add(new File(decoder.readString()));
}
} catch (EOFException e) {
System.out.println("DaemonMain doAction 4");
throw new UncheckedIOException(e);
}
NativeServices.initialize(gradleHomeDir);
DaemonServerConfiguration parameters = new DefaultDaemonServerConfiguration(daemonUid, daemonBaseDir, idleTimeoutMs, periodicCheckIntervalMs, startupOpts);
LoggingServiceRegistry loggingRegistry = LoggingServiceRegistry.newCommandLineProcessLogging();
LoggingManagerInternal loggingManager = loggingRegistry.newInstance(LoggingManagerInternal.class);
TrueTimeProvider timeProvider = new TrueTimeProvider();
DaemonServices daemonServices = new DaemonServices(parameters, loggingRegistry, loggingManager, new DefaultClassPath(additionalClassPath), timeProvider.getCurrentTime());
File daemonLog = daemonServices.getDaemonLogFile();
// Any logging prior to this point will not end up in the daemon log file.
initialiseLogging(loggingManager, daemonLog);
LOGGER.debug("Assuming the daemon was started with following jvm opts: {}", startupOpts);
Daemon daemon = daemonServices.get(Daemon.class);
daemon.start();
try {
DaemonContext daemonContext = daemonServices.get(DaemonContext.class);
Long pid = daemonContext.getPid();
daemonStarted(pid, daemon.getUid(), daemon.getAddress(), daemonLog);
DaemonExpirationStrategy expirationStrategy = daemonServices.get(MasterExpirationStrategy.class);
daemon.stopOnExpiration(expirationStrategy, parameters.getPeriodicCheckIntervalMs());
} finally {
daemon.stop();
}
}
} 五. 守护进程的日志
守护进程的日志没有打印在控制台，而是打印在文件中，通过下面这行代码，进行了日志输出流转向。
// Any logging prior to this point will not end up in the daemon log file. initialiseLogging(loggingManager, daemonLog);
日志保存的位置在 GRADLE_USER_HOME/daemon/版本号/daemon-进程号.out.log
如果没有配置GRADLE_USER_HOME，那就在根目录。windows的话在'c:\Users\rongwei.huang\.gradle\'
我自己的日志目录是："d:\gradle_jar_cache\daemon\3.1-snapshot-1\daemon-10972.out.log"
最后附加自己编译的gradle3.1源代码和编译生成文件
gradle3.1源代码
gradle3.1源代码编译后文件
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