New daemon start/stop methods for use with Procrun

Added additional entry points GerritLauncher.daemonStart and
GerritLauncher.daemonStop for use when hosting Gerrit in some other
process. The intention of this is to make it an easy fit to the [Apache
Commons Daemon Procrun][1]. This adds an easy way to host Gerrit with
embedded Jetty as Windows Service.

Also moved a bit of logic in Daemon from anonymous thread into the stop
method.

[1]: http://commons.apache.org/proper/commons-daemon/procrun.html

Change-Id: Ie1fd3b7fceb56e159dc7f02fbcf481b0fcdb08e2

Documentation/install.txt

@@ -170,6 +170,50 @@ To install Gerrit into an existing servlet container instead of using
 the embedded Jetty server, see
 link:install-j2ee.html[J2EE installation].
 
+[[installation_on_windows]]
+== Installation on Windows
+
+If new site is going to be initialized with Bouncy Castle cryptography,
+ssh-keygen command must be available during the init phase. If you have
+link:https://git-for-windows.github.io/[Git for Windows] installed,
+start Command Prompt and temporary add directory with ssh-keygen to the
+PATH environment variable just before running init command:
+
+====
+  PATH=%PATH%;c:\Program Files\Git\usr\bin
+====
+
+Please note that the path in the above example must not be
+double-quoted.
+
+To run the daemon after site initialization execute:
+
+====
+  cd C:\MY\GERRIT\SITE
+  java.exe -jar bin\gerrit.war daemon --console-log
+====
+
+To stop the daemon press Ctrl+C.
+
+=== Install the daemon as Windows Service
+
+To install Gerrit as Windows Service use the
+link:http://commons.apache.org/proper/commons-daemon/procrun.html[Apache
+Commons Daemon Procrun].
+
+Sample install command:
+
+====
+  prunsrv.exe //IS//Gerrit --DisplayName="Gerrit Code Review" --Startup=auto ^
+        --Jvm="C:\Program Files\Java\jre1.8.0_65\bin\server\jvm.dll" ^
+        --Classpath=C:\MY\GERRIT\SITE\bin\gerrit.war ^
+        --LogPath=C:\MY\GERRIT\SITE\logs ^
+        --StartPath=C:\MY\GERRIT\SITE ^
+        --StartMode=jvm --StopMode=jvm ^
+        --StartClass=com.google.gerrit.launcher.GerritLauncher --StartMethod=daemonStart ^
+        --StopClass=com.google.gerrit.launcher.GerritLauncher --StopMethod=daemonStop ^
+        ++DependsOn=postgresql-x64-9.4
+====
 
 [[customize]]
 == Site Customization

gerrit-launcher/src/main/java/com/google/gerrit/launcher/GerritLauncher.java

@@ -55,6 +55,8 @@ public final class GerritLauncher {
   private static final String pkg = "com.google.gerrit.pgm";
   public static final String NOT_ARCHIVED = "NOT_ARCHIVED";
 
+  private static ClassLoader daemonClassLoader;
+
   public static void main(final String[] argv) throws Exception {
     System.exit(mainImpl(argv));
   }
@@ -102,6 +104,44 @@ public final class GerritLauncher {
     return invokeProgram(cl, argv);
   }
 
+  public static void daemonStart(final String[] argv) throws Exception {
+    if (daemonClassLoader != null) {
+      throw new IllegalStateException(
+        "daemonStart can be called only once per JVM instance");
+    }
+    final ClassLoader cl = libClassLoader(false);
+    Thread.currentThread().setContextClassLoader(cl);
+
+    daemonClassLoader = cl;
+
+    String[] daemonArgv = new String[argv.length + 1];
+    daemonArgv[0] = "daemon";
+    for (int i = 0; i < argv.length; i++) {
+      daemonArgv[i + 1] = argv[i];
+    }
+    int res = invokeProgram(cl, daemonArgv);
+    if (res != 0) {
+      throw new Exception("Unexpected return value: " + res);
+    }
+  }
+
+  public static void daemonStop(final String[] argv) throws Exception {
+    if (daemonClassLoader == null) {
+      throw new IllegalStateException(
+        "daemonStop can be called only after call to daemonStop");
+    }
+    String[] daemonArgv = new String[argv.length + 2];
+    daemonArgv[0] = "daemon";
+    daemonArgv[1] = "--stop-only";
+    for (int i = 0; i < argv.length; i++) {
+      daemonArgv[i + 2] = argv[i];
+    }
+    int res = invokeProgram(daemonClassLoader, daemonArgv);
+    if (res != 0) {
+      throw new Exception("Unexpected return value: " + res);
+    }
+  }
+
   private static boolean isProlog(String cn) {
     return "PrologShell".equals(cn) || "Rulec".equals(cn);
   }

gerrit-pgm/src/main/java/com/google/gerrit/pgm/Daemon.java

@@ -124,7 +124,7 @@ public class Daemon extends SiteProgram {
   private boolean sshd = true;
 
   @Option(name = "--disable-sshd", usage = "Disable the internal SSH daemon")
-  void setDisableSshd(@SuppressWarnings("unused")  boolean arg) {
+  void setDisableSshd(@SuppressWarnings("unused") boolean arg) {
     sshd = false;
   }
 
@@ -150,6 +150,9 @@ public class Daemon extends SiteProgram {
       usage = "Init site before starting the daemon")
   private boolean doInit;
 
+  @Option(name = "--stop-only", usage = "Stop the daemon", hidden = true)
+  private boolean stopOnly;
+
   private final LifecycleManager manager = new LifecycleManager();
   private Injector dbInjector;
   private Injector cfgInjector;
@@ -180,6 +183,10 @@ public class Daemon extends SiteProgram {
 
   @Override
   public int run() throws Exception {
+    if (stopOnly) {
+      RuntimeShutdown.manualShutdown();
+      return 0;
+    }
     if (doInit) {
       try {
         new Init(getSitePath()).run();
@@ -213,14 +220,7 @@ public class Daemon extends SiteProgram {
         @Override
         public void run() {
           log.info("caught shutdown, cleaning up");
-          if (runId != null) {
+          stop();
-            try {
-              Files.delete(runFile);
-            } catch (IOException err) {
-              log.warn("failed to delete " + runFile, err);
-            }
-          }
-          manager.stop();
         }
       });
 
@@ -312,6 +312,13 @@ public class Daemon extends SiteProgram {
 
   @VisibleForTesting
   public void stop() {
+    if (runId != null) {
+      try {
+        Files.delete(runFile);
+      } catch (IOException err) {
+        log.warn("failed to delete " + runFile, err);
+      }
+    }
     manager.stop();
   }
 

gerrit-pgm/src/main/java/com/google/gerrit/pgm/util/RuntimeShutdown.java

@@ -39,6 +39,10 @@ public class RuntimeShutdown {
     cb.waitForShutdown();
   }
 
+  public static void manualShutdown() {
+    cb.manualShutdown();
+  }
+
   private RuntimeShutdown() {
   }
 
@@ -97,6 +101,11 @@ public class RuntimeShutdown {
       }
     }
 
+    void manualShutdown() {
+      Runtime.getRuntime().removeShutdownHook(this);
+      run();
+    }
+
     void waitForShutdown() {
       synchronized (this) {
         while (!shutdownComplete) {