Class ExitWatchdog

java.lang.Object
com.iizix.server.ExitWatchdog
public final class ExitWatchdog extends Object
The halt watchdog of a server exit: armed when the server begins to dispose for an exit, it halts the JVM with the exit code when the dispose has not ended within its time, so that a restart or an update the administrator asked for happens even when a module, the worker or the logger hangs on the way out (order CC-SERVER-RESTART-UPDATE-V5; NetPhantom's inactivityKillServer is the idea). A dispose that ends disarms it.

The halt is Runtime.halt(int): no shutdown hook runs, which is the point - the hooks are what may be hanging. What the halt costs is said on the standard error first.

The time is 90000L ms, or the system property "iizi.exit.watchdog.ms" in milliseconds (a rig shortens it). The halt itself is a parameter, so that a test proves the timing without ending its own JVM.

Author:
Christopher Mindus

  • Field Details

    • PROPERTY

      public static final String PROPERTY
      The system property that sets the time in milliseconds: -Diizi.exit.watchdog.ms=.
      See Also:

    • DEFAULT_MILLIS

      public static final long DEFAULT_MILLIS
      The default time: 90 seconds. The server's own dispose waits up to 60 seconds for the worker and up to 60 seconds for the logger, so a normal shutdown is well inside it.
      See Also:

  • Method Details

    • getMillis

      public static long getMillis()
      Gets the time of the watchdog: the system property PROPERTY, or the default.
      Returns:
      The time in milliseconds, always positive.

    • arm

      public static ExitWatchdog arm(int exitCode)
      Arms a watchdog that halts the JVM with an exit code after getMillis().
      Parameters:
      exitCode - The exit code of the halt.
      Returns:
      The watchdog, to disarm when the dispose has ended.

    • arm

      public static ExitWatchdog arm(int exitCode, long millis, IntConsumer halt)
      Arms a watchdog with its time and its halt.
      Parameters:
      exitCode - The exit code handed to the halt.
      millis - The time in milliseconds.
      halt - What fires: in the server Runtime.getRuntime()::halt.
      Returns:
      The watchdog, to disarm when the dispose has ended.
      Throws:
      IllegalArgumentException - If the time is not positive.
      NullPointerException - If the halt is null.

    • disarm

      public boolean disarm()
      Disarms the watchdog: nothing fires after this call returns true.
      Returns:
      true when it was armed and is now disarmed, false when it had fired already or was disarmed before.

    • hasFired

      public boolean hasFired()
      Checks if the watchdog fired.
      Returns:
      true when the halt was called.

    • getExitCode

      public int getExitCode()
      Gets the exit code of the halt.
      Returns:
      The exit code.