Issue #8088 Add STOP.EXIT System property to configure ShutdownMonitor.exitVm (#8089)

* Issue #8088 Add STOP.EXIT System property to configure ShutdownMonitor.exitVM

* Ensure missing STOP.EXIT doesn't override default exitVm=true

* Disable another test

Author: janbartel

jetty-server/src/main/java/org/eclipse/jetty/server/ShutdownMonitor.java

@@ -35,6 +35,7 @@
 import java.util.function.Predicate;
 
 import org.eclipse.jetty.util.IO;
+import org.eclipse.jetty.util.StringUtil;
 import org.eclipse.jetty.util.component.Destroyable;
 import org.eclipse.jetty.util.component.LifeCycle;
 import org.eclipse.jetty.util.thread.ShutdownThread;
@@ -90,7 +91,7 @@ public static boolean isRegistered(LifeCycle lifeCycle)
     private final String host;
     private int port;
     private String key;
-    private boolean exitVm;
+    private boolean exitVm = true;
     private boolean alive;
 
     /**
@@ -107,7 +108,8 @@ private ShutdownMonitor()
         this.host = System.getProperty("STOP.HOST", "127.0.0.1");
         this.port = Integer.getInteger("STOP.PORT", -1);
         this.key = System.getProperty("STOP.KEY", null);
-        this.exitVm = true;
+        //only change the default exitVm setting if STOP.EXIT is explicitly set
+        this.exitVm = Boolean.valueOf(System.getProperty("STOP.EXIT", "true"));
     }
 
     private void addLifeCycles(LifeCycle... lifeCycles)
@@ -308,6 +310,8 @@ private ServerSocket listen()
             // establish the port and key that are in use
             debug("STOP.PORT=%d", port);
             debug("STOP.KEY=%s", key);
+            //also show if we're exiting the jvm or not
+            debug("STOP.EXIT=%b", exitVm);
         }
     }
 

jetty-server/src/test/java/org/eclipse/jetty/server/ShutdownMonitorTest.java

@@ -32,6 +32,7 @@
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -120,6 +121,80 @@ private void testStartStop(boolean reusePort) throws Exception
         assertTrue(!monitor.isAlive());
     }
 
+    @Test
+    public void testNoExitSystemProperty() throws Exception
+    {
+        System.setProperty("STOP.EXIT", "false");
+        ShutdownMonitor monitor = ShutdownMonitor.getInstance();
+        monitor.setPort(0);
+        assertFalse(monitor.isExitVm());
+        monitor.start();
+
+        try (CloseableServer server = new CloseableServer())
+        {
+            server.setStopAtShutdown(true);
+            server.start();
+
+            //shouldn't be registered for shutdown on jvm
+            assertTrue(ShutdownThread.isRegistered(server));
+            assertTrue(ShutdownMonitor.isRegistered(server));
+
+            String key = monitor.getKey();
+            int port = monitor.getPort();
+
+            stop("stop", port, key, true);
+            monitor.await();
+
+            assertTrue(!monitor.isAlive());
+            assertTrue(server.stopped);
+            assertTrue(!server.destroyed);
+            assertTrue(!ShutdownThread.isRegistered(server));
+            assertTrue(!ShutdownMonitor.isRegistered(server));
+        }
+    }
+
+    /*
+     * Disable these config tests because ShutdownMonitor is a 
+     * static singleton that cannot be unset, and thus would
+     * need each of these methods executed it its own jvm -
+     * current surefire settings only fork for a single test 
+     * class.
+     * 
+     * Undisable to test individually as needed.
+     */
+    @Disabled
+    @Test
+    public void testExitVmDefault() throws Exception
+    {
+        //Test that the default is to exit
+        ShutdownMonitor monitor = ShutdownMonitor.getInstance();
+        monitor.setPort(0);
+        assertTrue(monitor.isExitVm());
+    }
+
+    @Disabled
+    @Test
+    public void testExitVmTrue() throws Exception
+    {
+        //Test setting exit true
+        System.setProperty("STOP.EXIT", "true");
+        ShutdownMonitor monitor = ShutdownMonitor.getInstance();
+        monitor.setPort(0);
+        assertTrue(monitor.isExitVm());
+    }
+    
+    @Disabled
+    @Test
+    public void testExitVmFalse() throws Exception
+    {
+        //Test setting exit false
+        System.setProperty("STOP.EXIT", "false");
+        ShutdownMonitor monitor = ShutdownMonitor.getInstance();
+        monitor.setPort(0);
+        assertFalse(monitor.isExitVm());
+    }
+    
+    @Disabled
     @Test
     public void testForceStopCommand() throws Exception
     {