Add io.openliberty.before.checkpoint condition

dev/com.ibm.ws.kernel.boot.common/src/io/openliberty/checkpoint/spi/CheckpointPhase.java

@@ -70,6 +70,13 @@ public enum CheckpointPhase {
      */
     public static final String CONDITION_PROCESS_RUNNING_ID = "io.openliberty.process.running";
 
+    /**
+     * The ID of the condition service that indicates the Liberty process will have a checkpoint done
+     * in the future. This condition will be unregistered just before the JVM goes into single-thread
+     * mode to prepare for the checkpoint.
+     */
+    public static final String CONDITION_BEFORE_CHECKPOINT_ID = "io.openliberty.before.checkpoint";
+
     private static final String SERVICE_RANKING = "service.ranking";
 
     /**

dev/com.ibm.ws.kernel.boot.nested/src/com/ibm/ws/kernel/launch/internal/FrameworkManager.java

@@ -655,6 +655,12 @@ public void restore() {
 
                 }, FrameworkUtil.asDictionary(Collections.singletonMap(Constants.SERVICE_RANKING, Integer.MIN_VALUE)));
 
+                final ServiceRegistration<Condition> beforeCheckpointReg = //
+                                fwkContext.registerService(Condition.class,
+                                                           Condition.INSTANCE,
+                                                           FrameworkUtil.asDictionary(Collections.singletonMap(Condition.CONDITION_ID,
+                                                                                                               CheckpointPhase.CONDITION_BEFORE_CHECKPOINT_ID)));
+
                 Hashtable<String, Object> restoredHookProps = new Hashtable<>();
                 restoredHookProps.put(Constants.SERVICE_RANKING, Integer.MIN_VALUE);
                 restoredHookProps.put(CheckpointHook.MULTI_THREADED_HOOK, Boolean.TRUE);
@@ -663,6 +669,7 @@ public void restore() {
                     public void prepare() {
                         // kick equinox to force a save before checkpoint single-threaded mode
                         saveEquinoxStateNow(fwkContext);
+                        beforeCheckpointReg.unregister();
                     }
 
                     @Override

dev/io.openliberty.checkpoint_fat/fat/src/io/openliberty/checkpoint/fat/CheckpointSPITest.java

@@ -81,6 +81,14 @@ public void testAddImmutableEnvKey() throws Exception {
     public void testRunningConditionLaunch() throws Exception {
         server.startServer(getTestMethodNameOnly(testName) + ".log");
         findLogMessage("Activate should have non-null running condition", "TESTING - activate running condition: ", "io.openliberty.process.running null", 500);
+        findLogMessage("Activate should have null before checkpoint condition", "TESTING - activate before checkpoint condition: ", "null", 500);
+    }
+
+    @Test
+    public void testBeforeCheckpointAndRunningCondition() throws Exception {
+        // The before checkpoint condition is tested in the lambda setup in setCheckpoint
+        server.startServer(getTestMethodNameOnly(testName) + ".log");
+        findLogMessage("Should bind running condition on restore", "TESTING - bind running condition:", " io.openliberty.process.running AFTER_APP_START", 500);
     }
 
     @Test
@@ -152,6 +160,8 @@ private void setCheckpoint(TestMethod testMethod) {
             findLogMessage("No RESTORED false found in prepare", "TESTING - in prepare method RESTORED", " - false -- false", 500);
             findLogMessage("Activate should have null running condition", "TESTING - activate running condition: ", "null", 500);
             findLogMessage("Prepare should have null running condition", "TESTING - prepare running condition: ", "null", 500);
+            findLogMessage("Should activate the before checkpoint component", "TESTING - activate before checkpoint condition component", "", 500);
+            findLogMessage("Should deactivate the before checkpoint component", "TESTING - deactivate before checkpoint condition component", "", 500);
             runBeforeRestore(testMethod);
         }));
     }
@@ -193,6 +203,7 @@ static enum TestMethod {
         testRunningConditionLaunch,
         testFailedCheckpoint,
         testFailedRestore,
+        testBeforeCheckpointAndRunningCondition,
         unknown
     }
 

dev/io.openliberty.checkpoint_fat/test-bundles/test.checkpoint.config.bundle/src/test/checkpoint/config/bundle/TestBeforeCheckpointComponent.java

@@ -0,0 +1,40 @@
+/*******************************************************************************
+ * Copyright (c) 2024 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+
+package test.checkpoint.config.bundle;
+
+import org.osgi.service.component.ComponentContext;
+import org.osgi.service.component.annotations.Activate;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Deactivate;
+import org.osgi.service.component.propertytypes.SatisfyingConditionTarget;
+import org.osgi.service.condition.Condition;
+
+import io.openliberty.checkpoint.spi.CheckpointPhase;
+
+/**
+ *
+ */
+@Component
+@SatisfyingConditionTarget("(" + Condition.CONDITION_ID + "=" + CheckpointPhase.CONDITION_BEFORE_CHECKPOINT_ID + ")")
+public class TestBeforeCheckpointComponent {
+    @Activate
+    public TestBeforeCheckpointComponent(ComponentContext cc) {
+        System.out.println("TESTING - activate before checkpoint condition component");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        System.out.println("TESTING - deactivate before checkpoint condition component");
+    }
+}

dev/io.openliberty.checkpoint_fat/test-bundles/test.checkpoint.config.bundle/src/test/checkpoint/config/bundle/TestCheckpointHook.java

@@ -43,6 +43,7 @@ public class TestCheckpointHook implements CheckpointHook {
     private final CheckpointPhase phase;
     private final ServiceReference<CheckpointPhase> phaseRef;
     private volatile ServiceReference<Condition> runningCondition = null;
+    private volatile ServiceReference<Condition> beforeCheckpointCondition = null;
 
     @Activate
     public TestCheckpointHook(Map<String, Object> config,
@@ -58,6 +59,7 @@ public TestCheckpointHook(Map<String, Object> config,
     @Activate
     void activate() {
         System.out.println("TESTING - activate running condition: " + getRunningCondition());
+        System.out.println("TESTING - activate before checkpoint condition: " + getBeforeCheckpointCondition());
     }
 
     @Reference(service = Condition.class, //
@@ -73,6 +75,19 @@ protected void unsetRunningCondition(ServiceReference<Condition> runningConditio
         this.runningCondition = null;
     }
 
+    @Reference(service = Condition.class, //
+               policy = ReferencePolicy.DYNAMIC, //
+               cardinality = ReferenceCardinality.OPTIONAL, //
+               target = "(" + Condition.CONDITION_ID + "=" + CheckpointPhase.CONDITION_BEFORE_CHECKPOINT_ID + ")")
+    protected void setBeforeCheckpointCondition(ServiceReference<Condition> beforeCheckpointCondition) {
+        this.beforeCheckpointCondition = beforeCheckpointCondition;
+        System.out.println("TESTING - bind before checkpoint condition: " + getBeforeCheckpointCondition());
+    }
+
+    protected void unsetBeforeCheckpointCondition(ServiceReference<Condition> runningCondition) {
+        this.beforeCheckpointCondition = null;
+    }
+
     /**
      * @return
      */
@@ -84,6 +99,14 @@ private String getRunningCondition() {
         }
     }
 
+    private String getBeforeCheckpointCondition() {
+        if (beforeCheckpointCondition == null) {
+            return "null";
+        } else {
+            return (String) beforeCheckpointCondition.getProperty(Condition.CONDITION_ID);
+        }
+    }
+
     @Modified
     public void modifiedConfig(Map<String, Object> modified) {
         config.putAll(modified);

dev/io.openliberty.checkpoint_fat/test.checkpoint.config.bundle.bnd

@@ -1,5 +1,5 @@
 #*******************************************************************************
-# Copyright (c) 2019, 2023 IBM Corporation and others.
+# Copyright (c) 2019, 2024 IBM Corporation and others.
 # All rights reserved. This program and the accompanying materials
 # are made available under the terms of the Eclipse Public License 2.0
 # which accompanies this distribution, and is available at
@@ -24,7 +24,8 @@ Private-Package: \
 
 -dsannotations: \
  test.checkpoint.config.bundle.TestCheckpointHook, \
- test.checkpoint.config.bundle.TestStaticHookRegister
+ test.checkpoint.config.bundle.TestStaticHookRegister, \
+ test.checkpoint.config.bundle.TestBeforeCheckpointComponent
 
 IBM-Default-Config: OSGI-INF/wlp/defaultInstances.xml