Consider emergency reconnect in PlatformStatus system (#7725)

Signed-off-by: Austin Littley <austin@swirldslabs.com>

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/PlatformStatusStateMachine.java

@@ -27,6 +27,7 @@
 import com.swirlds.common.notification.listeners.PlatformStatusChangeNotification;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.PlatformStatusAction;
@@ -121,6 +122,9 @@ private PlatformStatusLogic getNewLogic(@NonNull final PlatformStatusAction acti
                 return currentStatusLogic.processCatastrophicFailureAction((CatastrophicFailureAction) action);
             } else if (actionClass == DoneReplayingEventsAction.class) {
                 return currentStatusLogic.processDoneReplayingEventsAction((DoneReplayingEventsAction) action);
+            } else if (actionClass == EmergencyReconnectStartedAction.class) {
+                return currentStatusLogic.processEmergencyReconnectStartedAction(
+                        (EmergencyReconnectStartedAction) action);
             } else if (actionClass == FallenBehindAction.class) {
                 return currentStatusLogic.processFallenBehindAction((FallenBehindAction) action);
             } else if (actionClass == FreezePeriodEnteredAction.class) {

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/actions/EmergencyReconnectStartedAction.java

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2023 Hedera Hashgraph, LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.swirlds.common.system.status.actions;
+
+/**
+ * An action that is triggered when the platform begins an emergency reconnect.
+ */
+public record EmergencyReconnectStartedAction() implements PlatformStatusAction {}

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/ActiveStatusLogic.java

@@ -21,6 +21,7 @@
 import com.swirlds.common.system.status.PlatformStatusConfig;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -90,6 +91,22 @@ public PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneR
         throw new IllegalPlatformStatusException(action, getStatus());
     }
 
+    /**
+     * {@inheritDoc}
+     * <p>
+     * Receiving an {@link EmergencyReconnectStartedAction} while in {@link PlatformStatus#ACTIVE} throws an exception,
+     * since an emergency reconnect is only ever performed right after the platform starts up.
+     */
+    @NonNull
+    @Override
+    public PlatformStatusLogic processEmergencyReconnectStartedAction(
+            @NonNull final EmergencyReconnectStartedAction action) {
+
+        Objects.requireNonNull(action);
+
+        throw new IllegalPlatformStatusException(action, getStatus());
+    }
+
     /**
      * {@inheritDoc}
      * <p>

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/BehindStatusLogic.java

@@ -21,6 +21,7 @@
 import com.swirlds.common.system.status.PlatformStatusConfig;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -80,6 +81,22 @@ public PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneR
         throw new IllegalPlatformStatusException(action, getStatus());
     }
 
+    /**
+     * {@inheritDoc}
+     * <p>
+     * Receiving an {@link EmergencyReconnectStartedAction} while in {@link PlatformStatus#BEHIND} throws an exception,
+     * since an emergency reconnect should never be started when the platform is already behind.
+     */
+    @NonNull
+    @Override
+    public PlatformStatusLogic processEmergencyReconnectStartedAction(
+            @NonNull final EmergencyReconnectStartedAction action) {
+
+        Objects.requireNonNull(action);
+
+        throw new IllegalPlatformStatusException(action, getStatus());
+    }
+
     /**
      * {@inheritDoc}
      * <p>

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/CatastrophicFailureStatusLogic.java

@@ -19,6 +19,7 @@
 import com.swirlds.common.system.status.PlatformStatus;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -52,6 +53,17 @@ public PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneR
         return this;
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    @NonNull
+    @Override
+    public PlatformStatusLogic processEmergencyReconnectStartedAction(
+            @NonNull final EmergencyReconnectStartedAction action) {
+
+        return this;
+    }
+
     /**
      * {@inheritDoc}
      */

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/CheckingStatusLogic.java

@@ -21,6 +21,7 @@
 import com.swirlds.common.system.status.PlatformStatusConfig;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -75,6 +76,20 @@ public PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneR
         throw new IllegalPlatformStatusException(action, getStatus());
     }
 
+    /**
+     * {@inheritDoc}
+     * <p>
+     * {@link PlatformStatus#CHECKING} status unconditionally transitions to {@link PlatformStatus#BEHIND} when an
+     * {@link EmergencyReconnectStartedAction} is processed.
+     */
+    @NonNull
+    @Override
+    public PlatformStatusLogic processEmergencyReconnectStartedAction(
+            @NonNull final EmergencyReconnectStartedAction action) {
+
+        return new BehindStatusLogic(config);
+    }
+
     /**
      * {@inheritDoc}
      * <p>

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/FreezeCompleteStatusLogic.java

@@ -19,6 +19,7 @@
 import com.swirlds.common.system.status.PlatformStatus;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -52,6 +53,17 @@ public PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneR
         return this;
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    @NonNull
+    @Override
+    public PlatformStatusLogic processEmergencyReconnectStartedAction(
+            @NonNull final EmergencyReconnectStartedAction action) {
+
+        return this;
+    }
+
     /**
      * {@inheritDoc}
      */

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/FreezingStatusLogic.java

@@ -20,6 +20,7 @@
 import com.swirlds.common.system.status.PlatformStatus;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -74,6 +75,23 @@ public PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneR
         throw new IllegalPlatformStatusException(action, getStatus());
     }
 
+    /**
+     * {@inheritDoc}
+     * <p>
+     * Receiving an {@link EmergencyReconnectStartedAction} while in {@link PlatformStatus#FREEZING} throws an
+     * exception. If an emergency reconnect was required, the action should have happened already, before arriving
+     * in {@link PlatformStatus#FREEZING}.
+     */
+    @NonNull
+    @Override
+    public PlatformStatusLogic processEmergencyReconnectStartedAction(
+            @NonNull final EmergencyReconnectStartedAction action) {
+
+        Objects.requireNonNull(action);
+
+        throw new IllegalPlatformStatusException(action, getStatus());
+    }
+
     /**
      * {@inheritDoc}
      * <p>

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/ObservingStatusLogic.java

@@ -21,6 +21,7 @@
 import com.swirlds.common.system.status.PlatformStatusConfig;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -89,6 +90,20 @@ public PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneR
         throw new IllegalPlatformStatusException(action, getStatus());
     }
 
+    /**
+     * {@inheritDoc}
+     * <p>
+     * {@link PlatformStatus#OBSERVING} status unconditionally transitions to {@link PlatformStatus#BEHIND} when an
+     * {@link EmergencyReconnectStartedAction} is processed.
+     */
+    @NonNull
+    @Override
+    public PlatformStatusLogic processEmergencyReconnectStartedAction(
+            @NonNull final EmergencyReconnectStartedAction action) {
+
+        return new BehindStatusLogic(config);
+    }
+
     /**
      * {@inheritDoc}
      * <p>

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/PlatformStatusLogic.java

@@ -19,6 +19,7 @@
 import com.swirlds.common.system.status.PlatformStatus;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.PlatformStatusAction;
@@ -61,6 +62,15 @@ public interface PlatformStatusLogic {
     @NonNull
     PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneReplayingEventsAction action);
 
+    /**
+     * Process an {@link EmergencyReconnectStartedAction} action.
+     *
+     * @param action the action to process
+     * @return the {@link PlatformStatusLogic} to manage the resulting status
+     */
+    @NonNull
+    PlatformStatusLogic processEmergencyReconnectStartedAction(@NonNull final EmergencyReconnectStartedAction action);
+
     /**
      * Process a {@link FallenBehindAction}
      *

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/ReconnectCompleteStatusLogic.java

@@ -21,6 +21,7 @@
 import com.swirlds.common.system.status.PlatformStatusConfig;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -94,6 +95,22 @@ public PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneR
         throw new IllegalPlatformStatusException(action, getStatus());
     }
 
+    /**
+     * {@inheritDoc}
+     * <p>
+     * Receiving an {@link EmergencyReconnectStartedAction} while in {@link PlatformStatus#RECONNECT_COMPLETE} throws
+     * and exception, since if a reconnect was just completed, we shouldn't be starting another emergency reconnect.
+     */
+    @NonNull
+    @Override
+    public PlatformStatusLogic processEmergencyReconnectStartedAction(
+            @NonNull final EmergencyReconnectStartedAction action) {
+
+        Objects.requireNonNull(action);
+
+        throw new IllegalPlatformStatusException(action, getStatus());
+    }
+
     /**
      * {@inheritDoc}
      * <p>

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/ReplayingEventsStatusLogic.java

@@ -21,6 +21,7 @@
 import com.swirlds.common.system.status.PlatformStatusConfig;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -88,6 +89,23 @@ public PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneR
         }
     }
 
+    /**
+     * {@inheritDoc}
+     * <p>
+     * Receiving an {@link EmergencyReconnectStartedAction} while in {@link PlatformStatus#REPLAYING_EVENTS} throws an
+     * exception, since the check for potentially beginning an emergency reconnect doesn't happen until after
+     * the platform has transitioned out of the {@link PlatformStatus#REPLAYING_EVENTS} status.
+     */
+    @NonNull
+    @Override
+    public PlatformStatusLogic processEmergencyReconnectStartedAction(
+            @NonNull final EmergencyReconnectStartedAction action) {
+
+        Objects.requireNonNull(action);
+
+        throw new IllegalPlatformStatusException(action, getStatus());
+    }
+
     /**
      * {@inheritDoc}
      * <p>

platform-sdk/swirlds-common/src/main/java/com/swirlds/common/system/status/logic/StartingUpStatusLogic.java

@@ -21,6 +21,7 @@
 import com.swirlds.common.system.status.PlatformStatusConfig;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -75,6 +76,22 @@ public PlatformStatusLogic processDoneReplayingEventsAction(@NonNull final DoneR
         throw new IllegalPlatformStatusException(action, getStatus());
     }
 
+    /**
+     * {@inheritDoc}
+     * <p>
+     * Receiving an {@link EmergencyReconnectStartedAction} while in {@link PlatformStatus#STARTING_UP} throws an
+     * exception, since the check to begin an emergency reconnect should not have been made yet.
+     */
+    @NonNull
+    @Override
+    public PlatformStatusLogic processEmergencyReconnectStartedAction(
+            @NonNull final EmergencyReconnectStartedAction action) {
+
+        Objects.requireNonNull(action);
+
+        throw new IllegalPlatformStatusException(action, getStatus());
+    }
+
     /**
      * {@inheritDoc}
      * <p>

platform-sdk/swirlds-common/src/test/java/com/swirlds/common/system/status/logic/ActiveStatusLogicTests.java

@@ -25,6 +25,7 @@
 import com.swirlds.common.system.status.PlatformStatusConfig;
 import com.swirlds.common.system.status.actions.CatastrophicFailureAction;
 import com.swirlds.common.system.status.actions.DoneReplayingEventsAction;
+import com.swirlds.common.system.status.actions.EmergencyReconnectStartedAction;
 import com.swirlds.common.system.status.actions.FallenBehindAction;
 import com.swirlds.common.system.status.actions.FreezePeriodEnteredAction;
 import com.swirlds.common.system.status.actions.ReconnectCompleteAction;
@@ -118,6 +119,10 @@ void unexpectedActions() {
                 logic::processReconnectCompleteAction, new ReconnectCompleteAction(0), logic.getStatus());
         triggerActionAndAssertException(
                 logic::processDoneReplayingEventsAction, new DoneReplayingEventsAction(time.now()), logic.getStatus());
+        triggerActionAndAssertException(
+                logic::processEmergencyReconnectStartedAction,
+                new EmergencyReconnectStartedAction(),
+                logic.getStatus());
         triggerActionAndAssertException(
                 logic::processStartedReplayingEventsAction, new StartedReplayingEventsAction(), logic.getStatus());
     }