Fix the problem that notification might not work anymore (#7643)

#### What type of PR is this?

/kind improvement
/area core
/milestone 2.21.x

#### What this PR does / why we need it:

This PR sets timeout on notification trigger to make sure the procedure won't getting stuck forever.

#### Does this PR introduce a user-facing change?

```release-note
修复运行过程中通知器可能失效的问题
```

application/src/main/java/run/halo/app/notification/DefaultNotificationCenter.java

@@ -11,7 +11,6 @@ import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Component;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
-import reactor.core.scheduler.Schedulers;
 import run.halo.app.core.extension.User;
 import run.halo.app.core.extension.notification.Notification;
 import run.halo.app.core.extension.notification.NotifierDescriptor;
@@ -52,7 +51,6 @@ public class DefaultNotificationCenter implements NotificationCenter {
                 log.debug("Dispatching notification to subscriber [{}] for reason [{}]",
                     subscriber, reason.getMetadata().getName());
             })
-            .publishOn(Schedulers.boundedElastic())
             .flatMap(subscriber -> dispatchNotification(reason, subscriber))
             .then();
     }

application/src/main/java/run/halo/app/notification/DefaultNotificationSender.java

@@ -11,6 +11,7 @@ import lombok.extern.slf4j.Slf4j;
 import org.springframework.context.SmartLifecycle;
 import org.springframework.stereotype.Component;
 import reactor.core.publisher.Mono;
+import reactor.core.scheduler.Schedulers;
 import run.halo.app.extension.ReactiveExtensionClient;
 import run.halo.app.extension.controller.Controller;
 import run.halo.app.extension.controller.ControllerBuilder;
@@ -32,6 +33,7 @@ import run.halo.app.plugin.extensionpoint.ExtensionGetter;
 public class DefaultNotificationSender
     implements NotificationSender, Reconciler<DefaultNotificationSender.QueueItem>,
     SmartLifecycle {
+    private static final Duration TIMEOUT = Duration.ofSeconds(30);
     private final ReactiveExtensionClient client;
     private final ExtensionGetter extensionGetter;
 
@@ -56,11 +58,14 @@ public class DefaultNotificationSender
     @Override
     public Mono<Void> sendNotification(String notifierExtensionName, NotificationContext context) {
         return selectNotifier(notifierExtensionName)
-            .doOnNext(notifier -> {
-                var item = new QueueItem(UUID.randomUUID().toString(),
-                    () -> notifier.notify(context).block(), 0);
-                requestQueue.addImmediately(item);
-            })
+            .flatMap(notifier -> Mono.fromRunnable(
+                    () -> {
+                        var item = new QueueItem(UUID.randomUUID().toString(),
+                            () -> notifier.notify(context).block(TIMEOUT), 0);
+                        requestQueue.addImmediately(item);
+                    })
+                .subscribeOn(Schedulers.boundedElastic())
+            )
             .then();
     }
 
@@ -84,7 +89,7 @@ public class DefaultNotificationSender
         log.debug("Executing send notification task, [{}] remaining to-do tasks",
             requestQueue.size());
         request.setTimes(request.getTimes() + 1);
-        request.getTask().execute();
+        request.getTask().run();
         return Result.doNotRetry();
     }
 
@@ -120,8 +125,8 @@ public class DefaultNotificationSender
 
     /**
      * <p>Queue item for {@link #requestQueue}.</p>
-     * <p>It holds a {@link SendNotificationTask} and a {@link #times} field.</p>
-     * <p>{@link SendNotificationTask} used to send email when consuming.</p>
+     * <p>It holds a {@link Runnable} and a {@link #times} field.</p>
+     * <p>{@link Runnable} used to send email when consuming.</p>
      * <p>{@link #times} will be used to record the number of
      * times the task has been executed, if retry three times on failure, it will be discarded.</p>
      * <p>It also holds a {@link #id} field, which is used to identify the item. queue item with
@@ -136,15 +141,11 @@ public class DefaultNotificationSender
         @EqualsAndHashCode.Include
         private final String id;
 
-        private final SendNotificationTask task;
+        private final Runnable task;
 
         @Setter
         private int times;
     }
 
-    @FunctionalInterface
-    interface SendNotificationTask {
-        void execute();
-    }
 }
 

application/src/main/java/run/halo/app/notification/NotificationTrigger.java

@@ -1,7 +1,9 @@
 package run.halo.app.notification;
 
+import java.time.Duration;
 import java.util.Set;
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Component;
 import run.halo.app.core.extension.notification.Reason;
 import run.halo.app.extension.ExtensionClient;
@@ -20,11 +22,13 @@ import run.halo.app.extension.controller.Reconciler;
  * @author guqing
  * @since 2.10.0
  */
+@Slf4j
 @Component
 @RequiredArgsConstructor
 public class NotificationTrigger implements Reconciler<Reconciler.Request> {
 
     public static final String TRIGGERED_FINALIZER = "triggered";
+    private static final Duration TIMEOUT = Duration.ofMinutes(1);
 
     private final ExtensionClient client;
     private final NotificationCenter notificationCenter;
@@ -44,14 +48,18 @@ public class NotificationTrigger implements Reconciler<Reconciler.Request> {
         return Result.doNotRetry();
     }
 
-    public void onNewReasonReceived(Reason reason) {
-        notificationCenter.notify(reason).block();
+    private void onNewReasonReceived(Reason reason) {
+        var name = reason.getMetadata().getName();
+        log.info("Sending notification for reason: {}", name);
+        notificationCenter.notify(reason).block(TIMEOUT);
+        log.info("Notification sent for reason: {}", name);
     }
 
     @Override
     public Controller setupWith(ControllerBuilder builder) {
         return builder
             .extension(new Reason())
+            .workerCount(10)
             .build();
     }
 }

application/src/test/java/run/halo/app/notification/DefaultNotificationSenderTest.java

@@ -21,10 +21,10 @@ class DefaultNotificationSenderTest {
         void equalsTest() {
             var item1 =
                 new DefaultNotificationSender.QueueItem("1",
-                    mock(DefaultNotificationSender.SendNotificationTask.class), 0);
+                    mock(Runnable.class), 0);
             var item2 =
                 new DefaultNotificationSender.QueueItem("1",
-                    mock(DefaultNotificationSender.SendNotificationTask.class), 1);
+                    mock(Runnable.class), 1);
 
             assertThat(item1).isEqualTo(item2);
         }