Fix 4858 deduplicate

spring-boot-admin-server-ui/src/main/frontend/views/journal/deduplicate-events.spec.ts

@@ -0,0 +1,67 @@
+/*!
+ * Copyright 2014-2025 the original author or authors.
+ *
+ * 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.
+ */
+import { describe, expect, it } from 'vitest';
+
+import { InstanceEvent } from '@/views/journal/InstanceEvent';
+
+import { deduplicateInstanceEvents } from './deduplicate-events';
+
+const createEvent = (instance: string, version: number) =>
+  new InstanceEvent({
+    instance,
+    version,
+    type: 'REGISTERED',
+    timestamp: '2024-01-01T10:00:00Z',
+    registration: { name: instance },
+  });
+
+describe('deduplicateInstanceEvents', () => {
+  it('removes events with identical instance and version', () => {
+    const events = [
+      createEvent('instance-1', 1),
+      createEvent('instance-1', 1),
+      createEvent('instance-2', 3),
+      createEvent('instance-2', 3),
+      createEvent('instance-3', 2),
+    ];
+
+    const result = deduplicateInstanceEvents(events);
+
+    expect(result).toHaveLength(3);
+    expect(result.map((event) => event.key)).toEqual([
+      'instance-1-1',
+      'instance-2-3',
+      'instance-3-2',
+    ]);
+  });
+
+  it('preserves the order of the first occurrences', () => {
+    const events = [
+      createEvent('instance-1', 2),
+      createEvent('instance-2', 1),
+      createEvent('instance-1', 2),
+      createEvent('instance-3', 4),
+    ];
+
+    const result = deduplicateInstanceEvents(events);
+
+    expect(result.map((event) => event.key)).toEqual([
+      'instance-1-2',
+      'instance-2-1',
+      'instance-3-4',
+    ]);
+  });
+});

spring-boot-admin-server-ui/src/main/frontend/views/journal/deduplicate-events.ts

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2014-2025 the original author or authors.
+ *
+ * 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.
+ */
+import { InstanceEvent } from '@/views/journal/InstanceEvent';
+
+export function deduplicateInstanceEvents(events: InstanceEvent[]) {
+  const seen = new Set<string>();
+  return events.filter((event) => {
+    if (seen.has(event.key)) {
+      return false;
+    }
+    seen.add(event.key);
+    return true;
+  });
+}

spring-boot-admin-server-ui/src/main/frontend/views/journal/index.vue

@@ -47,6 +47,7 @@ import subscribing from '@/mixins/subscribing';
 import Instance from '@/services/instance';
 import { compareBy } from '@/utils/collections';
 import { InstanceEvent } from '@/views/journal/InstanceEvent';
+import { deduplicateInstanceEvents } from '@/views/journal/deduplicate-events';
 import JournalTable from '@/views/journal/JournalTable.vue';
 
 export default {
@@ -64,6 +65,7 @@ export default {
   data: () => ({
     Event,
     events: [],
+    seenEventKeys: new Set(),
     listOffset: 0,
     showPayload: {},
     pageSize: 25,
@@ -101,7 +103,9 @@ export default {
         .reverse()
         .map((e) => new InstanceEvent(e));
 
-      this.events = Object.freeze(events);
+      const deduplicated = deduplicateInstanceEvents(events);
+      this.seenEventKeys = new Set(deduplicated.map((event) => event.key));
+      this.events = Object.freeze(deduplicated);
       this.error = null;
     } catch (error) {
       console.warn('Fetching events failed:', error);
@@ -116,10 +120,12 @@ export default {
       return Instance.getEventStream().subscribe({
         next: (message) => {
           this.error = null;
-          this.events = Object.freeze([
-            new InstanceEvent(message.data),
-            ...this.events,
-          ]);
+          const incomingEvent = new InstanceEvent(message.data);
+          if (this.seenEventKeys.has(incomingEvent.key)) {
+            return;
+          }
+          this.seenEventKeys.add(incomingEvent.key);
+          this.events = Object.freeze([incomingEvent, ...this.events]);
           this.listOffset += 1;
         },
         error: (error) => {