feat(webserver, ui): avoid cancelled SSE connection from following exec

Send a fake "start" event from the Execution following endpoint so that the UI didn't cancell it. I'm not sure when the UI would cancel the SSE connection but it can ocurs if any of the view that opens an SSE connection are left but no event are received yet. Sending a fake event immediatly lower the risk of occuring.
kestra-io · Jan 16, 2025 · 317cc02 · 317cc02
1 parent b0ae3b6
commit 317cc02
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Showing 4 changed files with 16 additions and 4 deletions.
diff --git a/ui/src/components/executions/ExecutionRoot.vue b/ui/src/components/executions/ExecutionRoot.vue
@@ -92,7 +92,10 @@
                             if (isEnd) {
                                 this.closeSSE();
                             }
-                            this.throttledExecutionUpdate(executionEvent);
+                            // we are receiving a first "fake" event to force initializing the connection: ignoring it
+                            if (executionEvent.lastEventId !== "start") {
+                                this.throttledExecutionUpdate(executionEvent);
+                            }
                             if (isEnd) {
                                 this.throttledExecutionUpdate.flush();
                             }

diff --git a/ui/src/components/executions/Topology.vue b/ui/src/components/executions/Topology.vue
@@ -225,7 +225,10 @@
                             if (isEnd) {
                                 this.closeSubExecutionSSE(subflow);
                             }
-                            this.throttledExecutionUpdate(subflow, executionEvent);
+                            // we are receiving a first "fake" event to force initializing the connection: ignoring it
+                            if (executionEvent.lastEventId !== "start") {
+                                this.throttledExecutionUpdate(subflow, executionEvent);
+                            }
                             if (isEnd) {
                                 this.throttledExecutionUpdate.flush();
                             }

diff --git a/ui/src/components/logs/TaskRunDetails.vue b/ui/src/components/logs/TaskRunDetails.vue
@@ -477,7 +477,10 @@
                             if (isEnd) {
                                 this.closeExecutionSSE();
                             }
-                            this.throttledExecutionUpdate(executionEvent);
+                            // we are receiving a first "fake" event to force initializing the connection: ignoring it
+                            if (executionEvent.lastEventId !== "start") {
+                                this.throttledExecutionUpdate(executionEvent);
+                            }
                             if (isEnd) {
                                 this.throttledExecutionUpdate.flush();
                             }

diff --git a/webserver/src/main/java/io/kestra/webserver/controllers/api/ExecutionController.java b/webserver/src/main/java/io/kestra/webserver/controllers/api/ExecutionController.java
@@ -1472,8 +1472,11 @@ public Flux<Event<Execution>> follow(
 
         return Flux
             .<Event<Execution>>create(emitter -> {
+                // send a first "empty" event so the SSE is correctly initialized in the frontend in case there are no logs
+                emitter.next(Event.of(Execution.builder().id(executionId).build()).id("start"));
+
                 // already finished execution
-                Execution execution = null;
+                Execution execution;
                 try {
                     execution = Await.until(
                         () -> executionRepository.findById(tenantService.resolveTenant(), executionId).orElse(null),