fix: telemetry init channel unsuccessful leads to panic (#20160)

Co-authored-by: tabversion <[email protected]>

src/common/src/telemetry/report.rs

@@ -101,25 +101,33 @@ where
             });
 
         let (tx, mut event_rx) = tokio::sync::mpsc::unbounded_channel::<PbEventMessage>();
+
+        let mut enable_event_report = true;
         TELEMETRY_EVENT_REPORT_TX.set(tx).unwrap_or_else(|_| {
             tracing::warn!(
                 "Telemetry failed to set event reporting tx, event reporting will be disabled"
             );
+            // possible failure:
+            // When running in standalone mode, the static TELEMETRY_EVENT_REPORT_TX is shared
+            // and can be set by meta/compute nodes.
+            // In such case, the one first set the static will do the event reporting and others'
+            // event report is disabled.
+            enable_event_report = false;
         });
         let mut event_stash = Vec::new();
 
         loop {
             tokio::select! {
                 _ = interval.tick() => {},
-                event = event_rx.recv() => {
+                event = event_rx.recv(), if enable_event_report => {
                     debug_assert!(event.is_some());
                     event_stash.push(event.unwrap());
                     if event_stash.len() >= TELEMETRY_EVENT_REPORT_STASH_SIZE {
                         do_telemetry_event_report(&mut event_stash).await;
                     }
                     continue;
                 }
-                _ = event_interval.tick() => {
+                _ = event_interval.tick(), if enable_event_report => {
                     do_telemetry_event_report(&mut event_stash).await;
                     continue;
                 },

src/common/telemetry_event/src/lib.rs

@@ -46,6 +46,10 @@ pub fn get_telemetry_risingwave_cloud_uuid() -> Option<String> {
 }
 
 pub async fn do_telemetry_event_report(event_stash: &mut Vec<PbEventMessage>) {
+    if event_stash.is_empty() {
+        return;
+    }
+
     const TELEMETRY_EVENT_REPORT_TYPE: &str = "events"; // the batch report url
     let url = (TELEMETRY_REPORT_URL.to_owned() + "/" + TELEMETRY_EVENT_REPORT_TYPE).to_owned();
     let batch_message = PbBatchEventMessage {