fix(telemetry): fix websocket connection leaks during reconnection (#…

…10214)

When a WebSocket connection to analytics fails (for example, due to certificate validation issues), telemetry will attempt to reconnect without actively closing the previously established connection. The Lua VM's garbage collection does not immediately recycle the WebSocket connection after the function returns. So we need to close the connection proactively to avoid connection leaks.

https://konghq.atlassian.net/browse/KAG-5256

changelog/unreleased/kong-ee/fix-telemetry-websocket-connection-leaks.yml

@@ -0,0 +1,3 @@
+message: Fixed a connection leak issue where the websocket connection was not closed promptly during reconnection.
+type: bugfix
+scope: Clustering

kong/clustering/telemetry.lua

@@ -219,6 +219,10 @@ local function telemetry_communicate(premature, self, uri, server_name, on_conne
 
   local res, err = c:connect(uri, opts)
   if not res then
+    -- close it proactively to avoid connection leaks (CLOSE-WAIT) if the Lua VM
+    -- does not recycle it in time
+    c:close()
+
     local delay = math.random(5, 10)
 
     ngx_log(ngx_ERR, "connection to control plane ", uri, " broken: ", err,