probe fallback: basic TCP/UDP connectivity when capture service is offline

services/mam-api/src/routes/recorders.js

@@ -650,13 +650,13 @@ router.delete('/:id', async (req, res, next) => {
   }
 });
 
-// POST /probe - Test source connectivity.
-// Tries the capture service first (full SRT/RTMP handshake + metadata).
-// Falls back to a basic TCP/UDP reachability check if capture is offline.
+// POST /probe - Probe a source URL for reachability.
+// Tries the capture service first; falls back to basic TCP/UDP connectivity
+// check when capture is not running.
 router.post('/probe', async (req, res) => {
   const { source_type, url } = req.body || {};
 
-  // Try capture service first — it can do a real SRT/RTMP handshake
+  // Try the capture service first (5s timeout)
   try {
     const r = await fetch('http://capture:3001/capture/probe', {
       method: 'POST',
@@ -689,11 +689,15 @@ router.post('/probe', async (req, res) => {
   const port = parseInt(parsed.port, 10) || (isUdp ? 9000 : 1935);
 
   const reachable = await (isUdp ? probeUdp(host, port) : probeTcp(host, port));
+
   return res.json({
     reachable,
     mode: 'basic',
     note: `Capture service offline · ${isUdp ? 'UDP' : 'TCP'} connectivity check only`,
-    ...(reachable ? { source: `${host}:${port}` } : { error: `${host}:${port} did not respond` }),
+    ...(reachable
+      ? { source: `${host}:${port}` }
+      : { error: `${host}:${port} did not respond` }
+    ),
   });
 });
 
@@ -719,13 +723,13 @@ function probeUdp(host, port) {
       try { sock.close(); } catch (_) {}
       resolve(ok);
     };
+    // ICMP port-unreachable will fire sock.on('error') within ~100ms if nothing is listening
     sock.on('error', () => finish(false));
     sock.send(Buffer.alloc(16, 0), 0, 16, port, host, (err) => {
       if (err) return finish(false);
-      // If no ICMP port-unreachable arrives within 2.5s, assume port is open
+      // No ICMP error after 2.5s → assume something is listening
       setTimeout(() => finish(true), 2500);
     });
-    // Hard timeout — give up after 5s regardless
     setTimeout(() => finish(false), 5000);
   });
 }