From 53eb06a7815fb7e474d360df571d565f57f4b869 Mon Sep 17 00:00:00 2001
From: Lorenzo Blasa <lblasa@meta.com>
Date: Wed, 4 Oct 2023 05:37:12 -0700
Subject: [PATCH] Exit if unable to listen at port

Summary: If we are unable to bind to the specified port, exit process.

Reviewed By: passy

Differential Revision: D49908107

fbshipit-source-id: 6d76f3d661ec61867be5307c756e372a7b20a9f6
---
 desktop/flipper-server-core/src/server/startServer.tsx | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/desktop/flipper-server-core/src/server/startServer.tsx b/desktop/flipper-server-core/src/server/startServer.tsx
index d7f6171d0..371eee93d 100644
--- a/desktop/flipper-server-core/src/server/startServer.tsx
+++ b/desktop/flipper-server-core/src/server/startServer.tsx
@@ -168,8 +168,14 @@ async function startHTTPServer(
     server.close();
   });
 
-  server.on('error', (e: Error) => {
-    console.warn('[flipper-server] HTTP server error: ', e);
+  server.on('error', (e: NodeJS.ErrnoException) => {
+    console.warn('[flipper-server] HTTP server error: ', e.code);
+    if (e.code === 'EADDRINUSE') {
+      console.warn(
+        `[flipper-server] Unable to listen at port: ${config.port}, is already in use`,
+      );
+      process.exit(1);
+    }
   });
 
   server.listen(config.port);