Ignore HTTP requests to socket.io

For some reason I haven't quite managed to understand in full, our
HTTP instrumentation breaks socket.io by wrapping one of the event
callbacks in the request object. It is unclear why wrapping it
breaks it -- you can read more about it on [this comment for the
related support issue][descent-into-madness].

This commit adds the default path used by the server-side socket.io
library to the list of ignored paths in the HTTP instrumentation.
While this does not address the underlying issue, it will hopefully
side-step it for most socket.io users.

[descent-into-madness]: appsignal/support#173 (comment)

packages/nodejs/.changesets/ignore-http-requests-to-socket-io.md

@@ -0,0 +1,6 @@
+---
+bump: "patch"
+type: "fix"
+---
+
+Do not instrument HTTP requests to the default socket.io path. This works around an issue where our HTTP instrumentation breaks socket.io's server side, causing the client side to get stuck in a connection loop.

packages/nodejs/src/instrumentation/http/lifecycle/incoming.ts

@@ -20,7 +20,9 @@ const DEFAULT_IGNORED_URLS = [
   // gatsby hot reloading
   /(\/__webpack_hmr)/i,
   // next.js integration web vitals endpoint
-  /(\/__appsignal-web-vitals)$/i
+  /(\/__appsignal-web-vitals)$/i,
+  // socket.io default path
+  /^(\/socket.io)/i
 ]
 
 function incomingRequest(