AppHosting emulator: "TIMEOUT: Port 5002 on localhost was not active within 60000ms"

[nguyentrungtu]

[REQUIRED] Environment info

firebase-tools: 15.1.0

Platform: macOS

[REQUIRED] Test case

[REQUIRED] Steps to reproduce

Run firebase emulators:start, with apphosting enabled.
My Angular 20 app is served on localhost:4200
Wait 1 minute.

[REQUIRED] Expected behavior

No error on the console. User should be able to continue developing.

[REQUIRED] Actual behavior

After 1 minute of not browsing the app, this error appears on the console:
"TIMEOUT: Port 5002 on localhost was not active within 60000ms"
The app stops working on localhost:4200.

[aalej]

Hey @nguyentrungtu, thanks for reaching out. To help us verify what's causing this issue, could you share with us you firebase-debug.log file? Please remove any PIIs before sharing the contents. Based on the info you've shared, my guess is that the firebase.json#emulators.apphosting.port value is not correctly being passed into start command, so the app is being served in port 4200 instead of the specified 5002 port.

What value do you have set for your startCommand? Does setting it to ng serve resolve the issue? Something similar to:

...
"emulators": {
    "apphosting": {
      "port": 5002,
      "rootDirectory": "./test-app",
      "startCommand": "ng serve" // <- this value
    },
    "ui": {
      "enabled": true
    },
    ...
  }
...

[nguyentrungtu]

@aalej this is fixed after I change my start command from npm run dev to ng serve.

[aalej]

Thanks @nguyentrungtu, it's good to know ng serve works. It does seem like the value for port isn't being passed to the npm run dev start command while ng serve passes it

firebase-tools/src/emulator/apphosting/serve.ts

Lines 121 to 123 in 94e980d

	if (startCommand.includes("ng serve")) {
	startCommand += ` --port ${port}`;
	}

I'll ask our engineering team to see if there's anything we can do to better support start commands like npm run dev. Sharing my mcve here - https://github.com/aalej/issues-9699

[annajowang]

This is running into a known caveat / trade-off of #9113

The code snippet aalej pointed to above is our hack to get around: angular/angular-cli#32236