[Error: Internal] when calling a callable cloud function using local emulator

[REQUIRED] Environment info

firebase-tools: 7.12.1

Platform: macOS

[REQUIRED] Test case

1. Run firebase emulators:start --only functions within ProjectName/functions/
2. Add

{
  "functions": {
    "predeploy": [
      "npm --prefix \"$RESOURCE_DIR\" run lint"
    ],
    "source": "functions"
  },
  "emulators": {
    "functions": {
      "port": 5001
    }
  }
}

To firebase.json

1. Add app.functions().useFunctionsEmulator('http://localhost:5001'); after initializing firebase app (e.g. const app = firebase.initializeApp(config);)
2. Disable App Transport Security in info.plist (Building ios app using react-native)
3. Call callable function from app

[REQUIRED] Steps to reproduce

1. Create a callable function and call it using the steps from the test case

[REQUIRED] Expected behavior

The app calls the function and the functions returns the expected response with no Internal server error.

[REQUIRED] Actual behavior

[Error: Internal] after making the call to the cloud function. Logs do not output anything. console logging on the first line of the cloud function doesn’t output anything, so it doesn’t even get inside the function.

However, if I paste the url generated from the emulator into my browser, the emulator does output logs, which tells me that there’s something wrong with how the app is calling the function.

[lucasgismondi]

@samtstern @JoshLiquornik I found the issue. Since I’m attempting to call the emulated functions on a mobile device, I had to run firebase serve --only functions -o 0.0.0.0 then use app.functions().useFunctionsEmulator('http://<local ip>:<port>');

I just forgot that you can’t call localhost functions from other devices…

[samtstern]

Thanks for following up! I’ve made that same mistake many times.