[FR]: Ability to remove emulator from a functions instance

[SoylentGraham]

Description

1. During development of firebase functions, I want to use the emulator if I've spun it up locally, and I want to use the deployed version if it's not running. I create the Functions and associate with an emulator first and check a basic function call succeeds. If not, I make a new one, "without" an emulator.

2. The SDK currently can't tell the difference between an instance with an emulator and without, and when "allocating" a new Functions it just does an app/region match, so returns the previous Functions with the emulator still associated.
   I cannot remove the old emulator association (to reverse useEmulator())
   I cannot remove the old instance to create a clean one.

3. a) Provide emulator params when construction functions, and make this a core part of distinguishing between different Functions instances.
   b) Allow me to destroy my Functions instance once I'm done with it (seems like a sensible thing to add anyway :)
   c) Allow me to remove the emulator association on an existing instance (hacky!)

API Proposal

class Functions ....
{
@objc open func removeEmulator() {
    emulatorOrigin = nil
  }
}

Firebase Product(s)

Functions

[SoylentGraham]

For anyone reading, I've just realised I can work around this.... ditch the whole emulator thing and bodge the custom domain to use the emulator's address.

if let firebaseEmulator
{
			let customDomain = "http://\(firebaseEmulator.host):\(firebaseEmulator.port)/\(projectId)/\(region)"
			self.firebaseFunctions = Functions.functions(app: firebaseApp, customDomain:customDomain)
}
else
{
			self.firebaseFunctions = Functions.functions(app: firebaseApp, region:region)
}

[morganchen12]

re: the second bullet in your initial post, the Functions instances are created and retained on a per-app (Firebase app, not UIApplication) basis, so you could create a non-default Firebase app for the purpose of testing emulation.

let filePath = Bundle.main.path(forResource: "GoogleService-Info", ofType: "plist")
guard let options = filePath.flatMap(FirebaseOptions(contentsOfFile:)) else {
    fatalError()
}
FirebaseApp.configure(name: "EmulatedApp", options: secondaryOptions)

let app = FirebaseApp.app(name: "EmulatedApp")!
let functions = Functions.functions(app: secondaryApp)
functions.useEmulator(/* ... */)

You would have to check if the emulator is running in your app logic for truly seamless hand-off, which would require more client code.