Firebase emulators set database target - firebase

Question

Setting
I am developing on a test Firestore instance hosted on firebase, and I would like to run firebase emulators:start targeting this database. Currently it's targeting an emulator suite accessible through localhost:4000. In the codebase, I have initialized firebase instance with parameters for the actual instance as follows:
const fireAdmin = admin.initializeApp({
credential : admin.credential.applicationDefault()
, databaseURL : DatabaseConfig['databaseURL']
, storageBucket: DatabaseConfig['storageBucket']
});
where DatabaseConfig = { databaseURL: "https://mytestingserversite.firebaseio.com", ... }.
Problem
However, the functions are still writing/reading from the emulator instance. This is my firebase.json:
{
"firestore": {
"rules": "firestore.rules",
"indexes": "firestore.indexes.json"
},
"hosting": {
"rewrites": [
{
"source": "**",
"function": "app"
}
]
},
"functions": {
"source": "functions"
},
"emulators": {
"functions": {
"port": 5001
},
"firestore": {
"port": 8080
},
"hosting": {
"port": 5000
},
"ui": {
"enabled": true
}
}
}
Am I missing some env variable here?

Answer 1

The databaseURL parameter isn't really doing something here, as it is for specifying the Realtime Database URL.
Regardless of which emulator you are actually using, you can omit the Firestore emulator by just running the emulators you want.
For instance: firebase emulators:run --only functions,hosting
That should tell the CLI to use the actual Firestore instance in the Cloud and not the emulator.