Allow emulators to select TimeZone

When I emulate my cloud functions it uses my local time zone. It would be great to run emulators by setting the TimeZone I’d like to, in order to test the system as it can be in production (I’m most interested in testing cloud functions with UTC locale set, as I think that actually firebase uses UTC in the containers and not the region locale, right ? ).

Something like: firebase emulators:start --tz='UTC' firebase emulators:start --tz='Europe/Amsterdam' or other format.

I tried to use (in node.js) process.env.TZ = 'UTC' and it worked, so I was wondering if could be possible to have an environment variable like that one that can be changed by param.

[samtstern]

@emanuelevivoli ok I think we’re on the same page. Once I find out what production behavior is I will make sure the emulators automatically match that.

[samtstern]

But if I set TZ=UTC it works better locally:

$ TZ=UTC firebase functions:shell
i  functions: Loaded functions: checkTimeZone
⚠  functions: The following emulators are not running, calls to these services will affect production: firestore, database, pubsub
firebase > checkTimeZone()
Sent request to function.
firebase > >  {"tz":"UTC","time":"15:56:16 GMT+0000 (Coordinated Universal Time)","offset":0}

RESPONSE RECEIVED FROM FUNCTION: 200, {
  "tz": "UTC",
  "time": "15:56:16 GMT+0000 (Coordinated Universal Time)",
  "offset": 0
}