How to set hash-key option for auth:import after default auth:export in firebase?

Solution:

So you can now get the hash key and the salt info from the firebase console GUI. I had to enter incognito mode in chrome for some reason (firebase support suggested this).

I could then log into my firebase console in the incognito browser.

(Note that you need to use the firebase instance that you are copying users from, not the one that you are copying users to)

You click on Authentication -> Users and then click on the three vertical dots next to the reload button and a popup menu will show up with a single menu item: "Password hash parameters".

password hash parameters

Click on this menu item and all of the settings you need for doing the firebase auth:import command will show up. Here's what I see:

hash_config {
  algorithm: SCRYPT,
  base64_signer_key: <long string of random characters>,
  base64_salt_separator: <short string of random characters>,
  rounds: 8,
  mem_cost: 14,
}

I can then do the command successfully

firebase auth:import ./users.json --hash-algo=scrypt --rounds=8 --mem-cost=14 --hash-key=<long string of random characters> --salt-separator=<short string of random characters>