Allow emulators to export on exit

Originally requested through FIrebase support, there is some demand for a flag like this:

firebase emulators:start --import=./seed --export-on-exit

This would import from a location but save any mutations made on exit.

[samtstern]

@michi88 thanks for asking all the right questions. My personal take:

• I like the name --export-on-exit

• I think it should take an optional path --export-on-exit=./some-path. When unspecified it would use the same path as --import. If you do a bare --export-on-exit with no --import=something flag that’s an error. So:

  • ✅ VALID: emulators:start --import=./foo --export-on-exit
  • ✅ VALID: emulators:start --import=./foo --export-on-exit=./bar
  • ✅ VALID: emulators:start --export-on-exit=./bar
  • ❌ NOT VALID: emulators:start --export-on-exit

If that sounds good to you I’ll propose it to the API people.

[quantuminformation]

Waiting with anticipation. I didn’t realise that data was not saved automatically after restarting and was wondering what was wrong with my app until I checked the db, I’m glad I’m not crazy.