docker pull ghcr.io/io-digital/firebase-emulator-suite

start by generating a ci token with firebase login:ci and keep this aside for later.

ensure you've got a firebase.json file for instructing the emulator suite which emulators to use.

example firebase.json:

{
  "emulators": {
    "firestore": {
      "enabled": true,
      "port": "8080",
      "host": "0.0.0.0"
    },
    "ui": {
      "enabled": true,
      "port": "4000",
      "host": "0.0.0.0"
    },
    "auth": {
      "enabled": true,
      "port": "9099",
      "host": "0.0.0.0"
    }
  }
}

link everything together in a docker-compose.yml:

firebase:
  image: ghcr.io/io-digital/firebase-emulator-suite
  environment:
    - FIREBASE_TOKEN=YOUR_FIREBASE_CI_TOKEN
    - FIREBASE_PROJECT=YOUR_FIREBASE_PROJECT_NAME
  volumes:
    - ./path/to/keep/cached/firebase/emulators:/home/firebase/.cache/
    - ./path/to/your/firebase.json:/home/firebase/firebase.json
  ports:
    - '9099:9099'
    - '4000:4000'
    - '5001:5001'
    - '9000:9000'
    - '8080:8080'
    - '8085:8085'
    - '5000:5000'

take note of:

• the port mappings, which have to match your assigned ports in firebase.json
• the volume mappings, paying special attention to:
  • volume /home/firebase/.cache will prevent re-downloading of individual firebase emulators every time the container is restarted
  • volume /home/firebase/firebase.json will not only configure which emulators run, but also configure the host/container networking as long as each emulator host is set to 0.0.0.0
• the environment variables, which include your firebase token generated earlier with firebase login:ci

with all of the above in place, bring up the docker-compose system as normal.

you will notice on the first build/run that the firebase-emulator-suite will not respond for a while. this is normal, it is downloading the emulators.

eventually, it will print to stdout indicating that the emulators are live along with a link for opening the emulator control-plane in your browser.

this download step will only occur once, provided the cache volume was not invalidated or more emulators were configured in firebase.json to be run that have not yet been downloaded.