environment variables for firebase when hosting flutter

Question

I am hosting flutter web app on firebase. How do I pass env (non secret) variables to firebase? I deploy with firebase deploy command.

When running flutter locally, I pass env variable as a flag in command line argument:

flutter run --dart-define=envFileName=local.env --web-browser-flag "--disable-web-security"

Answer 1

I just spent all day figuring this out. I was trying to get Github actions working. So the official docs say to use 'source' in your firebase.json file. https://firebase.google.com/docs/hosting/frameworks/flutter What isn't clear is that when you have source in the config, it will build the flutter app when you run firebase deploy. That clears out any build parameters you sent in previously, even if you just built with --dart-define parameters.

The solution is to change your firebase.conf file to something like this:

{
  "hosting": {
    "public": "build/web",
    "ignore": [
      "firebase.json",
      "**/.*",
      "**/node_modules/**"
    ],
    "frameworksBackend": {
      "region": "us-central1"
    },
    "rewrites": [ {
   "source": "**",
   "destination": "/index.html"
} ]
  }
}

Then build your app

flutter build --dart-define=envFileName=local.env

Then deploy

firebase deploy