How do you setup local environment variables for Cloud Functions for Firebase

I'm using http cloud functions to listen for a request and then return a simple message.

I'm developing cloud functions locally using:

firebase serve --only functions

I've setup some custom environment variables using

firebase functions:config:set

Accessing the custom config variables using the below code works fine when the project is deployed

 functions.config()

but it does not work when developing locally. When the function is triggered by hitting: http://localhost:5002/my-project-name/us-central1/functionName I can't access the custom config variables. when using functions.config() locally, I can see the default config, just not my custom config variables

Is there an alternate solution or best practice for environment variables when working locally?

As of now, you have to manually create a .runtimeconfig.json file inside your functions directory by running this command. Then run the serve command.

firebase functions:config:get > .runtimeconfig.json

If you are using Windows Powershell, replace the above with:

firebase functions:config:get | ac .runtimeconfig.json

You can learn more in https://firebase.google.com/docs/functions/local-emulator

For those who want to use the environment variables (process.env), I follow this workaround.

Set the config values before deploying

firebase functions:config:set envs.db_host=$DB_HOST_PROD envs.db_user=$DB_USER_PROD envs.db_password=$DB_PASSWORD_PROD envs.db_name=$DB_NAME_PROD envs.db_use_ssl=false

Read the config and update the env variables first thing under your functions code.

const functions = require('firebase-functions');
const config = functions.config();

// Porting envs from firebase config
for (const key in config.envs) {
    process.env[key.toUpperCase()] = config.envs[key];
}

You can keep a file called .env.json and load it when you trigger deploy command

{
  "name": "project",
  "version": "0.0.0",
  "scripts": {
    "deploy": "npm run env && firebase deploy --only functions",
    "env": "test -f env.json && firebase functions:config:unset env && firebase functions:config:set env=\"$(cat env.json)\" || echo \"Please add the file env.json before deploy.\""
  },
  "dependencies": {
    "firebase-functions": "^3.1.0"
  },
  "devDependencies": {
    "firebase-functions-test": "^0.1.6"
  }
}

I've narrowed down the issue to Windows Powershell.

Running firebase functions:config:get > .runtimeconfig.json in powershell generates a broken json I don't know why, which when parsed gives Unexpected token � in JSON at position 0.

I've managed to sort it out by running .runtimeconfig.json generation command in Windows command prompt.

If you are using Nrwl NX, you will have to generate your .runtimeconfig.json inside of the dist/apps/functions directory.

Example package.json:

{
  "scripts": {
    "firebase:emulators:start": "firebase functions:config:get > dist/apps/functions/.runtimeconfig.json && env-cmd firebase emulators:start --export-on-exit=\".firebase-emulator\" --import=\".firebase-emulator\""
  }
}

I am not sure if the top-rated answer works or not but for firebase function on mac (to-serve locally), I do something like this

npm run admin-keys && export dev=true && firebase emulators:start

Where admin keys is

"admin-keys": "export GOOGLE_APPLICATION_CREDENTIALS='./.keys/admin.keys.json'"

This will load configuration from .runtimeconfig.json

For production, you would manually have to set it by doing something like this

firebase functions:config:set facebookCred.secret="something"