Long posts

Technology mash:

• Firebase Cloud Messaging
• AWS Lambda cron
• Serverless

I found the least haphazard way to authenticate was to just take the variables that are needed from the google-application-credentials.json file that Firebase gives me, and set them up as Lambda environment variables.

Serverless Variables

I added the JSON file to .gitignore, and let Serverless extract the variables from the file:

environment:
    FIREBASE_PROJECT_ID: ${file(./google-application-credentials.json):project_id}
    FIREBASE_CLIENT_EMAIL: ${file(./google-application-credentials.json):client_email}
    FIREBASE_PRIVATE_KEY: ${file(./google-application-credentials.json):private_key}

Firebase Initialization

Now I can recreate the cert object:

const firebase = require("firebase-admin")

firebase.initializeApp({
    credential: firebase.credential.cert({
        projectId: process.env.FIREBASE_PROJECT_ID,
        clientEmail: process.env.FIREBASE_CLIENT_EMAIL,
        privateKey: process.env.FIREBASE_PRIVATE_KEY,
    }),
})

export { firebase }

I have this within its own service file, so it's easily mocked and imported variously.

Then I'm free to call firebase.messaging().sendToDevice(id, payload, options) wherever needed.