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Go beyond web development with Firebase Cloud Functions Sofia Huts Software Engineer @ JustAnswer Manager @ GDG Lviv

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https://firebase.google.com/

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https://firebase.google.com/

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Platform-as-a-Service (PaaS)

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CLIENT WEB SERVER DATABASE

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CLIENT WEB SERVER DATABASE

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CLIENT WEB SERVER DATABASE

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CLIENT WEB SERVER DATABASE

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WEB SERVER DATABASE CLIENTS

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But what if I want to.. ● synchronize data from another source, outside the database ● send an email or push notification based on changes that happened in database ● perform heavy operations (e.g. image resizing, video transcoding) ● expose HTTP endpoints

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Cloud functions for Firebase

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App + Firebase SDK Firebase Cloud Functions Database Storage

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Event driven model Function triggered Event emitted Your code executed

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In other words...all you know tooth fairy abracadabra result Action / trigger / event

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● Run in serverless environment ● Isolated backend code pieces as “microservice” ● Autoscales up on load, and down to zero ● Node JS code

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But I am a mobile developer

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Triggers HTTP Firebase real-time database / firestore Firebase authentication Firebase analytics / crashlytics Cloud pub / sub Cloud storage HTTP

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What can I do with it?

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Notify users when something interesting happens https://firebase.google.com/docs/functions/use-cases

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Post GitHub commits to a workgroup chat room in Slack https://firebase.google.com/docs/functions/use-cases

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Let’s code!

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$ npm install -g firebase-tools $ firebase init functions

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myproject +- .firebaserc # hidden file which help you quickly switch between | # Firebase projects using ‘firebase use’ | +- firebase.json # describes properties for your project | +- functions/ # directory containing all your functions code | +- package.json # npm package file describing your Cloud Functions | # code and all dependencies | +- index.js # main source file for your Cloud Functions code | +- node_modules/ # directory where your dependencies (declared in # package.json ) are installed

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const functions = require('firebase-functions'); exports.helloWorld = functions.https.onRequest((req, res) => { res.send('Hello World!'); }); functions/index.js

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const functions = require('firebase-functions'); exports.helloWorld = functions.https.onRequest((req, res) => { res.send('Hello World!'); }); functions/index.js

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const functions = require('firebase-functions'); exports.helloWorld = functions.https.onRequest((req, res) => { res.send('Hello World!'); }); functions/index.js

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const functions = require('firebase-functions'); exports.helloWorld = functions.https.onRequest((req, res) => { res.send('Hello World!'); }); functions/index.js

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const functions = require('firebase-functions'); exports.helloWorld = functions.https.onRequest((req, res) => { res.send('Hello World!'); }); functions/index.js

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$ firebase deploy

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const functions = require('firebase-functions'); exports.lastUpdate = functions.database .ref("/messages/{messageId}").onUpdate(event => { const msg = event.data.val(); msg.lastUpdated = new Date().getTime(); return event.data.adminRef.set(msg); })

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const functions = require('firebase-functions'); exports.lastUpdate = functions.database .ref("/messages/{messageId}").onUpdate(event => { const msg = event.data.val() msg.lastUpdated = new Date().getTime() return event.data.adminRef.set(msg); })

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const functions = require('firebase-functions'); exports.lastUpdate = functions.database .ref("/messages/{messageId}").onUpdate(event => { const msg = event.data.val() msg.lastUpdated = new Date().getTime() return event.data.adminRef.set(msg); })

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const functions = require('firebase-functions'); exports.lastUpdate = functions.database .ref("/messages/{messageId}").onUpdate(event => { const msg = event.data.val() msg.lastUpdated = new Date().getTime() return event.data.adminRef.set(msg); })

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const functions = require('firebase-functions'); exports.lastUpdate = functions.database .ref("/messages/{messageId}").onUpdate(event => { const msg = event.data.val(); msg.lastUpdated = new Date().getTime() return event.data.adminRef.set(msg); })

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const functions = require('firebase-functions'); exports.lastUpdate = functions.database .ref("/messages/{messageId}").onUpdate(event => { const msg = event.data.val(); msg.lastUpdated = new Date().getTime(); return event.data.adminRef.set(msg); })

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Pricing

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Flame Plan $25/month Spark Plan Free Blaze Plan Pay as you go 125K/month 40K/month 40K/month Google services only 2M/month 400K/month 200K/month 5 GB/month $0.40/million $0.0025/thousand $0.01/thousand $0.12/GB Invocations GB-seconds CPU-seconds Outbound networking Cloud Functions

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Blaze Plan Calculator https://firebase.google.com/pricing/

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Blaze Plan Calculator https://firebase.google.com/pricing/

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Resources Invocation time ● 0.7 sec RAM/CPU ● 256 MB ● 400 MHz Invocations ● 10K Compute time (256/1024) x 0.7s = 0.175 GB-seconds per invocation (400/1000) x 0.7s = 0.280 GHz-seconds per invocation 10 000 x 0.175 = 1 175 GB-seconds per month 10 000 x 0.280 = 1 280 GHz-seconds per month Networking 0 GB egress traffic Calculations

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Billing Metric Gross Value Free Tier Net Value Unit Price Total Price Invocations 10 000 2 000 000 -1 990 000,00 $0.0000004 $0,004 GB-seconds 1 175 400 000 -398 825,00 $0.0000025 $0,0029375 GHz-seconds 1 280 200 000 -198 720,00 $0.00001 $0,0128 Networking 0 5 -5,00 $0.12 $0 Total / Month $0,0197375

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My own drama

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https://2017.devfest.cz/

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https://github.com/gdg-x/hoverboard/tree/hoverboard-v2 @ozasadnyy

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Firebase console / real-time database

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Firebase console / real-time database

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https://github.com/gdg-x/hoverboard/blob/master/scripts/helper/schedule-webworker.js

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const functions = require('firebase-functions'); const admin = require('firebase-admin'); admin.initializeApp(functions.config().firebase); const scheduleGenerator = require('./schedule-generator-helper.js').generateSchedule; exports.scheduleWrite = functions.database .ref("/schedule").onWrite(event => { const schedulePromise = event.data; const sessionsPromise = admin.database().ref('/sessions').once('value'); const speakersPromise = admin.database().ref('/speakers').once('value'); return generateScheduleOnChange(schedulePromise, sessionsPromise, speakersPromise); });

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Firebase console / real-time database

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Drama #2

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Me Ostap ~ 10 min range time

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Where the changes I’ve made?

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My plan was ● Start free 300$ trial on GCP ● Use pub/sub, so we can trigger function in GCP ● In Firebase function publish topic “db-updated” ● In Cloud function subscribe for that topic ● In Cloud function use Slack webhook to send messages in channel

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Firebase GCP $300 free credit

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const functions = require('firebase-functions'); const admin = require('firebase-admin'); exports.scheduleWrite = functions.database .ref("/schedule").onWrite(event => { if (event.auth.admin) { const topic = createTopic('db-changed'); const data = { changedData: event.data._delta, dataPath: '/schedule', database: functions.config().firebase.databaseURL }; publishMessage(topic, data); } }); Only if Admin changes

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function createTopic(topicName) { const pubsubClient = pubsub(); const topic = pubsubClient.topic(topicName); if (topic) { console.log(`Topic ${topic.name} already exists.`); return topic; } pubsubClient.createTopic(topicName) .then((results) => { const topic = results[0]; console.log(`Topic ${topic.name} created.`); return topic; }); }; const pubsub = require('@google-cloud/pubsub'); Returns topic object if exists Create topic for pub / sub

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function publishMessage (topic, data) { // Create a publisher for the topic (which can include additional batching configuration) const publisher = topic.publisher(); // Publishes the message as a string, e.g. "Hello, world!" or JSON.stringify(someObject) const dataBuffer = Buffer.from(JSON.stringify(data)); return publisher.publish(dataBuffer) .then((results) => { const messageId = results[0]; console.log(`Message ${messageId} published.`); return messageId; }) .catch((err) => { console.error(`An error occured during publish: ${err}`); }); } Accepts only encoded string Publish to pub / sub

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Subscribe in GCP

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Subscribe in GCP exports.subscribe = function subscribe(event, callback) { // The Cloud Pub/Sub Message object. const pubsubMessage = event.data; let data = Buffer.from(pubsubMessage.data, 'base64').toString(); let dataObj = JSON.parse(data); postToSlack(dataObj).then(() => { console.log("Message sent"); }).catch(error => { console.error(error); }); // Don't forget to call the callback. callback(); };

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Post to Slack const rp = require('request-promise'); function postToSlack(data) { return rp({ method: 'POST', uri: 'https://hooks.slack.com/services/....', body: { text: `:fire: Hello from GCP! New changes arrived in ${data.dataPath}, attachments: [ { title: `Check ${data.database}`, title_link: `${data.database}${data.dataPath}`, text: `${JSON.stringify(data.changedData)}`, color: "#FFC107" } ] }, json: true }); }

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Post to Slack

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Google Cloud functions Functions for Firebase == billing billing == SDK SDK

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const functions = require('firebase-functions'); const admin = require('firebase-admin'); exports.scheduleWrite = functions.database .ref("/schedule").onWrite(event => { if (event.auth.admin) { const topic = createTopic('db-changed'); const data = { changedData: event.data._delta, dataPath: '/schedule', database: functions.config().firebase.databaseURL }; publishMessage(topic, data); } });

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const functions = require('firebase-functions'); const admin = require('firebase-admin'); exports.scheduleWrite = functions.database .ref("/schedule").onWrite(event => { if (event.auth.admin) { const data = { changedData: event.data._delta, dataPath: '/schedule', database: functions.config().firebase.databaseURL }; postToSlack(data).then(() => { console.log("Message sent"); }).catch(error => { console.error(error); }); } });

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Drama #3

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What if I... ● Want to have backups of my DB ● Don’t wanna enable Blaze plan ● My DB is quite small, so I can store data for FREE

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5 Gb Free DB Function Storage

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Let’s code!

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const functions = require('firebase-functions'); const fse = require('fs-extra'); exports.saveBackup = functions.database.ref('/{node}').onWrite(event => { const maxBackupsCount = 10; const data = event.data.val(); fse.writeJson('/tmp/db-data.json', data) .then(() => { console.log('Successfuly written data to /tmp folder') }) .catch(err => { console.error(err) }); const gcs = require('@google-cloud/storage')(); // Reference to an existing bucket. const bucket = gcs.bucket('.appspot.com');

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//Check files count. If get to limit - delete the oldest one bucket.getFiles({ prefix: 'backup/db-data'}).then((result) => { let files = result[0]; if (files.length < maxBackupsCount) { return; } else { // sort by date desc - oldest first const sortedFiles = files.sort(function(a,b) { return new Date(a.metadata.updated) - new Date(b.metadata.updated); }); const fileNameToDelete = sortedFiles[0].name; bucket .file(fileNameToDelete ) .delete() .then(() => { console.log(`${fileNameToDelete} deleted.`); }) .catch(err => { console.error('ERROR:', err); }); } }) .catch(err => console.error(err));

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//Upload a local file to a new file to be created in bucket. bucket.upload('/tmp/db-data.json', { destination: `/backup/db-data-${new Date().getTime()}.json` }) .then(() => { console.log('Backup was successfuly uploaded!'); }) .catch((err) => { console.error(`Error occured during upload: ${err}`); }); }); //End of saveBackup functions for Firebase

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To sum up ● Let the Cloud functions help you, delegate your work ● Try to write optimised function as much as you can (time of execution matters, you pay for it) ● Use GSP free tier with 300$ trial, and it will apply to your Firebase project as well ● Enjoy this magic!

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Thank you! Questions? @sophie_h29 sophie.huts.7