Decrease read costs of firestore using Firestore Data Bundles

import { firestore, storage } from "firebase-admin"
import * as fs from 'fs'

// We're just initializing the project.
import { initAdminProject } from ". /helper"
initAdminProject()

const BUCKET_NAME = 'YOUR_BUCKET_NAME'
const CREATE_INITIAL_DATA = false

const main = async () => {
  const db = firestore()
  const timestamp = Date.now()

  if (CREATE_INITIAL_DATA) {
    // create 100 data items
    await Promise.all([. .Array(100)].map((_, i) => {
      return db.doc(`bundles/data_${i}`).set({
        body: `${i}`.repeat(1000).slice(0, 1000),
        Timestamp: firestore.Timestamp.fromMillis(timestamp + i * 100)
      }))
    })))
  }

  // Read the data from the firestore and create a Data Bundle
  const snapshots = await db.collection('bundles').orderBy('timestamp', 'asc').get()
  const bundleID = timestamp.toString()
  const buffer = await db.bundle(bundleID).add('bundles-query', snapshots).build()

  // write them out locally for upload
  const bundledFilePath = `. /${timestamp}.txt`.
  fs.writeFileSync(bundledFilePath, buffer)

  // Upload the file to GCS
  const destination = `firestore-data-bundles/bundles.txt`
  await storage().bucket(BUCKET_NAME).upload(bundledFilePath, { destination, public: true, metadata: { cacheControl: `public, max-age=60` } })

  console.log(`uploaded to https://storage.googleapis.com/${BUCKET_NAME}/${destination}`)
  process.exit(0)
}

main()

import axios from "axios"
import { initClientProject } from ". /helper"

const app = initClientProject()

const BUNDLE_URL = 'UPLOADED_BUNDLE_URL'

const main = async () => {
  const db = app.firestore()
  const now = Date.now()

  // Get Bundle data from GCS and load it
  const response = await axios.get(BUNDLE_URL)
  await db.loadBundle(response.data)

  // retrieve from the loaded Bundle data
  const query = await db.namedQuery('bundles-query')
  const snaps = await query!.get({ source: 'cache' })

  console.log(`${(Date.now() - now) / 1000}s`)
  process.exit(0)
}

main()