Serverless image pipeline with aws lambda+node+wasm: from 11.5mb to 91.2kb

npm install

sam build

sam deploy

import { S3Client, GetObjectCommand, PutObjectCommand } from "@aws-sdk/client-s3"

import { image } from "beautiful-image/node"

import path from "node:path"



const SOURCE_BUCKET = process.env.SOURCE_BUCKET!

const DEST_BUCKET = process.env.DEST_BUCKET!



const s3 = new S3Client({})



const VARIANTS = [

  { folder: "optimized",  width: 800, quality: 80 },

  { folder: "thumbnails", width: 200, quality: 80 },

] as const



const ALLOWED_EXTENSIONS = new Set([".jpg", ".jpeg", ".png", ".webp"])



export const handler = async (event: AWSLambda.S3Event): Promise<void> => {

  for (const record of event.Records) {

    const key = decodeURIComponent(record.s3.object.key.replace(/\+/g, " "))



    const ext = path.extname(key).toLowerCase()

    if (!ALLOWED_EXTENSIONS.has(ext)) {

      console.log(`Skipping unsupported file type: ${key}`)

      continue

    }



    const t0 = performance.now()

    console.log(`Processing: ${key}`)



    let input: Buffer

    try {

      const t1 = performance.now()

      const { Body } = await s3.send(

        new GetObjectCommand({ Bucket: SOURCE_BUCKET, Key: key })

      )

      if (!Body) {

        console.error(`Empty body for key: ${key}`)

        continue

      }

      input = Buffer.from(await Body.transformToByteArray())

      console.log(`[timer] download: ${(performance.now() - t1).toFixed(0)}ms ${input.length}B`)

    } catch (err) {

      console.error(`Failed to download ${key}:`, err)

      continue

    }



    const filename = path.parse(key).name



    for (const { folder, width, quality } of VARIANTS) {

      const tp = performance.now()

      let result: Awaited<ReturnType<ReturnType<typeof image>["toJpeg"]>>

      try {

        result = await image(input).resize(width).toJpeg(quality)

      } catch (err) {

        console.error(`Failed to process variant ${folder} for ${key}:`, err)

        continue

      }

      console.log(`[timer] wasm ${folder} (${width}px): ${(performance.now() - tp).toFixed(0)}ms`)



      const destKey = `${folder}/${filename}.jpg`

      const tu = performance.now()

      try {

        await s3.send(

          new PutObjectCommand({

            Bucket: DEST_BUCKET,

            Key: destKey,

            Body: result.data,

            ContentType: "image/jpeg",

          })

        )

      } catch (err) {

        console.error(`Failed to upload ${destKey}:`, err)

        continue

      }

      console.log(`[timer] upload ${destKey}: ${(performance.now() - tu).toFixed(0)}ms`)



      console.log(

        `Saved ${destKey} - ${result.originalSize}B → ${result.optimizedSize}B (${Math.round(result.compressionRatio * 100)}% smaller)`

      )

    }



    console.log(`[timer] total: ${(performance.now() - t0).toFixed(0)}ms`)

  }

}