frames/packages/aws-lambda

@frames/aws-lambda

AWS Lambda adapter for Frames distributed rendering. Ships three things together:

1. The Lambda handler that wraps the OSS plan / renderChunk / assemble primitives behind a single dispatch boundary Step Functions can drive (src/handler.ts).
2. A client-side SDK — renderToLambda, getRenderProgress, deploySite, plus validateDistributedRenderConfig and computeRenderCost (src/sdk/).
3. An aws-cdk-lib L2 construct (HyperframesRenderStack) that provisions the same topology as examples/aws-lambda/template.yaml inside an adopter's own CDK app (src/cdk/).

The handler ZIP and the SAM template still drive a maintainer-run real-AWS smoke flow; the SDK + CDK are the supported public surface for adopters.

Architecture

┌──────────────────────────────────────────────────────────────────┐
│ Step Functions state machine                                     │
│   Plan → Map(N) RenderChunk → Assemble                           │
└──────────────────────────────────────────────────────────────────┘
                              │ dispatches by event.Action
                              ▼
┌──────────────────────────────────────────────────────────────────┐
│ One Lambda function (this package's `dist/handler.zip`)          │
│   handler.mjs                                                    │
│     ├─ Action="plan"        → @frames/producer/distributed  │
│     ├─ Action="renderChunk" → @frames/producer/distributed  │
│     └─ Action="assemble"    → @frames/producer/distributed  │
│   bin/ffmpeg                — ffmpeg-static                      │
│   node_modules/@sparticuz/chromium/ — Lambda-optimised Chromium  │
└──────────────────────────────────────────────────────────────────┘
                              │ pure functions over local paths
                              ▼
┌──────────────────────────────────────────────────────────────────┐
│ S3 bucket — v1 plan tar or v2 manifest/blobs + chunks + output  │
└──────────────────────────────────────────────────────────────────┘

The handler downloads inputs from S3 into /tmp, calls the OSS primitive, uploads outputs back to S3, and returns a small JSON result that fits inside Step Functions' history budget (under 200 bytes per chunk).

Plan transport selection

renderToLambda defaults to the existing monolithic v1 plan transport. Plan v2 is an explicit whole-render opt-in:

await renderToLambda({
  // ...bucket, state machine, project, and config...
  planProtocol: "v2",
});

V2 never overloads PlanS3Uri. The planner returns PlanV2ManifestS3Uri and PlanV2ArtifactS3Prefix; chunk workers fetch only manifest-selected chunk artifacts, while the assembler fetches its own metadata and audio subset. Blobs are immutable SHA-256-addressed objects, verified on upload and download, and the manifest is published last. Unknown protocols and digest mismatches are terminal Step Functions errors. Omit the selector—or use "v1"—to retain the prior wire contract.

Chrome runtime

The package supports two Chromium sources:

Source	Default	Size	When to pick it
@sparticuz/chromium	yes	~70 MiB compressed	Lambda. Decompresses into /tmp at runtime; the rest of the ecosystem already uses it for headless-Chrome-in-Lambda.
Bundled chrome-headless-shell	no	~140 MiB	Fallback. Used if @sparticuz/chromium ever drops HeadlessExperimental.beginFrame support.

Pick the source at build time:

bun run --cwd packages/aws-lambda build:zip
bun run --cwd packages/aws-lambda build:zip -- --source=chrome-headless-shell

The handler reads FRAMES_LAMBDA_CHROME_SOURCE at boot. The build script sets that env var via Lambda function configuration in examples/aws-lambda/template.yaml.

BeginFrame regression guard

Frames' renderer drives Chrome via the CDP HeadlessExperimental.beginFrame command — same path the K8s deploy uses. The Lambda adapter assumes that @sparticuz/chromium's chrome-headless-shell build honours BeginFrame. To prove it (and re-prove it on every release), the package ships a Docker probe:

# Build the Lambda-like container and run the probe.
bun run --cwd packages/aws-lambda probe:beginframe:docker

The probe boots @sparticuz/chromium inside public.ecr.aws/lambda/nodejs:22 and asserts CDP beginFrame with screenshot: true returns a PNG buffer. Exit code 0 = green; non-zero = fall back to bundling chrome-headless-shell directly via --source=chrome-headless-shell.

Building the ZIP

bun install                                          # at the monorepo root
bun run --cwd packages/aws-lambda build:zip          # → packages/aws-lambda/dist/handler.zip
bun run --cwd packages/aws-lambda verify:zip-size    # CI gate

The build script bundles src/handler.ts via esbuild, stages @sparticuz/chromium and puppeteer-core under node_modules/, copies ffmpeg-static into bin/, and zips the result. The unzipped layout is designed to extract cleanly into Lambda's /var/task/.

verify:zip-size enforces:

• Unzipped ≤ 248 MiB (in-house budget; Lambda hard ceiling is 250 MiB unzipped — AWS docs label this "250 MB" but use binary mebibytes)
• Zipped ≤ 150 MiB (in-house budget; Lambda has no hard zipped cap for S3-deployed functions)

CI fails the PR if either is exceeded.

Running tests

bun run --cwd packages/aws-lambda test               # unit tests (no Chrome)
bun run --cwd packages/aws-lambda probe:beginframe   # local probe (Linux only)

Using the SDK

After deploying the stack (via the SAM template, CDK construct below, or your own CFN of choice), drive renders from Node:

import { deploySite, getRenderProgress, renderToLambda } from "@frames/aws-lambda";

// One-time upload per project version.
const site = await deploySite({
  projectDir: "./my-composition",
  bucketName: "frames-render-bucket",
});

// Start a render. Returns immediately — does NOT poll.
const handle = await renderToLambda({
  siteHandle: site,
  bucketName: site.bucketName,
  stateMachineArn: "arn:aws:states:us-east-1:123:stateMachine:frames-render",
  config: {
    fps: 30,
    width: 1920,
    height: 1080,
    format: "mp4",
    chunkSize: 240,
    maxParallelChunks: 16,
    runtimeCap: "lambda",
  },
});

// Poll progress + cost on your own cadence.
const progress = await getRenderProgress({ executionArn: handle.executionArn });
console.log(progress.overallProgress, progress.costs.displayCost);
if (progress.status === "SUCCEEDED" && progress.outputFile) {
  console.log("Render landed at", progress.outputFile.s3Uri);
}

renderToLambda validates the config client-side via validateDistributedRenderConfig and throws a typed InvalidConfigError before the Step Functions execution starts, so shape errors surface synchronously instead of as opaque ExecutionFailed results.

getRenderProgress reports an approximate per-render cost (accruedSoFarUsd plus a formatted displayCost) derived from Lambda billed-duration × memory × the us-east-1 on-demand rate plus the Step Functions transition price. The math is documented in src/sdk/costAccounting.ts; numbers are best-effort and exclude S3 transfer.

Using the CDK construct

import { App, Stack } from "aws-cdk-lib";
import { HyperframesRenderStack } from "@frames/aws-lambda/cdk";

const app = new App();
const stack = new Stack(app, "MyApp");
const render = new HyperframesRenderStack(stack, "Render", {
  // optional: reservedConcurrency: 8,
  // optional: lambdaMemoryMb: 10240,
  // optional: chromeSource: "sparticuz",
});

// Re-export so an adopter app can wire dashboards / SNS topics.
new CfnOutput(stack, "RenderBucketName", { value: render.bucket.bucketName });
new CfnOutput(stack, "StateMachineArn", { value: render.stateMachine.stateMachineArn });

aws-cdk-lib and constructs are optional peer dependencies: SDK-only consumers don't pull them at runtime. The construct itself imports from @frames/aws-lambda/cdk.

What's still ahead

• frames lambda CLI (deploy / sites create / render / progress / destroy) — PR 6.5.
• IAM bootstrap subcommand (policies role | user | validate) — PR 6.9.
• Lambda-local regression harness (--mode=lambda-local) — PR 6.6.
• Adopter-facing migration guide — PR 6.8.