Durable Object-managed Containers demo

A minimal Worker whose Durable Objects start namespace-backed containers on demand.

Prerequisites

• Node.js 22 or newer, pnpm 10.33.0, and Docker
• A Cloudflare account with Workers, Containers, and the new runtime enabled.

Wrangler is pinned to the published 4.132.0 release in package.json and the lockfile. All package scripts use that local version.

Deploy

Install dependencies and verify the CLI version:

pnpm install
pnpm exec wrangler --version

Check the generated bindings, TypeScript, and Worker bundle locally:

pnpm check
pnpm deploy:dry

Check your account, then deploy. Run pnpm exec wrangler login first if you are not already logged in:

pnpm exec wrangler whoami
pnpm run deploy

Wrangler builds and pushes the image, prepares it to run on Cloudflare, uploads the Worker, and creates the namespace-backed application if it is missing. Normal deploys apply explicitly configured application settings; omitted settings are preserved.

Try it

Use the Worker URL printed by Wrangler:

curl "https://<worker-url>/?instance=first"
curl "https://<worker-url>/_status?instance=first"
curl "https://<worker-url>/_destroy?instance=first"

Each instance value selects a different Durable Object and container.

Configuration and runtime

• The existing v1 migration declares the SQLite-backed Sandbox class. containers[].class_name attaches its container.
• scheduling_policy: "durable_object" makes each Durable Object own its container lifecycle.
• The named images.app configuration uses dockerfile: "./container/Dockerfile" and build_context: "./container". Wrangler builds, pushes, and prepares that image. The Dockerfile's COPY instructions resolve against the container directory. Per-image build_vars can supply Docker build arguments when needed; this Dockerfile requires none.
• The Worker reads the resolved image from this.ctx.container.images.app and passes it to container.start().
• Instance size, entrypoint, environment, and inactivity timeout are set in src/index.ts at runtime.
• Top-level observability enables Worker logs. Container application logs are configured separately with containers[].observability; omitting that setting preserves the application's existing configuration.