Application example Bindings

Use Containers in a real application path

Containers let a Worker hand requests to stateful code running from a container image.

A compact Containers recipe with config and worker usage in one application path.

Use this as the copyable starter before threading the feature into a larger application.

Config focus: containers
Runtime shape: Container class config plus a Durable Object container binding
Best use: routing requests to a stateful container instance that runs code outside the Workers runtime

Start by wiring the binding clearly in config

Smallest Containers config

import { defineConfig } from 'devflare/config'

export default defineConfig({

name: 'container-worker',

files: {

fetch: 'src/container.api.ts',

durableObjects: 'src/container.api.ts'

bindings: {

durableObjects: {

API_CONTAINER: {

className: 'ApiContainer'

}

containers: [

{

className: 'ApiContainer',

image: 'localhost/devflare-api:latest',

imageBuildContext: './containers/api',

maxInstances: 1

}

migrations: [

{

tag: 'v1',

new_sqlite_classes: ['ApiContainer']

}

]

})

Build the application flow around the binding

Treat this as the app-level Containers path: the route, event handler, or service module receives a real request and uses the binding to do useful work.

Keep product limits, remote ownership, and fallback behavior visible in the code around the binding instead of hiding everything behind a vague utility too early.

Keep the first example short enough to paste into a new Worker.
Cloudflare owns deployed container rollout, managed registry availability, SSH, scaling, and hosted platform behavior; Devflare owns the Docker/Podman local loop.

Proxy one application route to a container instance

import { Container, getContainer } from '@cloudflare/containers'

import { env } from 'devflare/runtime'

export class ApiContainer extends Container {

defaultPort = 8080

sleepAfter = '10m'

}

export async function fetch(request: Request): Promise<Response> {

const url = new URL(request.url)

const sessionId = url.searchParams.get('session') ?? 'public'

const container = getContainer(env.API_CONTAINER, sessionId)

return container.fetch(request)

}

Keep production boundaries visible

Config focus: containers.
Runtime shape: Container class config plus a Durable Object container binding.
Best use: routing requests to a stateful container instance that runs code outside the Workers runtime.

Thread this into the next recipe

Once this smallest path works, add routing, generated types, and feature-specific abstraction in that order.

Testing Containers

Test Containers by choosing the local harness that matches the product boundary instead of reaching for Cloudflare by default.