exec() is now available for Containers

exec() is now available for Containers. Use this.ctx.container.exec() to start processes inside a running Container, stream standard input and output, inspect exit codes, and signal each process.

Call exec() from a class extending Container, or from another Durable Object through this.ctx.container. The associated Container must already be running.

This example starts the Container when needed, then reads its Node.js version:

src/index.js

import { Container } from "@cloudflare/containers"; export class MyContainer extends Container { async readVersion() { if (!this.ctx.container.running) { await this.start(); } const process = await this.ctx.container.exec(["node", "--version"]); const output = await process.output(); const decoder = new TextDecoder(); return { exitCode: output.exitCode, stdout: decoder.decode(output.stdout), stderr: decoder.decode(output.stderr), }; } }

src/index.ts

import { Container } from "@cloudflare/containers"; export class MyContainer extends Container { async readVersion() { if (!this.ctx.container.running) { await this.start(); } const process = await this.ctx.container.exec(["node", "--version"]); const output = await process.output(); const decoder = new TextDecoder(); return { exitCode: output.exitCode, stdout: decoder.decode(output.stdout), stderr: decoder.decode(output.stderr), }; } }

The command array starts an executable directly, without an implicit shell. Invoke a shell explicitly for pipes, redirects, or variable expansion.

One RPC method can coordinate multiple exec() calls in one caller-to-Durable Object round trip. It can also pass byte-oriented ReadableStream input or return streamed output with flow control.

For options and streaming examples, refer to Execute commands.