Command cancellation

Deno Sandbox provides a sandboxed Linux microVM. This is useful for evaluating code that is not trusted or for testing code that is not safe to run in your main runtime.

Being able to cancel sandbox commands is key when tasks hang or you need to enforce timeouts. You can cancel commands in a sandbox using the KillController class.

import { KillController, Sandbox } from "@deno/sandbox";

await using sandbox = await Sandbox.create();

// Start a long-running command
const controller = new KillController();
const cmd = sandbox.sh`sleep 30`.signal(controller.signal);
const promise = cmd.text();

// Cancel after 2 seconds
setTimeout(() => {
  controller.kill(); // Kill the process
}, 2000);

try {
  await promise;
} catch (error) {
  console.log("Command was cancelled:", error);
}

KillController lets you attach a cancellation signal to any sandbox command, so you can abort long-running processes if they exceed a limit or the user cancels the operation.

After triggering controller.kill(), the awaiting call rejects; you can intercept that rejection to log, clean up, or retry as needed.

This pattern keeps sandbox automation responsive and prevents orphaned processes from consuming resources indefinitely.

For more information, see the Deno Sandbox documentation.