Capture OS signals during prompts about deno-cliffy HOT 9 CLOSED

@c4spar I've opened another issue denoland/deno#8343 that would help solve this. If we could use another TTY mode that forwards keystrokes, but handles interrupts/suspend, the whole problem disappears.

from deno-cliffy.

Hi @marcushultman,

Yes, we should definitely improve that! And if you want to make a PR this would be great 👍 But i'm not shure if we should use a callback method.

I think the best would be if it were possible to emit a SIGINT signal on ctrl+c. Then you can simply register a handler with Deno.signal() or Deno.signals.interrupt(). But I haven't found a way to emit a signal yet.

If we use a callback method, than you have to register two SIGINT handler. One with the prompt method and one with Deno.singal() in case the prompt isn't running actually.

from deno-cliffy.

@c4spar Deno.kill(Deno.pid, Deno.Signal.SIGINT); would work (it's even used in std/signal tests). I'll experiment some more on my own fork by raising a signal (the callback solution I sketched up works, but indeed requires two handlers just as you say.

from deno-cliffy.

Made a PR #106

from deno-cliffy.

Awesome! thanks for this PR @marcushultman.

This works great but i'm also not so happy with the --allow-run flag. Because this forces the user to disable the sandbox mode of deno and indicates that we want to run a child process but we only want to kill our own process.
Deno should provide a way to allow a script to kill itself with a SIGINT without the need of the --allow-run flag.

We could ask the user for the run permissions berfor calling Deno.kill() but than it would be possible the user disagrees and the sigint event doesn't fires and there will be also no sandboxing mode.

I found also an issue with the SIGINT handler. The default SIGINT actions wan't be restored after calling sig.dispose() atm.
For example, if you exit following script with ctrl+c, ctrl+c is no longer working for the shell prompt and other programms like tail -f <file-name>.

import { Input } from "https://raw.githubusercontent.com/marcushultman/deno-cliffy/raise-signal/prompt/input.ts";

const sigint = Deno.signals.interrupt();

(async () => {
  for await (const _ of sigint) {
    sigint.dispose();
    Deno.exit(0);
  }
})();

const name: string = await Input.prompt("What's your github user name?");
console.log({ name });
sigint.dispose();

There is already a deno issue for this: denoland/deno#7164

Maybe we should first implement the callback solution and as soon as the above bug is fixed and there is a way to trigger the SIGINT event without the need of the --allow-run flag, we can implement the new version. We can do this without a breaking change. If a callback is passed to the prompt, the callback will be executed, otherwise the kill api is used.

What do you think?

from deno-cliffy.

Another issue is, Deno.kill() doesn't work on windows as mentioned in the documentation: This functionality currently only works on Linux and Mac OS.
https://doc.deno.land/builtin/unstable#Deno.kill

from deno-cliffy.

I think it's not unreasonable to want a way to raise a signal from within Deno itself, and I know the Deno core team are susceptible for ideas that improve stuff like this.

Another issue I found is also that cliffy prevents other tasks such as suspending the process (ctrl+z). Not sure what options there are.

from deno-cliffy.

I have opend an deno issue denoland/deno#8299. Let's see what they will say.

from deno-cliffy.

Cool, that would be even better! thanks @marcushultman

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