RoXuS•15mo ago

Usage of Deno.Command?

Hey guys we use Deno.run to launch shell cmd and pipe the result to log. But Deno.run will be deprecated and I am not able to write a good equivalent with Deno.Command, do you have a suggestion? Here is my simple Deno.run:

import * as log from "https://deno.land/std@0.204.0/log/mod.ts";

export default async (
  cmd: string,
  args: Array<string>,
  cwd?: string,
  dry = false,
) => {
  const logger = log.getLogger();
  if (dry) {
    logger.debug([`dry ${cwd} ${cmd}`, ...args].join(" "));
    return Promise.resolve("");
  }
  logger.debug([cwd, cmd, ...args].join(" "));
  const p = Deno.run({
    cmd: [cmd, ...args],
    cwd,
    stdout: "piped",
    stderr: "piped",
  });

  const [stderr, stdout, status] = await Promise.all([
    p.stderrOutput(),
    p.output(),
    p.status(),
  ]);

  p.close();

  if (status.code === 0) {
    return new TextDecoder().decode(stdout);
  } else {
    const errorString = new TextDecoder().decode(stderr);
    throw new Error(
      `\n${Deno.cwd()} ${cwd} ${cmd} ${args} ${errorString}`,
    );
  }
};

import * as log from "https://deno.land/std@0.204.0/log/mod.ts";

export default async (
  cmd: string,
  args: Array<string>,
  cwd?: string,
  dry = false,
) => {
  const logger = log.getLogger();
  if (dry) {
    logger.debug([`dry ${cwd} ${cmd}`, ...args].join(" "));
    return Promise.resolve("");
  }
  logger.debug([cwd, cmd, ...args].join(" "));
  const p = Deno.run({
    cmd: [cmd, ...args],
    cwd,
    stdout: "piped",
    stderr: "piped",
  });

  const [stderr, stdout, status] = await Promise.all([
    p.stderrOutput(),
    p.output(),
    p.status(),
  ]);

  p.close();

  if (status.code === 0) {
    return new TextDecoder().decode(stdout);
  } else {
    const errorString = new TextDecoder().decode(stderr);
    throw new Error(
      `\n${Deno.cwd()} ${cwd} ${cmd} ${args} ${errorString}`,
    );
  }
};

5 Replies

RoXuSOP•15mo ago

if I use the example of Deno.Command, something like

const command = new Deno.Command(Deno.execPath(), {
  args: [
    "eval",
    "console.log('hello'); console.error('world')",
  ],
});
const { code, stdout, stderr } = await command.output();

const command = new Deno.Command(Deno.execPath(), {
  args: [
    "eval",
    "console.log('hello'); console.error('world')",
  ],
});
const { code, stdout, stderr } = await command.output();

It works but I have the log after total execution, I would like the log as execution progresses

Deno AI Helper•15mo ago

Sure, I can help you with that. The Deno.Command class is used to create a child process. It has methods like output(), outputSync(), and spawn() to execute the command and collect its output. Here's how you can rewrite your function using Deno.Command:

import * as log from "https://deno.land/std@0.204.0/log/mod.ts";

export default async (
  cmd: string,
  args: Array<string>,
  cwd?: string,
  dry = false,
) => {
  const logger = log.getLogger();
  if (dry) {
    logger.debug([`dry ${cwd} ${cmd}`, ...args].join(" "));
    return Promise.resolve("");
  }
  logger.debug([cwd, cmd, ...args].join(" "));
  
  const command = new Deno.Command(cmd, {
    args,
    cwd,
    stdin: "piped",
    stdout: "piped",
    stderr: "piped",
  });

  const { code, stdout, stderr } = await command.output();

  if (code === 0) {
    return new TextDecoder().decode(stdout);
  } else {
    const errorString = new TextDecoder().decode(stderr);
    throw new Error(
      `\n${Deno.cwd()} ${cwd} ${cmd} ${args} ${errorString}`,
    );
  }
};

import * as log from "https://deno.land/std@0.204.0/log/mod.ts";

export default async (
  cmd: string,
  args: Array<string>,
  cwd?: string,
  dry = false,
) => {
  const logger = log.getLogger();
  if (dry) {
    logger.debug([`dry ${cwd} ${cmd}`, ...args].join(" "));
    return Promise.resolve("");
  }
  logger.debug([cwd, cmd, ...args].join(" "));
  
  const command = new Deno.Command(cmd, {
    args,
    cwd,
    stdin: "piped",
    stdout: "piped",
    stderr: "piped",
  });

  const { code, stdout, stderr } = await command.output();

  if (code === 0) {
    return new TextDecoder().decode(stdout);
  } else {
    const errorString = new TextDecoder().decode(stderr);
    throw new Error(
      `\n${Deno.cwd()} ${cwd} ${cmd} ${args} ${errorString}`,
    );
  }
};

Please note that the Deno.Command API is still unstable, so you need to run your script with the --unstable flag. Also, the Deno.Command class does not have a cwd option, so you might need to adjust your command and arguments to account for the working directory.

Helpful Links: Deno.Command | Runtime APIs | Deno Subprocesses: Collecting Output - Deno by Example Deno 1.28: Featuring 1.3 Million New Modules Deno.Command | Runtime APIs | Deno

RoXuSOP•15mo ago

No u can't use command.output with stdin to piped

ry•15mo ago

@RoXuS You would use command.spawn()

RoXuSOP•15mo ago

yes finally I have try :

import { log } from "../deps.ts";

export default async (
  cmd: string,
  args: Array<string>,
  cwd?: string,
  dry = false,
) => {
  const logger = log.getLogger();
  if (dry) {
    logger.debug([`dry ${cwd} ${cmd}`, ...args].join(" "));
    return Promise.resolve("");
  }
  logger.debug([cwd, cmd, ...args].join(" "));
  const p = new Deno.Command(cmd, {
    args,
    cwd,
    stdin: "piped",
    stdout: "piped",
  });

  const child = p.spawn();

  const status = await child.status;

  if (status.code === 0) {
    return Promise.resolve();
  } else {
    throw new Error(
      `\n${Deno.cwd()} ${cwd} ${cmd} ${args}`,
    );
  }
};

import { log } from "../deps.ts";

export default async (
  cmd: string,
  args: Array<string>,
  cwd?: string,
  dry = false,
) => {
  const logger = log.getLogger();
  if (dry) {
    logger.debug([`dry ${cwd} ${cmd}`, ...args].join(" "));
    return Promise.resolve("");
  }
  logger.debug([cwd, cmd, ...args].join(" "));
  const p = new Deno.Command(cmd, {
    args,
    cwd,
    stdin: "piped",
    stdout: "piped",
  });

  const child = p.spawn();

  const status = await child.status;

  if (status.code === 0) {
    return Promise.resolve();
  } else {
    throw new Error(
      `\n${Deno.cwd()} ${cwd} ${cmd} ${args}`,
    );
  }
};

And it is ok, I don't understand why the result are piped to the log but it works haha thx for your response!

Usage of Deno.Command?

Did you find this page helpful?