I have the following code:
const cp = require('child_process');
function spawnInstance () {
const c = cp.spawn('bash');
return command => {
return new Promise((resolve, reject) => {
c.stdout.on('data', d => resolve(String(d || 'empty stdout.\n')));
c.stderr.once('data', d => reject(String(d || 'empty stderr.\n')));
c.stdin.write(`echo "${command}" | bash;`);
c.stdin.write('\n');
});
};
}
(async () => {
const bash = spawnInstance();
console.log(await bash('ls'));
console.log(await bash('cd node_modules'));
console.log(await bash('ls'));
})()
.catch(e =>
console.error(e)
);
What I want to do is to reuse the same bash process, and get the stdout for each command that I run. Is there a way to do this, or do I need to start a new bash process for each command I run?
The problem is my code gets stuck on the cd node_modules command.
I don't think you can keep a bash process alive after a bash call and then re-enter the process with some new call. You can however run multiple bash commands after each other in the same process, e.g. by separating them with semicolons:
console.log(await bash('cd node_modules; ls'));
This article states that now there is an NPM package that allows for a persistent bash process.
The github url:
https://github.com/bitsofinfo/stateful-process-command-proxy
Quote from the him homepage:
This node module can be used for proxying long-lived bash process, windows console etc. It works and has been tested on both linux, os-x and windows hosts running the latest version of node.
Related
I'm tired of trying to solve this. First off, here is my deployment code
const { REST, Routes } = require('discord.js');
const fs = require('node:fs');
const { client_id } = require('./config.json')
const commands = [];
// Grab all the command files from the commands directory you created earlier
const commandFiles = fs.readdirSync('./slashCommands').filter(file => file.endsWith('.js'));
// Grab the SlashCommandBuilder#toJSON() output of each command's data for deployment
for (const file of commandFiles) {
const command = require(`./slashCommands/${file}`);
commands.push(command.data.toJSON());
}
// Construct and prepare an instance of the REST module
const rest = new REST({ version: '10' }).setToken(process.env.TOKEN);
// and deploy your commands!
(async () => {
try {
console.log(`Started refreshing ${commands.length} application (/) commands.`);
// The put method is used to fully refresh all commands in the guild with the current set
const data = await rest.put(
Routes.applicationCommands(client_id),
{ body: commands },
);
console.log(`Successfully reloaded ${data.length} application (/) commands.`);
} catch (error) {
// And of course, make sure you catch and log any errors!
console.error(error);
}
})();
It is supposed to get the command from the "slashCommand" folder. So I run 'node deploy-commands.js' and it works.
The problem is when I do the slash command '/ping', I get this error:
/home/runner/Nocinel/commands/ping.js:8
message.reply('🏓 **Ball is going over the net...**').then(m => { m.edit(`**🏓 Pong!\n:stopwatch: Uptime: ${Math.round(message.client.uptime / 60000)} minutes\n:sparkling_heart: Websocket Heartbeat: ${message.client.ws.ping}ms\n:round_pushpin: Rountrip Latency: ${m.createdTimestamp - message.createdTimestamp}ms**`) });
^
TypeError: m.edit is not a function
at /home/runner/Nocinel/commands/ping.js:8:73
repl process died unexpectedly: exit status 1
Now this error indicates that I am running a command from my "command" folder rather than my "slashCommand" folder. Which doesnt make sense because I explicitly coded it to only get commands from the "slash command folder"
I have restarted, deleted, waited for an hour, and tested it multiple times, it always gives the same disappointing result. I see absolutely nothing wrong with my code.
There is no problem with registring comannd (deploy-comannds.js is only registring comannds not using making them work). Problem have to be in your index.js you have to handle interaction comannds to your folder slashComannds. Registring comannds was sucessfull.
Documentation:
https://discordjs.guide/creating-your-bot/command-handling.html#loading-command-files
I'm writing a small utility tool for development to sync files over ssh. Normally I use ssh-agent set up in .bashrc file to connect to my dev server easily. I'd like to use exec in the script, but calling ssh-agent, every time I make a request sounds a bit inoptimal.
Is there a way I could execute the agent code once, and then have it working for all subsequent ssh requests I make? E.g. to spawn a shell process like a terminal emulator, and then use that process to execute a command, rather than invoking a new shell with each command.
The reason I want to do this, is I don't want to store the password in a config file.
You can create one ssh process, and then execute other commands using same process. Here is an example how to use it for bash. I'm creating a new bash shell and execugte the command ls -la and exit you can execute other commands.
const cp = require("child_process")
class MyShell {
constructor(command) {
this._spawned = cp.spawn(command, {
stdio: ["pipe", "pipe", "inherit"],
})
}
execute(command, callback) {
this._spawned.stdin.write(command + "\n")
this._spawned.stdout.on("data", (chunk) => {
if (callback) {
callback(chunk.toString())
}
})
}
}
var myShell = new MyShell("bash")
myShell.execute("ls -la", (result) => {
console.log(result)
})
myShell.execute("exit")
How to set what would otherwise be command-line arguments to node for a NodeJS process run from a launcher script? (The sh/CMD scripts npm places into node_modules/.bin.)
Plenty of NodeJS libraries / frameworks come with their own runner script, e.g. zeit/micro or moleculer that's usually executed from a npm script. This presents a problem in development, since in my case I want to do the equivalent of:
node --inspect -r ts-node/register -r dotenv-safe/config src/index.ts
(Except, of course, that does nothing since index.ts just exports something for the runner to pick up.)
Is there some "clean", preferably generic (i.e. not specific to a given framework's runner exposing those command line params) way that I'm missing to do this, ideally one that works as a npm script? The only thing that seems like it would work would be for e.g. micro:
node-dev -r ts-node/register ./node_modules/micro-dev/bin/micro-dev.js ./src/index.ts
which is kind of a mouthful from the Redundant Department of Redundancy Department and seems to obviate the point of having those launcher scripts. (It also won't work if the runner spawns other Node processes, but that's not a problem I'm actually having.) I'd like to not have to duplicate what the launcher scripts are already doing. I'm also aware of npx having --node-arg but npx is a whole another can of worms. (On Windows it's five seconds of startup time and one spurious error message just to run a script I already have installed; it also won't find an already installed package if it can't find its .cmd launcher script, e.g. when using Docker to run the dev environment. In short I'd rather not use npx for this.)
To clear up the confusion that seems to crop up in the comments: I want to override the command line parameters that affect the behaviour of the NodeJS runtime itself executing the runner script, not pass parameters to the script itself or to my code. That is, the options listed here: https://nodejs.org/api/cli.html
One option is to write a little wrapper script that uses the current process execPath to run child_process.execFile.
So the sample here is to be able to do
node --expose-http2 --zero-fill-buffers -r ./some-module.js ./test.js
but not actually write that out, instead have wrap.js inject the args:
node ./wrap.js ./test.js
I tested running this via npm in a package.json, and it works fine. I tested that it was working by having some-module.js stick a value on the global object, and then logging it in test.js.
Files involved:
wrap.js
const child_process = require('child_process');
const nodeArgs = ['--expose-http2', '--zero-fill-buffers', '-r', './some-module.js'];
const runTarget = process.argv[2];
console.log('going to wrap', runTarget, 'with', nodeArgs);
const finalArgs = nodeArgs.concat(runTarget).concat(process.argv.slice(2));
const child = child_process.execFile(
process.execPath,
finalArgs,
{
env: process.env,
cwd: process.cwd(),
stdio: 'inherit'
}, (e, stdout, stderr) => {
console.log('process completed');
if (e) {
process.emit('uncaughtException', e);
}
});
child.stdout.pipe(process.stdout);
child.stderr.pipe(process.stderr);
and
some-module.js
global.testval = 2;
and
test.js
console.log('hi guys, did the wrap work?', global.testval)
EDIT: So upon further thought, this solution really only satisfies wrapping the initial runner. But most tools, such as mocha re-spawn a sub process which would then lose this effect. To really get the job done, you can proxy each of the child process calls and somewhat enforce that calls to spawn and such also include your args.
I rewrote the code to reflect this. Here's a new setup:
package.json
{
"scripts": {
"test": "node -r ./ensure-wrapped.js node_modules/mocha/$(npm view mocha bin.mocha) ./test.js"
},
"dependencies": {
"mocha": "^5.1.0"
}
}
ensure-wrapped.js
const child_process = require('child_process');
// up here we can require code or do whatever we want;
global.testvalue = 'hi there'
const customParams = ['--zero-fill-buffers'];
// the code below injects itself into any child process's spawn/fork/exec calls
// so that it propogates
const matchNodeRe = /((:?\s|^|\/)node(:?(:?\.exe)|(:?\.js)|(:?\s+)|$))/;
const ensureWrappedLocation = __filename;
const injectArgsAndAddToParamsIfPathMatchesNode = (cmd, args, params) => {
params.unshift(...customParams);
params.unshift(args);
if (!Array.isArray(args)) { // all child_proc functions do [] optionally, then other params
args = []
params.unshift(args);
}
if (!matchNodeRe.test(cmd)) {
return params;
}
args.unshift(ensureWrappedLocation);
args.unshift('-r');
return params;
}
child_process._exec = child_process.exec;
child_process.exec = (cmd, ...params) => {
// replace node.js node.exe or /path/to/node to inject -r ensure-wrapped.js ...args..
// leaves alone exec if it isn't calling node
cmd = cmd.replace(matchNodeRe, '$1 -r ' + ensureWrappedLocation + ' ');
return child_process._exec(cmd, ...params)
}
child_process._execFile = child_process.execFile;
child_process.execFile = (path, args, ...params) => {
params = injectArgsAndAddToParamsIfPathMatchesNode(path, args, params);
return child_process._execFile(path, ...params)
}
child_process._execFileSync = child_process.execFileSync;
child_process.execFileSync = (path, args, ...params) => {
params = injectArgsAndAddToParamsIfPathMatchesNode(path, args, params);
return child_process._execFileSync(path, ...params);
}
child_process._execSync = child_process.execSync;
child_process.execSync = (cmd, ...params) => {
cmd = cmd.replace(matchNodeRe, '$1 -r ' + ensureWrappedLocation + ' ');
return child_process._exec(bin, ...args)
}
child_process._fork = child_process.fork;
child_process.fork = (module, args, ...params) => {
params = injectArgsAndAddToParamsIfPathMatchesNode(process.execPath, args, params);
return child_process._fork(module, ...params);
}
child_process._spawn = child_process.spawn;
child_process.spawn = (cmd, args, ...params) => {
params = injectArgsAndAddToParamsIfPathMatchesNode(cmd, args, params);
return child_process._spawn(cmd, ...params)
}
child_process._spawnSync = child_process.spawnSync;
child_process.spawnSync = (cmd, args, ...params) => {
params = injectArgsAndAddToParamsIfPathMatchesNode(cmd, args, params);
return child_process._spawnSync(cmd, ...params);
}
test.js
describe('test', () => {
it('should have the global value pulled in by some-module.js', (done) => {
if (global.testvalue !== 'hi there') {
done(new Error('test value was not globally set'))
}
return done();
})
})
Please never put code like this into a node module that's published. modifying the global library functions is pretty bad.
Everything passed in the command line AFTER your nodejs application is parsed into an array called process.argv. So...
node myapp.js foo bar hello 5000
In your nodejs code...
const args = process.argv;
console.log(args[0]);
console.log(args[1]);
console.log(args[2]);
console.log(args[3]);
would yield...
foo
bar
hello
5000
I didnt get clear scenario of your problem,but as your question title ,we can execute the any cmd command from nodejs using npm libraries like:
import Promise from 'bluebird'
import cmd from 'node-cmd'
const getAsync = Promise.promisify(cmd.get, { multiArgs: true, context: cmd })
getAsync('node -v').then(data => {
console.log('cmd data', data)
}).catch(err => {
console.log('cmd err', err)
})
I'm trying to launch a cordova command with a target device. I've tested the command and it works but when I try to generate it with my code, it ignores the equal sign and therefore won't run. This code does work just not with the addition of "--target='iPhone-7-Plus"
return new Promise((resolve, reject) => {
const executable = "ionic";
const arguments = [
"cordova",
buildOnly ? "build" : "run",
platform,
"--no-interactive",
"--verbose",
"--target='iPhone-7-Plus'"
].concat(releaseDev === "release" ? ["--prod", "--release"] : []);
console.log(executable, arguments.join(" "));
const child = spawn(executable, arguments, {
stdio: "inherit"
});
child.on("close", () => resolve());
child.on("error", err => reject(err));
});
What am I doing wrong here? Why would it be ignoring my equal sign only but the rest of the command gets added?
If I run cordova run ios --target='iPhone-7-Plus' the command will execute and launch the 7+ simulator without issues.
When spawning I had to add shell: true in order to use the default shell for my os. The shell that spawn was using would strip special characters.
const child = spawn(executable, arguments, {
stdio: "inherit",
shell: true
});
I would like to
C:\>ACommandThatGetsData > save.txt
But instead of parsing and saving the data in the console, I would like to do the above command with Node.JS
How to execute a shell command with Node.JS?
Use process.execPath():
process.execPath('/path/to/executable');
Update
I should have read the documentations better.
There is a Child Process Module which allows to execute a child process. You will need either child_process.exec, child_process.execFile or child_process.spawn. All of these are similar in use, but each has its own advantages. Which of them to use depends on your needs.
You could also try the node-cmd package:
const nodeCmd = require('node-cmd');
nodeCmd.get('dir', (err, data, stderr) => console.log(data));
On newer versions of the package, the syntax changed a little:
const nodeCmd = require('node-cmd');
nodeCmd.run('dir', (err, data, stderr) => console.log(data));
I know this question is old, but it helped me get to my solution using promises.
Also see: this question & answer
const util = require('util');
const exec = util.promisify(require('child_process').exec);
async function runCommand(command) {
const { stdout, stderr, error } = await exec(command);
if(stderr){console.error('stderr:', stderr);}
if(error){console.error('error:', error);}
return stdout;
}
async function myFunction () {
// your code here building the command you wish to execute ...
const command = 'dir';
const result = await runCommand(command);
console.log("_result", result);
// your code here processing the result ...
}
// just calling myFunction() here so it runs when the file is loaded
myFunction();