Asyncproc

Asynchronous child process spawner, with high flexibility on its stream handling for input/output/erro handles. It was specially built to close the gap from shell language and nim.

Features

• Developped with interactivness in mind (you can easily mixed user input/output, and automated input)
• Developped with remote execution in mind: running a command remotly (ssh), on a chrooted system or locally should need to modify only one line of the whole code
• Concise: even complex configurations can be one-lined (see also implicitAsync macro to avoid repetition of await keyword)
• Flexible and straightforward. All options can be tweaked using a flag :
  • Can be easily put in true foreground, keeping the ability to terminal process control (ctrl+c, ctrl+z in linux) and to have shell history
  • Can capture input/output/output error streams, even when put on foreground
  • Can separate error stream or keep it merged with preserving writing order
  • Have other facilities to help logging, printing what is done, managing process environment, making daemons (command surviving its parent), etc.
• Powerful streams manipulation thanks to asyncio library

Getting started

Installation

nimble install asyncproc

Example usage (linux)

import std/options
import asyncproc
import asyncio/asyncstring

const myFile = "myfile.txt"

proc main() {.async.} =
  ## Create a file
  await sh.runDiscard(@["touch", myFile])

  ## Check the file has been created
  echo true == (await sh.runCheck(@["test", "-f", myFile]))

  ## List its content
  echo await sh.runGetOutput(@["cat", myFile])

  ## List all files in current directory
  echo await sh.runGetLines(@["ls"])

  ## Write to the file
  await sh.runDiscard(@["dd", "of=" & myFile], input = some AsyncString.new("Hello world\n").AsyncIoBase, toRemove = { Interactive })

waitFor main()

To go further

Full docs can be browsered here

Please see tests to see more usages.

You can also see shellcmd source code to view what you can do and how with asyncproc api

Before using it

• Unstable API : How you use asyncproc is susceptible to change. It could occur to serve shellcmd library development. If you want to use as a pre-release, please only install and use a tagged version and don't update frequently until v1.0.0 is reached. Releases with breaking change will make the second number of semver be updated (eg: v0.1.1 to v0.2.0)
• Only available in unix. Support for windows is not in the priority list
• Only support one async backend: std/asyncdispatch (This project is not related to chronos/asyncproc)
• Don't expect more performance. Although development is focused to avoid unecessary or costly operations, asynchronous code has a large overhead and is usually far slower than sync one in many situations. Furthermore concisness and flexibilty are proritized