getguaka/process

A POSIX compliant library to run external applications in Swift.

Process

A posix-compliant library to run external applications and capture the standard out and standard error.

Why?

If you are developing cross platform command line apps, you need an easy way to run external applications. Process provides just that.

You can use Process with Guaka to create aweseome command line applications.

Usage

To execute a simple command you would do:

let result = Process.exec("ls -a -l")
print(result.stdout)

result type is RunResults, it contains:

• exitStatus: The command exit status
• stdout: The standard output for the command executed
• stderr: The standard error for the command executed

To customize the run function, you can pass in a customization block:

let result = Process.exec("ls -all") { settings in
    settings.dryRun = true
    settings.echo = [.Stdout, .Stderr, .Command]
    settings.interactive = false
}

settings is an instance of RunSettings, which contains the following variables:

• settings.dryRun: defaults to false. If false, the command is actually run. If true, the command is logged to the stdout paramter of result
• settings.echo: Customize the message printed to stdout, echo can contain any of the following:
  • EchoSettings.Stdout: The stdout returned from running the command will be printed to the terminal
  • EchoSettings.Stderr: The stderr returned from running the command will be printed to the terminal
  • EchoSettings.Command: The command executed will be printed to the terminal

Installation

You can install Process using Swift package manager (SPM) and carthage

Swift Package Manager

Add Process as dependency in your Package.swift

  import PackageDescription

  let package = Package(name: "YourPackage",
    dependencies: [
      .Package(url: "https://github.com/oarrabi/Process.git", majorVersion: 0),
    ]
  )

Carthage

github 'oarrabi/Process'

Tests

Tests can be found here.

Run them with

swift test

Contributing

Just send a PR! We don't bite ;)

process's Issues

Cannot get live output

In some cases I want to parse the output from a long running Process and selectively output it to the terminal, but it seems that is not currently supported? Any suggestions on where to look if I wanted to add it?

Can't get output

I can't get the results of executing curl https://swift.org/download/

Here is my code:

import Process

let result = Process.exec("curl https://swift.org/download/") 

print(result.stdout)

error: module 'Process' has no member named 'exec'

Whenever I import and try to use 'Process.exec("blah blah")' with Guaka I'm given:
error: module 'Process' has no member named 'exec'

All other "Batteries included" packages work fine.

Stray characters in stdout, stderr

When running commands with echo configuration I’m seeing stray characters in the console:

Stdout:
Login Succeeded
X�@Q��
Stderr:

I first noticed this also when reading from RunResults.stdout and trying to parse it. It looks like something is reading past EOF. I once got an entire extra line from another command in the output stream.