jshwi / spall

Object-oriented commandline

Status: Archived

This repository has been archived and is no longer maintained

Use subprocess.run instead

spall

Object-oriented commandline

Install

$ pip install spall

Development

$ pip install spall

Usage

Import Subprocess from spall

>>> from spall import Subprocess

Instantiate individual executables

>>> cat = Subprocess("cat")
>>> echo = Subprocess("echo")
>>> fails = Subprocess("false")

Default is to return returncode and print stdout and stderr to console

>>> returncode = echo.call("Hello, world")
Hello, world
>>> returncode
0

Capture stdout with the capture keyword argument

>>> echo.call("Hello, world", capture=True)
0

Stdout is consumed by calling stdout() which returns a list

>>> echo.stdout()
['Hello, world']
>>> echo.stdout()
[]

Stdout is accrued until stdout() is called

>>> echo.call("Hello, world", capture=True)
0
>>> echo.call("Goodbye, world", capture=True)
0
>>> echo.stdout()
['Hello, world', 'Goodbye, world']
>>> echo.stdout()
[]

Pipe stdout to file with the file keyword argument

>>> import os
>>> import tempfile
>>>
>>> tmp = tempfile.NamedTemporaryFile(delete=False)
>>> echo.call("Hello, world", file=tmp.name)
0
>>> returncode = cat.call(tmp.name)
Hello, world
>>> returncode
0
>>> os.remove(tmp.name)

# redirect to /dev/null
>>> echo.call("Hello, world", file=os.devnull)
0

Failing command will raise a subprocess.CalledProcessError

>>> import contextlib
>>> from subprocess import CalledProcessError
>>>
>>> with contextlib.redirect_stderr(None):
...     try:
...         returncode = fails.call()
...     except CalledProcessError as err:
...         str(err)
"Command 'false' returned non-zero exit status 1."
>>> returncode
0

This, however, will not

>>> with contextlib.redirect_stderr(None):
...     fails.call(suppress=True)
1

All the keyword arguments above can be set as the default for the instantiated object

>>> echo = Subprocess("echo", capture=True)
>>> echo.call("Hello, world")
0
>>> echo.stdout()
['Hello, world']

Which can then be overridden

>>> returncode = echo.call("Hello, world", capture=False)
Hello, world
>>> returncode
0
>>> echo.stdout()
[]