🏃 Run a block of text as a subprocess 🏃
Project description
runs has improved versions of call(), check_call(), check_output(), and run() from Python’s subprocess module that handle multiple commands and blocks of text, fix some defects, and add some features.
import runs
runs('''
ls
df -k # or perhaps -h?
echo 'Done and done'
''')
—
subprocess is essential but:
You can only run one command at a time
Commands to subprocess must be either a sequence of strings or a string, depending on whether shell=True or not
Results are returned by default as bytes and not strings
—
The runs functions let you run a block of text as a sequence of subprocess calls.
runs provides call-compatible replacements for the functions subprocess.call(), subprocess.check_call(), subprocess.check_output(), and subprocess.run()
Each replacement function takes a block of text, which is split into individual command lines, or a list of commands, and returns a list of values, one for each command. A block of text can contain line continuations, and comments, which are ignored.
The replacement functions also add optional logging, error handling, and lazy evaluation, and use UTF-8 encoding by default.
The module runs is callable - runs() is a synonym for runs.run().
EXAMPLES:
# ``runs()`` or ``runs.run()`` writes to stdout and stderr just as if you'd run
# the commands from the terminal
import runs
runs('echo "hello, world!"') # prints hello, world!
# runs.check_output() returns a list, one string result for each command
results = check_output('''
echo line one # Here's line one.
echo 'line " two "' # and two!
''')
assert results == ['line one', 'line " two "']
# Line continuations work too, either single or double
runs('''
ls -cail
# One command that takes many lines.
g++ -DDEBUG -O0 -g -std=c++17 -pthread -I ./include -lm -lstdc++ \
-Wall -Wextra -Wno-strict-aliasing -Wpedantic \\
-MMD -MP -MF -c src/tests.cpp -o build/./src/tests.cpp.o
echo DONE
''')
NOTES:
Exactly like subprocess, runs differs from the shell in a few ways, so you can’t just paste your shell scripts in:
Redirection doesn’t work.
result = runs.check_output('echo foo > bar.txt')
assert result == ['foo > bar.txt\n']
Pipes don’t work.
result = runs.check_output('echo foo | wc')
assert result == ['foo | wc \n']
Environment variables are not expanded in command lines
result = runs.check_output('echo $FOO', env={'FOO': 'bah!'})
assert result == ['$FOO\n']
Environment variables are exported to the subprocess, absolutely, but no environment variable expension happens on command lines.
API
runs()
runs(
commands,
*args,
iterate=False,
encoding='utf8',
on_exception=None,
echo=False,
**kwargs,
)
Call subprocess.run() on each command. Return a list of subprocess.CompletedProcess instances. See the help for subprocess.run() for more information.
- Arguments:
- commands:
A string, which gets split into lines on line endings, or a list of strings.
- args:
Positional arguments to subprocess.run() (but prefer keyword arguments!)
- on_exception:
If on_exception is False, the default, exceptions from subprocess.run() are raised as usual.
If on_exception is True, they are ignored.
If on_exception is a callable, the line that caused the exception is passed to it.
If on_exception is a string, the line causing the exception is printed, prefixed with that string.
- echo:
If echo is False, the default, then commands are silently executed. If echo is True, commands are printed prefixed with $ If echo is a string, commands are printed prefixed with that string If echo is callable, then each command is passed to it.
- iterate:
If iterate is False, the default, then a list of results is returned.
Otherwise an iterator of results which is returned, allowing for lazy evaluation.
- encoding:
Like the argument to subprocess.run(), except the default is 'utf8'
- kwargs:
Named arguments passed on to subprocess.run()
runs.call()
runs.call(
commands,
*args,
iterate=False,
encoding='utf8',
on_exception=None,
echo=False,
**kwargs,
)
Call subprocess.call() on each command. Return a list of integer returncodes, one for each command executed. See the help for subprocess.call() for more information.
- Arguments:
- commands:
A string, which gets split into lines on line endings, or a list of strings.
- args:
Positional arguments to subprocess.call() (but prefer keyword arguments!)
- on_exception:
If on_exception is False, the default, exceptions from subprocess.call() are raised as usual.
If on_exception is True, they are ignored.
If on_exception is a callable, the line that caused the exception is passed to it.
If on_exception is a string, the line causing the exception is printed, prefixed with that string.
- echo:
If echo is False, the default, then commands are silently executed. If echo is True, commands are printed prefixed with $ If echo is a string, commands are printed prefixed with that string If echo is callable, then each command is passed to it.
- iterate:
If iterate is False, the default, then a list of results is returned.
Otherwise an iterator of results which is returned, allowing for lazy evaluation.
- encoding:
Like the argument to subprocess.call(), except the default is 'utf8'
- kwargs:
Named arguments passed on to subprocess.call()
runs.check_call()
runs.check_call(
commands,
*args,
iterate=False,
encoding='utf8',
on_exception=None,
echo=False,
**kwargs,
)
Call subprocess.check_call() on each command. If any command has a non-zero returncode, raise subprocess.CallProcessError.
See the help for subprocess.check_call() for more information.
- Arguments:
- commands:
A string, which gets split into lines on line endings, or a list of strings.
- args:
Positional arguments to subprocess.check_call() (but prefer keyword arguments!)
- on_exception:
If on_exception is False, the default, exceptions from subprocess.check_call() are raised as usual.
If on_exception is True, they are ignored.
If on_exception is a callable, the line that caused the exception is passed to it.
If on_exception is a string, the line causing the exception is printed, prefixed with that string.
- echo:
If echo is False, the default, then commands are silently executed. If echo is True, commands are printed prefixed with $ If echo is a string, commands are printed prefixed with that string If echo is callable, then each command is passed to it.
- iterate:
If iterate is False, the default, then a list of results is returned.
Otherwise an iterator of results which is returned, allowing for lazy evaluation.
- encoding:
Like the argument to subprocess.check_call(), except the default is 'utf8'
- kwargs:
Named arguments passed on to subprocess.check_call()
runs.check_output()
runs.check_output(
commands,
*args,
iterate=False,
encoding='utf8',
on_exception=None,
echo=False,
**kwargs,
)
Call subprocess.check_output() on each command. If a command has a non-zero exit code, raise a subprocess.CallProcessError. Otherwise, return the results as a list of strings, one for each command. See the help for subprocess.check_output() for more information.
- Arguments:
- commands:
A string, which gets split into lines on line endings, or a list of strings.
- args:
Positional arguments to subprocess.check_output() (but prefer keyword arguments!)
- on_exception:
If on_exception is False, the default, exceptions from subprocess.check_output() are raised as usual.
If on_exception is True, they are ignored.
If on_exception is a callable, the line that caused the exception is passed to it.
If on_exception is a string, the line causing the exception is printed, prefixed with that string.
- echo:
If echo is False, the default, then commands are silently executed. If echo is True, commands are printed prefixed with $ If echo is a string, commands are printed prefixed with that string If echo is callable, then each command is passed to it.
- iterate:
If iterate is False, the default, then a list of results is returned.
Otherwise an iterator of results which is returned, allowing for lazy evaluation.
- encoding:
Like the argument to subprocess.check_output(), except the default is 'utf8'
- kwargs:
Named arguments passed on to subprocess.check_output()
(automatically generated by doks on 2020-12-16T13:48:26.579866)
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