EasyProcess is an easy to use python subprocess interface.

Links:

• home: https://github.com/ponty/EasyProcess
• PYPI: https://pypi.python.org/pypi/EasyProcess

Features:

• layer on top of subprocess module
• easy to start, stop programs
• easy to get standard output/error, return code of programs
• command can be list (preferred) or string (command string is converted to list using shlex.split)
• logging
• timeout
• shell is not supported
• pipes are not supported
• stdout/stderr is set only after the subprocess has finished
• stop() does not kill whole subprocess tree
• unicode support
• supported python versions: 3.6, 3.7, 3.8, 3.9
• Method chaining

Installation:

$ python3 -m pip install EasyProcess

Usage

Examples:

# easyprocess/examples/hello.py

from easyprocess import EasyProcess

cmd = ["echo", "hello"]
s = EasyProcess(cmd).call().stdout
print(s)

Output:

$ python3 -m easyprocess.examples.hello
hello

# easyprocess/examples/cmd.py

import sys

from easyprocess import EasyProcess

python = sys.executable

print("-- Run program, wait for it to complete, get stdout:")
s = EasyProcess([python, "-c", "print(3)"]).call().stdout
print(s)

print("-- Run program, wait for it to complete, get stderr:")
s = EasyProcess([python, "-c", "import sys;sys.stderr.write('4\\n')"]).call().stderr
print(s)

print("-- Run program, wait for it to complete, get return code:")
s = EasyProcess([python, "--version"]).call().return_code
print(s)

print("-- Run program, wait 1.5 second, stop it, get stdout:")
prog = """
import time
for i in range(10):
    print(i, flush=True)
    time.sleep(1)
"""
s = EasyProcess([python, "-c", prog]).start().sleep(1.5).stop().stdout
print(s)

Output:

$ python3 -m easyprocess.examples.cmd
-- Run program, wait for it to complete, get stdout:
3
-- Run program, wait for it to complete, get stderr:
4
-- Run program, wait for it to complete, get return code:
0
-- Run program, wait 1.5 second, stop it, get stdout:
0
1

Shell commands

Shell commands are not supported.

echo is a shell command on Windows (there is no echo.exe), but it is a program on Linux.

return_code

EasyProcess.return_code is None until EasyProcess.stop or EasyProcess.wait is called.

With

By using with statement the process is started and stopped automatically:

from easyprocess import EasyProcess
with EasyProcess('ping 127.0.0.1') as proc: # start()
    # communicate with proc
    pass
# stopped

Equivalent with:

from easyprocess import EasyProcess
proc = EasyProcess('ping 127.0.0.1').start()
try:
    # communicate with proc
    pass
finally:
    proc.stop()

Timeout

This was implemented with "daemon thread".

"The entire Python program exits when only daemon threads are left." https://docs.python.org/library/threading.html

# easyprocess/examples/timeout.py

import sys

from easyprocess import EasyProcess

python = sys.executable

prog = """
import time
for i in range(3):
    print(i, flush=True)
    time.sleep(1)
"""

print("-- no timeout")
stdout = EasyProcess([python, "-c", prog]).call().stdout
print(stdout)

print("-- timeout=1.5s")
stdout = EasyProcess([python, "-c", prog]).call(timeout=1.5).stdout
print(stdout)

print("-- timeout=50s")
stdout = EasyProcess([python, "-c", prog]).call(timeout=50).stdout
print(stdout)

Output:

$ python3 -m easyprocess.examples.timeout
-- no timeout
0
1
2
-- timeout=1.5s
0
1
-- timeout=50s
0
1
2