EasyProcess is a simple 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: 3.7, 3.8, 3.9, 3.10, 3.11, 3.12
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:

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

Full example:

# easyprocess/examples/with.py
import os
import sys
import urllib.request
from os.path import abspath, dirname
from time import sleep
from easyprocess import EasyProcess
webserver_code = """
from http.server import HTTPServer, CGIHTTPRequestHandler
srv = HTTPServer(server_address=("", 8080), RequestHandlerClass=CGIHTTPRequestHandler)
srv.serve_forever()
"""
os.chdir(dirname(abspath(__file__)))
with EasyProcess([sys.executable, "-c", webserver_code]):
    sleep(2)  # wait for server
    html = urllib.request.urlopen("http://localhost:8080").read().decode("utf-8")
print(html)

Output:

$ python3 -m easyprocess.examples.with
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Directory listing for /</title>
</head>
<body>
<h1>Directory listing for /</h1>
<hr>
<ul>
<li><a href="__init__.py">__init__.py</a></li>
<li><a href="__pycache__/">__pycache__/</a></li>
<li><a href="cmd.py">cmd.py</a></li>
<li><a href="hello.py">hello.py</a></li>
<li><a href="log.py">log.py</a></li>
<li><a href="timeout.py">timeout.py</a></li>
<li><a href="ver.py">ver.py</a></li>
<li><a href="with.py">with.py</a></li>
</ul>
<hr>
</body>
</html>

Timeout

# 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