check for updates and optionally upgrade packages via pip

pip-upgrade.py

#!/usr/bin/env python3

"""
check for updates and optionally upgrade packages via pip
"""

import os
import subprocess
import sys
import termios
import tty

_trace = lambda x: print(f'$ {x} [cwd={os.getcwd()}]', file=sys.stderr) or x
_kw = dict(shell=True, executable='/bin/bash')
_fmt = lambda a: _trace(' '.join(map(str, a)))
co = lambda *a: subprocess.check_output(_fmt(a), **_kw).decode('utf-8').strip()
cc = lambda *a: subprocess.check_call(_fmt(a), **_kw)

def getch():
    fd = sys.stdin.fileno()
    old = termios.tcgetattr(fd)
    try:
        tty.setraw(fd)
        val = sys.stdin.read(1).lower()
        if val == '\x03':
            sys.exit(1)
        else:
            return val
    except KeyboardInterrupt:
        sys.exit(1)
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old)

def pip_checks():
    checks = co('pip check || echo failed: $?').splitlines()
    failed = (checks[-1].startswith('failed: ')
              and len(checks[-1].split()) == 2
              and checks[-1].split()[1].isdigit())
    if failed:
        gits = co('pip freeze').splitlines()
        gits = {x.split('egg=')[-1]
                 .split('&')[0]
                 .replace('-', '_')
                for x in gits
                if 'egg=' in x}
        checks = {x.split()[0].replace('-', '_')
                  for x in checks[:-1]}
        return checks - gits
    else:
        return []

def pip_packages():
    pip = os.environ.get('pip', 'pip')
    for outdated in co(pip, 'list --outdated').splitlines()[2:]:
        try:
            name, old, new, kind, location = outdated.split()
            print('skip:', name, location)
            continue
        except ValueError:
            name, old, new, kind = outdated.split()
            print('upgrade:', name, old, '->', new)
            yield name

if __name__ == '__main__':
    packages = list(pip_packages())
    if packages:
        print('\nwould you like to proceed? y/n\n')
        assert getch() == 'y', 'abort'
        cc('pip install --upgrade', *packages)
    else:
        print('nothing to upgrade')

    for package in pip_checks():
        cc('pip install', package)

    checks = pip_checks()
    if checks:
        print('error: pip check failed', file=sys.stderr)
        print('\n'.join(checks))
        sys.exit(1)