sctl

#!/usr/bin/env python
"""
sctl -- a systemctl wrapper that provides instant feedback
"""
import sys
import subprocess
import os
import time

NUM_LOG_LINES = 5
SHOW_DESCRIPTION = True
WAIT_FOR_ERROR_SECONDS = 0.2

EXPECT_ACTIVE = ("start", "reload", "restart")
EXPECT_INACTIVE = ("stop", "kill")
SUPPORTS_COLOR = ("xterm", "xterm-256color", "vt100", "vt102")


def run_verbose(cmd, unit):
    pre_status = get_status(unit)
    ret = subprocess.call(["systemctl"] + sys.argv[1:])
    if ret != 0:
        sys.exit(ret)
    time.sleep(WAIT_FOR_ERROR_SECONDS)
    post_status = get_status(unit)
    active = post_status["ActiveState"] == "active"
    failed = post_status["ActiveState"] == "failed"
    expect_active = cmd in EXPECT_ACTIVE
    ok = (not failed and active == expect_active)
    if SHOW_DESCRIPTION:
        print "%s %s: %s" % (cmd, pre_status["Id"], pre_status["Description"])
    print "%s %s (%s) -> %s (%s)" % (ok_fail(ok), pre_status["ActiveState"],
            pre_status["SubState"], post_status["ActiveState"],
            post_status["SubState"])
    if not ok:
        subprocess.call(["journalctl", "--quiet", "--lines",
                         str(NUM_LOG_LINES),
                         "_SYSTEMD_UNIT=%s" % pre_status["Id"]])
        sys.exit(1)


def ok_fail(some_bool):
    color = False
    if "TERM" in os.environ and os.environ["TERM"] in SUPPORTS_COLOR:
        color = True
    if some_bool and color:
        return "[ \033[92mOK\033[0m ]"
    elif some_bool:
        return "[ OK ]"
    elif color:
        return "[ \033[91mFAIL\033[0m ]"
    else:
        return "[ FAIL ]"


def get_status(unit):
    show = subprocess.check_output(["systemctl", "show", unit]).splitlines()
    show = map(lambda x: x.rsplit("=", 1), show)
    return dict(show)


def main():
    cmds = EXPECT_ACTIVE + EXPECT_INACTIVE
    for i in range(1, len(sys.argv)):
        if sys.argv[i] in cmds:
            run_verbose(sys.argv[i], sys.argv[i+1])
            return
    subprocess.call(["systemctl"] + sys.argv[1:])


if __name__ == "__main__":
    main()