systemd oneshot 完成的是一次激活

from pathlib import Path
from tempfile import TemporaryDirectory
import subprocess

unit='xbcatm-oneshot-lab.service';path=Path('/run/systemd/system')/unit
assert not path.exists()
def ctl(*args,success=True):
    result=subprocess.run(['systemctl',*args],text=True,capture_output=True,timeout=10)
    assert (result.returncode==0)==success,(args,result.stderr)
    return result.stdout.strip()
def value(key):return ctl('show',unit,'-p',key,'--value')
with TemporaryDirectory(prefix='xbcatm-oneshot-',dir='/run') as directory:
    root=Path(directory);worker=root/'step.py';calls=root/'calls'
    worker.write_text("""from pathlib import Path
import sys
root=Path(__file__).parent
with (root/'calls').open('a') as output: output.write(sys.argv[1]+'\\n')
if sys.argv[1]=='second' and not (root/'healthy').exists(): sys.exit(7)
""")
    definition=f'''[Service]
Type=oneshot
RemainAfterExit=yes
TimeoutStartSec=3s
ExecStart=/usr/bin/python3 {worker} first
ExecStart=/usr/bin/python3 {worker} second
ExecStart=/usr/bin/python3 {worker} third
'''
    path.write_text(definition)
    try:
        subprocess.run(['systemd-analyze','verify',str(path)],check=True)
        ctl('daemon-reload');ctl('start',unit,success=False)
        assert calls.read_text().splitlines()==['first','second']
        assert value('Result')=='exit-code' and value('ExecMainStatus')=='7'
        print('second command fails; third command does not run')
        (root/'healthy').touch();ctl('reset-failed',unit);ctl('start',unit)
        assert calls.read_text().splitlines()==['first','second','first','second','third']
        assert (value('ActiveState'),value('SubState'),value('MainPID'))==('active','exited','0')
        before=calls.read_text();ctl('start',unit);assert calls.read_text()==before
        print('active/exited with PID 0; repeated start does not rerun')
        ctl('restart',unit)
        assert calls.read_text()==before+'first\nsecond\nthird\n'
        print('restart executes all commands again')
        ctl('stop',unit);path.write_text(definition.replace('RemainAfterExit=yes','RemainAfterExit=no'))
        ctl('daemon-reload');before=calls.read_text()
        for _ in range(2):
            ctl('start',unit)
            assert value('ActiveState')=='inactive' and value('Result')=='success'
        assert calls.read_text()==before+'first\nsecond\nthird\n'*2
        print('without RemainAfterExit: two starts, two successful executions')
    finally:
        ctl('stop',unit)
        if value('ActiveState')=='failed':ctl('reset-failed',unit)
        path.unlink();ctl('daemon-reload')