我用Python编写了一个小守护进程:
#!/usr/bin/python3
import time
import click
import daemonocle
from daemonocle.cli import DaemonCLI
@click.command(cls=DaemonCLI, daemon_params={'pidfile': '/var/run/daemon.pid'})
def main():
while True:
time.sleep(3)
if __name__ == '__main__':
main()
它的效果很好。如果我做以下我得到一个良好的退出状态0
$ sudo ./daemon start
Starting daemon ... OK
$ echo $?
0
然后我写了一个systemd
服务文件:
[Unit]
SourcePath=/home/pi/daemon/daemon
Description=My First Daemon
Before=multi-user.target
After=mosquitto.target
[Service]
Type=forking
PIDFile=/var/run/daemon.pid
Restart=no
ExecStart=/home/pi/daemon/daemon start
ExecStop=/home/pi/daemon/daemon stop
ExecReload=/home/pi/daemon/daemon reload
如果我尝试用systemctl
运行我的守护进程,命令仍会阻塞:
$ sudo systemctl start daemon
^C
$ sudo systemctl status daemon
? daemon.service - XEMWAY Demo Service
Loaded: loaded (/home/pi/daemon/daemon; static; vendor preset: enabled)
Active: activating (start) since Wed 2019-02-13 13:47:40 GMT; 12s ago
Process: 13044 ExecStop=/home/pi/daemon/daemon stop (code=exited, status=0/SUCCESS)
Main PID: 12304 (code=exited, status=143); Control PID: 13079 (daemon)
CGroup: /system.slice/daemon.service
+-13079 /usr/bin/python3 /home/pi/daemon/daemon start
+-13081 /usr/bin/python3 /home/pi/daemon/daemon start
一分钟后,systemd
说:
2月13日13:49:10 raspberrypi systemd [1]:daemon.service:单位进入失败状态。 2月13日13:49:10 raspberrypi systemd [1]:daemon.service:结果'超时'失败。
这有什么问题?
问题是你的服务是由它自己创建守护进程的,而systemd并不知道它。它只是一个简单的程序,在systemd的少量时间后运行并退出。而不是forking
你想使用simple
:
Type=simple
Systemd仍然会将您的进程作为守护进程跟踪,因为它知道它的pid:
systemctl status test2.service
* test2.service - My First Daemon
Loaded: loaded (/tmp/a.py; static; vendor preset: disabled)
Active: active (running) since Wed 2019-02-13 16:06:27 EET; 5s ago
Main PID: 18104 (python)
Tasks: 2 (limit: 4915)
Memory: 10.1M
CGroup: /system.slice/test2.service
|-18104 /usr/bin/python /tmp/a.py start
`-18115 /usr/bin/python /tmp/a.py start