系统用户定时器不重复

Question

我试图以用户的身份每分钟运行一个systemd计时器，但在初始触发器之后不会重复。ffmpeg-timelapse.timer被配置为每分钟触发一次OnCalendar=minutely，而ffmpeg-timelapse.target是依赖服务的WantedBy。这使我可以轻松地添加/删除相机的时间流逝配置。

我遇到的问题是，当我启动ffmpeg-timelapse.timer单元时，它将安排在下一分钟，但不会重复。如果我用--now参数启动它，也会发生同样的问题。

ffmpeg-timelapse.timer

[Unit]
Description=Runs ffmpeg timelapse units every minute

[Timer]
OnCalendar=minutely
Unit=ffmpeg-timelapse.target

[Install]
WantedBy=timers.target

ffmpeg-timelapse.target

[Unit]
Description=Triggers the individual timelapse units for each camera.
StopWhenUnneeded=yes

照相机服务文件的示例。

ffmpeg-timelapse01-front-yard.service

[Unit]
Description=Front Yard Timelapse Unit
Wants=ffmpeg-timelapse.timer

[Service]
ExecStart=/bin/bash -ac '. camera01.conf ; exec ffmpeg-timelapse.sh'

[Install]
WantedBy=ffmpeg-timelapse.target

启用和启动服务会将其安排在下一分钟。

$ systemctl --user start ffmpeg-timelapse.timer 
$ systemctl --user list-timers 
NEXT                         LEFT     LAST PASSED UNIT                   ACTIVATES
Sat 2020-06-06 12:08:00 EDT  12s left n/a  n/a    ffmpeg-timelapse.timer ffmpeg-timelapse.target

1 timers listed.
Pass --all to see loaded but inactive timers, too.

然而，一旦它运行，它就不会第二次发射。

$ systemctl --user list-timers 
NEXT LEFT LAST                         PASSED      UNIT                   ACTIVATES
n/a  n/a  Sat 2020-06-06 12:08:42 EDT  1min 2s ago ffmpeg-timelapse.timer ffmpeg-timelapse.target

1 timers listed.
Pass --all to see loaded but inactive timers, too.

我正在运行的用户已经启用了linger。

$ loginctl show-user timelapse
UID=1000
GID=1000
Name=timelapse
Timestamp=Tue 2020-04-07 16:16:20 EDT
TimestampMonotonic=3291000946930
RuntimePath=/run/user/1000
Service=user@1000.service
Slice=user-1000.slice
Display=411982
State=active
Sessions=412092 411982 163185
IdleHint=no
IdleSinceHint=0
IdleSinceHintMonotonic=0
Linger=yes

在我看来，状态输出是正确的。

$ systemctl --user status ffmpeg-timelapse.target 
● ffmpeg-timelapse.target - Triggers the individual timelapse units for each camera.
   Loaded: loaded (/home/timelapse/.config/systemd/user/ffmpeg-timelapse.target; static; vendor preset: enabled)
   Active: active since Sat 2020-06-06 10:50:42 EDT; 1h 23min ago

$ systemctl --user status ffmpeg-timelapse.timer 
● ffmpeg-timelapse.timer - Runs ffmpeg timelapse units every 5 minutes
   Loaded: loaded (/home/timelapse/.config/systemd/user/ffmpeg-timelapse.timer; enabled; vendor preset: enabled)
   Active: active (running) since Sat 2020-06-06 12:13:25 EDT; 1min 1s ago

$ systemctl --user status ffmpeg-timelapse01-front-yard.service 
● ffmpeg-timelapse01-front-yard.service - Front Yard Timelapse Unit
   Loaded: loaded (/home/timelapse/.config/systemd/user/ffmpeg-timelapse01-front-yard.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Sat 2020-06-06 12:14:03 EDT; 35s ago
  Process: 4491 ExecStart=/bin/bash -ac '. camera01.conf ; exec ffmpeg-timelapse.sh'
 Main PID: 4491 (code=exited, status=0/SUCCESS)

下面是journalctl -xe的输出

Jun 06 12:13:25 srv01 systemd[26482]: Started Runs ffmpeg timelapse units every minute.
-- Subject: Unit UNIT has finished start-up
-- Defined-By: systemd
-- Support: https://www.debian.org/support
-- 
-- Unit UNIT has finished starting up.
-- 
-- The start-up result is done.
Jun 06 12:14:02 srv01 systemd[26482]: Started Front Yard Timelapse Unit.
-- Subject: Unit UNIT has finished start-up
-- Defined-By: systemd
-- Support: https://www.debian.org/support
-- 
-- Unit UNIT has finished starting up.
-- 
-- The start-up result is done.

Answer 1

我通过查看systemctl --user list-units --all ffmpeg*输出来确定这个问题。ffmpeg-timelapse.target仍在加载/活动/活动。在实际触发事件之前，ffmpeg-timelapse.timer将SUB设置为waiting。

UNIT                                LOAD   ACTIVE     SUB     JOB   DESCRIPTION                                             
ffmpeg-timelapse.target             loaded active     active  start Triggers the individual timelapse units for each camera.
ffmpeg-timelapse.timer              loaded active     running       Runs ffmpeg timelapse units every minute                

错误在于ffmpeg-timelapse.target的D7配置。我需要向其添加oneshot配置，否则目标单元将保持活动状态。

$ cat ffmpeg-timelapse.target
[Unit]
Type=oneshot
Description=Triggers the individual timelapse units for each camera.
StopWhenUnneeded=yes

现在它正在按预期的每一分钟重复。

$ systemctl --user list-timers 
NEXT                         LEFT     LAST                         PASSED UNIT                   ACTIVATES
Sat 2020-06-06 12:58:00 EDT  13s left Sat 2020-06-06 12:57:42 EDT  3s ago ffmpeg-timelapse.timer ffmpeg-timelapse.target

这就是部队现在的样子。

UNIT                                  LOAD   ACTIVE   SUB     DESCRIPTION                                             
ffmpeg-timelapse01-front-yard.service loaded inactive dead    Front Yard Timelapse Unit                               
ffmpeg-timelapse.target               loaded inactive dead    Triggers the individual timelapse units for each camera.
ffmpeg-timelapse.timer                loaded active   waiting Runs ffmpeg timelapse units every minute       

每个状态输出。

$ systemctl --user status ffmpeg-timelapse.timer
● ffmpeg-timelapse.timer - Runs ffmpeg timelapse units every minute
   Loaded: loaded (/home/timelapse/.config/systemd/user/ffmpeg-timelapse.timer; enabled; vendor preset: enabled)
   Active: active (waiting) since Sat 2020-06-06 12:59:30 EDT; 3min 43s ago

$ systemctl --user status ffmpeg-timelapse.target 
● ffmpeg-timelapse.target - Triggers the individual timelapse units for each camera.
   Loaded: loaded (/home/timelapse/.config/systemd/user/ffmpeg-timelapse.target; static; vendor preset: enabled)
   Active: inactive (dead) since Sat 2020-06-06 13:03:11 EDT; 6s ago

$ systemctl --user status ffmpeg-timelapse01-front-yard.service 
● ffmpeg-timelapse01-front-yard.service - Front Yard Timelapse Unit
   Loaded: loaded (/home/timelapse/.config/systemd/user/ffmpeg-timelapse01-front-yard.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Sat 2020-06-06 13:03:12 EDT; 8s ago
  Process: 9607 ExecStart=/bin/bash -ac '. camera01.conf ; exec ffmpeg-timelapse.sh'
 Main PID: 9607 (code=exited, status=0/SUCCESS)