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使用 systemd 服务的通知发送时冻结

tag-icon • tag-icon python systemd services notification
使用 systemd 服务的通知发送时冻结

我有以下 Python 脚本：

# /path/to/__main.py__

[..]

subprocess.call("DISPLAY=:0 dbus-launch /usr/bin/notify-send -i dialog-information \'foo\' \'bar\'", shell=True)

[..]

以及以下 .service 文件：

# /etc/systemd/system/notification.service

[Unit]
Description=Notification service

[Service]

# Run permission service
ExecStart=/usr/bin/python3 /path/to/__main__.py

# keep process after user logs off
RemainAfterExit=false

[Install]
WantedBy=default.target

当我呼叫/usr/bin/python3 /path/to/__main__.py我的终端时，会出现弹出窗口，并且没有任何冻结或任何情况。

但是，当我调用时sudo systemctl restart notification.service，系统（UI）会冻结约 20 秒（UI 中无法进行交互），然后出现弹出窗口。

问题是：为什么仅当通过 systemd 服务调用脚本时才会出现此问题？

进一步的输出（可能对调查有帮助）

这是输出sudo systemctl status notification.service：

user@host:~$ sudo systemctl status notification.service 
● notification.service - Notification service
   Loaded: loaded (/etc/systemd/system/notification.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2019-12-13 11:54:37 +08; 1h 41min ago
  Process: 18420 ExecStartPre=/bin/bash -c test $(/usr/bin/id -u) -eq 0 (code=exited, status=0/SUCCESS)
 Main PID: 18433 (python3)
    Tasks: 25 (limit: 4915)
   CGroup: /system.slicenotification.service
           ├─18433 /usr/bin/python3 /path/to/__main__.py
           ├─18583 /usr/bin/dbus-daemon --syslog --fork --print-pid 5 --print-address 7 --session
           ├─18588 /usr/lib/x86_64-linux-gnu/notify-osd
           ├─18715 /usr/lib/gvfs/gvfsd
           ├─18822 /usr/bin/dbus-daemon --syslog --fork --print-pid 5 --print-address 7 --session
           ├─18827 /usr/lib/x86_64-linux-gnu/notify-osd
           ├─18990 /usr/lib/gvfs/gvfsd
           ├─19055 /usr/bin/dbus-daemon --syslog --fork --print-pid 5 --print-address 7 --session
           ├─19059 /usr/lib/x86_64-linux-gnu/notify-osd
           └─19222 /usr/lib/gvfs/gvfsd

Dec 13 11:55:34 host notify-osd[18827]: dnd_is_screensaver_active(): Got error "The name org.gnome.ScreenSaver was not provided by any .service files"
Dec 13 11:55:34 host notify-osd[18827]: dnd_is_idle_inhibited(): got error "The name org.gnome.SessionManager was not provided by any .service files"
Dec 13 11:55:43 host dbus-daemon[19055]: [session uid=0 pid=19053] AppArmor D-Bus mediation is enabled
Dec 13 11:55:43 host dbus-daemon[19055]: [session uid=0 pid=19053] Activating service name='org.freedesktop.Notifications' requested by ':1.0' (uid=0 pid=19001 comm="/usr/bin/notify-send -i dialog-information UpdateR" label="unconfined")
Dec 13 11:56:01 host dbus-daemon[19055]: [session uid=0 pid=19053] Activating service name='org.gtk.vfs.Daemon' requested by ':1.1' (uid=0 pid=19059 comm="/usr/lib/x86_64-linux-gnu/notify-osd " label="unconfined")
Dec 13 11:56:01 host dbus-daemon[19055]: [session uid=0 pid=19053] Successfully activated service 'org.gtk.vfs.Daemon'
Dec 13 11:56:01 host org.gtk.vfs.Daemon[19055]: fuse: bad mount point `/root/.gvfs': Transport endpoint is not connected
Dec 13 11:56:01 host dbus-daemon[19055]: [session uid=0 pid=19053] Successfully activated service 'org.freedesktop.Notifications'
Dec 13 11:56:01 host notify-osd[19059]: dnd_is_screensaver_active(): Got error "The name org.gnome.ScreenSaver was not provided by any .service files"
Dec 13 11:56:01 host notify-osd[19059]: dnd_is_idle_inhibited(): got error "The name org.gnome.SessionManager was not provided by any .service files"
lines 1-28/28 (END)

答案1

好的，以下是我在从 root 的 crontab 运行脚本时修复此问题的方法。我仍在学习 Python，因此您需要根据需要转换此信息。

首先，我在 .bashrc 中添加了 root 的 xhost 权限：

xhost + SI:localuser:root > /dev/null

其次，我在root的crontab中添加了以下变量：

DISPLAY=":0.0"
XAUTHORITY="/home/me/.Xauthority"
XDG_RUNTIME_DIR="/run/user/1000"
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus

第三，我跑了每一个通知发送像我一样，是这样的：

su me -c '/usr/bin/notify-send "Weekly backup started - $(date +%Y-%m-%d) @ $(date +%H:%M:%S)"'

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