mplugd

mplugd is a daemon that listens on events (e.g. xrandr, pulseaudio, ...) and executes user-defined actions on certain events. In contrast to other approaches, it listens to events by registering callback handlers instead of polling and parsing tool output, if possible. Event processing is done through a threaded producer/consumer architecture that can be extended by plugins to insert new event types. Actions can be defined using INI-like rule files or simple scripts.

A common use-case is automatic configuration of plugged-in devices like HDMI or DisplayPort displays including switch of audio output using pulseaudio. It also enables automatic actions on udev events without root privileges.

Requirements:

* For pulseaudio: dbus-python
* For X events: python-xlib (SVN revision > r160 or version > 0.15)
* For udev: pyudev
* For MIDI: pyportmidi

Examples of supported events

• New/removed Xorg displays
• Applications starting/ending audio output through PulseAudio
• PulseAudio port changes (e.g., plugged-in headphones)
• Udev events (e.g., new/removed devices or changed properties)
• MIDI events

Usage

1. Place your rules/scripts either into /etc/mplugd/action.d/, ~/mplugd/action.d/ or $SRCDIR/mplugd/action.d/. For examples, look into mplugd/examples/action.d/. Only files ending with .py or .rules are considered. You can look-up the values for your current system using mplugd -d.
2. Start mplugd. In case you manually installed python-xlib, you might need to add its location to PYTHONPATH before starting mplugd.

Rules example

• If DP-[0-9] gets connected to a display with ID "SAMC900", change default sink to the sink known as "HDA NVidia" card to ALSA and set the display configuration to automatic.

    [rule on_dpX_connect]
    on_type=OutputChangeNotify
    on_name*=DP-[0-9]
    on_connected=1
    on_crtc=0
    on_id_string=SAMC900
    true_stream_set_defaultsink_to_alsa.card_name=HDA NVidia
    true_exec=xrandr --output %event_name% --auto
  

• If a process with the binary mplayer starts audio output and if output DP-0 is connected, move this stream to sink "HDA NVidia", display a message in the console and send a notification to the desktop.

    [rule move_new_mplayer_to_intel]
    on_type=NewPlaybackStream
    on_application.process.binary=mplayer
    if_output_DP-0_connected=1
    true_stream_move_event_to_alsa.card_name=HDA NVidia
    true_exec=echo "moving mplayer to HDA NVidia"
    true_exec=notify-send "mplugd moves mplayer to HDA NVidia"
  

• If a device with a name matching dvb[0-9].frontend[0-9] appears and if block device sdc is present, start recording with mplayer

    [rule udev_example]
    on_type=UdevAdd
    on_name*=dvb[0-9].frontend[0-9]
    if_udev_device_block_name=sdc
    true_exec=echo "%event_type% device: %event_name%, starting record"
    true_exec_thread=mplayer dvb:// -dumpstream -dumpfile /mnt/sdc/dump.ts