bloopvolume.py

#!/usr/bin/env python

# BloopVolume - A command line volume control wth audible & visible
#               notification.


from argparse import ArgumentParser
from subprocess import call
from pulsectl import Pulse


NOTIFICATION_ID = '6788'
DEFAULT_STEP = 5
DEFAULT_SOUND_FILE = (
    '/usr/share/sounds/freedesktop/stereo/audio-volume-change.oga'
)


def call_subprocess(command):
    """
    Run an external program
    Args:
        command (list): list of arguments
    Returns:
        boolean for success or failure
    """

    try:
        result = call(command) == 0
    except FileNotFoundError:
        return False
    else:
        return result


def playsound(sink_index, soundfile):
    """
    Use external program 'pactl' to play a sound file
    Args:
        sink_index (int): sink to use for output
        soundfile (str): full path of file to play
    Returns:
        boolean for success or failure
    """

    # pactl first needs the sound file stored on the server
    command = [
        "pactl", "upload-sample", soundfile, "volume-change"
    ]
    if call_subprocess(command):
        # if the upload succeeds we can play the sound
        command = [
            "pactl", "play-sample", "volume-change", str(sink_index)
        ]
        return call_subprocess(command)
    else:
        return False


def get_active_sink(pulse):
    """
    Use pulsectl to select the active sound sink
    A sink list is retrieved and iterated, the last found as 'running' is used
    If no sink is 'running', we default to the first entry
    Args:
        pulse (Pulse): an instance of pulsectl.Pulse
    Returns:
        PulseSinkInfo: an instance of pulsectl.PuleSinkInfo
    """

    active_sink = None
    sink_list = pulse.sink_list()
    for sink in sink_list:
        if sink.state == 'running':
            active_sink = sink
    if active_sink is None:
        active_sink = sink_list[0]
    return active_sink


def send_notification(volume, mute):
    """
    Use external program 'dunstify' to display a notification
    Args:
        volume (int): the volume level to display
        mute (bool): mute status
    Returns:
        boolean for success or failure
    """

    command = [
        "dunstify",
        "-r", NOTIFICATION_ID,
        "-u", "normal"
    ]

    if mute:
        mute_symbol = '🔇'        # U+1F507
        command += [
            mute_symbol+" Volume: Mute",
            "-h", "int:value:0"  # show zero bar to keep notification size
        ]

    else:
        if volume < 0.3:
            volume_symbol = '🔈'  # U+1F508
        elif volume < 0.6:
            volume_symbol = '🔉'  # U+1F509
        else:
            volume_symbol = '🔊'  # U+1F50A
        command += [
            volume_symbol+" Volume: ",
            "-h",                 # pass hint and value to show progress bar
            "int:value:{:.0f}".format(volume*100)
        ]

    return call_subprocess(command)


def do_action(action, step=DEFAULT_STEP, sound_file=DEFAULT_SOUND_FILE):
    """
    Change volume of the active sound sink
    Args:
        action (str): options 'up', 'down' or 'mute'
        step (int): the amount to change the volume (up or down)
        sound_file (str): sound to play when notification is shown
    Returns:
        boolean for success or failure
    """

    with Pulse('volume-changer') as pulse:
        active_sink = get_active_sink(pulse)

        # round volume to nearest step value
        volume = step * round((active_sink.volume.value_flat * 100) / step)
        is_mute = (action == 'mute')

        if action == 'up':
            volume += step
            if volume > 150:
                volume = 150

        elif action == 'down':
            volume -= step
            if volume < 0:
                volume = 0

        elif action == 'mute':
            is_mute = not (active_sink.mute == 1)

        else:
            return False

        pulse.mute(active_sink, is_mute)
        pulse.volume_set_all_chans(active_sink, volume / 100)
        playsound(active_sink.index, sound_file)

    return send_notification(active_sink.volume.value_flat, is_mute)


def main():
    """
    entry point to parse command line arguments
    """
    parser = ArgumentParser(description='Pulseaudio volume controller')
    parser.add_argument('action', choices=['up', 'down', 'mute'])
    parser.add_argument('--step', dest='step', type=int, default=DEFAULT_STEP,
                        help='Percentage to change the volume')
    parser.add_argument('--sound', dest='sound', default=DEFAULT_SOUND_FILE,
                        help='Specify a sound file to play')

    args = parser.parse_args()
    do_action(args.action, args.step, args.sound)


if __name__ == "__main__":
    main()