Listen for pulse sink (device) state changes/updates.

pulse_dbus.py

import dbus
import os
from subprocess import call

def pulse_bus_address():
    if 'PULSE_DBUS_SERVER' in os.environ:
        address = os.environ['PULSE_DBUS_SERVER']
    else:
        bus = dbus.SessionBus()
        server_lookup = bus.get_object("org.PulseAudio1", "/org/pulseaudio/server_lookup1")
        address = server_lookup.Get("org.PulseAudio.ServerLookup1", "Address", dbus_interface="org.freedesktop.DBus.Properties")
        print(address)

    return address

# setup the glib mainloop
from dbus.mainloop.glib import DBusGMainLoop
DBusGMainLoop(set_as_default=True)
import gobject
loop = gobject.MainLoop()

pulse_bus = dbus.connection.Connection(pulse_bus_address())

#source1 = conn.get_object(object_path='/org/pulseaudio/core1/source6')
#source1_status = source1.Get('org.PulseAudio.Core1.Device', 'State', dbus_interface='org.freedesktop.DBus.Properties')
#print(source1_status)

pulse_core = pulse_bus.get_object(object_path='/org/pulseaudio/core1')
# pulse_core.ListenForSignal('org.PulseAudio.Core1.Device.StateUpdated', dbus.Array(signature='o'))
device_path = dbus.ObjectPath('/org/pulseaudio/core1/source6')
pulse_core.ListenForSignal('org.PulseAudio.Core1.Device.StateUpdated', [device_path])

DEVICE_RUNNING = 0
DEVICE_IDLE = 1
DEVICE_SUSPENDED = 2

def sig_handler(state):
    print("State changed to %s" % state)
    if state == DEVICE_RUNNING:
        print("Device is now running.")
    elif state == DEVICE_IDLE:
        print("Device is now idle.")
    elif state == DEVICE_SUSPENDED:
        print("Device is now suspended")
    # os.system("some_command with args")

pulse_bus.add_signal_receiver(sig_handler, 'StateUpdated')

loop.run()