lock sessions

Added

• MQTT message on topic systemctl/hostname/lock-all-sessions
  instructs all sessions to activate screen locks
  (functionally equivalent to command loginctl lock-sessions)
• command line option --poweroff-delay-seconds (default: 4 seconds)

Changed

• docker image:
  • upgrade paho-mqtt to no longer suppress exceptions occuring in mqtt callbacks
    ( https://github.com/eclipse/paho.mqtt.python/blob/v1.5.1/ChangeLog.txt#L4 )
  • build stage: revert user after applying chown workaround for inter-stage copy

optionally disable TLS

Added

• command line option --mqtt-disable-tls

home assistant auto discovery

Added

• home assistant: enable automatic discovery for logind's PreparingForShutdown signal

Fixed

• fatal error on MQTT reconnect: tried to re-acquire shutdown inhibitor lock

report shutdown

Added

• forward logind's PreparingForShutdown to systemctl/hostname/preparing-for-shutdown
• log inhibitor locks when scheduling a shutdown

Fixed

• explicit timestamp type specification to avoid OverflowError: Python int too large to convert to C long

python3.5 compatibility

Fixed

• compatibility with python3.5:
  • replaced PEP526-style variable type hints with PEP484-compatible
  • fixed AttributeError due to unavailable MagicMock.assert_called_once
  • fixed TypeError when calling datetime.datetime.isoformat(datespec=…)

v0.1.0

Added

• MQTT message on topic systemctl/hostname/poweroff
  schedules a poweroff via systemd's dbus interface (4 seconds delay)