feat(linux): add sensors for tracking shutdown/suspend state via D-Bus

internal/agent/device_linux.go

@@ -35,6 +35,7 @@ func sensorWorkers() []func(context.Context, device.SensorTracker) {
 		linux.ScreenLockUpdater,
 		linux.UsersUpdater,
 		linux.Versions,
-		linux.TempUpdater)
+		linux.TempUpdater,
+		linux.PowerMgmtUpdater)
 	return workers
 }

internal/linux/powerMgmtSensor.go

@@ -0,0 +1,87 @@
+// Copyright (c) 2023 Joshua Rich <[email protected]>
+//
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+package linux
+
+import (
+	"context"
+
+	"github.com/godbus/dbus/v5"
+	"github.com/joshuar/go-hass-agent/internal/device"
+	"github.com/joshuar/go-hass-agent/internal/hass/sensor"
+	"github.com/rs/zerolog/log"
+)
+
+type powerMgmtSensor struct {
+	linuxSensor
+}
+
+func (s *powerMgmtSensor) SensorType() sensor.SensorType {
+	return sensor.TypeBinary
+}
+
+func (s *powerMgmtSensor) Icon() string {
+	if isTrue, ok := s.value.(bool); ok && isTrue {
+		switch s.sensorType {
+		case isSuspended:
+			return "mdi:power-sleep"
+		case isShutdown:
+			return "mdi:power-off"
+		}
+	}
+	return "mdi:power-on"
+}
+
+func PowerMgmtUpdater(ctx context.Context, tracker device.SensorTracker) {
+	r := NewBusRequest(ctx, SystemBus).
+		Path("/org/freedesktop/login1").
+		Match([]dbus.MatchOption{
+			dbus.WithMatchInterface("org.freedesktop.login1.Manager"),
+		})
+
+	err := NewBusRequest(ctx, SystemBus).
+		Path("/org/freedesktop/login1").
+		Match([]dbus.MatchOption{
+			dbus.WithMatchInterface("org.freedesktop.login1.Manager"),
+		}).Event("org.freedesktop.login1.Manager.PrepareForSleep").
+		Handler(func(s *dbus.Signal) {
+			if s.Name != "org.freedesktop.login1.Manager.PrepareForSleep" {
+				return
+			}
+			if err := tracker.UpdateSensors(ctx, newPowerMgmtSensor(isSuspended, s.Body[0].(bool))); err != nil {
+				log.Error().Err(err).Msg("Could not update suspended sensor.")
+			}
+		}).
+		AddWatch(ctx)
+	if err != nil {
+		log.Warn().Err(err).
+			Msg("Failed to create user D-Bus watch. Will not track suspend state.")
+	}
+	err = r.Event("org.freedesktop.login1.Manager.PrepareForShutdown").
+		Handler(func(s *dbus.Signal) {
+			if s.Name != "org.freedesktop.login1.Manager.PrepareForShutdown" {
+				return
+			}
+			if err = tracker.UpdateSensors(ctx, newPowerMgmtSensor(isShutdown, s.Body[0].(bool))); err != nil {
+				log.Error().Err(err).Msg("Could not update powered off sensor.")
+			}
+		}).
+		AddWatch(ctx)
+	if err != nil {
+		log.Warn().Err(err).
+			Msg("Failed to create user D-Bus watch. Will not track powered off state.")
+	}
+}
+
+func newPowerMgmtSensor(t sensorType, v interface{}) *powerMgmtSensor {
+	return &powerMgmtSensor{
+		linuxSensor: linuxSensor{
+			value:      v,
+			sensorType: t,
+			source:     srcDbus,
+			diagnostic: true,
+		},
+	}
+}

internal/linux/sensorType.go

@@ -55,6 +55,8 @@ const (
 	version                                 // Distribution Version
 	users                                   // Current Users
 	deviceTemp                              // Temperature
+	isSuspended                             // Suspended
+	isShutdown                              // Powered Off
 )
 
 // sensorType represents the unique type of sensor data being reported. Every