Get Battery Information in darwin

battery_darwin.go

package main

import (
	"encoding/json"
	"fmt"
	"os/exec"

	plist "howett.net/plist"
)

type PowerTelemetry struct {
	AccumulatedAdapterEfficiencyLoss      int `json:"accumulated_adapter_efficiency_loss"`
	AccumulatedSystemEnergyConsumed       int `json:"accumulated_system_energy_consumed"`
	AccumulatedSystemLoad                 int `json:"accumulated_system_load"`
	AccumulatedSystemPowerIn              int `json:"accumulated_system_power_in"`
	AccumulatedWallEnergyEstimate         int `json:"accumulated_wall_energy_estimate"`
	AdapterEfficiencyLoss                 int `json:"adapter_efficiency_loss"`
	AdapterEfficiencyLossAccumulatorCount int `json:"adapter_efficiency_loss_accumulator_count"`
	SystemEnergyConsumed                  int `json:"system_energy_consumed"`
	SystemLoad                            int `json:"system_load"`
	SystemLoadAccumulatorCount            int `json:"system_load_accumulator_count"`
	SystemPowerIn                         int `json:"system_power_in"`
	SystemPowerInAccumulatorCount         int `json:"system_power_in_accumulator_count"`
	WallEnergyEstimate                    int `json:"wall_energy_estimate"`
}

type battery struct {
	AdapterInfo               int         `plist:"AdapterInfo" json:"adapter"`
	Amperage                  int         `plist:"Amperage" json:"amperage"`
	BatteryInstalled          bool        `plist:"BatteryInstalled" json:"battery_installed"`
	BatteryInvalidWakeSeconds int         `plist:"BatteryInvalidWakeSeconds" json:"battery_invalid_wake_seconds"`
	BootPathUpdated           int         `plist:"BootPathUpdated" json:"boot_bath_updated"`
	CurrentCapacity           int         `plist:"CurrentCapacity" json:"current_capacity"`
	CycleCount                int         `plist:"CycleCount" json:"cycle_capacity"`
	ExternalChargeCapable     bool        `plist:"ExternalChargeCapable" json:"external_charge_capable"`
	ExternalConnected         bool        `plist:"ExternalConnected" json:"external_connected"`
	FullPathUpdated           int         `plist:"FullPathUpdated" json:"full_path_updated"`
	IOGeneralInterest         string      `plist:"IOGeneralInterest" json:"io_general_interest"`
	IOObjectClass             string      `plist:"IOObjectClass" json:"io_object_class"`
	IOObjectRetainCount       int         `plist:"IOObjectRetainCount" json:"io_object_retain_count"`
	IORegistryEntryID         int         `plist:"IORegistryEntryID" json:"io_registry_entry_id"`
	IORegistryEntryName       string      `plist:"IORegistryEntryName" json:"io_registry_entry_name"`
	IOReportLegend            interface{} `plist:"IOReportLegend" json:"io_report_legend"`
	IOReportLegendPublic      bool        `plist:"IOReportLegendPublic" json:"io_report_legend_public"`
	IOServiceBusyState        int         `plist:"IOServiceBusyState" json:"io_service_busy_state"`
	IOServiceBusyTime         int         `plist:"IOServiceBusyTime" json:"io_service_busy_time"`
	IOServiceState            int         `plist:"IOServiceState" json:"io_service_state"`
	IsCharging                bool        `plist:"IsCharging" json:"is_charging"`
	Location                  int         `plist:"Location" json:"location"`
	MaxCapacity               int         `plist:"MaxCapacity" json:"max_capacity"`
	PostChargeWaitSeconds     int         `json:"post_charge_wait_seconds"`
	PostDischargeWaitSeconds  int         `json:"post_discharge_wait_seconds"`
	PowerTelemetryData        interface{} `json:"power_telemetry_data"`
	TimeRemaining             int         `json:"time_remaining"`
	UpdateTime                int         `json:"update_time"`
	Voltage                   int         `json:"voltage"`
	BuiltIn                   bool        `plist:"built-in"`
}

func readBatteries() ([]*battery, error) {
	out, err := exec.Command("ioreg", "-n", "AppleSmartBattery", "-r", "-a").Output()
	if err != nil {
		return nil, err
	}

	if len(out) == 0 {
		// No batteries.
		return nil, nil
	}

	var data []*battery
	if _, err = plist.Unmarshal(out, &data); err != nil {
		return nil, err
	}
	return data, nil
}

func main() {
	batt, err := readBatteries()
	if err == nil {
		for _, b := range batt {
			mar, _ := json.Marshal(b)
			fmt.Println(string(mar))
		}
	}
}