agent: refactor new battery package (#1872)

agent/battery/battery.go

@@ -1,14 +1,11 @@
-//go:build !freebsd && !darwin && !linux && !windows
-
 // Package battery provides functions to check if the system has a battery and to get the battery stats.
 package battery
 
-import "errors"
+const (
-
+	stateUnknown uint8 = iota
-func HasReadableBattery() bool {
+	stateEmpty
-	return false
+	stateFull
-}
+	stateCharging
-
+	stateDischarging
-func GetBatteryStats() (uint8, uint8, error) {
+	stateIdle
-	return 0, 0, errors.ErrUnsupported
+)
-}

agent/battery/battery_darwin.go

@@ -7,19 +7,11 @@ import (
 	"log/slog"
 	"math"
 	"os/exec"
+	"sync"
 
 	"howett.net/plist"
 )
 
-const (
-	stateUnknown     uint8 = 0
-	stateEmpty       uint8 = 1
-	stateFull        uint8 = 2
-	stateCharging    uint8 = 3
-	stateDischarging uint8 = 4
-	stateIdle        uint8 = 5
-)
-
 type macBattery struct {
 	CurrentCapacity   int  `plist:"CurrentCapacity"`
 	MaxCapacity       int  `plist:"MaxCapacity"`
@@ -28,11 +20,6 @@ type macBattery struct {
 	ExternalConnected bool `plist:"ExternalConnected"`
 }
 
-var (
-	systemHasBattery   = false
-	haveCheckedBattery = false
-)
-
 func readMacBatteries() ([]macBattery, error) {
 	out, err := exec.Command("ioreg", "-n", "AppleSmartBattery", "-r", "-a").Output()
 	if err != nil {
@@ -49,11 +36,8 @@ func readMacBatteries() ([]macBattery, error) {
 }
 
 // HasReadableBattery checks if the system has a battery and returns true if it does.
-func HasReadableBattery() bool {
+var HasReadableBattery = sync.OnceValue(func() bool {
-	if haveCheckedBattery {
+	systemHasBattery := false
-		return systemHasBattery
-	}
-	haveCheckedBattery = true
 	batteries, err := readMacBatteries()
 	for _, bat := range batteries {
 		if bat.MaxCapacity > 0 {
@@ -65,7 +49,7 @@ func HasReadableBattery() bool {
 		slog.Debug("No battery found", "err", err)
 	}
 	return systemHasBattery
-}
+})
 
 // GetBatteryStats returns the current battery percent and charge state.
 // Uses CurrentCapacity/MaxCapacity to match the value macOS displays.

agent/battery/battery_linux.go

@@ -9,27 +9,14 @@ import (
 	"os"
 	"path/filepath"
 	"strconv"
+	"sync"
 
 	"github.com/henrygd/beszel/agent/utils"
 )
 
-const (
-	stateUnknown     uint8 = 0
-	stateEmpty       uint8 = 1
-	stateFull        uint8 = 2
-	stateCharging    uint8 = 3
-	stateDischarging uint8 = 4
-	stateIdle        uint8 = 5
-)
-
 const sysfsPowerSupply = "/sys/class/power_supply"
 
-var (
+var getBatteryPaths = sync.OnceValues(func() ([]string, error) {
-	systemHasBattery   = false
-	haveCheckedBattery = false
-)
-
-func getBatteryPaths() ([]string, error) {
 	entries, err := os.ReadDir(sysfsPowerSupply)
 	if err != nil {
 		return nil, err
@@ -42,7 +29,7 @@ func getBatteryPaths() ([]string, error) {
 		}
 	}
 	return paths, nil
-}
+})
 
 func parseSysfsState(status string) uint8 {
 	switch status {
@@ -62,11 +49,8 @@ func parseSysfsState(status string) uint8 {
 }
 
 // HasReadableBattery checks if the system has a battery and returns true if it does.
-func HasReadableBattery() bool {
+var HasReadableBattery = sync.OnceValue(func() bool {
-	if haveCheckedBattery {
+	systemHasBattery := false
-		return systemHasBattery
-	}
-	haveCheckedBattery = true
 	paths, err := getBatteryPaths()
 	for _, path := range paths {
 		if _, ok := utils.ReadStringFileOK(filepath.Join(path, "capacity")); ok {
@@ -78,7 +62,7 @@ func HasReadableBattery() bool {
 		slog.Debug("No battery found", "err", err)
 	}
 	return systemHasBattery
-}
+})
 
 // GetBatteryStats returns the current battery percent and charge state.
 // Reads /sys/class/power_supply/*/capacity directly so the kernel-reported

agent/battery/battery_stub.go

@@ -1,4 +1,4 @@
-//go:build freebsd
+//go:build !darwin && !linux && !windows
 
 package battery
 

agent/battery/battery_windows.go

@@ -6,21 +6,13 @@ import (
 	"errors"
 	"log/slog"
 	"math"
+	"sync"
 	"syscall"
 	"unsafe"
 
 	"golang.org/x/sys/windows"
 )
 
-const (
-	stateUnknown     uint8 = 0
-	stateEmpty       uint8 = 1
-	stateFull        uint8 = 2
-	stateCharging    uint8 = 3
-	stateDischarging uint8 = 4
-	stateIdle        uint8 = 5
-)
-
 type batteryQueryInformation struct {
 	BatteryTag       uint32
 	InformationLevel int32
@@ -77,15 +69,16 @@ var guidDeviceBattery = winGUID{
 }
 
 var (
-	setupapi                        = &windows.LazyDLL{Name: "setupapi.dll", System: true}
+	setupapi                         = &windows.LazyDLL{Name: "setupapi.dll", System: true}
-	setupDiGetClassDevsW            = setupapi.NewProc("SetupDiGetClassDevsW")
+	setupDiGetClassDevsW             = setupapi.NewProc("SetupDiGetClassDevsW")
-	setupDiEnumDeviceInterfaces     = setupapi.NewProc("SetupDiEnumDeviceInterfaces")
+	setupDiEnumDeviceInterfaces      = setupapi.NewProc("SetupDiEnumDeviceInterfaces")
 	setupDiGetDeviceInterfaceDetailW = setupapi.NewProc("SetupDiGetDeviceInterfaceDetailW")
-	setupDiDestroyDeviceInfoList    = setupapi.NewProc("SetupDiDestroyDeviceInfoList")
+	setupDiDestroyDeviceInfoList     = setupapi.NewProc("SetupDiDestroyDeviceInfoList")
 )
 
 func setupDiSetup(proc *windows.LazyProc, nargs, a1, a2, a3, a4, a5, a6 uintptr) (uintptr, error) {
-	r1, _, errno := syscall.Syscall6(proc.Addr(), nargs, a1, a2, a3, a4, a5, a6)
+	_ = nargs
+	r1, _, errno := syscall.SyscallN(proc.Addr(), a1, a2, a3, a4, a5, a6)
 	if windows.Handle(r1) == windows.InvalidHandle {
 		if errno != 0 {
 			return 0, error(errno)
@@ -96,7 +89,8 @@ func setupDiSetup(proc *windows.LazyProc, nargs, a1, a2, a3, a4, a5, a6 uintptr)
 }
 
 func setupDiCall(proc *windows.LazyProc, nargs, a1, a2, a3, a4, a5, a6 uintptr) syscall.Errno {
-	r1, _, errno := syscall.Syscall6(proc.Addr(), nargs, a1, a2, a3, a4, a5, a6)
+	_ = nargs
+	r1, _, errno := syscall.SyscallN(proc.Addr(), a1, a2, a3, a4, a5, a6)
 	if r1 == 0 {
 		if errno != 0 {
 			return errno
@@ -137,7 +131,7 @@ func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
 	if err != nil {
 		return 0, 0, stateUnknown, err
 	}
-	defer syscall.Syscall(setupDiDestroyDeviceInfoList.Addr(), 1, hdev, 0, 0)
+	defer syscall.SyscallN(setupDiDestroyDeviceInfoList.Addr(), hdev)
 
 	var did spDeviceInterfaceData
 	did.cbSize = uint32(unsafe.Sizeof(did))
@@ -256,17 +250,9 @@ func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
 	return bi.FullChargedCapacity, bs.Capacity, readWinBatteryState(bs.PowerState), nil
 }
 
-var (
-	systemHasBattery   = false
-	haveCheckedBattery = false
-)
-
 // HasReadableBattery checks if the system has a battery and returns true if it does.
-func HasReadableBattery() bool {
+var HasReadableBattery = sync.OnceValue(func() bool {
-	if haveCheckedBattery {
+	systemHasBattery := false
-		return systemHasBattery
-	}
-	haveCheckedBattery = true
 	full, _, _, err := winBatteryGet(0)
 	if err == nil && full > 0 {
 		systemHasBattery = true
@@ -275,7 +261,7 @@ func HasReadableBattery() bool {
 		slog.Debug("No battery found", "err", err)
 	}
 	return systemHasBattery
-}
+})
 
 // GetBatteryStats returns the current battery percent and charge state.
 func GetBatteryStats() (batteryPercent uint8, batteryState uint8, err error) {

go.mod

@@ -5,7 +5,7 @@ go 1.26.1
 require (
 	github.com/blang/semver v3.5.1+incompatible
 	github.com/coreos/go-systemd/v22 v22.7.0
-github.com/ebitengine/purego v0.10.0
+	github.com/ebitengine/purego v0.10.0
 	github.com/fxamacker/cbor/v2 v2.9.0
 	github.com/gliderlabs/ssh v0.3.8
 	github.com/google/uuid v1.6.0

go.sum

@@ -17,8 +17,6 @@ github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/disintegration/imaging v1.6.2 h1:w1LecBlG2Lnp8B3jk5zSuNqd7b4DXhcjwek1ei82L+c=
 github.com/disintegration/imaging v1.6.2/go.mod h1:44/5580QXChDfwIclfc/PCwrr44amcmDAg8hxG0Ewe4=
-github.com/distatus/battery v0.11.0 h1:KJk89gz90Iq/wJtbjjM9yUzBXV+ASV/EG2WOOL7N8lc=
-github.com/distatus/battery v0.11.0/go.mod h1:KmVkE8A8hpIX4T78QRdMktYpEp35QfOL8A8dwZBxq2k=
 github.com/domodwyer/mailyak/v3 v3.6.2 h1:x3tGMsyFhTCaxp6ycgR0FE/bu5QiNp+hetUuCOBXMn8=
 github.com/domodwyer/mailyak/v3 v3.6.2/go.mod h1:lOm/u9CyCVWHeaAmHIdF4RiKVxKUT/H5XX10lIKAL6c=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=