Go で Windows Service を作成する

lxn / win の PR をマージしたやつに、Windows Service 関連の API を追加したので、Golang で Windows のサービスプログラムの開発がまぁまぁ簡単にできるようになった。

後の人のために以下に載せておきます。

main.go

package main

import (
    "os"
    "syscall"
    "unsafe"

    "winut"
    "github.com/blono/win" // Fork of lxn/win see https://qiita.com/manymanyuni/items/c41f5bf0fd141e299336
)

func registerService() {
    scManager := win.OpenSCManager(nil, nil, win.SC_MANAGER_CREATE_SERVICE|win.SC_MANAGER_LOCK)
    if scManager == 0 {
        return
    }

    service := win.CreateService(scManager, "my-service", "my-service",
        win.SERVICE_ALL_ACCESS, win.SERVICE_WIN32_OWN_PROCESS, win.SERVICE_AUTO_START,
        win.SERVICE_ERROR_NORMAL, winut.Getwd()+"\\my-service.exe", nil, nil, nil, nil, nil)
    if service == 0 {
        return
    }
    defer win.CloseServiceHandle(service)

    desc := win.SERVICE_DESCRIPTION{
        LpDescription: winut.NewUTF16("サービスの説明"),
    }
    win.LockServiceDatabase(scManager)
    win.ChangeServiceConfig2(service, win.SERVICE_CONFIG_DESCRIPTION, uintptr(unsafe.Pointer(&desc)))
    win.UnlockServiceDatabase(scManager)
    win.StartService(service, 0, nil)
}

func unregisterService() {
    scManager := win.OpenSCManager(nil, nil, win.SC_MANAGER_CONNECT)
    if scManager == 0 {
        return
    }

    service := win.OpenService(scManager, "my-service", win.SERVICE_STOP|win.SERVICE_QUERY_STATUS|win.DELETE)
    if service == 0 {
        return
    }
    defer win.CloseServiceHandle(service)

    var ss win.SERVICE_STATUS

    win.QueryServiceStatus(service, &ss)
    if ss.DwCurrentState == win.SERVICE_RUNNING {
        win.ControlService(service, win.SERVICE_CONTROL_STOP, &ss)
    }

    win.DeleteService(service)
}

var serviceStatus win.SERVICE_STATUS
var serviceHandle win.HANDLE
var events []win.HANDLE

func serviceHandler(control, eventType uint32, eventData, context uintptr) uintptr {
    switch control {
    case win.SERVICE_CONTROL_STOP:
        serviceStatus.DwCurrentState = win.SERVICE_STOP_PENDING
        serviceStatus.DwCheckPoint = 0
        serviceStatus.DwWaitHint = 1000

        win.SetServiceStatus(serviceHandle, &serviceStatus)
        win.SetEvent(events[0])
    case win.SERVICE_CONTROL_INTERROGATE:
        win.SetServiceStatus(serviceHandle, &serviceStatus)
    }

    return uintptr(uint32(0))
}

func serviceMain(numServicesArgs uint32, serviceArgVectors *uint16) uintptr {
    events = make([]win.HANDLE, 1)
    events[0] = win.CreateEvent(nil, win.FALSE, win.FALSE, nil)
    defer win.CloseHandle(events[0])

    serviceHandle = win.RegisterServiceCtrlHandlerEx("my-service", syscall.NewCallback(serviceHandler), uintptr(unsafe.Pointer(nil)))

    serviceStatus.DwServiceType = win.SERVICE_WIN32_OWN_PROCESS
    serviceStatus.DwCurrentState = win.SERVICE_RUNNING
    serviceStatus.DwControlsAccepted = win.SERVICE_ACCEPT_STOP
    serviceStatus.DwWin32ExitCode = 0
    serviceStatus.DwServiceSpecificExitCode = 0
    serviceStatus.DwCheckPoint = 0
    serviceStatus.DwWaitHint = 0

    win.SetServiceStatus(serviceHandle, &serviceStatus)
    win.WaitForMultipleObjects(uint32(len(events)), &events[0], win.TRUE, win.INFINITE)

    serviceStatus.DwCurrentState = win.SERVICE_STOPPED
    serviceStatus.DwCheckPoint = 0
    serviceStatus.DwWaitHint = 0

    win.SetServiceStatus(serviceHandle, &serviceStatus)

    return uintptr(unsafe.Pointer(nil))
}

func main() {
    if len(os.Args) >= 2 {
        if os.Args[1] == "/register" || os.Args[1] == "-register" {
            registerService()
        } else if os.Args[1] == "/unregister" || os.Args[1] == "-unregister" {
            unregisterService()
        }
    } else {
        services := []win.SERVICE_TABLE_ENTRY{
            {
                LpServiceName: winut.NewUTF16("my-service"),
                LpServiceProc: syscall.NewCallback(serviceMain),
            },
            {
                LpServiceName: nil,
                LpServiceProc: uintptr(unsafe.Pointer(nil)),
            },
        }

        win.StartServiceCtrlDispatcher(&services[0])
    }
}

winut.go

// package, import は省略

func NewUTF16(s string) *uint16 {
    result, _ := syscall.UTF16PtrFromString(s)

    return result
}

func Getwd() string {
    dir, _ := os.Getwd()

    return dir
}

というか、普通にあったんですねこういうの。
https://godoc.org/golang.org/x/sys/windows/svc/example