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Provide a way to control Windows service state #394

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Provide a way to control Windows service state #394

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8 changes: 8 additions & 0 deletions controls_nwin.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
//go:build !windows
// +build !windows

package service

// ControlsHandler is a stub of windows specific helper for common code.
type ControlsHandler struct {
}
88 changes: 45 additions & 43 deletions service.go
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Original file line number Diff line number Diff line change
Expand Up @@ -167,42 +167,44 @@ func New(i Interface, c *Config) (Service, error) {
}

// KeyValue provides a list of system specific options.
// * OS X
// - LaunchdConfig string () - Use custom launchd config.
// - KeepAlive bool (true) - Prevent the system from stopping the service automatically.
// - RunAtLoad bool (false) - Run the service after its job has been loaded.
// - SessionCreate bool (false) - Create a full user session.
//
// * Solaris
// - Prefix string ("application") - Service FMRI prefix.
// * OS X
// - LaunchdConfig string () - Use custom launchd config.
// - KeepAlive bool (true) - Prevent the system from stopping the service automatically.
// - RunAtLoad bool (false) - Run the service after its job has been loaded.
// - SessionCreate bool (false) - Create a full user session.
// - Solaris
// - Prefix string ("application") - Service FMRI prefix.
//
// * POSIX
// - UserService bool (false) - Install as a current user service.
// - SystemdScript string () - Use custom systemd script.
// - UpstartScript string () - Use custom upstart script.
// - SysvScript string () - Use custom sysv script.
// - OpenRCScript string () - Use custom OpenRC script.
// - RunWait func() (wait for SIGNAL) - Do not install signal but wait for this function to return.
// - ReloadSignal string () [USR1, ...] - Signal to send on reload.
// - PIDFile string () [/run/prog.pid] - Location of the PID file.
// - LogOutput bool (false) - Redirect StdErr & StandardOutPath to files.
// - Restart string (always) - How shall service be restarted.
// - SuccessExitStatus string () - The list of exit status that shall be considered as successful,
// in addition to the default ones.
// - LogDirectory string(/var/log) - The path to the log files directory
// * POSIX
// - UserService bool (false) - Install as a current user service.
// - SystemdScript string () - Use custom systemd script.
// - UpstartScript string () - Use custom upstart script.
// - SysvScript string () - Use custom sysv script.
// - OpenRCScript string () - Use custom OpenRC script.
// - RunWait func() (wait for SIGNAL) - Do not install signal but wait for this function to return.
// - ReloadSignal string () [USR1, ...] - Signal to send on reload.
// - PIDFile string () [/run/prog.pid] - Location of the PID file.
// - LogOutput bool (false) - Redirect StdErr & StandardOutPath to files.
// - Restart string (always) - How shall service be restarted.
// - SuccessExitStatus string () - The list of exit status that shall be considered as successful,
// in addition to the default ones.
// - LogDirectory string(/var/log) - The path to the log files directory
//
// * Linux (systemd)
// - LimitNOFILE int (-1) - Maximum open files (ulimit -n)
// (https://serverfault.com/questions/628610/increasing-nproc-for-processes-launched-by-systemd-on-centos-7)
// * Windows
// - DelayedAutoStart bool (false) - After booting, start this service after some delay.
// - Password string () - Password to use when interfacing with the system service manager.
// - Interactive bool (false) - The service can interact with the desktop. (more information https://docs.microsoft.com/en-us/windows/win32/services/interactive-services)
// - DelayedAutoStart bool (false) - after booting start this service after some delay.
// - StartType string ("automatic") - Start service type. (automatic | manual | disabled)
// - OnFailure string ("restart" ) - Action to perform on service failure. (restart | reboot | noaction)
// - OnFailureDelayDuration string ( "1s" ) - Delay before restarting the service, time.Duration string.
// - OnFailureResetPeriod int ( 10 ) - Reset period for errors, seconds.
// * Linux (systemd)
// - LimitNOFILE int (-1) - Maximum open files (ulimit -n)
// (https://serverfault.com/questions/628610/increasing-nproc-for-processes-launched-by-systemd-on-centos-7)
//
// * Windows
// - DelayedAutoStart bool (false) - After booting, start this service after some delay.
// - Password string () - Password to use when interfacing with the system service manager.
// - Interactive bool (false) - The service can interact with the desktop. (more information https://docs.microsoft.com/en-us/windows/win32/services/interactive-services)
// - DelayedAutoStart bool (false) - After booting start this service after some delay.
// - StartType string ("automatic") - Start service type. (automatic | manual | disabled)
// - OnFailure string ("restart" ) - Action to perform on service failure. (restart | reboot | noaction)
// - OnFailureDelayDuration string ( "1s" ) - Delay before restarting the service, time.Duration string.
// - OnFailureResetPeriod int ( 10 ) - Reset period for errors, seconds.
// - ExtraControls ControlsHandler (nil, nil) - Handle controls other than Stop and Shutdown.
type KeyValue map[string]interface{}

// bool returns the value of the given name, assuming the value is a boolean.
Expand Down Expand Up @@ -325,16 +327,16 @@ type System interface {
// Interface represents the service interface for a program. Start runs before
// the hosting process is granted control and Stop runs when control is returned.
//
// 1. OS service manager executes user program.
// 2. User program sees it is executed from a service manager (IsInteractive is false).
// 3. User program calls Service.Run() which blocks.
// 4. Interface.Start() is called and quickly returns.
// 5. User program runs.
// 6. OS service manager signals the user program to stop.
// 7. Interface.Stop() is called and quickly returns.
// - For a successful exit, os.Exit should not be called in Interface.Stop().
// 8. Service.Run returns.
// 9. User program should quickly exit.
// 1. OS service manager executes user program.
// 2. User program sees it is executed from a service manager (IsInteractive is false).
// 3. User program calls Service.Run() which blocks.
// 4. Interface.Start() is called and quickly returns.
// 5. User program runs.
// 6. OS service manager signals the user program to stop.
// 7. Interface.Stop() is called and quickly returns.
// - For a successful exit, os.Exit should not be called in Interface.Stop().
// 8. Service.Run returns.
// 9. User program should quickly exit.
type Interface interface {
// Start provides a place to initiate the service. The service doesn't
// signal a completed start until after this function returns, so the
Expand Down
137 changes: 106 additions & 31 deletions service_windows.go
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,30 @@ type WindowsLogger struct {
errs chan<- error
}

// ControlsHandler provides a way to set allowed controls and handle them.
// Note that Stop and Shutdown will not be passed throw this handler, also there are no
// Start control. User must handle Star, Stop and Shutdown with base service Interface.
type ControlsHandler struct {
Changes <-chan svc.Accepted
Handler func(request svc.ChangeRequest) svc.Status
}

// winControls is a helper function to extract ControlsHandler from Config
func (kv KeyValue) winControls() ControlsHandler {
const extraControlsName = "ExtraControls"
if v, found := kv[extraControlsName]; found {
if castValue, is := v.(ControlsHandler); is {
return castValue
}
}
return ControlsHandler{
Changes: nil,
Handler: func(req svc.ChangeRequest) svc.Status {
return req.CurrentStatus
},
}
}

type windowsSystem struct{}

func (windowsSystem) String() string {
Expand Down Expand Up @@ -178,48 +202,99 @@ func (ws *windowsService) getError() error {
return ws.stopStartErr
}

func (ws *windowsService) Execute(args []string, r <-chan svc.ChangeRequest, changes chan<- svc.Status) (bool, uint32) {
const cmdsAccepted = svc.AcceptStop | svc.AcceptShutdown
changes <- svc.Status{State: svc.StartPending}
type changesWrapper struct {
change chan<- svc.Status
last *svc.Status
}

func (w *changesWrapper) set(st svc.Status) {
w.last = &st
w.change <- st
}

func (w *changesWrapper) get() *svc.Status {
return w.last
}

func wrapChanges(ch chan<- svc.Status) *changesWrapper {
return &changesWrapper{
change: ch,
}
}

func (ws *windowsService) Execute(args []string, r <-chan svc.ChangeRequest, changesCh chan<- svc.Status) (bool, uint32) {
controls := ws.Config.Option.winControls()

changes := wrapChanges(changesCh)
changes.set(svc.Status{State: svc.StartPending})

if err := ws.i.Start(ws); err != nil {
ws.setError(err)
return true, 1
}

changes <- svc.Status{State: svc.Running, Accepts: cmdsAccepted}
loop:
cmdsAccepted := svc.AcceptStop | svc.AcceptShutdown
// give service a chance to init with proper accepts
// if it has nothing to init (or had no time to decide) we use defaults
select {
case cmdsAccepted = <-controls.Changes:
default:
}

changes.set(svc.Status{State: svc.Running, Accepts: cmdsAccepted})
err := ws.run(r, changes, controls)
if err != nil {
ws.setError(err)
return true, 2
}

return false, 0
}

func (ws *windowsService) run(r <-chan svc.ChangeRequest, changes *changesWrapper, controls ControlsHandler) error {
for {
c := <-r
switch c.Cmd {
case svc.Interrogate:
changes <- c.CurrentStatus
case svc.Stop:
changes <- svc.Status{State: svc.StopPending}
if err := ws.i.Stop(ws); err != nil {
ws.setError(err)
return true, 2
}
break loop
case svc.Shutdown:
changes <- svc.Status{State: svc.StopPending}
var err error
if wsShutdown, ok := ws.i.(Shutdowner); ok {
err = wsShutdown.Shutdown(ws)
} else {
err = ws.i.Stop(ws)
select {
case c := <-r:
switch c.Cmd {
case svc.Interrogate:
changes.set(c.CurrentStatus)
case svc.Stop:
changes.set(svc.Status{State: svc.StopPending})
if err := ws.i.Stop(ws); err != nil {
return err
}
return nil
case svc.Shutdown:
changes.set(svc.Status{State: svc.StopPending})
var err error
if wsShutdown, ok := ws.i.(Shutdowner); ok {
err = wsShutdown.Shutdown(ws)
} else {
err = ws.i.Stop(ws)
}
if err != nil {
return err
}
return nil
default:
res := c.CurrentStatus
if controls.Handler != nil {
res = controls.Handler(c)
}
changes.set(res)
}
if err != nil {
ws.setError(err)
return true, 2

case accepts := <-controls.Changes:
st := changes.get()
if st == nil {
st = &svc.Status{
State: svc.Stopped,
}
}
break loop
default:
continue loop
st.Accepts = accepts
changes.set(*st)
}
}

return false, 0
}

func lowPrivMgr() (*mgr.Mgr, error) {
Expand Down