svc

Documentation

Overview

Package svc provides everything required to build Windows service.

Index

• Constants
• func IsAnInteractiveSession() (bool, error)
• func Run(name string, handler Handler) error
• func StatusHandle() windows.Handle
• type Accepted
• type ChangeRequest
• type Cmd
• type Handler
• type State
• type Status
• Bugs

Constants

const (
	Stopped         = State(windows.SERVICE_STOPPED)
	StartPending    = State(windows.SERVICE_START_PENDING)
	StopPending     = State(windows.SERVICE_STOP_PENDING)
	Running         = State(windows.SERVICE_RUNNING)
	ContinuePending = State(windows.SERVICE_CONTINUE_PENDING)
	PausePending    = State(windows.SERVICE_PAUSE_PENDING)
	Paused          = State(windows.SERVICE_PAUSED)
)

const (
	Stop                  = Cmd(windows.SERVICE_CONTROL_STOP)
	Pause                 = Cmd(windows.SERVICE_CONTROL_PAUSE)
	Continue              = Cmd(windows.SERVICE_CONTROL_CONTINUE)
	Interrogate           = Cmd(windows.SERVICE_CONTROL_INTERROGATE)
	Shutdown              = Cmd(windows.SERVICE_CONTROL_SHUTDOWN)
	ParamChange           = Cmd(windows.SERVICE_CONTROL_PARAMCHANGE)
	NetBindAdd            = Cmd(windows.SERVICE_CONTROL_NETBINDADD)
	NetBindRemove         = Cmd(windows.SERVICE_CONTROL_NETBINDREMOVE)
	NetBindEnable         = Cmd(windows.SERVICE_CONTROL_NETBINDENABLE)
	NetBindDisable        = Cmd(windows.SERVICE_CONTROL_NETBINDDISABLE)
	DeviceEvent           = Cmd(windows.SERVICE_CONTROL_DEVICEEVENT)
	HardwareProfileChange = Cmd(windows.SERVICE_CONTROL_HARDWAREPROFILECHANGE)
	PowerEvent            = Cmd(windows.SERVICE_CONTROL_POWEREVENT)
	SessionChange         = Cmd(windows.SERVICE_CONTROL_SESSIONCHANGE)
)

const (
	AcceptStop                  = Accepted(windows.SERVICE_ACCEPT_STOP)
	AcceptShutdown              = Accepted(windows.SERVICE_ACCEPT_SHUTDOWN)
	AcceptPauseAndContinue      = Accepted(windows.SERVICE_ACCEPT_PAUSE_CONTINUE)
	AcceptParamChange           = Accepted(windows.SERVICE_ACCEPT_PARAMCHANGE)
	AcceptNetBindChange         = Accepted(windows.SERVICE_ACCEPT_NETBINDCHANGE)
	AcceptHardwareProfileChange = Accepted(windows.SERVICE_ACCEPT_HARDWAREPROFILECHANGE)
	AcceptPowerEvent            = Accepted(windows.SERVICE_ACCEPT_POWEREVENT)
	AcceptSessionChange         = Accepted(windows.SERVICE_ACCEPT_SESSIONCHANGE)
)

Functions

func IsAnInteractiveSession

func IsAnInteractiveSession() (bool, error)

IsAnInteractiveSession determines if calling process is running interactively. It queries the process token for membership in the Interactive group. http://stackoverflow.com/questions/2668851/how-do-i-detect-that-my-application-is-running-as-service-or-in-an-interactive-s

func Run

func Run(name string, handler Handler) error

Run executes service name by calling appropriate handler function.

func StatusHandle

func StatusHandle() windows.Handle

StatusHandle returns service status handle. It is safe to call this function from inside the Handler.Execute because then it is guaranteed to be set. This code will have to change once multiple services are possible per process.

Types

type Accepted

type Accepted uint32

Accepted is used to describe commands accepted by the service. Note that Interrogate is always accepted.

type ChangeRequest

type ChangeRequest struct {
	Cmd           Cmd
	EventType     uint32
	EventData     uintptr
	CurrentStatus Status
}

ChangeRequest is sent to the service Handler to request service status change.

type Cmd

type Cmd uint32

Cmd represents service state change request. It is sent to a service by the service manager, and should be actioned upon by the service.

type Handler

type Handler interface {

	// Execute will be called by the package code at the start of
	// the service, and the service will exit once Execute completes.
	// Inside Execute you must read service change requests from r and
	// act accordingly. You must keep service control manager up to date
	// about state of your service by writing into s as required.
	// args contains service name followed by argument strings passed
	// to the service.
	// You can provide service exit code in exitCode return parameter,
	// with 0 being "no error". You can also indicate if exit code,
	// if any, is service specific or not by using svcSpecificEC
	// parameter.
	Execute(args []string, r <-chan ChangeRequest, s chan<- Status) (svcSpecificEC bool, exitCode uint32)
}

Handler is the interface that must be implemented to build Windows service.

type State

type State uint32

State describes service execution state (Stopped, Running and so on).

type Status

type Status struct {
	State      State
	Accepts    Accepted
	CheckPoint uint32 // used to report progress during a lengthy operation
	WaitHint   uint32 // estimated time required for a pending operation, in milliseconds
}

Status combines State and Accepted commands to fully describe running service.

Notes

Bugs

• There is no mechanism to run multiple services inside one single executable. Perhaps, it can be overcome by using RegisterServiceCtrlHandlerEx Windows api.