status

Documentation

Index

• Constants
• Variables
• type Controller
  • func NewController() *Controller
  • func (c *Controller) Failed(err error)
  • func (c *Controller) KeepRunning() bool
  • func (c *Controller) KeepRunningWithContext(ctx context.Context) bool
  • func (c *Controller) ReleaseRunning()
  • func (c *Controller) Started()
  • func (c *Controller) Starting() bool
  • func (c *Controller) StatusError(err error) error
  • func (c *Controller) Stopped()
  • func (c *Controller) Stopping() bool

Constants

const (
	ErrTypeInvalidStatus = "status.invalid"
)

Variables

var (
	ErrInvalidStatus = errors.New("invalid status")
)

Types

type Controller

type Controller struct {
	// contains filtered or unexported fields
}

Controller is used for controlling the service or worker that has status, and widely used in projects. A service may have typical status, such as waiting_for_start, starting, running, stopping, stopped. When the service is not running, it could not be accepted operations, and it could not be operated when it's stopped. It's not allowed two or more called in difference goroutine do start a service at the same time, so the "starting" status is designed for protecting it and a sync.RWMutex is also required. Similarly, "stopping" status is useful when do stop operation. Typical usage is embed in an object for status controller. See testing example for more detail.

func NewController

func NewController() *Controller

func (*Controller) Failed

func (c *Controller) Failed(err error)

Failed is always called with Starting in pair. See Starting for more details.

func (*Controller) KeepRunning

func (c *Controller) KeepRunning() bool

KeepRunning is used for caller when requests the service to guarantee the service status is running. When caller request the service, follow step will happen 1. check if the service is running(if it's not running, the request is failed). 2. prevent the service stopping until the request is done. 3. remove the service stopping preventing. When the KeepRunning return false, it means the service is not running, you could not do any request to the service. When it returns true, caller must call ReleaseRunning after request is done. * Notice: forget to call ReleaseRunning when KeepRunning return true will cause deadlock.

func (*Controller) KeepRunningWithContext

func (c *Controller) KeepRunningWithContext(ctx context.Context) bool

KeepRunningWithContext accept a context for waiting control for KeepRunning. When the service is not running, KeepRunning will return false, then caller could not do any requests, use KeepRunningWithContext, caller can wait service status from "ready" to "running" by input context param. * Notice: If the service had been "stopped" or it's "stopping", KeepRunningWithContext will return false.

func (*Controller) ReleaseRunning

func (c *Controller) ReleaseRunning()

ReleaseRunning is always called with KeepRunning or KeepRunningWithContext in pair. See KeepRunning for more details.

func (*Controller) Started

func (c *Controller) Started()

Started is always called with Starting in pair. See Starting for more details.

func (*Controller) Starting

func (c *Controller) Starting() bool

Starting is called for start the service. It's always called with Started or Failed in pair. It returns true means the current goroutine got the permission for the service start, then you should call Started when the service start success or Failed with error when failed. The false return value means the service had been running, stopped or other goroutine has got the permission for starting. * Notice: forget to call Started or Failed when Starting return true will cause deadlock. * The usual usage is:

	if !Controller.Starting() {
	    return err
	}

	err = service.StartImp()    // do service start operation...

	if err != nil {
  		Controller.Failed(err)
	} else {
  		Controller.Started()
	}

func (*Controller) StatusError

func (c *Controller) StatusError(err error) error

StatusError return the error which set by Failed, if the error is nil, return the input error.

func (*Controller) Stopped

func (c *Controller) Stopped()

Stopped is always called with Stopping in pair. See Stopping for more details.

func (*Controller) Stopping

func (c *Controller) Stopping() bool

Stopping is called for stop the service. It returns false means the service is not running or had been stopped or other goroutine has got the permission for stopping. If the return value is true, you will do service stop operation and then call Stopped to change the status to "stopped". * Notice: forget to call Stopped when Stopping return true will cause deadlock. * The usual usage is:

if !Controller.Stopping() {
    return err
}
defer Controller.Stopped()
err = service.StopImp()    // do service stop operation...