suptree

Documentation

Index

• Variables
• type Service
• type ServiceToken
• type Spec
• type Supervisor
  • func New(name string, spec Spec) (s *Supervisor)
  • func NewSimple(name string) *Supervisor
  • func (s *Supervisor) Add(service Service) ServiceToken
  • func (s *Supervisor) Remove(id ServiceToken) error
  • func (s *Supervisor) Serve()
  • func (s *Supervisor) ServeBackground()
  • func (s *Supervisor) Services() []Service
  • func (s *Supervisor) Stop()
  • func (s *Supervisor) String() string

Variables

var ErrWrongSupervisor = errors.New("wrong supervisor for this service token, no service removed")

ErrWrongSupervisor is returned by the (*Supervisor).Remove method if you pass a ServiceToken from the wrong Supervisor.

Types

type Service

type Service interface {
	Serve()
	Stop()
}

type ServiceToken

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

ServiceToken is an opaque identifier that can be used to terminate a service that has been Add()ed to a Supervisor.

type Spec

type Spec struct {
	Log              func(string)
	FailureDecay     float64
	FailureThreshold float64
	FailureBackoff   time.Duration
	Timeout          time.Duration
}

type Supervisor

type Supervisor struct {
	Name string

	sync.Mutex
	// contains filtered or unexported fields
}

func New

func New(name string, spec Spec) (s *Supervisor)

New is the full constructor function for a supervisor.

The supervisor tracks the number of failures that have occurred, with an exponential decay on the count. Every FailureDecay seconds, the number of failures that have occurred is cut in half. (This is done smoothly with an exponential function.) When a failure occurs, the number of failures is incremented by one. When the number of failures passes the FailureThreshold, the entire service waits for FailureBackoff seconds before attempting any further restarts, at which point it resets its failure count to zero.

Timeout is how long Suptree will wait for a service to properly terminate.

func NewSimple

func NewSimple(name string) *Supervisor

NewSimple creates a service with sensible defaults.

func (*Supervisor) Add

func (s *Supervisor) Add(service Service) ServiceToken

Add adds a service to this supervisor.

func (*Supervisor) Remove

func (s *Supervisor) Remove(id ServiceToken) error

Remove will remove the given service from the Supervisor, and attempt to Stop() it. The ServiceID token comes from the Add() call.

func (*Supervisor) Serve

func (s *Supervisor) Serve()

Serve starts the supervisor. You should call this on the top-level supervisor, but nothing else.

func (*Supervisor) ServeBackground

func (s *Supervisor) ServeBackground()

ServeBackground starts running a supervisor in its own goroutine. This method does not return until it is safe to use .Add() on the Supervisor.

func (*Supervisor) Services

func (s *Supervisor) Services() []Service

Services returns a []Service containing a snapshot of the services this Supervisor is managing.

func (*Supervisor) Stop

func (s *Supervisor) Stop()

Stop stops the Supervisor.

This function will not return until either all Services have stopped, or they timeout after the timeout value given to the Supervisor at creation.

func (*Supervisor) String

func (s *Supervisor) String() string

String implements the fmt.Stringer interface.