sd

Documentation

Overview

Package sd defines some interfaces and implementations for service discovery

Index

• Variables
• func RegisterSubscriberFactory(name string, sf SubscriberFactory) error
• type Balancer
  • func NewBalancer(subscriber Subscriber) Balancer
  • func NewRandomLB(subscriber Subscriber) Balancer
  • func NewRoundRobinLB(subscriber Subscriber) Balancer
• type FixedSubscriber
  • func (s FixedSubscriber) Hosts() ([]string, error)
• type Register
  • func GetRegister() *Register
  • func (r *Register) Get(name string) SubscriberFactory
  • func (r *Register) Register(name string, sf SubscriberFactory) error
• type Subscriber
  • func FixedSubscriberFactory(cfg *config.Backend) Subscriber
  • func GetSubscriber(cfg *config.Backend) Subscriber
• type SubscriberFactory
• type SubscriberFunc
  • func (f SubscriberFunc) Hosts() ([]string, error)

Variables

var ErrNoHosts = errors.New("no hosts available")

ErrNoHosts is the error the balancer must return when there are 0 hosts ready

Functions

func RegisterSubscriberFactory

func RegisterSubscriberFactory(name string, sf SubscriberFactory) error

RegisterSubscriberFactory registers the received factory Deprecated: RegisterSubscriberFactory. Use the GetRegister function

Types

type Balancer

type Balancer interface {
	Host() (string, error)
}

Balancer applies a balancing stategy in order to select the backend host to be used

func NewBalancer

func NewBalancer(subscriber Subscriber) Balancer

NewBalancer returns the best perfomant balancer depending on the number of available processors. If GOMAXPROCS = 1, it returns a round robin LB due there is no contention over the atomic counter. If GOMAXPROCS > 1, it returns a pseudo random LB optimized for scaling over the number of CPUs.

func NewRandomLB

func NewRandomLB(subscriber Subscriber) Balancer

NewRandomLB returns a new balancer using a fastrand pseudorandom generator

func NewRoundRobinLB

func NewRoundRobinLB(subscriber Subscriber) Balancer

NewRoundRobinLB returns a new balancer using a round robin strategy

type FixedSubscriber

type FixedSubscriber []string

FixedSubscriber has a constant set of backend hosts and they never get updated

func (FixedSubscriber) Hosts

func (s FixedSubscriber) Hosts() ([]string, error)

Hosts implements the subscriber interface

type Register

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

Register is a SD register

func GetRegister

func GetRegister() *Register

GetRegister returns the package register

func (*Register) Get

func (r *Register) Get(name string) SubscriberFactory

Get implements the RegisterGetter interface

func (*Register) Register

func (r *Register) Register(name string, sf SubscriberFactory) error

Register implements the RegisterSetter interface

type Subscriber

type Subscriber interface {
	Hosts() ([]string, error)
}

Subscriber keeps the set of backend hosts up to date

func FixedSubscriberFactory

func FixedSubscriberFactory(cfg *config.Backend) Subscriber

FixedSubscriberFactory builds a FixedSubscriber with the received config

func GetSubscriber

func GetSubscriber(cfg *config.Backend) Subscriber

GetSubscriber returns a subscriber from package register Deprecated: GetSubscriber. Use the GetRegister function

type SubscriberFactory

type SubscriberFactory func(*config.Backend) Subscriber

SubscriberFactory builds subscribers with the received config

type SubscriberFunc

type SubscriberFunc func() ([]string, error)

SubscriberFunc type is an adapter to allow the use of ordinary functions as subscribers. If f is a function with the appropriate signature, SubscriberFunc(f) is a Subscriber that calls f.

func (SubscriberFunc) Hosts

func (f SubscriberFunc) Hosts() ([]string, error)

Hosts implements the Subscriber interface by executing the wrapped function