registry

Documentation

Overview

Package mdns is a multicast dns registry

Package registry is an interface for service discovery

Index

• Variables
• func Deregister(s *Service) error
• func Register(s *Service, opts ...RegisterOption) error
• func String() string
• type Endpoint
• type Event
• type EventType
  • func (t EventType) String() string
• type Node
• type Option
  • func Addrs(addrs ...string) Option
  • func Secure(b bool) Option
  • func TLSConfig(t *tls.Config) Option
  • func Timeout(t time.Duration) Option
• type Options
• type RegisterOption
  • func RegisterTTL(t time.Duration) RegisterOption
• type RegisterOptions
• type Registry
  • func NewRegistry(opts ...Option) Registry
• type Result
• type Service
  • func Copy(current []*Service) []*Service
  • func CopyService(service *Service) *Service
  • func GetService(name string) ([]*Service, error)
  • func ListServices() ([]*Service, error)
  • func Merge(olist []*Service, nlist []*Service) []*Service
  • func Remove(old, del []*Service) []*Service
• type Value
• type WatchOption
  • func WatchService(name string) WatchOption
• type WatchOptions
• type Watcher
  • func Watch(opts ...WatchOption) (Watcher, error)

Variables

var (
	DefaultRegistry = NewRegistry()

	// Not found error when GetService is called
	ErrNotFound = errors.New("service not found")
	// Watcher stopped error when watcher is stopped
	ErrWatcherStopped = errors.New("watcher stopped")
)

Functions

func Deregister

func Deregister(s *Service) error

Deregister a service node

func Register

func Register(s *Service, opts ...RegisterOption) error

Register a service node. Additionally supply options such as TTL.

func String

func String() string

Types

type Endpoint

type Endpoint struct {
	Name     string            `json:"name"`
	Request  *Value            `json:"request"`
	Response *Value            `json:"response"`
	Metadata map[string]string `json:"metadata"`
}

type Event

type Event struct {
	// Id is registry id
	Id string
	// Type defines type of event
	Type EventType
	// Timestamp is event timestamp
	Timestamp time.Time
	// Service is registry service
	Service *Service
}

Event is registry event

type EventType

type EventType int

EventType defines registry event type

const (
	// Create is emitted when a new service is registered
	Create EventType = iota
	// Delete is emitted when an existing service is deregsitered
	Delete
	// Update is emitted when an existing servicec is updated
	Update
)

func (EventType) String

func (t EventType) String() string

String returns human readable event type

type Node

type Node struct {
	Id       string            `json:"id"`
	Address  string            `json:"address"`
	Metadata map[string]string `json:"metadata"`
}

type Option

type Option func(*Options)

func Addrs

func Addrs(addrs ...string) Option

Addrs is the registry addresses to use

func Secure

func Secure(b bool) Option

Secure communication with the registry

func TLSConfig

func TLSConfig(t *tls.Config) Option

Specify TLS Config

func Timeout

func Timeout(t time.Duration) Option

type Options

type Options struct {
	Addrs     []string
	Timeout   time.Duration
	Secure    bool
	TLSConfig *tls.Config
	// Other options for implementations of the interface
	// can be stored in a context
	Context context.Context
}

type RegisterOption

type RegisterOption func(*RegisterOptions)

func RegisterTTL

func RegisterTTL(t time.Duration) RegisterOption

type RegisterOptions

type RegisterOptions struct {
	TTL time.Duration
	// Other options for implementations of the interface
	// can be stored in a context
	Context context.Context
}

type Registry

type Registry interface {
	Init(...Option) error
	Options() Options
	Register(*Service, ...RegisterOption) error
	Deregister(*Service) error
	GetService(string) ([]*Service, error)
	ListServices() ([]*Service, error)
	Watch(...WatchOption) (Watcher, error)
	String() string
}

The registry provides an interface for service discovery and an abstraction over varying implementations {consul, etcd, zookeeper, ...}

func NewRegistry

func NewRegistry(opts ...Option) Registry

NewRegistry returns a new default registry which is mdns

type Result

type Result struct {
	Action  string
	Service *Service
}

Result is returned by a call to Next on the watcher. Actions can be create, update, delete

type Service

type Service struct {
	Name      string            `json:"name"`
	Version   string            `json:"version"`
	Metadata  map[string]string `json:"metadata"`
	Endpoints []*Endpoint       `json:"endpoints"`
	Nodes     []*Node           `json:"nodes"`
}

func Copy

func Copy(current []*Service) []*Service

Copy makes a copy of services

func CopyService

func CopyService(service *Service) *Service

CopyService make a copy of service

func GetService

func GetService(name string) ([]*Service, error)

Retrieve a service. A slice is returned since we separate Name/Version.

func ListServices

func ListServices() ([]*Service, error)

List the services. Only returns service names

func Merge

func Merge(olist []*Service, nlist []*Service) []*Service

Merge merges two lists of services and returns a new copy

func Remove

func Remove(old, del []*Service) []*Service

Remove removes services and returns a new copy

type Value

type Value struct {
	Name   string   `json:"name"`
	Type   string   `json:"type"`
	Values []*Value `json:"values"`
}

type WatchOption

type WatchOption func(*WatchOptions)

func WatchService

func WatchService(name string) WatchOption

Watch a service

type WatchOptions

type WatchOptions struct {
	// Specify a service to watch
	// If blank, the watch is for all services
	Service string
	// Other options for implementations of the interface
	// can be stored in a context
	Context context.Context
}

type Watcher

type Watcher interface {
	// Next is a blocking call
	Next() (*Result, error)
	Stop()
}

Watcher is an interface that returns updates about services within the registry.

func Watch

func Watch(opts ...WatchOption) (Watcher, error)

Watch returns a watcher which allows you to track updates to the registry.