registry

README

Simple Service registry based on pub/sub pattern

This first version service registry use nats (https://nats.io/) or reids (https://redis.io/) to implement a service registry You just need to start nats before using this service registry

The project is still under development and is not ready for production.

A java implentation exist

Simple to use:

API is simple to use, simple to understand. No required external installation. No configuration file is required.

• Connect: registry.Connect(registry.Nats(c)) init the service both on the client/server side and return registry service instance.
• Register: reg.Register(registry.Service{Name: "httptest", URL: "http://localhost:8083/test"}) register you service on the service side.
• GetService: reg.GetService("myservice") on the client side
• Unregister: reg.Unregister("myservice") on the service side
• Close : reg.Close() on the server side 'Close' function deregisters all registered services. On the client and service side, unsubsribe to subscriptions

Safe

Can be used in concurrent context. Singleton design pattern is used. The first called to registry.Connect(registry.Nats(c), registry.Timeout(100*time.MilliSecond)) create instance of registry service. And then you can get an instance of registry service without argument reg, _ := registry.Connect()

Fast

This "service registry" uses a local cache as well as the pub / sub pattern. The registration of a new service is in real time. When a new service registers, all clients are notified in real time and update their cache.

Light

The project uses very few external dependencies. There is no service to install. Just your favorite pub/sub implementation (NATS)

Multi-tenant

Multi-tenant support is planned. The tool is based on pub / sub, each message can be pre-fixed by a text of your choice.

Exemple

on the server side :

    package main

import (
	"log"
	"net/http"

	"github.com/eddieraa/registry"
	rnats "github.com/eddieraa/registry/nats"
	"github.com/nats-io/nats.go"
)

func main() {
	//connect to nats server
	conn, err := nats.Connect(nats.DefaultURL)
	if err != nil {
		log.Fatal("Could not connect to nats ", err)
	}

	//create registry default instance
	reg, err := rnats.SetDefault(conn)
	if err != nil {
		log.Fatal("Could not create registry instance ", err)
	}

	addr, _ := registry.FindFreeLocalAddress(10000, 10010)
	//register "myservice"
	fnuregister, err := reg.Register(registry.Service{Name: "myservice", Address: addr})
	if err != nil {
		log.Fatal("Could not register service ", err)
	}

	server := http.NewServeMux()
	server.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("hello"))
	})
	if err = http.ListenAndServe(addr, server); err != nil {
		log.Fatal("could not create server ", err)
	}

	//Unregister
	fnuregister()
	reg.Close()
	conn.Close()

}
    

On the client side :

package main

import (
	"log"

	rnats "github.com/eddieraa/registry/nats"
	"github.com/nats-io/nats.go"
)

func main() {
	//connect to nats server
	conn, err := nats.Connect(nats.DefaultURL)
	if err != nil {
		log.Fatal("Could not connect to nats ", err)
	}

	//create registry default instance
	reg, err := rnats.SetDefault(conn)
	if err != nil {
		log.Fatal("Could not create registry instance ", err)
	}

	//lookup for "myservice"
	s, err := reg.GetService("myservice")
	if err != nil {
		log.Fatal("Could not get service")
	}

	//do something with your service
	log.Print("Find service with address ", s.Address)

	reg.Close()
	conn.Close()

}

Documentation

Index

• Variables
• func Close() error
• func FindFreeLocalAddress(from, to int) (freeaddr string, err error)
• func FindFreePort(from, to int) (freeport int, err error)
• func FreePort() (freeport int, err error)
• func LocalFreeAddr() (freeaddr string, err error)
• func LocalFreeIPv6Addr() (freeaddr string, err error)
• func Observe(name string) error
• func Unregister(s Service) error
• type Event
• type Filter
  • func LoadBalanceFilter() Filter
  • func LocalhostFilter() Filter
  • func PassingFilter() Filter
• type FnUnregister
  • func Register(s Service) (FnUnregister, error)
• type ObserveFilter
  • func LocalhostOFilter() ObserveFilter
• type ObserverEvent
• type Option
  • func AddFilter(f Filter) Option
  • func AddObserveFilter(f ObserveFilter) Option
  • func WithLoglevel(level logrus.Level) Option
  • func WithMainTopic(topic string) Option
  • func WithObserverEvent(ev ObserverEvent) Option
  • func WithPubsub(pb pubsub.Pubsub) Option
  • func WithRegisterInterval(duration time.Duration) Option
  • func WithTimeout(timeout time.Duration) Option
• type Options
• type Pong
  • func (p Pong) String() string
• type Registry
  • func GetDefault() (r Registry, err error)
  • func NewRegistry(opts ...Option) (r Registry, err error)
  • func SetDefault(opts ...Option) (r Registry, err error)
• type Service
  • func GetService(name string, f ...Filter) (*Service, error)
  • func GetServices(name string) ([]Service, error)
  • func (s Service) DueTime() time.Time
  • func (s Service) String() string
• type Status
  • func (s *Status) FromString(status string) Status
  • func (s Status) MarshalJSON() ([]byte, error)
  • func (s Status) String() string
  • func (s *Status) UnmarshalJSON(b []byte) error
• type Timestamps

Variables

var (
	//DefaultTimeout timeout for GetServices
	DefaultTimeout = 100 * time.Millisecond
	//DefaultRegisterInterval time between 2 registration
	DefaultRegisterInterval = 20 * time.Second
	//DefaultCheckDueInterval time between 2 checks
	DefaultCheckDueInterval = 200 * time.Millisecond
	//DefaultMainTopic default message base. All topics will start with this message
	DefaultMainTopic = "registry"
	//DefaultDueDurationFactor service expire when currentTime > lastRegisteredTime + registerInternal * dueDrationFactor
	DefaultDueDurationFactor = float32(1.5)
)

var (
	//ErrNotFound when no service found
	ErrNotFound = errors.New("No service found")
	//ErrNoDefaultInstance when intance singleton has not been set
	ErrNoDefaultInstance = errors.New("Default instance has not been set, call SetDefault before")
)

var ErrNoFreePort = errors.New("No free port available")

ErrNoFreePort when no free port is available

Functions

func Close

func Close() error

Close the registry instance

Call SetDefault before

func FindFreeLocalAddress

func FindFreeLocalAddress(from, to int) (freeaddr string, err error)

FindFreeLocalAddress return local free address using range of port

func FindFreePort

func FindFreePort(from, to int) (freeport int, err error)

FindFreePort from range of integer

func FreePort

func FreePort() (freeport int, err error)

FreePort request a new free port return -1 if error

func LocalFreeAddr

func LocalFreeAddr() (freeaddr string, err error)

LocalFreeAddr return local free address (127.0.0.1:34545)

func LocalFreeIPv6Addr

func LocalFreeIPv6Addr() (freeaddr string, err error)

LocalFreeIPv6Addr return local free address ([::1]:34545)

func Observe

func Observe(name string) error

Observe subscribe to service

Call SetDefault before use

func Unregister

func Unregister(s Service) error

Unregister unregister a service

Call SetDefault before use

Types

type Event

type Event string

Event represent event (register|unregister|unavailbale)

const (
	//EventRegister register event
	EventRegister Event = "register"
	//EventUnregister unregister event
	EventUnregister Event = "unregister"
)

type Filter

type Filter func(services []*Pong) []*Pong

Filter used for filtering service do not return nil Ex Load Balancing

func LoadBalanceFilter

func LoadBalanceFilter() Filter

LoadBalanceFilter basic loadbalancer

func LocalhostFilter

func LocalhostFilter() Filter

LocalhostFilter return true if hostname is equals to service host

func PassingFilter

func PassingFilter() Filter

type FnUnregister

type FnUnregister func()

FnUnregister call this func for unregister the service

func Register

func Register(s Service) (FnUnregister, error)

Register register a new service

Call SetDefault before use

type ObserveFilter

type ObserveFilter func(s *Pong) bool

ObserveFilter used to accept (or not) new registered service.

Ex: you want only service on same host

func LocalhostOFilter

func LocalhostOFilter() ObserveFilter

LocalhostOFilter accept only service on the same machine

type ObserverEvent

type ObserverEvent func(s Service, ev Event)

ObserverEvent event tigered

type Option

type Option func(opts *Options)

Option option func

func AddFilter

func AddFilter(f Filter) Option

AddFilter add filter

func AddObserveFilter

func AddObserveFilter(f ObserveFilter) Option

AddObserveFilter adding filter

func WithLoglevel

func WithLoglevel(level logrus.Level) Option

WithLoglevel set log level

func WithMainTopic

func WithMainTopic(topic string) Option

WithMainTopic all topic will start with topic. Usefull in multi-tenancy

func WithObserverEvent

func WithObserverEvent(ev ObserverEvent) Option

WithObserverEvent set handler for Observer Event

func WithPubsub

func WithPubsub(pb pubsub.Pubsub) Option

WithPubsub initialyse service registry with nats connection

func WithRegisterInterval

func WithRegisterInterval(duration time.Duration) Option

WithRegisterInterval time between 2 register publish

func WithTimeout

func WithTimeout(timeout time.Duration) Option

WithTimeout define timeout

type Options

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

Options all configurable option

type Pong

type Pong struct {
	Service
	Timestamps *Timestamps `json:"t,omitempty"`
	Status     Status      `json:"status,omitempty"`
}

Pong response to ping

func (Pong) String

func (p Pong) String() string

type Registry

type Registry interface {
	Register(s Service) (FnUnregister, error)
	Unregister(s Service) error
	GetServices(name string) ([]Service, error)
	GetService(name string, filters ...Filter) (*Service, error)
	Observe(serviceName string) error
	Subscribers() []string
	Close() error
	SetServiceStatus(s Service, status Status) error
}

Registry Register, Unregister

func GetDefault

func GetDefault() (r Registry, err error)

GetDefault return default instance. return err if no default instance had been set

func NewRegistry

func NewRegistry(opts ...Option) (r Registry, err error)

NewRegistry create a new service registry instance

func SetDefault

func SetDefault(opts ...Option) (r Registry, err error)

SetDefault set the default instance

ex pubsub transport

type Service

type Service struct {
	//Network tcp/unix/tpc6
	Network string `json:"net,omitempty"`
	//Bind address
	Address string `json:"add,omitempty"`
	//URL base used for communicate with this service
	URL string `json:"url,omitempty"`
	//Name service name
	Name string `json:"name,omitempty"`
	//Version semver version
	Version string `json:"v,omitempty"`
	//Host
	Host string `json:"h,omitempty"`
	//KV key value pair
	KV map[string]string `json:"kv,omitempty"`
	// contains filtered or unexported fields
}

Service service struct

func GetService

func GetService(name string, f ...Filter) (*Service, error)

GetService find service with service name

Call SetDefault before use

func GetServices

func GetServices(name string) ([]Service, error)

GetServices return all registered service

Call SetDefault before use

func (Service) DueTime

func (s Service) DueTime() time.Time

DueTime expiration time

func (Service) String

func (s Service) String() string

type Status

type Status int

const (
	Passing Status = iota
	Warning
	Critical
)

func (*Status) FromString

func (s *Status) FromString(status string) Status

func (Status) MarshalJSON

func (s Status) MarshalJSON() ([]byte, error)

func (Status) String

func (s Status) String() string

func (*Status) UnmarshalJSON

func (s *Status) UnmarshalJSON(b []byte) error

type Timestamps

type Timestamps struct {
	//Registered date registered in nanoseconds (unix timestamp in milliseconds)
	Registered int64
	//expiration duration in milliseconds
	Duration int
}

Timestamps define registered datetime and expiration duration