discovery

README

Discovery

Discovery builds on the go-micro.Registry and is backed by the Micro OS discovery service.

The go-micro registry provides a simple Registry abstraction for various service discovery systems. Heartbeating is also done through a simple form of re-registration. Because of this we end up with a system that has limited scaling potential and does not provide much information about service health.

Discovery provides heartbeating as events published via the Broker. This means anyone can subscribe to the heartbeats to determine "liveness" rather than querying the Registry. Discovery also includes an in-memory cache of the Registry using the Watcher. If the Registry fails for any reason Discovery continues to function.

Interface

// Discovery builds on the registry as a mechanism
// for finding services. It includes heartbeating
// to notify of liveness and caching of the registry.
type Discovery interface {
	// implements the registry interface
	registry.Registry
	Close() error
}

func NewDiscovery(opts ...registry.Option) Discovery {
	return newOS(opts...)
}

## Supported Backends

• Discovery Service

Usage

With Flag

import _ "github.com/micro/go-os/discovery"

go run main.go --registry=os --registry_address=addr1:port,addr2:port,addr3:port

Direct Use

import (
	"github.com/micro/go-micro"
	"github.com/micro/go-os/discovery"
)

func main() {
	r := discovery.NewDiscovery(
		discovery.Addrs("addr1:port", "addr2:port", "addr3:port"),
	)

	service := micro.NewService(
		micro.Name("my.service"),
		micro.Registry(r),
	)
}

Documentation

Overview

Package discovery is an interface for scalable service discovery.

Index

• Constants
• func Client(c client.Client) registry.Option
• func Interval(i time.Duration) registry.Option
• func NewContext(ctx context.Context, c Discovery) context.Context
• func NewRegistry(opts ...registry.Option) registry.Registry
• type Discovery
  • func FromContext(ctx context.Context) (Discovery, bool)
  • func NewDiscovery(opts ...registry.Option) Discovery
• type Options

Constants

const (
	HeartbeatTopic = "micro.discovery.heartbeat"
)

Functions

func Client

func Client(c client.Client) registry.Option

Client used to call the discovery service

func Interval

func Interval(i time.Duration) registry.Option

Interval on which to publish heartbeats

func NewContext

func NewContext(ctx context.Context, c Discovery) context.Context

func NewRegistry

func NewRegistry(opts ...registry.Option) registry.Registry

Types

type Discovery

type Discovery interface {
	Close() error
	registry.Registry
}

Discovery builds on the registry for heartbeating and client side caching

func FromContext

func FromContext(ctx context.Context) (Discovery, bool)

func NewDiscovery

func NewDiscovery(opts ...registry.Option) Discovery

type Options

type Options struct {
	Client   client.Client
	Interval time.Duration
}

Options holds discovery options stored in registry Options context