Update selector race, rename cache selector

implement some gossip options

README.md

@@ -1,8 +1,15 @@
 # Go Micro [![License](https://img.shields.io/:license-apache-blue.svg)](https://opensource.org/licenses/Apache-2.0) [![GoDoc](https://godoc.org/github.com/micro/go-micro?status.svg)](https://godoc.org/github.com/micro/go-micro) [![Travis CI](https://api.travis-ci.org/micro/go-micro.svg?branch=master)](https://travis-ci.org/micro/go-micro) [![Go Report Card](https://goreportcard.com/badge/micro/go-micro)](https://goreportcard.com/report/github.com/micro/go-micro)
 
-Go Micro is a pluggable framework for distributed systems development.
+Go Micro is a pluggable framework for micro service development.
+
+## Overview
+
+Go Micro provides the core requirements for distributed systems development including RPC and Event driven communication. 
+The **micro** philosophy is sane defaults with a pluggable architecture. We provide defaults to get you started quickly 
+but everything can be easily swapped out. 
+
+<img src="https://micro.mu/docs/images/go-micro.png" />
 
-The **micro** philosophy is sane defaults with a pluggable architecture. We provide defaults to get you started quickly but everything can be swapped out. 
 Plugins are available at [github.com/micro/go-plugins](https://github.com/micro/go-plugins).
 
 Follow us on [Twitter](https://twitter.com/microhq) or join the [Slack](http://slack.micro.mu/) community.
@@ -11,11 +18,29 @@ Follow us on [Twitter](https://twitter.com/microhq) or join the [Slack](http://s
 
 Go Micro abstracts away the details of distributed systems. Here are the main features.
 
-- **Service Discovery** - Automatic service registration and name resolution
-- **Load Balancing** - Client side load balancing built on discovery
-- **Message Encoding** - Dynamic encoding based on content-type with protobuf and json support
-- **Sync Streaming** - RPC based request/response with support for bidirectional streaming
-- **Async Messaging** - Native pubsub messaging built in for event driven architectures
+- **Service Discovery** - Automatic service registration and name resolution. Service discovery is at the core of micro service 
+development. When service A needs to speak to service B it needs the location of that service. Consul is the default discovery 
+system with multicast DNS (mdns) as a local option or the SWIM protocol (gossip) for zero dependency p2p networks.
+
+- **Load Balancing** - Client side load balancing built on service discovery. Once we have the addresses of any number of instances 
+of a service we now need a way to decide which node to route to. We use random hashed load balancing to provide even distribution 
+across the services and retry a different node if there's a problem. 
+
+- **Message Encoding** - Dynamic message encoding based on content-type. The client and server will use codecs along with content-type 
+to seamlessly encode and decode Go types for you. Any variety of messages could be encoded and sent from different clients. The client 
+and server handle this by default. This includes protobuf and json by default.
+
+- **Sync Streaming** - RPC based request/response with support for bidirectional streaming. We provide an abstraction for synchronous 
+communication. A request made to a service will be automatically resolved, load balanced, dialled and streamed. The default 
+transport is http/1.1 or http2 when tls is enabled.
+
+- **Async Messaging** - PubSub is built in as a first class citizen for asynchronous communication and event driven architectures. 
+Event notifications are a core pattern in micro service development. The default messaging is point-to-point http/1.1 or http2 when tls 
+is enabled.
+
+- **Pluggable Interfaces** - Go Micro makes use of Go interfaces for each distributed system abstraction. Because of this these interfaces 
+are pluggable and allows Go Micro to be runtime agnostic. You can plugin any underlying technology. Find plugins in 
+[github.com/micro/go-plugins](https://github.com/micro/go-plugins).
 
 ## Getting Started
 

broker/http_broker.go

@@ -27,6 +27,7 @@ import (
 	maddr "github.com/micro/util/go/lib/addr"
 	mnet "github.com/micro/util/go/lib/net"
 	mls "github.com/micro/util/go/lib/tls"
+	"golang.org/x/net/http2"
 )
 
 // HTTP Broker is a point to point async broker
@@ -78,6 +79,10 @@ func newTransport(config *tls.Config) *http.Transport {
 		}
 	}
 
+	dialTLS := func(network string, addr string) (net.Conn, error) {
+		return tls.Dial(network, addr, config)
+	}
+
 	t := &http.Transport{
 		Proxy: http.ProxyFromEnvironment,
 		Dial: (&net.Dialer{
@@ -85,11 +90,15 @@ func newTransport(config *tls.Config) *http.Transport {
 			KeepAlive: 30 * time.Second,
 		}).Dial,
 		TLSHandshakeTimeout: 10 * time.Second,
-		TLSClientConfig:     config,
+		DialTLS:             dialTLS,
 	}
 	runtime.SetFinalizer(&t, func(tr **http.Transport) {
 		(*tr).CloseIdleConnections()
 	})
+
+	// setup http2
+	http2.ConfigureTransport(t)
+
 	return t
 }
 
@@ -430,6 +439,13 @@ func (h *httpBroker) Init(opts ...Option) error {
 	// set registry
 	h.r = rcache.New(reg)
 
+	// reconfigure tls config
+	if c := h.opts.TLSConfig; c != nil {
+		h.c = &http.Client{
+			Transport: newTransport(c),
+		}
+	}
+
 	return nil
 }
 
@@ -507,7 +523,7 @@ func (h *httpBroker) Publish(topic string, msg *Message, opts ...PublishOption)
 }
 
 func (h *httpBroker) Subscribe(topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error) {
-	options := newSubscribeOptions(opts...)
+	options := NewSubscribeOptions(opts...)
 
 	// parse address for host, port
 	parts := strings.Split(h.Address(), ":")

broker/mock/mock.go

@@ -1,3 +1,4 @@
+// Package mock provides a mock broker for testing
 package mock
 
 import (

broker/options.go

@@ -50,7 +50,7 @@ var (
 	registryKey = contextKeyT("github.com/micro/go-micro/registry")
 )
 
-func newSubscribeOptions(opts ...SubscribeOption) SubscribeOptions {
+func NewSubscribeOptions(opts ...SubscribeOption) SubscribeOptions {
 	opt := SubscribeOptions{
 		AutoAck: true,
 	}

client/mock/mock.go

@@ -1,3 +1,4 @@
+// Package mock provides a mock client for testing
 package mock
 
 import (

client/rpc_client.go

@@ -132,7 +132,7 @@ func (r *rpcClient) call(ctx context.Context, address string, req Request, resp
 		return err
 	case <-ctx.Done():
 		grr = ctx.Err()
-		return errors.New("go.micro.client", fmt.Sprintf("request timeout: %v", ctx.Err()), 408)
+		return errors.Timeout("go.micro.client", fmt.Sprintf("%v", ctx.Err()))
 	}
 }
 
@@ -192,7 +192,7 @@ func (r *rpcClient) stream(ctx context.Context, address string, req Request, opt
 	case err := <-ch:
 		grr = err
 	case <-ctx.Done():
-		grr = errors.New("go.micro.client", fmt.Sprintf("request timeout: %v", ctx.Err()), 408)
+		grr = errors.Timeout("go.micro.client", fmt.Sprintf("%v", ctx.Err()))
 	}
 
 	if grr != nil {
@@ -274,7 +274,7 @@ func (r *rpcClient) Call(ctx context.Context, request Request, response interfac
 	// should we noop right here?
 	select {
 	case <-ctx.Done():
-		return errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
+		return errors.Timeout("go.micro.client", fmt.Sprintf("%v", ctx.Err()))
 	default:
 	}
 
@@ -329,7 +329,7 @@ func (r *rpcClient) Call(ctx context.Context, request Request, response interfac
 
 		select {
 		case <-ctx.Done():
-			return errors.New("go.micro.client", fmt.Sprintf("call timeout: %v", ctx.Err()), 408)
+			return errors.Timeout("go.micro.client", fmt.Sprintf("call timeout: %v", ctx.Err()))
 		case err := <-ch:
 			// if the call succeeded lets bail early
 			if err == nil {
@@ -367,7 +367,7 @@ func (r *rpcClient) Stream(ctx context.Context, request Request, opts ...CallOpt
 	// should we noop right here?
 	select {
 	case <-ctx.Done():
-		return nil, errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
+		return nil, errors.Timeout("go.micro.client", fmt.Sprintf("%v", ctx.Err()))
 	default:
 	}
 
@@ -416,7 +416,7 @@ func (r *rpcClient) Stream(ctx context.Context, request Request, opts ...CallOpt
 
 		select {
 		case <-ctx.Done():
-			return nil, errors.New("go.micro.client", fmt.Sprintf("call timeout: %v", ctx.Err()), 408)
+			return nil, errors.Timeout("go.micro.client", fmt.Sprintf("call timeout: %v", ctx.Err()))
 		case rsp := <-ch:
 			// if the call succeeded lets bail early
 			if rsp.err == nil {

client/rpc_codec.go

@@ -105,12 +105,16 @@ func newRpcPlusCodec(req *transport.Message, client transport.Client, c codec.Ne
 
 func (c *rpcPlusCodec) WriteRequest(req *request, body interface{}) error {
 	c.buf.wbuf.Reset()
+
 	m := &codec.Message{
 		Id:     req.Seq,
 		Target: req.Service,
 		Method: req.ServiceMethod,
 		Type:   codec.Request,
-		Header: map[string]string{},
+		Header: map[string]string{
+			"X-Micro-Target": req.Service,
+			"X-Micro-Method": req.ServiceMethod,
+		},
 	}
 	if err := c.codec.Write(m, body); err != nil {
 		return errors.InternalServerError("go.micro.client.codec", err.Error())

cmd/cmd.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/micro/cli"
+	"github.com/micro/go-log"
 	"github.com/micro/go-micro/client"
 	"github.com/micro/go-micro/server"
 
@@ -20,11 +21,11 @@ import (
 	// registries
 	"github.com/micro/go-micro/registry"
 	"github.com/micro/go-micro/registry/consul"
+	"github.com/micro/go-micro/registry/gossip"
 	"github.com/micro/go-micro/registry/mdns"
 
 	// selectors
 	"github.com/micro/go-micro/selector"
-	"github.com/micro/go-micro/selector/cache"
 
 	// transports
 	"github.com/micro/go-micro/transport"
@@ -147,7 +148,6 @@ var (
 			Name:   "selector",
 			EnvVar: "MICRO_SELECTOR",
 			Usage:  "Selector used to pick nodes for querying",
-			Value:  "cache",
 		},
 		cli.StringFlag{
 			Name:   "transport",
@@ -171,12 +171,13 @@ var (
 
 	DefaultRegistries = map[string]func(...registry.Option) registry.Registry{
 		"consul": consul.NewRegistry,
+		"gossip": gossip.NewRegistry,
 		"mdns":   mdns.NewRegistry,
 	}
 
 	DefaultSelectors = map[string]func(...selector.Option) selector.Selector{
 		"default": selector.NewSelector,
-		"cache":   cache.NewSelector,
+		"cache":   selector.NewSelector,
 	}
 
 	DefaultServers = map[string]func(...server.Option) server.Server{
@@ -299,10 +300,15 @@ func (c *cmd) Before(ctx *cli.Context) error {
 		serverOpts = append(serverOpts, server.Registry(*c.opts.Registry))
 		clientOpts = append(clientOpts, client.Registry(*c.opts.Registry))
 
-		(*c.opts.Selector).Init(selector.Registry(*c.opts.Registry))
+		if err := (*c.opts.Selector).Init(selector.Registry(*c.opts.Registry)); err != nil {
+			log.Fatalf("Error configuring registry: %v", err)
+		}
+
 		clientOpts = append(clientOpts, client.Selector(*c.opts.Selector))
 
-		(*c.opts.Broker).Init(broker.Registry(*c.opts.Registry))
+		if err := (*c.opts.Broker).Init(broker.Registry(*c.opts.Registry)); err != nil {
+			log.Fatalf("Error configuring broker: %v", err)
+		}
 	}
 
 	// Set the selector
@@ -347,15 +353,21 @@ func (c *cmd) Before(ctx *cli.Context) error {
 	}
 
 	if len(ctx.String("broker_address")) > 0 {
-		(*c.opts.Broker).Init(broker.Addrs(strings.Split(ctx.String("broker_address"), ",")...))
+		if err := (*c.opts.Broker).Init(broker.Addrs(strings.Split(ctx.String("broker_address"), ",")...)); err != nil {
+			log.Fatalf("Error configuring broker: %v", err)
+		}
 	}
 
 	if len(ctx.String("registry_address")) > 0 {
-		(*c.opts.Registry).Init(registry.Addrs(strings.Split(ctx.String("registry_address"), ",")...))
+		if err := (*c.opts.Registry).Init(registry.Addrs(strings.Split(ctx.String("registry_address"), ",")...)); err != nil {
+			log.Fatalf("Error configuring registry: %v", err)
+		}
 	}
 
 	if len(ctx.String("transport_address")) > 0 {
-		(*c.opts.Transport).Init(transport.Addrs(strings.Split(ctx.String("transport_address"), ",")...))
+		if err := (*c.opts.Transport).Init(transport.Addrs(strings.Split(ctx.String("transport_address"), ",")...)); err != nil {
+			log.Fatalf("Error configuring transport: %v", err)
+		}
 	}
 
 	if len(ctx.String("server_name")) > 0 {
@@ -410,12 +422,16 @@ func (c *cmd) Before(ctx *cli.Context) error {
 	// We have some command line opts for the server.
 	// Lets set it up
 	if len(serverOpts) > 0 {
-		(*c.opts.Server).Init(serverOpts...)
+		if err := (*c.opts.Server).Init(serverOpts...); err != nil {
+			log.Fatalf("Error configuring server: %v", err)
+		}
 	}
 
 	// Use an init option?
 	if len(clientOpts) > 0 {
-		(*c.opts.Client).Init(clientOpts...)
+		if err := (*c.opts.Client).Init(clientOpts...); err != nil {
+			log.Fatalf("Error configuring client: %v", err)
+		}
 	}
 
 	return nil

errors/errors.go

@@ -92,13 +92,13 @@ func MethodNotAllowed(id, format string, a ...interface{}) error {
 	}
 }
 
-// InternalServerError generates a 500 error.
-func InternalServerError(id, format string, a ...interface{}) error {
+// Timeout generates a 408 error.
+func Timeout(id, format string, a ...interface{}) error {
 	return &Error{
 		Id:     id,
-		Code:   500,
+		Code:   408,
 		Detail: fmt.Sprintf(format, a...),
-		Status: http.StatusText(500),
+		Status: http.StatusText(408),
 	}
 }
 
@@ -111,3 +111,13 @@ func Conflict(id, format string, a ...interface{}) error {
 		Status: http.StatusText(409),
 	}
 }
+
+// InternalServerError generates a 500 error.
+func InternalServerError(id, format string, a ...interface{}) error {
+	return &Error{
+		Id:     id,
+		Code:   500,
+		Detail: fmt.Sprintf(format, a...),
+		Status: http.StatusText(500),
+	}
+}

options.go

@@ -174,6 +174,7 @@ func RegisterInterval(t time.Duration) Option {
 
 // WrapClient is a convenience method for wrapping a Client with
 // some middleware component. A list of wrappers can be provided.
+// Wrappers are applied in reverse order so the last is executed first.
 func WrapClient(w ...client.Wrapper) Option {
 	return func(o *Options) {
 		// apply in reverse

registry/consul/consul.go

@@ -1,9 +1,11 @@
+// Package consul provides a consul based registry and is the default discovery system
 package consul
 
 import (
 	"github.com/micro/go-micro/registry"
 )
 
+// NewRegistry returns a new consul registry
 func NewRegistry(opts ...registry.Option) registry.Registry {
 	return registry.NewRegistry(opts...)
 }

registry/consul/options.go

@@ -27,6 +27,40 @@ func Config(c *consul.Config) registry.Option {
 	}
 }
 
+// AllowStale sets whether any Consul server (non-leader) can service
+// a read. This allows for lower latency and higher throughput
+// at the cost of potentially stale data.
+// Works similar to Consul DNS Config option [1].
+// Defaults to true.
+//
+// [1] https://www.consul.io/docs/agent/options.html#allow_stale
+//
+func AllowStale(v bool) registry.Option {
+	return func(o *registry.Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, "consul_allow_stale", v)
+	}
+}
+
+// QueryOptions specifies the QueryOptions to be used when calling
+// Consul. See `Consul API` for more information [1].
+//
+// [1] https://godoc.org/github.com/hashicorp/consul/api#QueryOptions
+//
+func QueryOptions(q *consul.QueryOptions) registry.Option {
+	return func(o *registry.Options) {
+		if q == nil {
+			return
+		}
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, "consul_query_options", q)
+	}
+}
+
 //
 // TCPCheck will tell the service provider to check the service address
 // and port every `t` interval. It will enabled only if `t` is greater than 0.

registry/consul_registry.go

@@ -22,6 +22,8 @@ type consulRegistry struct {
 	// connect enabled
 	connect bool
 
+	queryOptions *consul.QueryOptions
+
 	sync.Mutex
 	register map[string]uint64
 	// lastChecked tracks when a node was last checked as existing in Consul
@@ -80,6 +82,14 @@ func configure(c *consulRegistry, opts ...Option) {
 		if cn, ok := c.opts.Context.Value("consul_connect").(bool); ok {
 			c.connect = cn
 		}
+
+		// Use the consul query options passed in the options, if available
+		if qo, ok := c.opts.Context.Value("consul_query_options").(*consul.QueryOptions); ok && qo != nil {
+			c.queryOptions = qo
+		}
+		if as, ok := c.opts.Context.Value("consul_allow_stale").(bool); ok {
+			c.queryOptions.AllowStale = as
+		}
 	}
 
 	// check if there are any addrs
@@ -123,6 +133,9 @@ func newConsulRegistry(opts ...Option) Registry {
 		opts:        Options{},
 		register:    make(map[string]uint64),
 		lastChecked: make(map[string]time.Time),
+		queryOptions: &consul.QueryOptions{
+			AllowStale: true,
+		},
 	}
 	configure(cr, opts...)
 	return cr
@@ -177,21 +190,20 @@ func (c *consulRegistry) Register(s *Service, opts ...RegisterOption) error {
 	// use first node
 	node := s.Nodes[0]
 
-	// get existing hash
+	// get existing hash and last checked time
 	c.Lock()
 	v, ok := c.register[s.Name]
+	lastChecked := c.lastChecked[s.Name]
 	c.Unlock()
 
 	// if it's already registered and matches then just pass the check
 	if ok && v == h {
 		if options.TTL == time.Duration(0) {
 			// ensure that our service hasn't been deregistered by Consul
-			if time.Since(c.lastChecked[s.Name]) <= getDeregisterTTL(regInterval) {
+			if time.Since(lastChecked) <= getDeregisterTTL(regInterval) {
 				return nil
 			}
-			services, _, err := c.Client.Health().Checks(s.Name, &consul.QueryOptions{
-				AllowStale: true,
-			})
+			services, _, err := c.Client.Health().Checks(s.Name, c.queryOptions)
 			if err == nil {
 				for _, v := range services {
 					if v.ServiceID == node.Id {
@@ -276,9 +288,9 @@ func (c *consulRegistry) GetService(name string) ([]*Service, error) {
 
 	// if we're connect enabled only get connect services
 	if c.connect {
-		rsp, _, err = c.Client.Health().Connect(name, "", false, nil)
+		rsp, _, err = c.Client.Health().Connect(name, "", false, c.queryOptions)
 	} else {
-		rsp, _, err = c.Client.Health().Service(name, "", false, nil)
+		rsp, _, err = c.Client.Health().Service(name, "", false, c.queryOptions)
 	}
 	if err != nil {
 		return nil, err
@@ -347,7 +359,7 @@ func (c *consulRegistry) GetService(name string) ([]*Service, error) {
 }
 
 func (c *consulRegistry) ListServices() ([]*Service, error) {
-	rsp, _, err := c.Client.Catalog().Services(nil)
+	rsp, _, err := c.Client.Catalog().Services(c.queryOptions)
 	if err != nil {
 		return nil, err
 	}

registry/consul_registry_test.go

@@ -7,6 +7,7 @@ import (
 	"net"
 	"net/http"
 	"testing"
+	"time"
 
 	consul "github.com/hashicorp/consul/api"
 )
@@ -53,9 +54,14 @@ func newConsulTestRegistry(r *mockRegistry) (*consulRegistry, func()) {
 	go newMockServer(r, l)
 
 	return &consulRegistry{
-			Address:  cfg.Address,
-			Client:   cl,
-			register: make(map[string]uint64),
+			Address:     cfg.Address,
+			Client:      cl,
+			opts:        Options{},
+			register:    make(map[string]uint64),
+			lastChecked: make(map[string]time.Time),
+			queryOptions: &consul.QueryOptions{
+				AllowStale: true,
+			},
 		}, func() {
 			l.Close()
 		}

registry/gossip/README.md

@@ -0,0 +1,24 @@
+# Gossip Registry
+
+Gossip is a zero dependency registry which uses hashicorp/memberlist to broadcast registry information 
+via the SWIM protocol. 
+
+## Usage
+
+Start with the registry flag or env var
+
+```bash
+MICRO_REGISTRY=gossip go run service.go
+```
+
+On startup you'll see something like
+
+```bash
+2018/12/06 18:17:48 Registry Listening on 192.168.1.65:56390
+```
+
+To join this gossip ring set the registry address using flag or env var
+
+```bash
+MICRO_REGISTRY_ADDRESS= 192.168.1.65:56390 
+```

registry/gossip/gossip.go

@@ -0,0 +1,594 @@
+// Package Gossip provides a gossip registry based on hashicorp/memberlist
+package gossip
+
+import (
+	"context"
+	"encoding/json"
+	"io/ioutil"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/google/uuid"
+	"github.com/hashicorp/memberlist"
+	log "github.com/micro/go-log"
+	"github.com/micro/go-micro/registry"
+	pb "github.com/micro/go-micro/registry/gossip/proto"
+	"github.com/mitchellh/hashstructure"
+)
+
+const (
+	addAction  = "update"
+	delAction  = "delete"
+	syncAction = "sync"
+)
+
+type broadcast struct {
+	update *pb.Update
+	notify chan<- struct{}
+}
+
+type delegate struct {
+	queue   *memberlist.TransmitLimitedQueue
+	updates chan *update
+}
+
+type gossipRegistry struct {
+	queue    *memberlist.TransmitLimitedQueue
+	updates  chan *update
+	options  registry.Options
+	member   *memberlist.Memberlist
+	interval time.Duration
+
+	sync.RWMutex
+	services map[string][]*registry.Service
+
+	s        sync.RWMutex
+	watchers map[string]chan *registry.Result
+}
+
+type update struct {
+	Update  *pb.Update
+	Service *registry.Service
+	sync    chan *registry.Service
+}
+
+var (
+	// You should change this if using secure
+	DefaultSecret = []byte("micro-gossip-key") // exactly 16 bytes
+	ExpiryTick    = time.Second * 5
+)
+
+func configure(g *gossipRegistry, opts ...registry.Option) error {
+	// loop through address list and get valid entries
+	addrs := func(curAddrs []string) []string {
+		var newAddrs []string
+		for _, addr := range curAddrs {
+			if trimAddr := strings.TrimSpace(addr); len(trimAddr) > 0 {
+				newAddrs = append(newAddrs, trimAddr)
+			}
+		}
+		return newAddrs
+	}
+
+	// current address list
+	curAddrs := addrs(g.options.Addrs)
+
+	// parse options
+	for _, o := range opts {
+		o(&g.options)
+	}
+
+	// new address list
+	newAddrs := addrs(g.options.Addrs)
+
+	// no new nodes and existing member. no configure
+	if (len(newAddrs) == len(curAddrs)) && g.member != nil {
+		return nil
+	}
+
+	// shutdown old member
+	if g.member != nil {
+		g.member.Shutdown()
+	}
+
+	// replace addresses
+	curAddrs = newAddrs
+
+	// create a queue
+	queue := &memberlist.TransmitLimitedQueue{
+		NumNodes: func() int {
+			return len(curAddrs)
+		},
+		RetransmitMult: 3,
+	}
+
+	// create a new default config
+	c := memberlist.DefaultLocalConfig()
+
+	if optConfig, ok := g.options.Context.Value(contextConfig{}).(*memberlist.Config); ok && optConfig != nil {
+		c = optConfig
+	}
+
+	if hostport, ok := g.options.Context.Value(contextAddress{}).(string); ok {
+		host, port, err := net.SplitHostPort(hostport)
+		if err == nil {
+			pn, err := strconv.Atoi(port)
+			if err == nil {
+				c.BindPort = pn
+			}
+			c.BindAddr = host
+		}
+	} else {
+		// set bind to random port
+		c.BindPort = 0
+	}
+
+	if hostport, ok := g.options.Context.Value(contextAdvertise{}).(string); ok {
+		host, port, err := net.SplitHostPort(hostport)
+		if err == nil {
+			pn, err := strconv.Atoi(port)
+			if err == nil {
+				c.AdvertisePort = pn
+			}
+			c.AdvertiseAddr = host
+		}
+	}
+
+	// machine hostname
+	hostname, _ := os.Hostname()
+
+	// set the name
+	c.Name = strings.Join([]string{"micro", hostname, uuid.New().String()}, "-")
+
+	// set the delegate
+	c.Delegate = &delegate{
+		updates: g.updates,
+		queue:   queue,
+	}
+
+	// log to dev null
+	c.LogOutput = ioutil.Discard
+
+	// set a secret key if secure
+	if g.options.Secure {
+		k, ok := g.options.Context.Value(contextSecretKey{}).([]byte)
+		if !ok {
+			// use the default secret
+			k = DefaultSecret
+		}
+		c.SecretKey = k
+	}
+
+	// create the memberlist
+	m, err := memberlist.Create(c)
+	if err != nil {
+		return err
+	}
+
+	// join the memberlist
+	if len(curAddrs) > 0 {
+		_, err := m.Join(curAddrs)
+		if err != nil {
+			return err
+		}
+	}
+
+	// set internals
+	g.queue = queue
+	g.member = m
+	g.interval = c.GossipInterval
+
+	log.Logf("Registry Listening on %s", m.LocalNode().Address())
+	return nil
+}
+
+func (b *broadcast) Invalidates(other memberlist.Broadcast) bool {
+	up := new(pb.Update)
+	if err := proto.Unmarshal(other.Message(), up); err != nil {
+		return false
+	}
+
+	// ids do not match
+	if b.update.Id == up.Id {
+		return false
+	}
+
+	// timestamps do not match
+	if b.update.Timestamp != up.Timestamp {
+		return false
+	}
+
+	// type does not match
+	if b.update.Type != up.Type {
+		return false
+	}
+
+	// invalidates
+	return true
+}
+
+func (b *broadcast) Message() []byte {
+	up, err := proto.Marshal(b.update)
+	if err != nil {
+		return nil
+	}
+	return up
+}
+
+func (b *broadcast) Finished() {
+	if b.notify != nil {
+		close(b.notify)
+	}
+}
+
+func (d *delegate) NodeMeta(limit int) []byte {
+	return []byte{}
+}
+
+func (d *delegate) NotifyMsg(b []byte) {
+	if len(b) == 0 {
+		return
+	}
+
+	go func() {
+		up := new(pb.Update)
+		if err := proto.Unmarshal(b, up); err != nil {
+			return
+		}
+
+		// only process service action
+		if up.Type != "service" {
+			return
+		}
+
+		var service *registry.Service
+
+		switch up.Metadata["Content-Type"] {
+		case "application/json":
+			if err := json.Unmarshal(up.Data, &service); err != nil {
+				return
+			}
+		// no other content type
+		default:
+			return
+		}
+
+		// send update
+		d.updates <- &update{
+			Update:  up,
+			Service: service,
+		}
+	}()
+}
+
+func (d *delegate) GetBroadcasts(overhead, limit int) [][]byte {
+	return d.queue.GetBroadcasts(overhead, limit)
+}
+
+func (d *delegate) LocalState(join bool) []byte {
+	if !join {
+		return []byte{}
+	}
+
+	syncCh := make(chan *registry.Service, 1)
+	services := map[string][]*registry.Service{}
+
+	d.updates <- &update{
+		Update: &pb.Update{
+			Action: syncAction,
+		},
+		sync: syncCh,
+	}
+
+	for srv := range syncCh {
+		services[srv.Name] = append(services[srv.Name], srv)
+	}
+
+	b, _ := json.Marshal(services)
+	return b
+}
+
+func (d *delegate) MergeRemoteState(buf []byte, join bool) {
+	if len(buf) == 0 {
+		return
+	}
+	if !join {
+		return
+	}
+
+	var services map[string][]*registry.Service
+	if err := json.Unmarshal(buf, &services); err != nil {
+		return
+	}
+
+	for _, service := range services {
+		for _, srv := range service {
+			d.updates <- &update{
+				Update:  &pb.Update{Action: addAction},
+				Service: srv,
+				sync:    nil,
+			}
+		}
+	}
+}
+
+func (g *gossipRegistry) publish(action string, services []*registry.Service) {
+	g.s.RLock()
+	for _, sub := range g.watchers {
+		go func(sub chan *registry.Result) {
+			for _, service := range services {
+				sub <- &registry.Result{Action: action, Service: service}
+			}
+		}(sub)
+	}
+	g.s.RUnlock()
+}
+
+func (g *gossipRegistry) subscribe() (chan *registry.Result, chan bool) {
+	next := make(chan *registry.Result, 10)
+	exit := make(chan bool)
+
+	id := uuid.New().String()
+
+	g.s.Lock()
+	g.watchers[id] = next
+	g.s.Unlock()
+
+	go func() {
+		<-exit
+		g.s.Lock()
+		delete(g.watchers, id)
+		close(next)
+		g.s.Unlock()
+	}()
+
+	return next, exit
+}
+
+func (g *gossipRegistry) run() {
+	var mtx sync.Mutex
+	updates := map[uint64]*update{}
+
+	// expiry loop
+	go func() {
+		t := time.NewTicker(ExpiryTick)
+		defer t.Stop()
+
+		for _ = range t.C {
+			now := uint64(time.Now().UnixNano())
+
+			mtx.Lock()
+
+			// process all the updates
+			for k, v := range updates {
+				// check if expiry time has passed
+				if d := (v.Update.Timestamp + v.Update.Expires); d < now {
+					// delete from records
+					delete(updates, k)
+					// set to delete
+					v.Update.Action = delAction
+					// fire a new update
+					g.updates <- v
+				}
+			}
+
+			mtx.Unlock()
+		}
+	}()
+
+	// process the updates
+	for u := range g.updates {
+		switch u.Update.Action {
+		case addAction:
+			g.Lock()
+			if service, ok := g.services[u.Service.Name]; !ok {
+				g.services[u.Service.Name] = []*registry.Service{u.Service}
+
+			} else {
+				g.services[u.Service.Name] = addServices(service, []*registry.Service{u.Service})
+			}
+			g.Unlock()
+
+			// publish update to watchers
+			go g.publish(addAction, []*registry.Service{u.Service})
+
+			// we need to expire the node at some point in the future
+			if u.Update.Expires > 0 {
+				// create a hash of this service
+				if hash, err := hashstructure.Hash(u.Service, nil); err == nil {
+					mtx.Lock()
+					updates[hash] = u
+					mtx.Unlock()
+				}
+			}
+		case delAction:
+			g.Lock()
+			if service, ok := g.services[u.Service.Name]; ok {
+				if services := delServices(service, []*registry.Service{u.Service}); len(services) == 0 {
+					delete(g.services, u.Service.Name)
+				} else {
+					g.services[u.Service.Name] = services
+				}
+			}
+			g.Unlock()
+
+			// publish update to watchers
+			go g.publish(delAction, []*registry.Service{u.Service})
+
+			// delete from expiry checks
+			if hash, err := hashstructure.Hash(u.Service, nil); err == nil {
+				mtx.Lock()
+				delete(updates, hash)
+				mtx.Unlock()
+			}
+		case syncAction:
+			// no sync channel provided
+			if u.sync == nil {
+				continue
+			}
+
+			g.RLock()
+
+			// push all services through the sync chan
+			for _, service := range g.services {
+				for _, srv := range service {
+					u.sync <- srv
+				}
+
+				// publish to watchers
+				go g.publish(addAction, service)
+			}
+
+			g.RUnlock()
+
+			// close the sync chan
+			close(u.sync)
+		}
+	}
+}
+
+func (g *gossipRegistry) Init(opts ...registry.Option) error {
+	return configure(g, opts...)
+}
+
+func (g *gossipRegistry) Options() registry.Options {
+	return g.options
+}
+
+func (g *gossipRegistry) Register(s *registry.Service, opts ...registry.RegisterOption) error {
+	b, err := json.Marshal(s)
+	if err != nil {
+		return err
+	}
+
+	g.Lock()
+	if service, ok := g.services[s.Name]; !ok {
+		g.services[s.Name] = []*registry.Service{s}
+	} else {
+		g.services[s.Name] = addServices(service, []*registry.Service{s})
+	}
+	g.Unlock()
+
+	var options registry.RegisterOptions
+	for _, o := range opts {
+		o(&options)
+	}
+
+	up := &pb.Update{
+		Id:        uuid.New().String(),
+		Timestamp: uint64(time.Now().UnixNano()),
+		Expires:   uint64(options.TTL.Nanoseconds()),
+		Action:    "update",
+		Type:      "service",
+		Metadata: map[string]string{
+			"Content-Type": "application/json",
+		},
+		Data: b,
+	}
+
+	g.queue.QueueBroadcast(&broadcast{
+		update: up,
+		notify: nil,
+	})
+
+	// wait
+	<-time.After(g.interval * 2)
+
+	return nil
+}
+
+func (g *gossipRegistry) Deregister(s *registry.Service) error {
+	b, err := json.Marshal(s)
+	if err != nil {
+		return err
+	}
+
+	g.Lock()
+	if service, ok := g.services[s.Name]; ok {
+		if services := delServices(service, []*registry.Service{s}); len(services) == 0 {
+			delete(g.services, s.Name)
+		} else {
+			g.services[s.Name] = services
+		}
+	}
+	g.Unlock()
+
+	up := &pb.Update{
+		Id:        uuid.New().String(),
+		Timestamp: uint64(time.Now().UnixNano()),
+		Action:    "delete",
+		Type:      "service",
+		Metadata: map[string]string{
+			"Content-Type": "application/json",
+		},
+		Data: b,
+	}
+
+	g.queue.QueueBroadcast(&broadcast{
+		update: up,
+		notify: nil,
+	})
+
+	// wait
+	<-time.After(g.interval * 2)
+
+	return nil
+}
+
+func (g *gossipRegistry) GetService(name string) ([]*registry.Service, error) {
+	g.RLock()
+	service, ok := g.services[name]
+	g.RUnlock()
+	if !ok {
+		return nil, registry.ErrNotFound
+	}
+	return service, nil
+}
+
+func (g *gossipRegistry) ListServices() ([]*registry.Service, error) {
+	var services []*registry.Service
+	g.RLock()
+	for _, service := range g.services {
+		services = append(services, service...)
+	}
+	g.RUnlock()
+	return services, nil
+}
+
+func (g *gossipRegistry) Watch(opts ...registry.WatchOption) (registry.Watcher, error) {
+	n, e := g.subscribe()
+	return newGossipWatcher(n, e, opts...)
+}
+
+func (g *gossipRegistry) String() string {
+	return "gossip"
+}
+
+func NewRegistry(opts ...registry.Option) registry.Registry {
+	gossip := &gossipRegistry{
+		options: registry.Options{
+			Context: context.Background(),
+		},
+		updates:  make(chan *update, 100),
+		services: make(map[string][]*registry.Service),
+		watchers: make(map[string]chan *registry.Result),
+	}
+
+	// run the updater
+	go gossip.run()
+
+	// configure the gossiper
+	if err := configure(gossip, opts...); err != nil {
+		log.Fatalf("Error configuring registry: %v", err)
+	}
+
+	// wait for setup
+	<-time.After(gossip.interval * 2)
+
+	return gossip
+}

registry/gossip/options.go

@@ -0,0 +1,45 @@
+package gossip
+
+import (
+	"context"
+
+	"github.com/hashicorp/memberlist"
+	"github.com/micro/go-micro/registry"
+)
+
+type contextSecretKey struct{}
+
+// Secret specifies an encryption key. The value should be either
+// 16, 24, or 32 bytes to select AES-128, AES-192, or AES-256.
+func Secret(k []byte) registry.Option {
+	return func(o *registry.Options) {
+		o.Context = context.WithValue(o.Context, contextSecretKey{}, k)
+	}
+}
+
+type contextAddress struct{}
+
+// Address to bind to - host:port
+func Address(a string) registry.Option {
+	return func(o *registry.Options) {
+		o.Context = context.WithValue(o.Context, contextAddress{}, a)
+	}
+}
+
+type contextConfig struct{}
+
+// Config allow to inject a *memberlist.Config struct for configuring gossip
+func Config(c *memberlist.Config) registry.Option {
+	return func(o *registry.Options) {
+		o.Context = context.WithValue(o.Context, contextConfig{}, c)
+	}
+}
+
+type contextAdvertise struct{}
+
+// The address to advertise for other gossip members - host:port
+func Advertise(a string) registry.Option {
+	return func(o *registry.Options) {
+		o.Context = context.WithValue(o.Context, contextAdvertise{}, a)
+	}
+}

registry/gossip/proto/gossip.micro.go

@@ -0,0 +1,28 @@
+// Code generated by protoc-gen-micro. DO NOT EDIT.
+// source: github.com/micro/go-micro/registry/gossip/proto/gossip.proto
+
+/*
+Package gossip is a generated protocol buffer package.
+
+It is generated from these files:
+	github.com/micro/go-micro/registry/gossip/proto/gossip.proto
+
+It has these top-level messages:
+	Update
+*/
+package gossip
+
+import proto "github.com/golang/protobuf/proto"
+import fmt "fmt"
+import math "math"
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package

registry/gossip/proto/gossip.pb.go

@@ -0,0 +1,145 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// source: github.com/micro/go-micro/registry/gossip/proto/gossip.proto
+
+package gossip
+
+import (
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	math "math"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
+// Update is the message broadcast
+type Update struct {
+	// unique id of update
+	Id string `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`
+	// unix nano timestamp of update
+	Timestamp uint64 `protobuf:"varint,2,opt,name=timestamp,proto3" json:"timestamp,omitempty"`
+	// time to live for entry
+	Expires uint64 `protobuf:"varint,3,opt,name=expires,proto3" json:"expires,omitempty"`
+	// type of update; service
+	Type string `protobuf:"bytes,4,opt,name=type,proto3" json:"type,omitempty"`
+	// what action is taken; add, del, put
+	Action string `protobuf:"bytes,5,opt,name=action,proto3" json:"action,omitempty"`
+	// any other associated metadata about the data
+	Metadata map[string]string `protobuf:"bytes,6,rep,name=metadata,proto3" json:"metadata,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
+	// the payload data;
+	Data                 []byte   `protobuf:"bytes,7,opt,name=data,proto3" json:"data,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *Update) Reset()         { *m = Update{} }
+func (m *Update) String() string { return proto.CompactTextString(m) }
+func (*Update) ProtoMessage()    {}
+func (*Update) Descriptor() ([]byte, []int) {
+	return fileDescriptor_18cba623e76e57f3, []int{0}
+}
+
+func (m *Update) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Update.Unmarshal(m, b)
+}
+func (m *Update) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Update.Marshal(b, m, deterministic)
+}
+func (m *Update) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Update.Merge(m, src)
+}
+func (m *Update) XXX_Size() int {
+	return xxx_messageInfo_Update.Size(m)
+}
+func (m *Update) XXX_DiscardUnknown() {
+	xxx_messageInfo_Update.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Update proto.InternalMessageInfo
+
+func (m *Update) GetId() string {
+	if m != nil {
+		return m.Id
+	}
+	return ""
+}
+
+func (m *Update) GetTimestamp() uint64 {
+	if m != nil {
+		return m.Timestamp
+	}
+	return 0
+}
+
+func (m *Update) GetExpires() uint64 {
+	if m != nil {
+		return m.Expires
+	}
+	return 0
+}
+
+func (m *Update) GetType() string {
+	if m != nil {
+		return m.Type
+	}
+	return ""
+}
+
+func (m *Update) GetAction() string {
+	if m != nil {
+		return m.Action
+	}
+	return ""
+}
+
+func (m *Update) GetMetadata() map[string]string {
+	if m != nil {
+		return m.Metadata
+	}
+	return nil
+}
+
+func (m *Update) GetData() []byte {
+	if m != nil {
+		return m.Data
+	}
+	return nil
+}
+
+func init() {
+	proto.RegisterType((*Update)(nil), "gossip.Update")
+	proto.RegisterMapType((map[string]string)(nil), "gossip.Update.MetadataEntry")
+}
+
+func init() {
+	proto.RegisterFile("github.com/micro/go-micro/registry/gossip/proto/gossip.proto", fileDescriptor_18cba623e76e57f3)
+}
+
+var fileDescriptor_18cba623e76e57f3 = []byte{
+	// 251 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x54, 0x90, 0xcf, 0x4a, 0xc4, 0x30,
+	0x10, 0x87, 0x69, 0xb6, 0x9b, 0xb5, 0xe3, 0x1f, 0x64, 0x10, 0x09, 0xb2, 0x87, 0xe2, 0xa9, 0x17,
+	0x5b, 0xd0, 0xcb, 0xa2, 0x5e, 0x3d, 0x7a, 0x09, 0xf8, 0x00, 0xd9, 0x36, 0xd4, 0xa0, 0xd9, 0x84,
+	0x64, 0x56, 0xec, 0x13, 0xf8, 0xda, 0xb2, 0x69, 0x54, 0xbc, 0x7d, 0xdf, 0xcc, 0x24, 0x99, 0x5f,
+	0xe0, 0x71, 0x34, 0xf4, 0xba, 0xdf, 0xb6, 0xbd, 0xb3, 0x9d, 0x35, 0x7d, 0x70, 0xdd, 0xe8, 0x6e,
+	0x66, 0x08, 0x7a, 0x34, 0x91, 0xc2, 0xd4, 0x8d, 0x2e, 0x46, 0xe3, 0x3b, 0x1f, 0x1c, 0xb9, 0x2c,
+	0x6d, 0x12, 0xe4, 0xb3, 0x5d, 0x7f, 0x31, 0xe0, 0x2f, 0x7e, 0x50, 0xa4, 0xf1, 0x0c, 0x98, 0x19,
+	0x44, 0x51, 0x17, 0x4d, 0x25, 0x99, 0x19, 0x70, 0x0d, 0x15, 0x19, 0xab, 0x23, 0x29, 0xeb, 0x05,
+	0xab, 0x8b, 0xa6, 0x94, 0x7f, 0x05, 0x14, 0xb0, 0xd2, 0x9f, 0xde, 0x04, 0x1d, 0xc5, 0x22, 0xf5,
+	0x7e, 0x14, 0x11, 0x4a, 0x9a, 0xbc, 0x16, 0x65, 0xba, 0x29, 0x31, 0x5e, 0x02, 0x57, 0x3d, 0x19,
+	0xb7, 0x13, 0xcb, 0x54, 0xcd, 0x86, 0x1b, 0x38, 0xb2, 0x9a, 0xd4, 0xa0, 0x48, 0x09, 0x5e, 0x2f,
+	0x9a, 0xe3, 0xdb, 0x75, 0x9b, 0xf7, 0x9c, 0xb7, 0x6a, 0x9f, 0x73, 0xfb, 0x69, 0x47, 0x61, 0x92,
+	0xbf, 0xd3, 0x87, 0x57, 0xd2, 0xa9, 0x55, 0x5d, 0x34, 0x27, 0x32, 0xf1, 0xd5, 0x03, 0x9c, 0xfe,
+	0x1b, 0xc7, 0x73, 0x58, 0xbc, 0xe9, 0x29, 0x67, 0x3a, 0x20, 0x5e, 0xc0, 0xf2, 0x43, 0xbd, 0xef,
+	0x75, 0x0a, 0x54, 0xc9, 0x59, 0xee, 0xd9, 0xa6, 0xd8, 0xf2, 0xf4, 0x31, 0x77, 0xdf, 0x01, 0x00,
+	0x00, 0xff, 0xff, 0x06, 0x6e, 0x00, 0x3c, 0x58, 0x01, 0x00, 0x00,
+}

registry/gossip/proto/gossip.proto

@@ -0,0 +1,21 @@
+syntax = "proto3";
+
+package gossip;
+
+// Update is the message broadcast
+message Update {
+	// unique id of update
+	string id = 1;
+	// unix nano timestamp of update
+	uint64 timestamp = 2;
+	// time to live for entry
+	uint64 expires = 3;
+	// type of update; service
+	string type = 4;
+	// what action is taken; add, del, put
+	string action = 5;
+	// any other associated metadata about the data
+	map<string, string> metadata = 6;
+	// the payload data;
+	bytes data = 7;
+}

registry/gossip/util.go

@@ -0,0 +1,132 @@
+package gossip
+
+import (
+	"github.com/micro/go-micro/registry"
+)
+
+func cp(current []*registry.Service) []*registry.Service {
+	var services []*registry.Service
+
+	for _, service := range current {
+		// copy service
+		s := new(registry.Service)
+		*s = *service
+
+		// copy nodes
+		var nodes []*registry.Node
+		for _, node := range service.Nodes {
+			n := new(registry.Node)
+			*n = *node
+			nodes = append(nodes, n)
+		}
+		s.Nodes = nodes
+
+		// copy endpoints
+		var eps []*registry.Endpoint
+		for _, ep := range service.Endpoints {
+			e := new(registry.Endpoint)
+			*e = *ep
+			eps = append(eps, e)
+		}
+		s.Endpoints = eps
+
+		// append service
+		services = append(services, s)
+	}
+
+	return services
+}
+
+func addNodes(old, neu []*registry.Node) []*registry.Node {
+	var nodes []*registry.Node
+
+	// add all new nodes
+	for _, n := range neu {
+		node := *n
+		nodes = append(nodes, &node)
+	}
+
+	// look at old nodes
+	for _, o := range old {
+		var exists bool
+
+		// check against new nodes
+		for _, n := range nodes {
+			// ids match then skip
+			if o.Id == n.Id {
+				exists = true
+				break
+			}
+		}
+
+		// keep old node
+		if !exists {
+			node := *o
+			nodes = append(nodes, &node)
+		}
+	}
+
+	return nodes
+}
+
+func addServices(old, neu []*registry.Service) []*registry.Service {
+	for _, s := range neu {
+		var seen bool
+		for i, o := range old {
+			if o.Version == s.Version {
+				s.Nodes = addNodes(o.Nodes, s.Nodes)
+				seen = true
+				old[i] = s
+				break
+			}
+		}
+		if !seen {
+			old = append(old, s)
+		}
+	}
+	return old
+}
+
+func delNodes(old, del []*registry.Node) []*registry.Node {
+	var nodes []*registry.Node
+	for _, o := range old {
+		var rem bool
+		for _, n := range del {
+			if o.Id == n.Id {
+				rem = true
+				break
+			}
+		}
+		if !rem {
+			nodes = append(nodes, o)
+		}
+	}
+	return nodes
+}
+
+func delServices(old, del []*registry.Service) []*registry.Service {
+	var services []*registry.Service
+
+	for _, o := range old {
+		srv := new(registry.Service)
+		*srv = *o
+
+		var rem bool
+
+		for _, s := range del {
+			if srv.Version == s.Version {
+				srv.Nodes = delNodes(srv.Nodes, s.Nodes)
+
+				if len(srv.Nodes) == 0 {
+					rem = true
+				}
+			}
+		}
+
+		if !rem {
+			services = append(services, srv)
+		}
+	}
+
+	return services
+}

registry/gossip/util_test.go

@@ -0,0 +1,78 @@
+package gossip
+
+import (
+	"testing"
+
+	"github.com/micro/go-micro/registry"
+)
+
+func TestDelServices(t *testing.T) {
+	services := []*registry.Service{
+		{
+			Name:    "foo",
+			Version: "1.0.0",
+			Nodes: []*registry.Node{
+				{
+					Id:      "foo-123",
+					Address: "localhost",
+					Port:    9999,
+				},
+			},
+		},
+		{
+			Name:    "foo",
+			Version: "1.0.0",
+			Nodes: []*registry.Node{
+				{
+					Id:      "foo-123",
+					Address: "localhost",
+					Port:    6666,
+				},
+			},
+		},
+	}
+
+	servs := delServices([]*registry.Service{services[0]}, []*registry.Service{services[1]})
+	if i := len(servs); i > 0 {
+		t.Errorf("Expected 0 nodes, got %d: %+v", i, servs)
+	}
+	t.Logf("Services %+v", servs)
+}
+
+func TestDelNodes(t *testing.T) {
+	services := []*registry.Service{
+		{
+			Name:    "foo",
+			Version: "1.0.0",
+			Nodes: []*registry.Node{
+				{
+					Id:      "foo-123",
+					Address: "localhost",
+					Port:    9999,
+				},
+				{
+					Id:      "foo-321",
+					Address: "localhost",
+					Port:    6666,
+				},
+			},
+		},
+		{
+			Name:    "foo",
+			Version: "1.0.0",
+			Nodes: []*registry.Node{
+				{
+					Id:      "foo-123",
+					Address: "localhost",
+					Port:    6666,
+				},
+			},
+		},
+	}
+
+	nodes := delNodes(services[0].Nodes, services[1].Nodes)
+	if i := len(nodes); i != 1 {
+		t.Errorf("Expected only 1 node, got %d: %+v", i, nodes)
+	}
+	t.Logf("Nodes %+v", nodes)
+}

registry/gossip/watcher.go

@@ -0,0 +1,51 @@
+package gossip
+
+import (
+	"github.com/micro/go-micro/registry"
+)
+
+type gossipWatcher struct {
+	wo   registry.WatchOptions
+	next chan *registry.Result
+	stop chan bool
+}
+
+func newGossipWatcher(ch chan *registry.Result, stop chan bool, opts ...registry.WatchOption) (registry.Watcher, error) {
+	var wo registry.WatchOptions
+	for _, o := range opts {
+		o(&wo)
+	}
+
+	return &gossipWatcher{
+		wo:   wo,
+		next: ch,
+		stop: stop,
+	}, nil
+}
+
+func (m *gossipWatcher) Next() (*registry.Result, error) {
+	for {
+		select {
+		case r, ok := <-m.next:
+			if !ok {
+				return nil, registry.ErrWatcherStopped
+			}
+			// check watch options
+			if len(m.wo.Service) > 0 && r.Service.Name != m.wo.Service {
+				continue
+			}
+			return r, nil
+		case <-m.stop:
+			return nil, registry.ErrWatcherStopped
+		}
+	}
+}
+
+func (m *gossipWatcher) Stop() {
+	select {
+	case <-m.stop:
+		return
+	default:
+		close(m.stop)
+	}
+}

registry/mdns/mdns.go

@@ -1,3 +1,4 @@
+// Package mdns is a multicast dns registry
 package mdns
 
 /*

registry/mock/mock.go

@@ -1,3 +1,4 @@
+// Package mock provides a mock registry for testing
 package mock
 
 import (

registry/registry.go

@@ -28,7 +28,10 @@ type WatchOption func(*WatchOptions)
 var (
 	DefaultRegistry = newConsulRegistry()
 
+	// Not found error when GetService is called
 	ErrNotFound = errors.New("not found")
+	// Watcher stopped error when watcher is stopped
+	ErrWatcherStopped = errors.New("watcher stopped")
 )
 
 func NewRegistry(opts ...Option) Registry {

selector/cache/cache.go

@@ -1,424 +0,0 @@
-// Package cache is a caching selector. It uses the registry watcher.
-package cache
-
-import (
-	"sync"
-	"time"
-
-	"github.com/micro/go-log"
-	"github.com/micro/go-micro/registry"
-	"github.com/micro/go-micro/selector"
-)
-
-type cacheSelector struct {
-	so  selector.Options
-	ttl time.Duration
-
-	// registry cache
-	sync.Mutex
-	cache map[string][]*registry.Service
-	ttls  map[string]time.Time
-
-	watched map[string]bool
-
-	// used to close or reload watcher
-	reload chan bool
-	exit   chan bool
-}
-
-var (
-	DefaultTTL = time.Minute
-)
-
-func (c *cacheSelector) quit() bool {
-	select {
-	case <-c.exit:
-		return true
-	default:
-		return false
-	}
-}
-
-// cp copies a service. Because we're caching handing back pointers would
-// create a race condition, so we do this instead
-// its fast enough
-func (c *cacheSelector) cp(current []*registry.Service) []*registry.Service {
-	var services []*registry.Service
-
-	for _, service := range current {
-		// copy service
-		s := new(registry.Service)
-		*s = *service
-
-		// copy nodes
-		var nodes []*registry.Node
-		for _, node := range service.Nodes {
-			n := new(registry.Node)
-			*n = *node
-			nodes = append(nodes, n)
-		}
-		s.Nodes = nodes
-
-		// copy endpoints
-		var eps []*registry.Endpoint
-		for _, ep := range service.Endpoints {
-			e := new(registry.Endpoint)
-			*e = *ep
-			eps = append(eps, e)
-		}
-		s.Endpoints = eps
-
-		// append service
-		services = append(services, s)
-	}
-
-	return services
-}
-
-func (c *cacheSelector) del(service string) {
-	delete(c.cache, service)
-	delete(c.ttls, service)
-}
-
-func (c *cacheSelector) get(service string) ([]*registry.Service, error) {
-	c.Lock()
-	defer c.Unlock()
-
-	// watch service if not watched
-	if _, ok := c.watched[service]; !ok {
-		go c.run(service)
-		c.watched[service] = true
-	}
-
-	// get does the actual request for a service
-	// it also caches it
-	get := func(service string) ([]*registry.Service, error) {
-		// ask the registry
-		services, err := c.so.Registry.GetService(service)
-		if err != nil {
-			return nil, err
-		}
-
-		// cache results
-		c.set(service, c.cp(services))
-		return services, nil
-	}
-
-	// check the cache first
-	services, ok := c.cache[service]
-
-	// cache miss or no services
-	if !ok || len(services) == 0 {
-		return get(service)
-	}
-
-	// got cache but lets check ttl
-	ttl, kk := c.ttls[service]
-
-	// within ttl so return cache
-	if kk && time.Since(ttl) < c.ttl {
-		return c.cp(services), nil
-	}
-
-	// expired entry so get service
-	services, err := get(service)
-
-	// no error then return error
-	if err == nil {
-		return services, nil
-	}
-
-	// not found error then return
-	if err == registry.ErrNotFound {
-		return nil, selector.ErrNotFound
-	}
-
-	// other error
-
-	// return expired cache as last resort
-	return c.cp(services), nil
-}
-
-func (c *cacheSelector) set(service string, services []*registry.Service) {
-	c.cache[service] = services
-	c.ttls[service] = time.Now().Add(c.ttl)
-}
-
-func (c *cacheSelector) update(res *registry.Result) {
-	if res == nil || res.Service == nil {
-		return
-	}
-
-	c.Lock()
-	defer c.Unlock()
-
-	services, ok := c.cache[res.Service.Name]
-	if !ok {
-		// we're not going to cache anything
-		// unless there was already a lookup
-		return
-	}
-
-	if len(res.Service.Nodes) == 0 {
-		switch res.Action {
-		case "delete":
-			c.del(res.Service.Name)
-		}
-		return
-	}
-
-	// existing service found
-	var service *registry.Service
-	var index int
-	for i, s := range services {
-		if s.Version == res.Service.Version {
-			service = s
-			index = i
-		}
-	}
-
-	switch res.Action {
-	case "create", "update":
-		if service == nil {
-			c.set(res.Service.Name, append(services, res.Service))
-			return
-		}
-
-		// append old nodes to new service
-		for _, cur := range service.Nodes {
-			var seen bool
-			for _, node := range res.Service.Nodes {
-				if cur.Id == node.Id {
-					seen = true
-					break
-				}
-			}
-			if !seen {
-				res.Service.Nodes = append(res.Service.Nodes, cur)
-			}
-		}
-
-		services[index] = res.Service
-		c.set(res.Service.Name, services)
-	case "delete":
-		if service == nil {
-			return
-		}
-
-		var nodes []*registry.Node
-
-		// filter cur nodes to remove the dead one
-		for _, cur := range service.Nodes {
-			var seen bool
-			for _, del := range res.Service.Nodes {
-				if del.Id == cur.Id {
-					seen = true
-					break
-				}
-			}
-			if !seen {
-				nodes = append(nodes, cur)
-			}
-		}
-
-		// still got nodes, save and return
-		if len(nodes) > 0 {
-			service.Nodes = nodes
-			services[index] = service
-			c.set(service.Name, services)
-			return
-		}
-
-		// zero nodes left
-
-		// only have one thing to delete
-		// nuke the thing
-		if len(services) == 1 {
-			c.del(service.Name)
-			return
-		}
-
-		// still have more than 1 service
-		// check the version and keep what we know
-		var srvs []*registry.Service
-		for _, s := range services {
-			if s.Version != service.Version {
-				srvs = append(srvs, s)
-			}
-		}
-
-		// save
-		c.set(service.Name, srvs)
-	}
-}
-
-// run starts the cache watcher loop
-// it creates a new watcher if there's a problem
-// reloads the watcher if Init is called
-// and returns when Close is called
-func (c *cacheSelector) run(name string) {
-	for {
-		// exit early if already dead
-		if c.quit() {
-			return
-		}
-
-		// create new watcher
-		w, err := c.so.Registry.Watch(
-			registry.WatchService(name),
-		)
-		if err != nil {
-			if c.quit() {
-				return
-			}
-			log.Log(err)
-			time.Sleep(time.Second)
-			continue
-		}
-
-		// watch for events
-		if err := c.watch(w); err != nil {
-			if c.quit() {
-				return
-			}
-			log.Log(err)
-			continue
-		}
-	}
-}
-
-// watch loops the next event and calls update
-// it returns if there's an error
-func (c *cacheSelector) watch(w registry.Watcher) error {
-	defer w.Stop()
-
-	// manage this loop
-	go func() {
-		// wait for exit or reload signal
-		select {
-		case <-c.exit:
-		case <-c.reload:
-		}
-
-		// stop the watcher
-		w.Stop()
-	}()
-
-	for {
-		res, err := w.Next()
-		if err != nil {
-			return err
-		}
-		c.update(res)
-	}
-}
-
-func (c *cacheSelector) Init(opts ...selector.Option) error {
-	for _, o := range opts {
-		o(&c.so)
-	}
-
-	// reload the watcher
-	go func() {
-		select {
-		case <-c.exit:
-			return
-		default:
-			c.reload <- true
-		}
-	}()
-
-	return nil
-}
-
-func (c *cacheSelector) Options() selector.Options {
-	return c.so
-}
-
-func (c *cacheSelector) Select(service string, opts ...selector.SelectOption) (selector.Next, error) {
-	sopts := selector.SelectOptions{
-		Strategy: c.so.Strategy,
-	}
-
-	for _, opt := range opts {
-		opt(&sopts)
-	}
-
-	// get the service
-	// try the cache first
-	// if that fails go directly to the registry
-	services, err := c.get(service)
-	if err != nil {
-		return nil, err
-	}
-
-	// apply the filters
-	for _, filter := range sopts.Filters {
-		services = filter(services)
-	}
-
-	// if there's nothing left, return
-	if len(services) == 0 {
-		return nil, selector.ErrNoneAvailable
-	}
-
-	return sopts.Strategy(services), nil
-}
-
-func (c *cacheSelector) Mark(service string, node *registry.Node, err error) {
-}
-
-func (c *cacheSelector) Reset(service string) {
-}
-
-// Close stops the watcher and destroys the cache
-func (c *cacheSelector) Close() error {
-	c.Lock()
-	c.cache = make(map[string][]*registry.Service)
-	c.watched = make(map[string]bool)
-	c.Unlock()
-
-	select {
-	case <-c.exit:
-		return nil
-	default:
-		close(c.exit)
-	}
-	return nil
-}
-
-func (c *cacheSelector) String() string {
-	return "cache"
-}
-
-func NewSelector(opts ...selector.Option) selector.Selector {
-	sopts := selector.Options{
-		Strategy: selector.Random,
-	}
-
-	for _, opt := range opts {
-		opt(&sopts)
-	}
-
-	if sopts.Registry == nil {
-		sopts.Registry = registry.DefaultRegistry
-	}
-
-	ttl := DefaultTTL
-
-	if sopts.Context != nil {
-		if t, ok := sopts.Context.Value(ttlKey{}).(time.Duration); ok {
-			ttl = t
-		}
-	}
-
-	return &cacheSelector{
-		so:      sopts,
-		ttl:     ttl,
-		watched: make(map[string]bool),
-		cache:   make(map[string][]*registry.Service),
-		ttls:    make(map[string]time.Time),
-		reload:  make(chan bool, 1),
-		exit:    make(chan bool),
-	}
-}

selector/cache/cache_test.go

@@ -1,29 +0,0 @@
-package cache
-
-import (
-	"testing"
-
-	"github.com/micro/go-micro/registry/mock"
-	"github.com/micro/go-micro/selector"
-)
-
-func TestCacheSelector(t *testing.T) {
-	counts := map[string]int{}
-
-	cache := NewSelector(selector.Registry(mock.NewRegistry()))
-
-	next, err := cache.Select("foo")
-	if err != nil {
-		t.Errorf("Unexpected error calling cache select: %v", err)
-	}
-
-	for i := 0; i < 100; i++ {
-		node, err := next()
-		if err != nil {
-			t.Errorf("Expected node err, got err: %v", err)
-		}
-		counts[node.Id]++
-	}
-
-	t.Logf("Cache Counts %v", counts)
-}

selector/default.go

@@ -1,27 +1,341 @@
 package selector
 
 import (
+	"sync"
+	"time"
+
+	"github.com/micro/go-log"
 	"github.com/micro/go-micro/registry"
 )
 
-type defaultSelector struct {
-	so Options
+type registrySelector struct {
+	so  Options
+	ttl time.Duration
+
+	// registry cache
+	sync.RWMutex
+	cache map[string][]*registry.Service
+	ttls  map[string]time.Time
+
+	watched map[string]bool
+
+	// used to close or reload watcher
+	reload chan bool
+	exit   chan bool
 }
 
-func (r *defaultSelector) Init(opts ...Option) error {
-	for _, o := range opts {
-		o(&r.so)
+var (
+	DefaultTTL = time.Minute
+)
+
+func (c *registrySelector) quit() bool {
+	select {
+	case <-c.exit:
+		return true
+	default:
+		return false
 	}
+}
+
+// cp copies a service. Because we're caching handing back pointers would
+// create a race condition, so we do this instead
+// its fast enough
+func (c *registrySelector) cp(current []*registry.Service) []*registry.Service {
+	var services []*registry.Service
+
+	for _, service := range current {
+		// copy service
+		s := new(registry.Service)
+		*s = *service
+
+		// copy nodes
+		var nodes []*registry.Node
+		for _, node := range service.Nodes {
+			n := new(registry.Node)
+			*n = *node
+			nodes = append(nodes, n)
+		}
+		s.Nodes = nodes
+
+		// copy endpoints
+		var eps []*registry.Endpoint
+		for _, ep := range service.Endpoints {
+			e := new(registry.Endpoint)
+			*e = *ep
+			eps = append(eps, e)
+		}
+		s.Endpoints = eps
+
+		// append service
+		services = append(services, s)
+	}
+
+	return services
+}
+
+func (c *registrySelector) del(service string) {
+	delete(c.cache, service)
+	delete(c.ttls, service)
+}
+
+func (c *registrySelector) get(service string) ([]*registry.Service, error) {
+	// read lock
+	c.RLock()
+
+	// check the cache first
+	services, ok := c.cache[service]
+	// get cache ttl
+	ttl, kk := c.ttls[service]
+
+	// got services && within ttl so return cache
+	if ok && kk && time.Since(ttl) < c.ttl {
+		// make a copy
+		cp := c.cp(services)
+		// unlock the read
+		c.RUnlock()
+		// return servics
+		return cp, nil
+	}
+
+	// get does the actual request for a service and cache it
+	get := func(service string) ([]*registry.Service, error) {
+		// ask the registry
+		services, err := c.so.Registry.GetService(service)
+		if err != nil {
+			return nil, err
+		}
+
+		// cache results
+		c.Lock()
+		c.set(service, c.cp(services))
+		c.Unlock()
+
+		return services, nil
+	}
+
+	// watch service if not watched
+	if _, ok := c.watched[service]; !ok {
+		go c.run(service)
+	}
+
+	// unlock the read lock
+	c.RUnlock()
+
+	// get and return services
+	return get(service)
+}
+
+func (c *registrySelector) set(service string, services []*registry.Service) {
+	c.cache[service] = services
+	c.ttls[service] = time.Now().Add(c.ttl)
+}
+
+func (c *registrySelector) update(res *registry.Result) {
+	if res == nil || res.Service == nil {
+		return
+	}
+
+	c.Lock()
+	defer c.Unlock()
+
+	services, ok := c.cache[res.Service.Name]
+	if !ok {
+		// we're not going to cache anything
+		// unless there was already a lookup
+		return
+	}
+
+	if len(res.Service.Nodes) == 0 {
+		switch res.Action {
+		case "delete":
+			c.del(res.Service.Name)
+		}
+		return
+	}
+
+	// existing service found
+	var service *registry.Service
+	var index int
+	for i, s := range services {
+		if s.Version == res.Service.Version {
+			service = s
+			index = i
+		}
+	}
+
+	switch res.Action {
+	case "create", "update":
+		if service == nil {
+			c.set(res.Service.Name, append(services, res.Service))
+			return
+		}
+
+		// append old nodes to new service
+		for _, cur := range service.Nodes {
+			var seen bool
+			for _, node := range res.Service.Nodes {
+				if cur.Id == node.Id {
+					seen = true
+					break
+				}
+			}
+			if !seen {
+				res.Service.Nodes = append(res.Service.Nodes, cur)
+			}
+		}
+
+		services[index] = res.Service
+		c.set(res.Service.Name, services)
+	case "delete":
+		if service == nil {
+			return
+		}
+
+		var nodes []*registry.Node
+
+		// filter cur nodes to remove the dead one
+		for _, cur := range service.Nodes {
+			var seen bool
+			for _, del := range res.Service.Nodes {
+				if del.Id == cur.Id {
+					seen = true
+					break
+				}
+			}
+			if !seen {
+				nodes = append(nodes, cur)
+			}
+		}
+
+		// still got nodes, save and return
+		if len(nodes) > 0 {
+			service.Nodes = nodes
+			services[index] = service
+			c.set(service.Name, services)
+			return
+		}
+
+		// zero nodes left
+
+		// only have one thing to delete
+		// nuke the thing
+		if len(services) == 1 {
+			c.del(service.Name)
+			return
+		}
+
+		// still have more than 1 service
+		// check the version and keep what we know
+		var srvs []*registry.Service
+		for _, s := range services {
+			if s.Version != service.Version {
+				srvs = append(srvs, s)
+			}
+		}
+
+		// save
+		c.set(service.Name, srvs)
+	}
+}
+
+// run starts the cache watcher loop
+// it creates a new watcher if there's a problem
+// reloads the watcher if Init is called
+// and returns when Close is called
+func (c *registrySelector) run(name string) {
+	// set watcher
+	c.Lock()
+	c.watched[name] = true
+	c.Unlock()
+
+	// delete watcher on exit
+	defer func() {
+		c.Lock()
+		delete(c.watched, name)
+		c.Unlock()
+	}()
+
+	for {
+		// exit early if already dead
+		if c.quit() {
+			return
+		}
+
+		// create new watcher
+		w, err := c.so.Registry.Watch(
+			registry.WatchService(name),
+		)
+		if err != nil {
+			if c.quit() {
+				return
+			}
+			log.Log(err)
+			time.Sleep(time.Second)
+			continue
+		}
+
+		// watch for events
+		if err := c.watch(w); err != nil {
+			if c.quit() {
+				return
+			}
+			log.Log(err)
+			continue
+		}
+	}
+}
+
+// watch loops the next event and calls update
+// it returns if there's an error
+func (c *registrySelector) watch(w registry.Watcher) error {
+	defer w.Stop()
+
+	// manage this loop
+	go func() {
+		// wait for exit or reload signal
+		select {
+		case <-c.exit:
+		case <-c.reload:
+		}
+
+		// stop the watcher
+		w.Stop()
+	}()
+
+	for {
+		res, err := w.Next()
+		if err != nil {
+			return err
+		}
+		c.update(res)
+	}
+}
+
+func (c *registrySelector) Init(opts ...Option) error {
+	for _, o := range opts {
+		o(&c.so)
+	}
+
+	// reload the watcher
+	go func() {
+		select {
+		case <-c.exit:
+			return
+		default:
+			c.reload <- true
+		}
+	}()
+
 	return nil
 }
 
-func (r *defaultSelector) Options() Options {
-	return r.so
+func (c *registrySelector) Options() Options {
+	return c.so
 }
 
-func (r *defaultSelector) Select(service string, opts ...SelectOption) (Next, error) {
+func (c *registrySelector) Select(service string, opts ...SelectOption) (Next, error) {
 	sopts := SelectOptions{
-		Strategy: r.so.Strategy,
+		Strategy: c.so.Strategy,
 	}
 
 	for _, opt := range opts {
@@ -29,7 +343,9 @@ func (r *defaultSelector) Select(service string, opts ...SelectOption) (Next, er
 	}
 
 	// get the service
-	services, err := r.so.Registry.GetService(service)
+	// try the cache first
+	// if that fails go directly to the registry
+	services, err := c.get(service)
 	if err != nil {
 		return nil, err
 	}
@@ -47,21 +363,33 @@ func (r *defaultSelector) Select(service string, opts ...SelectOption) (Next, er
 	return sopts.Strategy(services), nil
 }
 
-func (r *defaultSelector) Mark(service string, node *registry.Node, err error) {
+func (c *registrySelector) Mark(service string, node *registry.Node, err error) {
 }
 
-func (r *defaultSelector) Reset(service string) {
+func (c *registrySelector) Reset(service string) {
 }
 
-func (r *defaultSelector) Close() error {
+// Close stops the watcher and destroys the cache
+func (c *registrySelector) Close() error {
+	c.Lock()
+	c.cache = make(map[string][]*registry.Service)
+	c.watched = make(map[string]bool)
+	c.Unlock()
+
+	select {
+	case <-c.exit:
+		return nil
+	default:
+		close(c.exit)
+	}
 	return nil
 }
 
-func (r *defaultSelector) String() string {
-	return "default"
+func (c *registrySelector) String() string {
+	return "registry"
 }
 
-func newDefaultSelector(opts ...Option) Selector {
+func NewSelector(opts ...Option) Selector {
 	sopts := Options{
 		Strategy: Random,
 	}
@@ -74,7 +402,21 @@ func newDefaultSelector(opts ...Option) Selector {
 		sopts.Registry = registry.DefaultRegistry
 	}
 
-	return &defaultSelector{
-		so: sopts,
+	ttl := DefaultTTL
+
+	if sopts.Context != nil {
+		if t, ok := sopts.Context.Value("selector_ttl").(time.Duration); ok {
+			ttl = t
+		}
+	}
+
+	return &registrySelector{
+		so:      sopts,
+		ttl:     ttl,
+		watched: make(map[string]bool),
+		cache:   make(map[string][]*registry.Service),
+		ttls:    make(map[string]time.Time),
+		reload:  make(chan bool, 1),
+		exit:    make(chan bool),
 	}
 }

selector/default_test.go

@@ -6,14 +6,14 @@ import (
 	"github.com/micro/go-micro/registry/mock"
 )
 
-func TestDefaultSelector(t *testing.T) {
+func TestRegistrySelector(t *testing.T) {
 	counts := map[string]int{}
 
-	rs := newDefaultSelector(Registry(mock.NewRegistry()))
+	cache := NewSelector(Registry(mock.NewRegistry()))
 
-	next, err := rs.Select("foo")
+	next, err := cache.Select("foo")
 	if err != nil {
-		t.Errorf("Unexpected error calling default select: %v", err)
+		t.Errorf("Unexpected error calling cache select: %v", err)
 	}
 
 	for i := 0; i < 100; i++ {
@@ -24,5 +24,5 @@ func TestDefaultSelector(t *testing.T) {
 		counts[node.Id]++
 	}
 
-	t.Logf("Default Counts %v", counts)
+	t.Logf("Selector Counts %v", counts)
 }

selector/registry/options.go

@@ -1,4 +1,4 @@
-package cache
+package registry
 
 import (
 	"context"
@@ -7,14 +7,12 @@ import (
 	"github.com/micro/go-micro/selector"
 )
 
-type ttlKey struct{}
-
-// Set the cache ttl
+// Set the registry cache ttl
 func TTL(t time.Duration) selector.Option {
 	return func(o *selector.Options) {
 		if o.Context == nil {
 			o.Context = context.Background()
 		}
-		o.Context = context.WithValue(o.Context, ttlKey{}, t)
+		o.Context = context.WithValue(o.Context, "selector_ttl", t)
 	}
 }

selector/registry/registry.go

@@ -0,0 +1,11 @@
+// Package registry is uses the go-micro registry for selection
+package registry
+
+import (
+	"github.com/micro/go-micro/selector"
+)
+
+// NewSelector returns a new registry selector
+func NewSelector(opts ...selector.Option) selector.Selector {
+	return selector.NewSelector(opts...)
+}

selector/selector.go

@@ -35,12 +35,8 @@ type Filter func([]*registry.Service) []*registry.Service
 type Strategy func([]*registry.Service) Next
 
 var (
-	DefaultSelector = newDefaultSelector()
+	DefaultSelector = NewSelector()
 
 	ErrNotFound      = errors.New("not found")
 	ErrNoneAvailable = errors.New("none available")
 )
-
-func NewSelector(opts ...Option) Selector {
-	return newDefaultSelector(opts...)
-}

server/handler.go

@@ -1,37 +1,5 @@
 package server
 
-import (
-	"github.com/micro/go-micro/registry"
-)
-
-// Handler interface represents a Service request handler. It's generated
-// by passing any type of public concrete object with methods into server.NewHandler.
-// Most will pass in a struct.
-//
-// Example:
-//
-//	type Service struct {}
-//
-//	func (s *Service) Method(context, request, response) error {
-//		return nil
-//	}
-//
-type Handler interface {
-	Name() string
-	Handler() interface{}
-	Endpoints() []*registry.Endpoint
-	Options() HandlerOptions
-}
-
-// Subscriber interface represents a subscription to a given topic using
-// a specific subscriber function or object with methods.
-type Subscriber interface {
-	Topic() string
-	Subscriber() interface{}
-	Endpoints() []*registry.Endpoint
-	Options() SubscriberOptions
-}
-
 type HandlerOptions struct {
 	Internal bool
 	Metadata map[string]map[string]string

server/rpc_codec.go

@@ -10,7 +10,7 @@ import (
 	"github.com/pkg/errors"
 )
 
-type rpcPlusCodec struct {
+type rpcCodec struct {
 	socket transport.Socket
 	codec  codec.Codec
 
@@ -47,12 +47,12 @@ func (rwc *readWriteCloser) Close() error {
 	return nil
 }
 
-func newRpcPlusCodec(req *transport.Message, socket transport.Socket, c codec.NewCodec) serverCodec {
+func newRpcCodec(req *transport.Message, socket transport.Socket, c codec.NewCodec) serverCodec {
 	rwc := &readWriteCloser{
 		rbuf: bytes.NewBuffer(req.Body),
 		wbuf: bytes.NewBuffer(nil),
 	}
-	r := &rpcPlusCodec{
+	r := &rpcCodec{
 		buf:    rwc,
 		codec:  c(rwc),
 		req:    req,
@@ -61,7 +61,7 @@ func newRpcPlusCodec(req *transport.Message, socket transport.Socket, c codec.Ne
 	return r
 }
 
-func (c *rpcPlusCodec) ReadRequestHeader(r *request, first bool) error {
+func (c *rpcCodec) ReadRequestHeader(r *request, first bool) error {
 	m := codec.Message{Header: c.req.Header}
 
 	if !first {
@@ -83,11 +83,11 @@ func (c *rpcPlusCodec) ReadRequestHeader(r *request, first bool) error {
 	return err
 }
 
-func (c *rpcPlusCodec) ReadRequestBody(b interface{}) error {
+func (c *rpcCodec) ReadRequestBody(b interface{}) error {
 	return c.codec.ReadBody(b)
 }
 
-func (c *rpcPlusCodec) WriteResponse(r *response, body interface{}, last bool) error {
+func (c *rpcCodec) WriteResponse(r *response, body interface{}, last bool) error {
 	c.buf.wbuf.Reset()
 	m := &codec.Message{
 		Method: r.ServiceMethod,
@@ -111,7 +111,7 @@ func (c *rpcPlusCodec) WriteResponse(r *response, body interface{}, last bool) e
 	})
 }
 
-func (c *rpcPlusCodec) Close() error {
+func (c *rpcCodec) Close() error {
 	c.buf.Close()
 	c.codec.Close()
 	return c.socket.Close()

server/rpc_codec_test.go

@@ -38,7 +38,7 @@ func TestCodecWriteError(t *testing.T) {
 		wbuf: new(bytes.Buffer),
 	}
 
-	c := rpcPlusCodec{
+	c := rpcCodec{
 		buf: &rwc,
 		codec: &testCodec{
 			buf: rwc.wbuf,

server/rpc_server.go

@@ -87,7 +87,7 @@ func (s *rpcServer) accept(sock transport.Socket) {
 			return
 		}
 
-		codec := newRpcPlusCodec(&msg, sock, cf)
+		codec := newRpcCodec(&msg, sock, cf)
 
 		// strip our headers
 		hdr := make(map[string]string)

server/server.go

@@ -9,8 +9,10 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/micro/go-log"
+	"github.com/micro/go-micro/registry"
 )
 
+// Server is a simple micro server abstraction
 type Server interface {
 	Options() Options
 	Init(...Option) error
@@ -25,12 +27,14 @@ type Server interface {
 	String() string
 }
 
+// Message is an async message interface
 type Message interface {
 	Topic() string
 	Payload() interface{}
 	ContentType() string
 }
 
+// Request is a synchronous request interface
 type Request interface {
 	Service() string
 	Method() string
@@ -43,7 +47,7 @@ type Request interface {
 // Stream represents a stream established with a client.
 // A stream can be bidirectional which is indicated by the request.
 // The last error will be left in Error().
-// EOF indicated end of the stream.
+// EOF indicates end of the stream.
 type Stream interface {
 	Context() context.Context
 	Request() Request
@@ -53,6 +57,34 @@ type Stream interface {
 	Close() error
 }
 
+// Handler interface represents a request handler. It's generated
+// by passing any type of public concrete object with methods into server.NewHandler.
+// Most will pass in a struct.
+//
+// Example:
+//
+//      type Greeter struct {}
+//
+//      func (g *Greeter) Hello(context, request, response) error {
+//              return nil
+//      }
+//
+type Handler interface {
+	Name() string
+	Handler() interface{}
+	Endpoints() []*registry.Endpoint
+	Options() HandlerOptions
+}
+
+// Subscriber interface represents a subscription to a given topic using
+// a specific subscriber function or object with methods.
+type Subscriber interface {
+	Topic() string
+	Subscriber() interface{}
+	Endpoints() []*registry.Endpoint
+	Options() SubscriberOptions
+}
+
 type Option func(*Options)
 
 type HandlerOption func(*HandlerOptions)