Merge pull request #815 from micro/broker

Add broker service implementation

broker/http_broker.go

@@ -324,15 +324,21 @@ func (h *httpBroker) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	p := &httpEvent{m: m, t: topic}
 	id := req.Form.Get("id")
 
+	var subs []Handler
+
 	h.RLock()
 	for _, subscriber := range h.subscribers[topic] {
-		if id == subscriber.id {
+		if id != subscriber.id {
-			// sub is sync; crufty rate limiting
+			continue
-			// so we don't hose the cpu
-			subscriber.fn(p)
 		}
+		subs = append(subs, subscriber.fn)
 	}
 	h.RUnlock()
+
+	// execute the handler
+	for _, fn := range subs {
+		fn(p)
+	}
 }
 
 func (h *httpBroker) Address() string {
@@ -420,7 +426,6 @@ func (h *httpBroker) Connect() error {
 }
 
 func (h *httpBroker) Disconnect() error {
-
 	h.RLock()
 	if !h.running {
 		h.RUnlock()

broker/service/handler/handler.go

@@ -0,0 +1,66 @@
+package handler
+
+import (
+	"context"
+
+	"github.com/micro/go-micro/broker"
+	pb "github.com/micro/go-micro/broker/service/proto"
+	"github.com/micro/go-micro/errors"
+	"github.com/micro/go-micro/util/log"
+)
+
+type Broker struct {
+	Broker broker.Broker
+}
+
+func (b *Broker) Publish(ctx context.Context, req *pb.PublishRequest, rsp *pb.Empty) error {
+	log.Debugf("Publishing message to %s topic", req.Topic)
+	err := b.Broker.Publish(req.Topic, &broker.Message{
+		Header: req.Message.Header,
+		Body:   req.Message.Body,
+	})
+	log.Debugf("Published message to %s topic", req.Topic)
+	if err != nil {
+		return errors.InternalServerError("go.micro.broker", err.Error())
+	}
+	return nil
+}
+
+func (b *Broker) Subscribe(ctx context.Context, req *pb.SubscribeRequest, stream pb.Broker_SubscribeStream) error {
+	errChan := make(chan error, 1)
+
+	// message handler to stream back messages from broker
+	handler := func(p broker.Event) error {
+		if err := stream.Send(&pb.Message{
+			Header: p.Message().Header,
+			Body:   p.Message().Body,
+		}); err != nil {
+			select {
+			case errChan <- err:
+				return err
+			default:
+				return err
+			}
+		}
+		return nil
+	}
+
+	log.Debugf("Subscribing to %s topic", req.Topic)
+	sub, err := b.Broker.Subscribe(req.Topic, handler, broker.Queue(req.Queue))
+	if err != nil {
+		return errors.InternalServerError("go.micro.broker", err.Error())
+	}
+	defer func() {
+		log.Debugf("Unsubscribing from topic %s", req.Topic)
+		sub.Unsubscribe()
+	}()
+
+	select {
+	case <-ctx.Done():
+		log.Debugf("Context done for subscription to topic %s", req.Topic)
+		return nil
+	case err := <-errChan:
+		log.Debugf("Subscription error for topic %s: %v", req.Topic, err)
+		return err
+	}
+}

broker/service/proto/broker.micro.go

@@ -0,0 +1,173 @@
+// Code generated by protoc-gen-micro. DO NOT EDIT.
+// source: github.com/micro/go-micro/broker/proto/broker.proto
+
+package go_micro_broker
+
+import (
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	math "math"
+)
+
+import (
+	context "context"
+	client "github.com/micro/go-micro/client"
+	server "github.com/micro/go-micro/server"
+)
+
+// 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
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ context.Context
+var _ client.Option
+var _ server.Option
+
+// Client API for Broker service
+
+type BrokerService interface {
+	Publish(ctx context.Context, in *PublishRequest, opts ...client.CallOption) (*Empty, error)
+	Subscribe(ctx context.Context, in *SubscribeRequest, opts ...client.CallOption) (Broker_SubscribeService, error)
+}
+
+type brokerService struct {
+	c    client.Client
+	name string
+}
+
+func NewBrokerService(name string, c client.Client) BrokerService {
+	if c == nil {
+		c = client.NewClient()
+	}
+	if len(name) == 0 {
+		name = "go.micro.broker"
+	}
+	return &brokerService{
+		c:    c,
+		name: name,
+	}
+}
+
+func (c *brokerService) Publish(ctx context.Context, in *PublishRequest, opts ...client.CallOption) (*Empty, error) {
+	req := c.c.NewRequest(c.name, "Broker.Publish", in)
+	out := new(Empty)
+	err := c.c.Call(ctx, req, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *brokerService) Subscribe(ctx context.Context, in *SubscribeRequest, opts ...client.CallOption) (Broker_SubscribeService, error) {
+	req := c.c.NewRequest(c.name, "Broker.Subscribe", &SubscribeRequest{})
+	stream, err := c.c.Stream(ctx, req, opts...)
+	if err != nil {
+		return nil, err
+	}
+	if err := stream.Send(in); err != nil {
+		return nil, err
+	}
+	return &brokerServiceSubscribe{stream}, nil
+}
+
+type Broker_SubscribeService interface {
+	SendMsg(interface{}) error
+	RecvMsg(interface{}) error
+	Close() error
+	Recv() (*Message, error)
+}
+
+type brokerServiceSubscribe struct {
+	stream client.Stream
+}
+
+func (x *brokerServiceSubscribe) Close() error {
+	return x.stream.Close()
+}
+
+func (x *brokerServiceSubscribe) SendMsg(m interface{}) error {
+	return x.stream.Send(m)
+}
+
+func (x *brokerServiceSubscribe) RecvMsg(m interface{}) error {
+	return x.stream.Recv(m)
+}
+
+func (x *brokerServiceSubscribe) Recv() (*Message, error) {
+	m := new(Message)
+	err := x.stream.Recv(m)
+	if err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+// Server API for Broker service
+
+type BrokerHandler interface {
+	Publish(context.Context, *PublishRequest, *Empty) error
+	Subscribe(context.Context, *SubscribeRequest, Broker_SubscribeStream) error
+}
+
+func RegisterBrokerHandler(s server.Server, hdlr BrokerHandler, opts ...server.HandlerOption) error {
+	type broker interface {
+		Publish(ctx context.Context, in *PublishRequest, out *Empty) error
+		Subscribe(ctx context.Context, stream server.Stream) error
+	}
+	type Broker struct {
+		broker
+	}
+	h := &brokerHandler{hdlr}
+	return s.Handle(s.NewHandler(&Broker{h}, opts...))
+}
+
+type brokerHandler struct {
+	BrokerHandler
+}
+
+func (h *brokerHandler) Publish(ctx context.Context, in *PublishRequest, out *Empty) error {
+	return h.BrokerHandler.Publish(ctx, in, out)
+}
+
+func (h *brokerHandler) Subscribe(ctx context.Context, stream server.Stream) error {
+	m := new(SubscribeRequest)
+	if err := stream.Recv(m); err != nil {
+		return err
+	}
+	return h.BrokerHandler.Subscribe(ctx, m, &brokerSubscribeStream{stream})
+}
+
+type Broker_SubscribeStream interface {
+	SendMsg(interface{}) error
+	RecvMsg(interface{}) error
+	Close() error
+	Send(*Message) error
+}
+
+type brokerSubscribeStream struct {
+	stream server.Stream
+}
+
+func (x *brokerSubscribeStream) Close() error {
+	return x.stream.Close()
+}
+
+func (x *brokerSubscribeStream) SendMsg(m interface{}) error {
+	return x.stream.Send(m)
+}
+
+func (x *brokerSubscribeStream) RecvMsg(m interface{}) error {
+	return x.stream.Recv(m)
+}
+
+func (x *brokerSubscribeStream) Send(m *Message) error {
+	return x.stream.Send(m)
+}

broker/service/proto/broker.pb.go

@@ -0,0 +1,364 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// source: github.com/micro/go-micro/broker/proto/broker.proto
+
+package go_micro_broker
+
+import (
+	context "context"
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	grpc "google.golang.org/grpc"
+	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
+
+type Empty struct {
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *Empty) Reset()         { *m = Empty{} }
+func (m *Empty) String() string { return proto.CompactTextString(m) }
+func (*Empty) ProtoMessage()    {}
+func (*Empty) Descriptor() ([]byte, []int) {
+	return fileDescriptor_5edf81766900dd99, []int{0}
+}
+
+func (m *Empty) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Empty.Unmarshal(m, b)
+}
+func (m *Empty) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Empty.Marshal(b, m, deterministic)
+}
+func (m *Empty) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Empty.Merge(m, src)
+}
+func (m *Empty) XXX_Size() int {
+	return xxx_messageInfo_Empty.Size(m)
+}
+func (m *Empty) XXX_DiscardUnknown() {
+	xxx_messageInfo_Empty.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Empty proto.InternalMessageInfo
+
+type PublishRequest struct {
+	Topic                string   `protobuf:"bytes,1,opt,name=topic,proto3" json:"topic,omitempty"`
+	Message              *Message `protobuf:"bytes,2,opt,name=message,proto3" json:"message,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *PublishRequest) Reset()         { *m = PublishRequest{} }
+func (m *PublishRequest) String() string { return proto.CompactTextString(m) }
+func (*PublishRequest) ProtoMessage()    {}
+func (*PublishRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_5edf81766900dd99, []int{1}
+}
+
+func (m *PublishRequest) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_PublishRequest.Unmarshal(m, b)
+}
+func (m *PublishRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_PublishRequest.Marshal(b, m, deterministic)
+}
+func (m *PublishRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_PublishRequest.Merge(m, src)
+}
+func (m *PublishRequest) XXX_Size() int {
+	return xxx_messageInfo_PublishRequest.Size(m)
+}
+func (m *PublishRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_PublishRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_PublishRequest proto.InternalMessageInfo
+
+func (m *PublishRequest) GetTopic() string {
+	if m != nil {
+		return m.Topic
+	}
+	return ""
+}
+
+func (m *PublishRequest) GetMessage() *Message {
+	if m != nil {
+		return m.Message
+	}
+	return nil
+}
+
+type SubscribeRequest struct {
+	Topic                string   `protobuf:"bytes,1,opt,name=topic,proto3" json:"topic,omitempty"`
+	Queue                string   `protobuf:"bytes,2,opt,name=queue,proto3" json:"queue,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *SubscribeRequest) Reset()         { *m = SubscribeRequest{} }
+func (m *SubscribeRequest) String() string { return proto.CompactTextString(m) }
+func (*SubscribeRequest) ProtoMessage()    {}
+func (*SubscribeRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_5edf81766900dd99, []int{2}
+}
+
+func (m *SubscribeRequest) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_SubscribeRequest.Unmarshal(m, b)
+}
+func (m *SubscribeRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_SubscribeRequest.Marshal(b, m, deterministic)
+}
+func (m *SubscribeRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_SubscribeRequest.Merge(m, src)
+}
+func (m *SubscribeRequest) XXX_Size() int {
+	return xxx_messageInfo_SubscribeRequest.Size(m)
+}
+func (m *SubscribeRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_SubscribeRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_SubscribeRequest proto.InternalMessageInfo
+
+func (m *SubscribeRequest) GetTopic() string {
+	if m != nil {
+		return m.Topic
+	}
+	return ""
+}
+
+func (m *SubscribeRequest) GetQueue() string {
+	if m != nil {
+		return m.Queue
+	}
+	return ""
+}
+
+type Message struct {
+	Header               map[string]string `protobuf:"bytes,1,rep,name=header,proto3" json:"header,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
+	Body                 []byte            `protobuf:"bytes,2,opt,name=body,proto3" json:"body,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}          `json:"-"`
+	XXX_unrecognized     []byte            `json:"-"`
+	XXX_sizecache        int32             `json:"-"`
+}
+
+func (m *Message) Reset()         { *m = Message{} }
+func (m *Message) String() string { return proto.CompactTextString(m) }
+func (*Message) ProtoMessage()    {}
+func (*Message) Descriptor() ([]byte, []int) {
+	return fileDescriptor_5edf81766900dd99, []int{3}
+}
+
+func (m *Message) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Message.Unmarshal(m, b)
+}
+func (m *Message) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Message.Marshal(b, m, deterministic)
+}
+func (m *Message) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Message.Merge(m, src)
+}
+func (m *Message) XXX_Size() int {
+	return xxx_messageInfo_Message.Size(m)
+}
+func (m *Message) XXX_DiscardUnknown() {
+	xxx_messageInfo_Message.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Message proto.InternalMessageInfo
+
+func (m *Message) GetHeader() map[string]string {
+	if m != nil {
+		return m.Header
+	}
+	return nil
+}
+
+func (m *Message) GetBody() []byte {
+	if m != nil {
+		return m.Body
+	}
+	return nil
+}
+
+func init() {
+	proto.RegisterType((*Empty)(nil), "go.micro.broker.Empty")
+	proto.RegisterType((*PublishRequest)(nil), "go.micro.broker.PublishRequest")
+	proto.RegisterType((*SubscribeRequest)(nil), "go.micro.broker.SubscribeRequest")
+	proto.RegisterType((*Message)(nil), "go.micro.broker.Message")
+	proto.RegisterMapType((map[string]string)(nil), "go.micro.broker.Message.HeaderEntry")
+}
+
+func init() {
+	proto.RegisterFile("github.com/micro/go-micro/broker/proto/broker.proto", fileDescriptor_5edf81766900dd99)
+}
+
+var fileDescriptor_5edf81766900dd99 = []byte{
+	// 309 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x7c, 0x91, 0xcf, 0x4a, 0xf3, 0x40,
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+	0x02, 0x2b, 0x02, 0x00, 0x00,
+}
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ context.Context
+var _ grpc.ClientConn
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the grpc package it is being compiled against.
+const _ = grpc.SupportPackageIsVersion4
+
+// BrokerClient is the client API for Broker service.
+//
+// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://godoc.org/google.golang.org/grpc#ClientConn.NewStream.
+type BrokerClient interface {
+	Publish(ctx context.Context, in *PublishRequest, opts ...grpc.CallOption) (*Empty, error)
+	Subscribe(ctx context.Context, in *SubscribeRequest, opts ...grpc.CallOption) (Broker_SubscribeClient, error)
+}
+
+type brokerClient struct {
+	cc *grpc.ClientConn
+}
+
+func NewBrokerClient(cc *grpc.ClientConn) BrokerClient {
+	return &brokerClient{cc}
+}
+
+func (c *brokerClient) Publish(ctx context.Context, in *PublishRequest, opts ...grpc.CallOption) (*Empty, error) {
+	out := new(Empty)
+	err := c.cc.Invoke(ctx, "/go.micro.broker.Broker/Publish", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *brokerClient) Subscribe(ctx context.Context, in *SubscribeRequest, opts ...grpc.CallOption) (Broker_SubscribeClient, error) {
+	stream, err := c.cc.NewStream(ctx, &_Broker_serviceDesc.Streams[0], "/go.micro.broker.Broker/Subscribe", opts...)
+	if err != nil {
+		return nil, err
+	}
+	x := &brokerSubscribeClient{stream}
+	if err := x.ClientStream.SendMsg(in); err != nil {
+		return nil, err
+	}
+	if err := x.ClientStream.CloseSend(); err != nil {
+		return nil, err
+	}
+	return x, nil
+}
+
+type Broker_SubscribeClient interface {
+	Recv() (*Message, error)
+	grpc.ClientStream
+}
+
+type brokerSubscribeClient struct {
+	grpc.ClientStream
+}
+
+func (x *brokerSubscribeClient) Recv() (*Message, error) {
+	m := new(Message)
+	if err := x.ClientStream.RecvMsg(m); err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+// BrokerServer is the server API for Broker service.
+type BrokerServer interface {
+	Publish(context.Context, *PublishRequest) (*Empty, error)
+	Subscribe(*SubscribeRequest, Broker_SubscribeServer) error
+}
+
+func RegisterBrokerServer(s *grpc.Server, srv BrokerServer) {
+	s.RegisterService(&_Broker_serviceDesc, srv)
+}
+
+func _Broker_Publish_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(PublishRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(BrokerServer).Publish(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/go.micro.broker.Broker/Publish",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(BrokerServer).Publish(ctx, req.(*PublishRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+func _Broker_Subscribe_Handler(srv interface{}, stream grpc.ServerStream) error {
+	m := new(SubscribeRequest)
+	if err := stream.RecvMsg(m); err != nil {
+		return err
+	}
+	return srv.(BrokerServer).Subscribe(m, &brokerSubscribeServer{stream})
+}
+
+type Broker_SubscribeServer interface {
+	Send(*Message) error
+	grpc.ServerStream
+}
+
+type brokerSubscribeServer struct {
+	grpc.ServerStream
+}
+
+func (x *brokerSubscribeServer) Send(m *Message) error {
+	return x.ServerStream.SendMsg(m)
+}
+
+var _Broker_serviceDesc = grpc.ServiceDesc{
+	ServiceName: "go.micro.broker.Broker",
+	HandlerType: (*BrokerServer)(nil),
+	Methods: []grpc.MethodDesc{
+		{
+			MethodName: "Publish",
+			Handler:    _Broker_Publish_Handler,
+		},
+	},
+	Streams: []grpc.StreamDesc{
+		{
+			StreamName:    "Subscribe",
+			Handler:       _Broker_Subscribe_Handler,
+			ServerStreams: true,
+		},
+	},
+	Metadata: "github.com/micro/go-micro/broker/proto/broker.proto",
+}

broker/service/proto/broker.proto

@@ -0,0 +1,25 @@
+syntax = "proto3";
+
+package go.micro.broker;
+
+service Broker {
+	rpc Publish(PublishRequest) returns (Empty) {};
+	rpc Subscribe(SubscribeRequest) returns (stream Message) {};
+}
+
+message Empty {}
+
+message PublishRequest {
+	string topic = 1;
+	Message message = 2;
+}
+
+message SubscribeRequest {
+	string topic = 1;
+	string queue = 2;
+}
+
+message Message {
+	map<string,string> header = 1;
+	bytes body = 2;
+}

broker/service/service.go

@@ -0,0 +1,132 @@
+// Package service provides the broker service client
+package service
+
+import (
+	"context"
+	"time"
+
+	"github.com/micro/go-micro/broker"
+	pb "github.com/micro/go-micro/broker/service/proto"
+	"github.com/micro/go-micro/client"
+	"github.com/micro/go-micro/util/log"
+)
+
+type serviceBroker struct {
+	Addrs   []string
+	Client  pb.BrokerService
+	options broker.Options
+}
+
+var (
+	DefaultName = "go.micro.broker"
+)
+
+func (b *serviceBroker) Address() string {
+	return b.Addrs[0]
+}
+
+func (b *serviceBroker) Connect() error {
+	return nil
+}
+
+func (b *serviceBroker) Disconnect() error {
+	return nil
+}
+
+func (b *serviceBroker) Init(opts ...broker.Option) error {
+	for _, o := range opts {
+		o(&b.options)
+	}
+	return nil
+}
+
+func (b *serviceBroker) Options() broker.Options {
+	return b.options
+}
+
+func (b *serviceBroker) Publish(topic string, msg *broker.Message, opts ...broker.PublishOption) error {
+	log.Debugf("Publishing to topic %s broker %v", topic, b.Addrs)
+	_, err := b.Client.Publish(context.TODO(), &pb.PublishRequest{
+		Topic: topic,
+		Message: &pb.Message{
+			Header: msg.Header,
+			Body:   msg.Body,
+		},
+	}, client.WithAddress(b.Addrs...))
+	return err
+}
+
+func (b *serviceBroker) Subscribe(topic string, handler broker.Handler, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+	var options broker.SubscribeOptions
+	for _, o := range opts {
+		o(&options)
+	}
+	log.Debugf("Subscribing to topic %s queue %s broker %v", topic, options.Queue, b.Addrs)
+	stream, err := b.Client.Subscribe(context.TODO(), &pb.SubscribeRequest{
+		Topic: topic,
+		Queue: options.Queue,
+	}, client.WithAddress(b.Addrs...), client.WithRequestTimeout(time.Hour))
+	if err != nil {
+		return nil, err
+	}
+
+	sub := &serviceSub{
+		topic:   topic,
+		queue:   options.Queue,
+		handler: handler,
+		stream:  stream,
+		closed:  make(chan bool),
+		options: options,
+	}
+
+	go func() {
+		for {
+			select {
+			case <-sub.closed:
+				log.Debugf("Unsubscribed from topic %s", topic)
+				return
+			default:
+				// run the subscriber
+				log.Debugf("Streaming from broker %v to topic [%s] queue [%s]", b.Addrs, topic, options.Queue)
+				if err := sub.run(); err != nil {
+					log.Debugf("Resubscribing to topic %s broker %v", topic, b.Addrs)
+					stream, err := b.Client.Subscribe(context.TODO(), &pb.SubscribeRequest{
+						Topic: topic,
+						Queue: options.Queue,
+					}, client.WithAddress(b.Addrs...), client.WithRequestTimeout(time.Hour))
+					if err != nil {
+						log.Debugf("Failed to resubscribe to topic %s: %v", topic, err)
+						time.Sleep(time.Second)
+						continue
+					}
+					// new stream
+					sub.stream = stream
+				}
+			}
+		}
+	}()
+
+	return sub, nil
+}
+
+func (b *serviceBroker) String() string {
+	return "service"
+}
+
+func NewBroker(opts ...broker.Option) broker.Broker {
+	var options broker.Options
+	for _, o := range opts {
+		o(&options)
+	}
+
+	addrs := options.Addrs
+	if len(addrs) == 0 {
+		addrs = []string{"127.0.0.1:8001"}
+	}
+
+	return &serviceBroker{
+		Addrs:   addrs,
+		Client:  pb.NewBrokerService(DefaultName, client.DefaultClient),
+		options: options,
+	}
+}

broker/service/subscriber.go

@@ -0,0 +1,101 @@
+package service
+
+import (
+	"github.com/micro/go-micro/broker"
+	pb "github.com/micro/go-micro/broker/service/proto"
+	"github.com/micro/go-micro/util/log"
+)
+
+type serviceSub struct {
+	topic   string
+	queue   string
+	handler broker.Handler
+	stream  pb.Broker_SubscribeService
+	closed  chan bool
+	options broker.SubscribeOptions
+}
+
+type serviceEvent struct {
+	topic   string
+	message *broker.Message
+}
+
+func (s *serviceEvent) Topic() string {
+	return s.topic
+}
+
+func (s *serviceEvent) Message() *broker.Message {
+	return s.message
+}
+
+func (s *serviceEvent) Ack() error {
+	return nil
+}
+
+func (s *serviceSub) isClosed() bool {
+	select {
+	case <-s.closed:
+		return true
+	default:
+		return false
+	}
+}
+
+func (s *serviceSub) run() error {
+	exit := make(chan bool)
+	go func() {
+		select {
+		case <-exit:
+		case <-s.closed:
+		}
+
+		// close the stream
+		s.stream.Close()
+	}()
+
+	for {
+		// TODO: do not fail silently
+		msg, err := s.stream.Recv()
+		if err != nil {
+			log.Debugf("Streaming error for subcription to topic %s: %v", s.Topic(), err)
+
+			// close the exit channel
+			close(exit)
+
+			// don't return an error if we unsubscribed
+			if s.isClosed() {
+				return nil
+			}
+
+			// return stream error
+			return err
+		}
+
+		// TODO: handle error
+		s.handler(&serviceEvent{
+			topic: s.topic,
+			message: &broker.Message{
+				Header: msg.Header,
+				Body:   msg.Body,
+			},
+		})
+	}
+}
+
+func (s *serviceSub) Options() broker.SubscribeOptions {
+	return s.options
+}
+
+func (s *serviceSub) Topic() string {
+	return s.topic
+}
+
+func (s *serviceSub) Unsubscribe() error {
+	select {
+	case <-s.closed:
+		return nil
+	default:
+		close(s.closed)
+	}
+	return nil
+}

config/cmd/cmd.go

@@ -23,6 +23,7 @@ import (
 	"github.com/micro/go-micro/broker/http"
 	"github.com/micro/go-micro/broker/memory"
 	"github.com/micro/go-micro/broker/nats"
+	brokerSrv "github.com/micro/go-micro/broker/service"
 
 	// registries
 	"github.com/micro/go-micro/registry"
@@ -179,9 +180,11 @@ var (
 	}
 
 	DefaultBrokers = map[string]func(...broker.Option) broker.Broker{
-		"http":   http.NewBroker,
+		"go.micro.broker": brokerSrv.NewBroker,
-		"memory": memory.NewBroker,
+		"service":         brokerSrv.NewBroker,
-		"nats":   nats.NewBroker,
+		"http":            http.NewBroker,
+		"memory":          memory.NewBroker,
+		"nats":            nats.NewBroker,
 	}
 
 	DefaultClients = map[string]func(...client.Option) client.Client{

registry/cache/cache.go

@@ -100,7 +100,7 @@ func (c *cache) quit() bool {
 
 func (c *cache) del(service string) {
 	// don't blow away cache in error state
-	if err := c.getStatus(); err != nil {
+	if err := c.status; err != nil {
 		return
 	}
 	// otherwise delete entries
@@ -116,14 +116,13 @@ func (c *cache) get(service string) ([]*registry.Service, error) {
 	services := c.cache[service]
 	// get cache ttl
 	ttl := c.ttls[service]
+	// make a copy
+	cp := registry.Copy(services)
 
 	// got services && within ttl so return cache
-	if c.isValid(services, ttl) {
+	if c.isValid(cp, ttl) {
-		// make a copy
-		cp := registry.Copy(services)
-		// unlock the read
 		c.RUnlock()
-		// return servics
+		// return services
 		return cp, nil
 	}
 
@@ -136,8 +135,9 @@ func (c *cache) get(service string) ([]*registry.Service, error) {
 			if len(cached) > 0 {
 				// set the error status
 				c.setStatus(err)
+
 				// return the stale cache
-				return registry.Copy(cached), nil
+				return cached, nil
 			}
 			// otherwise return error
 			return nil, err
@@ -165,7 +165,7 @@ func (c *cache) get(service string) ([]*registry.Service, error) {
 	c.RUnlock()
 
 	// get and return services
-	return get(service, services)
+	return get(service, cp)
 }
 
 func (c *cache) set(service string, services []*registry.Service) {