micro/broker/http_broker.go
2015-05-23 23:16:26 +01:00

261 lines
5.1 KiB
Go

package broker
import (
"bytes"
"encoding/json"
"fmt"
"io/ioutil"
"net"
"net/http"
"os"
"os/signal"
"strconv"
"strings"
"sync"
"syscall"
"time"
"code.google.com/p/go-uuid/uuid"
log "github.com/golang/glog"
c "github.com/myodc/go-micro/context"
"github.com/myodc/go-micro/errors"
"github.com/myodc/go-micro/registry"
"golang.org/x/net/context"
)
type httpBroker struct {
id string
address string
unsubscribe chan *httpSubscriber
sync.RWMutex
subscribers map[string][]*httpSubscriber
running bool
exit chan chan error
}
type httpSubscriber struct {
id string
topic string
ch chan *httpSubscriber
fn func(context.Context, *Message)
svc registry.Service
}
// used in brokers where there is no support for headers
type envelope struct {
Header map[string]string
Message *Message
}
var (
DefaultSubPath = "/_sub"
)
func newHttpBroker(addrs []string, opt ...Option) Broker {
addr := ":0"
if len(addrs) > 0 {
addr = addrs[0]
}
return &httpBroker{
id: Id,
address: addr,
subscribers: make(map[string][]*httpSubscriber),
unsubscribe: make(chan *httpSubscriber),
exit: make(chan chan error),
}
}
func (h *httpSubscriber) Topic() string {
return h.topic
}
func (h *httpSubscriber) Unsubscribe() error {
h.ch <- h
return nil
}
func (h *httpBroker) start() error {
h.Lock()
defer h.Unlock()
if h.running {
return nil
}
l, err := net.Listen("tcp", h.address)
if err != nil {
return err
}
log.Infof("Broker Listening on %s", l.Addr().String())
h.address = l.Addr().String()
go http.Serve(l, h)
go func() {
ce := make(chan os.Signal, 1)
signal.Notify(ce, syscall.SIGTERM, syscall.SIGINT, syscall.SIGKILL)
for {
select {
case ch := <-h.exit:
ch <- l.Close()
h.Lock()
h.running = false
h.Unlock()
return
case <-ce:
h.stop()
case subscriber := <-h.unsubscribe:
h.Lock()
var subscribers []*httpSubscriber
for _, sub := range h.subscribers[subscriber.topic] {
if sub.id == subscriber.id {
registry.Deregister(sub.svc)
}
subscribers = append(subscribers, sub)
}
h.subscribers[subscriber.topic] = subscribers
h.Unlock()
}
}
}()
h.running = true
return nil
}
func (h *httpBroker) stop() error {
ch := make(chan error)
h.exit <- ch
return <-ch
}
func (h *httpBroker) ServeHTTP(w http.ResponseWriter, req *http.Request) {
if req.Method != "POST" {
err := errors.BadRequest("go.micro.broker", "Method not allowed")
http.Error(w, err.Error(), http.StatusMethodNotAllowed)
return
}
defer req.Body.Close()
b, err := ioutil.ReadAll(req.Body)
if err != nil {
errr := errors.InternalServerError("go.micro.broker", fmt.Sprintf("Error reading request body: %v", err))
w.WriteHeader(500)
w.Write([]byte(errr.Error()))
return
}
var e *envelope
if err = json.Unmarshal(b, &e); err != nil {
errr := errors.InternalServerError("go.micro.broker", fmt.Sprintf("Error parsing request body: %v", err))
w.WriteHeader(500)
w.Write([]byte(errr.Error()))
return
}
if len(e.Message.Topic) == 0 {
errr := errors.InternalServerError("go.micro.broker", "Topic not found")
w.WriteHeader(500)
w.Write([]byte(errr.Error()))
return
}
ctx := c.WithMetaData(context.Background(), e.Header)
h.RLock()
for _, subscriber := range h.subscribers[e.Message.Topic] {
subscriber.fn(ctx, e.Message)
}
h.RUnlock()
}
func (h *httpBroker) Address() string {
return h.address
}
func (h *httpBroker) Connect() error {
return h.start()
}
func (h *httpBroker) Disconnect() error {
return h.stop()
}
func (h *httpBroker) Init() error {
if len(h.id) == 0 {
h.id = "broker-" + uuid.NewUUID().String()
}
http.Handle(DefaultSubPath, h)
return nil
}
func (h *httpBroker) Publish(ctx context.Context, topic string, body []byte) error {
s, err := registry.GetService("topic:" + topic)
if err != nil {
return err
}
message := &Message{
Id: uuid.NewUUID().String(),
Timestamp: time.Now().Unix(),
Topic: topic,
Body: body,
}
header, _ := c.GetMetaData(ctx)
b, err := json.Marshal(&envelope{
header,
message,
})
if err != nil {
return err
}
for _, node := range s.Nodes() {
r, err := http.Post(fmt.Sprintf("http://%s:%d%s", node.Address(), node.Port(), DefaultSubPath), "application/json", bytes.NewBuffer(b))
if err == nil {
r.Body.Close()
}
}
return nil
}
func (h *httpBroker) Subscribe(topic string, function func(context.Context, *Message)) (Subscriber, error) {
// parse address for host, port
parts := strings.Split(h.Address(), ":")
host := strings.Join(parts[:len(parts)-1], ":")
port, _ := strconv.Atoi(parts[len(parts)-1])
// register service
node := registry.NewNode(h.id, host, port)
service := registry.NewService("topic:"+topic, node)
subscriber := &httpSubscriber{
id: uuid.NewUUID().String(),
topic: topic,
ch: h.unsubscribe,
fn: function,
svc: service,
}
log.Infof("Registering subscriber %s", node.Id())
if err := registry.Register(service); err != nil {
return nil, err
}
h.Lock()
h.subscribers[topic] = append(h.subscribers[topic], subscriber)
h.Unlock()
return subscriber, nil
}