// This example demonstrates a trivial echo server.
func ExampleHandler() {
http.Handle("/echo", websocket.Handler(EchoServer))
err := http.ListenAndServe(":12345", nil)
if err != nil {
panic("ListenAndServe: " + err.Error())
}
}
// newWSProxy returns a websocket handler which forwards
// messages from an incoming WS connection to an outgoing
// WS connection. It builds upon the golang.org/x/net/websocket
// library for both incoming and outgoing connections.
func newWSProxy(t *url.URL) http.Handler {
return websocket.Handler(func(in *websocket.Conn) {
defer in.Close()
r := in.Request()
targetURL := "ws://" + t.Host + r.RequestURI
out, err := websocket.Dial(targetURL, "", r.Header.Get("Origin"))
if err != nil {
log.Printf("[INFO] WS error for %s. %s", r.URL, err)
return
}
defer out.Close()
errc := make(chan error, 2)
cp := func(dst io.Writer, src io.Reader) {
_, err := io.Copy(dst, src)
errc <- err
}
go cp(out, in)
go cp(in, out)
err = <-errc
if err != nil && err != io.EOF {
log.Printf("[INFO] WS error for %s. %s", r.URL, err)
}
})
}
func main() {
var addr, consul, name, prefix, proto string
flag.StringVar(&addr, "addr", "127.0.0.1:5000", "host:port of the service")
flag.StringVar(&consul, "consul", "127.0.0.1:8500", "host:port of the consul agent")
flag.StringVar(&name, "name", filepath.Base(os.Args[0]), "name of the service")
flag.StringVar(&prefix, "prefix", "", "comma-sep list of host/path prefixes to register")
flag.StringVar(&proto, "proto", "http", "protocol for endpoints: http or ws")
flag.Parse()
if prefix == "" {
flag.Usage()
os.Exit(1)
}
// register prefixes
prefixes := strings.Split(prefix, ",")
for _, p := range prefixes {
switch proto {
case "http":
http.HandleFunc(p, func(w http.ResponseWriter, r *http.Request) {
fmt.Fprintf(w, "Serving %s from %s on %s\n", r.RequestURI, name, addr)
})
case "ws":
http.Handle(p, websocket.Handler(EchoServer))
default:
log.Fatal("Invalid protocol ", proto)
}
}
// start http server
go func() {
log.Printf("Listening on %s serving %s", addr, prefix)
if err := http.ListenAndServe(addr, nil); err != nil {
log.Fatal(err)
}
}()
// register consul health check endpoint
http.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "OK")
})
// build urlprefix-host/path tag list
// e.g. urlprefix-/foo, urlprefix-/bar, ...
var tags []string
for _, p := range prefixes {
tags = append(tags, "urlprefix-"+p)
}
// get host and port as string/int
host, portstr, err := net.SplitHostPort(addr)
if err != nil {
log.Fatal(err)
}
port, err := strconv.Atoi(portstr)
if err != nil {
log.Fatal(err)
}
// register service with health check
serviceID := name + "-" + addr
service := &api.AgentServiceRegistration{
ID: serviceID,
Name: name,
Port: port,
Address: host,
Tags: tags,
Check: &api.AgentServiceCheck{
HTTP: "http://" + addr + "/health",
Interval: "1s",
Timeout: "1s",
},
}
config := &api.Config{Address: consul, Scheme: "http"}
client, err := api.NewClient(config)
if err != nil {
log.Fatal(err)
}
if err := client.Agent().ServiceRegister(service); err != nil {
log.Fatal(err)
}
log.Printf("Registered service %q in consul with tags %q", name, strings.Join(tags, ","))
// run until we get a signal
quit := make(chan os.Signal, 1)
signal.Notify(quit, os.Interrupt, os.Kill)
<-quit
// deregister service
if err := client.Agent().ServiceDeregister(serviceID); err != nil {
log.Fatal(err)
}
log.Printf("Deregistered service %q in consul", name)
}
func (p *wsProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
websocket.Handler(wsHandler).ServeHTTP(w, r)
}
