Add util

util/http/http.go

@@ -0,0 +1,23 @@
+package http
+
+import (
+	"net/http"
+
+	"github.com/micro/go-micro/registry"
+	"github.com/micro/go-micro/selector"
+)
+
+func NewRoundTripper(opts ...Option) http.RoundTripper {
+	options := Options{
+		Registry: registry.DefaultRegistry,
+	}
+	for _, o := range opts {
+		o(&options)
+	}
+
+	return &roundTripper{
+		rt:   http.DefaultTransport,
+		st:   selector.Random,
+		opts: options,
+	}
+}

util/http/http_test.go

@@ -0,0 +1,87 @@
+package http
+
+import (
+	"io/ioutil"
+	"net"
+	"net/http"
+	"strconv"
+	"testing"
+
+	"github.com/micro/go-micro/registry"
+	"github.com/micro/go-micro/registry/memory"
+)
+
+func TestRoundTripper(t *testing.T) {
+	m := memory.NewRegistry()
+
+	rt := NewRoundTripper(
+		WithRegistry(m),
+	)
+
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte(`hello world`))
+	})
+
+	l, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer l.Close()
+
+	go http.Serve(l, nil)
+
+	host, p, _ := net.SplitHostPort(l.Addr().String())
+	port, _ := strconv.Atoi(p)
+
+	m.Register(&registry.Service{
+		Name: "example.com",
+		Nodes: []*registry.Node{
+			{
+				Id:      "1",
+				Address: host,
+				Port:    port,
+			},
+		},
+	})
+
+	req, err := http.NewRequest("GET", "http://example.com", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	w, err := rt.RoundTrip(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	b, err := ioutil.ReadAll(w.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	w.Body.Close()
+
+	if string(b) != "hello world" {
+		t.Fatal("response is", string(b))
+	}
+
+	// test http request
+	c := &http.Client{
+		Transport: rt,
+	}
+
+	rsp, err := c.Get("http://example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	b, err = ioutil.ReadAll(rsp.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	rsp.Body.Close()
+
+	if string(b) != "hello world" {
+		t.Fatal("response is", string(b))
+	}
+
+}

util/http/options.go

@@ -0,0 +1,17 @@
+package http
+
+import (
+	"github.com/micro/go-micro/registry"
+)
+
+type Options struct {
+	Registry registry.Registry
+}
+
+type Option func(*Options)
+
+func WithRegistry(r registry.Registry) Option {
+	return func(o *Options) {
+		o.Registry = r
+	}
+}

util/http/roundtripper.go

@@ -0,0 +1,40 @@
+package http
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/micro/go-micro/selector"
+)
+
+type roundTripper struct {
+	rt   http.RoundTripper
+	st   selector.Strategy
+	opts Options
+}
+
+func (r *roundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	s, err := r.opts.Registry.GetService(req.URL.Host)
+	if err != nil {
+		return nil, err
+	}
+
+	next := r.st(s)
+
+	// rudimentary retry 3 times
+	for i := 0; i < 3; i++ {
+		n, err := next()
+		if err != nil {
+			continue
+		}
+		req.URL.Host = fmt.Sprintf("%s:%d", n.Address, n.Port)
+		w, err := r.rt.RoundTrip(req)
+		if err != nil {
+			continue
+		}
+		return w, nil
+	}
+
+	return nil, errors.New("failed request")
+}