Add k8s proxy

pkg/proxy/proxy.go

@@ -0,0 +1,101 @@
+package proxy
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/rancher/wrangler/pkg/kubeconfig"
+	utilnet "k8s.io/apimachinery/pkg/util/net"
+	"k8s.io/apimachinery/pkg/util/proxy"
+	"k8s.io/client-go/rest"
+	"k8s.io/client-go/transport"
+)
+
+// Mostly copied from "kubectl proxy" code
+func HandlerFromConfig(prefix, kubeConfig string) (http.Handler, error) {
+	loader := kubeconfig.GetInteractiveClientConfig(kubeConfig)
+	cfg, err := loader.ClientConfig()
+	if err != nil {
+		return nil, err
+	}
+
+	return Handler(prefix, cfg)
+}
+
+// Mostly copied from "kubectl proxy" code
+func Handler(prefix string, cfg *rest.Config) (http.Handler, error) {
+	host := cfg.Host
+	if !strings.HasSuffix(host, "/") {
+		host = host + "/"
+	}
+	target, err := url.Parse(host)
+	if err != nil {
+		return nil, err
+	}
+
+	transport, err := rest.TransportFor(cfg)
+	if err != nil {
+		return nil, err
+	}
+	upgradeTransport, err := makeUpgradeTransport(cfg, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	proxy := proxy.NewUpgradeAwareHandler(target, transport, false, false, er)
+	proxy.UpgradeTransport = upgradeTransport
+	proxy.UseRequestLocation = true
+
+	if len(prefix) > 2 {
+		return stripLeaveSlash(prefix, proxy), nil
+	}
+
+	return proxy, nil
+}
+
+// like http.StripPrefix, but always leaves an initial slash. (so that our
+// regexps will work.)
+func stripLeaveSlash(prefix string, h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		fmt.Println(req.Method, req.URL.Path)
+		p := strings.TrimPrefix(req.URL.Path, prefix)
+		if len(p) >= len(req.URL.Path) {
+			http.NotFound(w, req)
+			return
+		}
+		if len(p) > 0 && p[:1] != "/" {
+			p = "/" + p
+		}
+		req.URL.Path = p
+		h.ServeHTTP(w, req)
+	})
+}
+
+func makeUpgradeTransport(config *rest.Config, keepalive time.Duration) (proxy.UpgradeRequestRoundTripper, error) {
+	transportConfig, err := config.TransportConfig()
+	if err != nil {
+		return nil, err
+	}
+	tlsConfig, err := transport.TLSConfigFor(transportConfig)
+	if err != nil {
+		return nil, err
+	}
+	rt := utilnet.SetOldTransportDefaults(&http.Transport{
+		TLSClientConfig: tlsConfig,
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: keepalive,
+		}).DialContext,
+	})
+
+	upgrader, err := transport.HTTPWrappersForConfig(transportConfig, proxy.MirrorRequest)
+	if err != nil {
+		return nil, err
+	}
+
+	return proxy.NewUpgradeRequestRoundTripper(rt, upgrader), nil
+}