support apiserver url rewrite

Signed-off-by: huiwq1990 <huiwq1990@163.com>

pkg/apiserver/apiserver.go

@@ -17,15 +17,18 @@ import (
 	"k8s.io/client-go/discovery"
 	clientrest "k8s.io/client-go/rest"
 	"k8s.io/client-go/restmapper"
+	"k8s.io/klog/v2"
 
 	internal "github.com/clusterpedia-io/api/clusterpedia"
 	"github.com/clusterpedia-io/api/clusterpedia/install"
+	"github.com/clusterpedia-io/clusterpedia/pkg/apiserver/features"
 	"github.com/clusterpedia-io/clusterpedia/pkg/apiserver/registry/clusterpedia/collectionresources"
 	"github.com/clusterpedia-io/clusterpedia/pkg/apiserver/registry/clusterpedia/resources"
 	"github.com/clusterpedia-io/clusterpedia/pkg/generated/clientset/versioned"
 	informers "github.com/clusterpedia-io/clusterpedia/pkg/generated/informers/externalversions"
 	"github.com/clusterpedia-io/clusterpedia/pkg/kubeapiserver"
 	"github.com/clusterpedia-io/clusterpedia/pkg/storage"
+	clusterpediafeature "github.com/clusterpedia-io/clusterpedia/pkg/utils/feature"
 	"github.com/clusterpedia-io/clusterpedia/pkg/utils/filters"
 )
 
@@ -139,6 +142,10 @@ func (config completedConfig) New() (*ClusterPediaServer, error) {
 		handler := handlerChainFunc(apiHandler, c)
 		handler = filters.WithRequestQuery(handler)
 		handler = filters.WithAcceptHeader(handler)
+		if clusterpediafeature.FeatureGate.Enabled(features.ApiServerURLRewrite) {
+			klog.InfoS("Enable rewrite apiserver url")
+			handler = filters.WithRewriteFilter(handler)
+		}
 		return handler
 	}
 

pkg/apiserver/features/features.go

@@ -0,0 +1,26 @@
+package features
+
+import (
+	"k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/component-base/featuregate"
+
+	clusterpediafeature "github.com/clusterpedia-io/clusterpedia/pkg/utils/feature"
+)
+
+const (
+
+	// ApiServerURLRewrite is a feature gate for rewrite apiserver request's URL
+	// owner: @huiwq1990
+	// alpha: v0.7.0
+	ApiServerURLRewrite featuregate.Feature = "ApiServerURLRewrite"
+)
+
+func init() {
+	runtime.Must(clusterpediafeature.MutableFeatureGate.Add(defaultApiServerFeatureGates))
+}
+
+// defaultApiServerFeatureGates consists of all known apiserver feature keys.
+// To add a new feature, define a key for it above and add it here.
+var defaultApiServerFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
+	ApiServerURLRewrite: {Default: false, PreRelease: featuregate.Alpha},
+}

pkg/utils/filters/rewrite.go

@@ -0,0 +1,40 @@
+package filters
+
+import (
+	"net/http"
+	"net/url"
+	"strings"
+
+	"k8s.io/klog/v2"
+)
+
+const OriginPathHeaderKey = "X-Rewrite-Original-Path"
+const OldResourceApiServerPrefixWithoutSlash = "/apis/clusterpedia.io/v1beta1/resources"
+const OldResourceApiServerPrefix = OldResourceApiServerPrefixWithoutSlash + "/"
+
+func WithRewriteFilter(handler http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		oldPath := req.URL.EscapedPath()
+		if rewritePath, ok := urlPrefixRewrite(oldPath); ok {
+			req.URL.Path = rewritePath
+			req.Header.Set(OriginPathHeaderKey, oldPath)
+			klog.V(5).InfoS("request need rewrite", "oldPath", oldPath, "newPath", req.URL.EscapedPath())
+		} else {
+			klog.V(5).InfoS("request not need rewrite", "path", oldPath)
+		}
+
+		handler.ServeHTTP(w, req)
+	})
+}
+
+func urlPrefixRewrite(oldPath string) (string, bool) {
+	if strings.HasPrefix(oldPath, OldResourceApiServerPrefix) || oldPath == OldResourceApiServerPrefixWithoutSlash {
+		return "", false
+	}
+
+	rewritePath, err := url.JoinPath(OldResourceApiServerPrefix, oldPath)
+	if err != nil {
+		return "", false
+	}
+	return rewritePath, true
+}

pkg/utils/filters/rewrite_test.go

@@ -0,0 +1,136 @@
+package filters
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+)
+
+type testCase struct {
+	name string
+	urls []kubeRequest
+}
+
+type kubeRequest struct {
+	from    string
+	to      string
+	rewrite bool
+}
+
+var tests = []testCase{
+	{
+		name: "do rewrite",
+		urls: []kubeRequest{
+			{
+				from:    "/apis/clusterpedia.io/v1beta1/resourcesany",
+				to:      "/apis/clusterpedia.io/v1beta1/resources/apis/clusterpedia.io/v1beta1/resourcesany",
+				rewrite: true,
+			},
+			{from: "/api/v1/namespaces/default/pods?limit=100",
+				to:      "/apis/clusterpedia.io/v1beta1/resources/api/v1/namespaces/default/pods?limit=100",
+				rewrite: true},
+
+			{from: "/apis/clusterpedia.io/v1beta1/clusters",
+				to:      "/apis/clusterpedia.io/v1beta1/resources/apis/clusterpedia.io/v1beta1/clusters",
+				rewrite: true,
+			},
+		},
+	},
+	{
+		name: "not need rewrite",
+		urls: []kubeRequest{
+			{
+				from:    "/apis/clusterpedia.io/v1beta1/resources",
+				to:      "/apis/clusterpedia.io/v1beta1/resources",
+				rewrite: false,
+			},
+			{from: "/apis/clusterpedia.io/v1beta1/resources/api/v1/namespaces/default/pods",
+				to:      "/apis/clusterpedia.io/v1beta1/resources/api/v1/namespaces/default/pods",
+				rewrite: false,
+			},
+
+			{from: "/apis/clusterpedia.io/v1beta1/resources/apis/clusterpedia.io/v1beta1/clusters",
+				to:      "/apis/clusterpedia.io/v1beta1/resources/apis/clusterpedia.io/v1beta1/clusters",
+				rewrite: false,
+			},
+		},
+	},
+	{
+		name: "special cases",
+		urls: []kubeRequest{
+			{from: "/api/v1/namespaces/default/pods?name=abc#xx",
+				to:      "/apis/clusterpedia.io/v1beta1/resources/api/v1/namespaces/default/pods?name=abc#xx",
+				rewrite: true,
+			},
+		},
+	},
+}
+
+func TestUrlPrefixRewrite(t *testing.T) {
+	for _, test := range tests {
+		t.Logf("Test - name: %s", test.name)
+
+		for _, tmp := range test.urls {
+			fromPath, err := url.Parse(tmp.from)
+			if err != nil {
+				t.Error(err)
+			}
+
+			rewritePath, doRewrite := urlPrefixRewrite(fromPath.EscapedPath())
+			if doRewrite != tmp.rewrite {
+				t.Errorf("Test failed \n from  : %s \n to    : %s \n needRewrite: %v \n doRewrite: %v",
+					tmp.from, tmp.to, tmp.rewrite, doRewrite)
+			}
+
+			if doRewrite {
+				oldURL, err := url.Parse(tmp.to)
+				if err != nil {
+					t.Error(err)
+				}
+
+				if oldURL.EscapedPath() != rewritePath {
+					t.Errorf("Test failed \n from  : %s \n to    : %s \n oldPath: %s \n rewritePath: %s",
+						tmp.from, tmp.to, oldURL.EscapedPath(), rewritePath)
+				}
+			}
+		}
+	}
+}
+
+func TestRewrite(t *testing.T) {
+	for _, test := range tests {
+		t.Logf("Test - name: %s", test.name)
+
+		for _, tmp := range test.urls {
+			req, err := http.NewRequest("GET", tmp.from, nil)
+			if err != nil {
+				t.Fatalf("create HTTP request error: %v", err)
+			}
+
+			oldPath := req.URL.EscapedPath()
+
+			h := WithRewriteFilter(
+				http.HandlerFunc(func(_ http.ResponseWriter, req *http.Request) {
+				}),
+			)
+
+			t.Logf("From: %s", req.URL.String())
+
+			res := httptest.NewRecorder()
+			h.ServeHTTP(res, req)
+
+			t.Logf("Rewrited: %s", req.URL.String())
+			if req.URL.String() != tmp.to {
+				t.Errorf("Test failed \n from  : %s \n to    : %s \n result: %s",
+					tmp.from, tmp.to, req.URL.RequestURI())
+			}
+
+			if oldHeaderPath := req.Header.Get(OriginPathHeaderKey); oldHeaderPath != "" {
+				if oldPath != oldHeaderPath {
+					t.Error("incorrect flag")
+				}
+			}
+		}
+	}
+}