xds/federation: resource name parsing (#4991)

xds/internal/xdsclient/xdsresource/name.go

@@ -0,0 +1,130 @@
+/*
+ *
+ * Copyright 2021 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xdsresource
+
+import (
+	"net/url"
+	"sort"
+	"strings"
+
+	"google.golang.org/grpc/internal/envconfig"
+)
+
+// Name contains the parsed component of an xDS resource name.
+//
+// An xDS resource name is in the format of
+// xdstp://[{authority}]/{resource type}/{id/*}?{context parameters}{#processing directive,*}
+//
+// See
+// https://github.com/cncf/xds/blob/main/proposals/TP1-xds-transport-next.md#uri-based-xds-resource-names
+// for details, and examples.
+type Name struct {
+	Scheme    string
+	Authority string
+	Type      string
+	ID        string
+
+	ContextParams map[string]string
+
+	processingDirective string
+}
+
+// ParseName splits the name and returns a struct representation of the Name.
+//
+// If the name isn't a valid new-style xDS name, field ID is set to the input.
+// Note that this is not an error, because we still support the old-style
+// resource names (those not starting with "xdstp:").
+//
+// The caller can tell if the parsing is successful by checking the returned
+// Scheme.
+func ParseName(name string) *Name {
+	if !envconfig.XDSFederation {
+		// Return "" scheme to use the default authority for the server.
+		return &Name{ID: name}
+	}
+	if !strings.Contains(name, "://") {
+		// Only the long form URL, with ://, is valid.
+		return &Name{ID: name}
+	}
+	parsed, err := url.Parse(name)
+	if err != nil {
+		return &Name{ID: name}
+	}
+
+	ret := &Name{
+		Scheme:    parsed.Scheme,
+		Authority: parsed.Host,
+	}
+	split := strings.SplitN(parsed.Path, "/", 3)
+	if len(split) < 3 {
+		// Path is in the format of "/type/id". There must be at least 3
+		// segments after splitting.
+		return &Name{ID: name}
+	}
+	ret.Type = split[1]
+	ret.ID = split[2]
+	if len(parsed.Query()) != 0 {
+		ret.ContextParams = make(map[string]string)
+		for k, vs := range parsed.Query() {
+			if len(vs) > 0 {
+				// We only keep one value of each key. Behavior for multiple values
+				// is undefined.
+				ret.ContextParams[k] = vs[0]
+			}
+		}
+	}
+	// TODO: processing directive (the part comes after "#" in the URL, stored
+	// in parsed.RawFragment) is kept but not processed. Add support for that
+	// when it's needed.
+	ret.processingDirective = parsed.RawFragment
+	return ret
+}
+
+// String returns a canonicalized string of name. The context parameters are
+// sorted by the keys.
+func (n *Name) String() string {
+	if n.Scheme == "" {
+		return n.ID
+	}
+
+	// Sort and build query.
+	keys := make([]string, 0, len(n.ContextParams))
+	for k := range n.ContextParams {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	var pairs []string
+	for _, k := range keys {
+		pairs = append(pairs, strings.Join([]string{k, n.ContextParams[k]}, "="))
+	}
+	rawQuery := strings.Join(pairs, "&")
+
+	path := n.Type
+	if n.ID != "" {
+		path = path + "/" + n.ID
+	}
+
+	tempURL := &url.URL{
+		Scheme:      n.Scheme,
+		Host:        n.Authority,
+		Path:        path,
+		RawQuery:    rawQuery,
+		RawFragment: n.processingDirective,
+	}
+	return tempURL.String()
+}

xds/internal/xdsclient/xdsresource/name_test.go

@@ -0,0 +1,104 @@
+/*
+ *
+ * Copyright 2021 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xdsresource
+
+import (
+	"reflect"
+	"testing"
+
+	"google.golang.org/grpc/internal/envconfig"
+)
+
+func TestParseName(t *testing.T) {
+	tests := []struct {
+		name string
+		env  bool // Whether federation env is set to true.
+		in   string
+		want *Name
+	}{
+		{
+			name: "env off",
+			env:  false,
+			in:   "xdstp://auth/type/id",
+			want: &Name{ID: "xdstp://auth/type/id"},
+		},
+		{
+			name: "old style name",
+			env:  true,
+			in:   "test-resource",
+			want: &Name{ID: "test-resource"},
+		},
+		{
+			name: "invalid not url",
+			env:  true,
+			in:   "a:/b/c",
+			want: &Name{ID: "a:/b/c"},
+		},
+		{
+			name: "invalid no resource type",
+			env:  true,
+			in:   "xdstp://auth/id",
+			want: &Name{ID: "xdstp://auth/id"},
+		},
+		{
+			name: "valid no ctx params",
+			env:  true,
+			in:   "xdstp://auth/type/id",
+			want: &Name{Scheme: "xdstp", Authority: "auth", Type: "type", ID: "id"},
+		},
+		{
+			name: "valid with ctx params",
+			env:  true,
+			in:   "xdstp://auth/type/id?a=1&b=2",
+			want: &Name{Scheme: "xdstp", Authority: "auth", Type: "type", ID: "id", ContextParams: map[string]string{"a": "1", "b": "2"}},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.env {
+				defer func() func() {
+					oldEnv := envconfig.XDSFederation
+					envconfig.XDSFederation = true
+					return func() { envconfig.XDSFederation = oldEnv }
+				}()()
+			}
+			if got := ParseName(tt.in); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("ParseName() = %#v, want %#v", got, tt.want)
+			}
+		})
+	}
+}
+
+// TestNameStringCtxParamsOrder covers the case that if two names differ only in
+// context parameter __order__, the parsed name.String() has the same value.
+func TestNameStringCtxParamsOrder(t *testing.T) {
+	oldEnv := envconfig.XDSFederation
+	envconfig.XDSFederation = true
+	defer func() { envconfig.XDSFederation = oldEnv }()
+
+	const (
+		a = "xdstp://auth/type/id?a=1&b=2"
+		b = "xdstp://auth/type/id?b=2&a=1"
+	)
+	aParsed := ParseName(a).String()
+	bParsed := ParseName(b).String()
+
+	if aParsed != bParsed {
+		t.Fatalf("aParsed.String() = %q, bParsed.String() = %q, want them to be the same", aParsed, bParsed)
+	}
+}