composited type systems for CEL.

staging/src/k8s.io/apiserver/pkg/cel/composited.go

@@ -0,0 +1,119 @@
+/*
+Copyright 2023 The Kubernetes 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 cel
+
+import (
+	"github.com/google/cel-go/common/types/ref"
+	exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
+)
+
+var _ ref.TypeProvider = (*CompositedTypeProvider)(nil)
+var _ ref.TypeAdapter = (*CompositedTypeAdapter)(nil)
+
+// CompositedTypeProvider is the provider that tries each of the underlying
+// providers in order, and returns result of the first successful attempt.
+type CompositedTypeProvider struct {
+	// Providers contains the underlying type providers.
+	// If Providers is empty, the CompositedTypeProvider becomes no-op provider.
+	Providers []ref.TypeProvider
+}
+
+// EnumValue finds out the numeric value of the given enum name.
+// The result comes from first provider that returns non-nil.
+func (c *CompositedTypeProvider) EnumValue(enumName string) ref.Val {
+	for _, p := range c.Providers {
+		val := p.EnumValue(enumName)
+		if val != nil {
+			return val
+		}
+	}
+	return nil
+}
+
+// FindIdent takes a qualified identifier name and returns a Value if one
+// exists. The result comes from first provider that returns non-nil.
+func (c *CompositedTypeProvider) FindIdent(identName string) (ref.Val, bool) {
+	for _, p := range c.Providers {
+		val, ok := p.FindIdent(identName)
+		if ok {
+			return val, ok
+		}
+	}
+	return nil, false
+}
+
+// FindType finds the Type given a qualified type name, or return false
+// if none of the providers finds the type.
+// If any of the providers find the type, the first provider that returns true
+// will be the result.
+func (c *CompositedTypeProvider) FindType(typeName string) (*exprpb.Type, bool) {
+	for _, p := range c.Providers {
+		typ, ok := p.FindType(typeName)
+		if ok {
+			return typ, ok
+		}
+	}
+	return nil, false
+}
+
+// FindFieldType returns the field type for a checked type value. Returns
+// false if none of the providers can find the type.
+// If multiple providers can find the field, the result is taken from
+// the first that does.
+func (c *CompositedTypeProvider) FindFieldType(messageType string, fieldName string) (*ref.FieldType, bool) {
+	for _, p := range c.Providers {
+		ft, ok := p.FindFieldType(messageType, fieldName)
+		if ok {
+			return ft, ok
+		}
+	}
+	return nil, false
+}
+
+// NewValue creates a new type value from a qualified name and map of field
+// name to value.
+// If multiple providers can create the new type, the first that returns
+// non-nil will decide the result.
+func (c *CompositedTypeProvider) NewValue(typeName string, fields map[string]ref.Val) ref.Val {
+	for _, p := range c.Providers {
+		v := p.NewValue(typeName, fields)
+		if v != nil {
+			return v
+		}
+	}
+	return nil
+}
+
+// CompositedTypeAdapter is the adapter that tries each of the underlying
+// type adapter in order until the first successfully conversion.
+type CompositedTypeAdapter struct {
+	// Adapters contains underlying type adapters.
+	// If Adapters is empty, the CompositedTypeAdapter becomes a no-op adapter.
+	Adapters []ref.TypeAdapter
+}
+
+// NativeToValue takes the value and convert it into a ref.Val
+// The result comes from the first TypeAdapter that returns non-nil.
+func (c *CompositedTypeAdapter) NativeToValue(value interface{}) ref.Val {
+	for _, a := range c.Adapters {
+		v := a.NativeToValue(value)
+		if v != nil {
+			return v
+		}
+	}
+	return nil
+}

staging/src/k8s.io/apiserver/pkg/cel/openapi/compiling_test.go

@@ -0,0 +1,176 @@
+/*
+Copyright 2023 The Kubernetes 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 openapi
+
+import (
+	"testing"
+
+	"github.com/google/cel-go/cel"
+	"github.com/google/cel-go/common/types"
+	"github.com/google/cel-go/common/types/ref"
+	"github.com/google/cel-go/interpreter"
+
+	apiservercel "k8s.io/apiserver/pkg/cel"
+	"k8s.io/apiserver/pkg/cel/common"
+	"k8s.io/apiserver/pkg/cel/library"
+	"k8s.io/kube-openapi/pkg/validation/spec"
+)
+
+func TestMultipleTypes(t *testing.T) {
+	env, err := buildTestEnv()
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, tc := range []struct {
+		expression         string
+		expectCompileError bool
+		expectEvalResult   bool
+	}{
+		{
+			expression:       "foo.foo == bar.bar",
+			expectEvalResult: true,
+		},
+		{
+			expression:         "foo.bar == 'value'",
+			expectCompileError: true,
+		},
+		{
+			expression:       "foo.foo == 'value'",
+			expectEvalResult: true,
+		},
+		{
+			expression:       "bar.bar == 'value'",
+			expectEvalResult: true,
+		},
+		{
+			expression:       "foo.common + bar.common <= 2",
+			expectEvalResult: false, // 3 > 2
+		},
+		{
+			expression:         "foo.confusion == bar.confusion",
+			expectCompileError: true,
+		},
+	} {
+		t.Run(tc.expression, func(t *testing.T) {
+			ast, issues := env.Compile(tc.expression)
+			if issues != nil {
+				if tc.expectCompileError {
+					return
+				}
+				t.Fatalf("compile error: %v", issues)
+			}
+			if issues != nil {
+				t.Fatal(issues)
+			}
+			p, err := env.Program(ast)
+			if err != nil {
+				t.Fatal(err)
+			}
+			ret, _, err := p.Eval(&simpleActivation{
+				foo: map[string]any{"foo": "value", "common": 1, "confusion": "114514"},
+				bar: map[string]any{"bar": "value", "common": 2, "confusion": 114514},
+			})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if ret.Type() != types.BoolType {
+				t.Errorf("bad result type: %v", ret.Type())
+			}
+			if res := ret.Value().(bool); tc.expectEvalResult != res {
+				t.Errorf("expectEvalResult expression evaluates to %v, got %v", tc.expectEvalResult, res)
+			}
+		})
+	}
+
+}
+
+// buildTestEnv sets up an environment that contains two variables, "foo" and
+// "bar".
+// foo is an object with a string field "foo", an integer field "common", and a string field "confusion"
+// bar is an object with a string field "bar", an integer field "common", and an integer field "confusion"
+func buildTestEnv() (*cel.Env, error) {
+	var opts []cel.EnvOption
+	opts = append(opts, cel.HomogeneousAggregateLiterals())
+	opts = append(opts, cel.EagerlyValidateDeclarations(true), cel.DefaultUTCTimeZone(true))
+	opts = append(opts, library.ExtensionLibs...)
+	env, err := cel.NewEnv(opts...)
+	if err != nil {
+		return nil, err
+	}
+	reg := apiservercel.NewRegistry(env)
+
+	declType := common.SchemaDeclType(simpleMapSchema("foo", spec.StringProperty()), true)
+	fooRT, err := apiservercel.NewRuleTypes("fooType", declType, reg)
+	if err != nil {
+		return nil, err
+	}
+	fooRT, err = fooRT.WithTypeProvider(env.TypeProvider())
+	if err != nil {
+		return nil, err
+	}
+	fooType, _ := fooRT.FindDeclType("fooType")
+
+	declType = common.SchemaDeclType(simpleMapSchema("bar", spec.Int64Property()), true)
+	barRT, err := apiservercel.NewRuleTypes("barType", declType, reg)
+	if err != nil {
+		return nil, err
+	}
+	barRT, err = barRT.WithTypeProvider(env.TypeProvider())
+	if err != nil {
+		return nil, err
+	}
+	barType, _ := barRT.FindDeclType("barType")
+
+	opts = append(opts, cel.CustomTypeProvider(&apiservercel.CompositedTypeProvider{Providers: []ref.TypeProvider{fooRT, barRT}}))
+	opts = append(opts, cel.CustomTypeAdapter(&apiservercel.CompositedTypeAdapter{Adapters: []ref.TypeAdapter{fooRT, barRT}}))
+	opts = append(opts, cel.Variable("foo", fooType.CelType()))
+	opts = append(opts, cel.Variable("bar", barType.CelType()))
+	return env.Extend(opts...)
+}
+
+func simpleMapSchema(fieldName string, confusionSchema *spec.Schema) common.Schema {
+	return &Schema{Schema: &spec.Schema{
+		SchemaProps: spec.SchemaProps{
+			Type: []string{"object"},
+			Properties: map[string]spec.Schema{
+				fieldName:   *spec.StringProperty(),
+				"common":    *spec.Int64Property(),
+				"confusion": *confusionSchema,
+			},
+		},
+	}}
+}
+
+type simpleActivation struct {
+	foo any
+	bar any
+}
+
+func (a *simpleActivation) ResolveName(name string) (interface{}, bool) {
+	switch name {
+	case "foo":
+		return a.foo, true
+	case "bar":
+		return a.bar, true
+	default:
+		return nil, false
+	}
+}
+
+func (a *simpleActivation) Parent() interpreter.Activation {
+	return nil
+}

staging/src/k8s.io/apiserver/pkg/cel/types.go

@@ -360,6 +360,23 @@ func (rt *RuleTypes) EnvOptions(tp ref.TypeProvider) ([]cel.EnvOption, error) {
 	if rt == nil {
 		return []cel.EnvOption{}, nil
 	}
+	rtWithTypes, err := rt.WithTypeProvider(tp)
+	if err != nil {
+		return nil, err
+	}
+	return []cel.EnvOption{
+		cel.CustomTypeProvider(rtWithTypes),
+		cel.CustomTypeAdapter(rtWithTypes),
+		cel.Variable("rule", rt.ruleSchemaDeclTypes.root.CelType()),
+	}, nil
+}
+
+// WithTypeProvider returns a new RuleTypes that sets the given TypeProvider
+// If the original RuleTypes is nil, the returned RuleTypes is still nil.
+func (rt *RuleTypes) WithTypeProvider(tp ref.TypeProvider) (*RuleTypes, error) {
+	if rt == nil {
+		return nil, nil
+	}
 	var ta ref.TypeAdapter = types.DefaultTypeAdapter
 	tpa, ok := tp.(ref.TypeAdapter)
 	if ok {
@@ -382,11 +399,7 @@ func (rt *RuleTypes) EnvOptions(tp ref.TypeProvider) ([]cel.EnvOption, error) {
 				"type %s definition differs between CEL environment and rule", name)
 		}
 	}
-	return []cel.EnvOption{
-		cel.CustomTypeProvider(rtWithTypes),
-		cel.CustomTypeAdapter(rtWithTypes),
-		cel.Variable("rule", rt.ruleSchemaDeclTypes.root.CelType()),
-	}, nil
+	return rtWithTypes, nil
 }
 
 // FindType attempts to resolve the typeName provided from the rule's rule-schema, or if not