refactor: scalar projection (#510)

Signed-off-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>

pkg/apis/policy/v1alpha1/any.go

@@ -1,6 +1,8 @@
 package v1alpha1
 
 import (
+	"github.com/kyverno/kyverno-json/pkg/core/projection"
+	hashutils "github.com/kyverno/kyverno-json/pkg/utils/hash"
 	"k8s.io/apimachinery/pkg/util/json"
 )
 
@@ -10,27 +12,18 @@ import (
 // +kubebuilder:validation:Type:=""
 type Any struct {
 	_value any
+	_hash  string
 }
 
 func NewAny(value any) Any {
-	return Any{value}
-}
-
-func (t *Any) Value() any {
-	return t._value
-}
-
-func (in *Any) DeepCopyInto(out *Any) {
-	out._value = deepCopy(in._value)
+	return Any{
+		_value: value,
+		_hash:  hashutils.Hash(value),
+	}
 }
 
-func (in *Any) DeepCopy() *Any {
-	if in == nil {
-		return nil
-	}
-	out := new(Any)
-	in.DeepCopyInto(out)
-	return out
+func (t *Any) Compile(compiler func(string, any, string) (projection.ScalarHandler, error), defaultCompiler string) (projection.ScalarHandler, error) {
+	return compiler(t._hash, t._value, defaultCompiler)
 }
 
 func (a *Any) MarshalJSON() ([]byte, error) {
@@ -44,5 +37,20 @@ func (a *Any) UnmarshalJSON(data []byte) error {
 		return err
 	}
 	a._value = v
+	a._hash = hashutils.Hash(a._value)
 	return nil
 }
+
+func (in *Any) DeepCopyInto(out *Any) {
+	out._value = deepCopy(in._value)
+	out._hash = in._hash
+}
+
+func (in *Any) DeepCopy() *Any {
+	if in == nil {
+		return nil
+	}
+	out := new(Any)
+	in.DeepCopyInto(out)
+	return out
+}

pkg/apis/policy/v1alpha1/any_test.go

@@ -9,40 +9,36 @@ import (
 func TestAny_DeepCopyInto(t *testing.T) {
 	tests := []struct {
 		name string
-		in   *Any
-		out  *Any
+		in   Any
 	}{{
 		name: "nil",
-		in:   &Any{nil},
-		out:  &Any{nil},
+		in:   NewAny(nil),
 	}, {
 		name: "int",
-		in:   &Any{42},
-		out:  &Any{nil},
+		in:   NewAny(42),
 	}, {
 		name: "string",
-		in:   &Any{"foo"},
-		out:  &Any{nil},
+		in:   NewAny("foo"),
 	}, {
 		name: "slice",
-		in:   &Any{[]any{42, "string"}},
-		out:  &Any{nil},
+		in:   NewAny([]any{42, "string"}),
 	}}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			tt.in.DeepCopyInto(tt.out)
-			assert.Equal(t, tt.in, tt.out)
+			var out Any
+			tt.in.DeepCopyInto(&out)
+			assert.Equal(t, tt.in, out)
 		})
 	}
 	{
 		inner := map[string]any{
 			"foo": 42,
 		}
-		in := Any{map[string]any{"inner": inner}}
+		in := NewAny(map[string]any{"inner": inner})
 		out := in.DeepCopy()
-		inPtr := in.Value().(map[string]any)["inner"].(map[string]any)
+		inPtr := in._value.(map[string]any)["inner"].(map[string]any)
 		inPtr["foo"] = 55
-		outPtr := out.Value().(map[string]any)["inner"].(map[string]any)
+		outPtr := out._value.(map[string]any)["inner"].(map[string]any)
 		assert.NotEqual(t, inPtr, outPtr)
 	}
 }

pkg/commands/jp/query/command.go

@@ -155,7 +155,7 @@ func loadInput(cmd *cobra.Command, file string) (any, error) {
 }
 
 func evaluate(input any, query string) (any, error) {
-	result, err := compilers.Execute(query, input, nil, compilers.DefaultCompiler.Jp)
+	result, err := compilers.Execute(query, input, nil, compilers.DefaultCompilers.Jp)
 	if err != nil {
 		if syntaxError, ok := err.(parsing.SyntaxError); ok {
 			return nil, fmt.Errorf("%s\n%s", syntaxError, syntaxError.HighlightLocation())

pkg/commands/scan/options.go

@@ -77,7 +77,7 @@ func (c *options) run(cmd *cobra.Command, _ []string) error {
 	}
 	out.println("Pre processing ...")
 	for _, preprocessor := range c.preprocessors {
-		result, err := compilers.Execute(preprocessor, payload, nil, compilers.DefaultCompiler.Jp)
+		result, err := compilers.Execute(preprocessor, payload, nil, compilers.DefaultCompilers.Jp)
 		if err != nil {
 			return err
 		}

pkg/core/assertion/assertion.go

@@ -91,7 +91,7 @@ func parseMap(assertion any, compiler compilers.Compilers, defaultCompiler strin
 		}
 		entry := assertions[key]
 		entry.node = assertion
-		entry.Projection = projection.Parse(key, compiler, defaultCompiler)
+		entry.Projection = projection.ParseMapKey(key, compiler, defaultCompiler)
 		assertions[key] = entry
 	}
 	return func(path *field.Path, value any, bindings binding.Bindings) (field.ErrorList, error) {

pkg/core/assertion/assertion_test.go

@@ -6,7 +6,7 @@ import (
 	"github.com/jmespath-community/go-jmespath/pkg/binding"
 	"github.com/kyverno/kyverno-json/pkg/core/compilers"
 	"github.com/kyverno/kyverno-json/pkg/core/expression"
-	tassert "github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/assert"
 	"k8s.io/apimachinery/pkg/util/validation/field"
 )
 
@@ -49,16 +49,16 @@ func TestAssert(t *testing.T) {
 	}}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			compiler := compilers.DefaultCompiler
+			compiler := compilers.DefaultCompilers
 			parsed, err := Parse(tt.assertion, compiler, expression.CompilerJP)
-			tassert.NoError(t, err)
+			assert.NoError(t, err)
 			got, err := parsed.Assert(nil, tt.value, tt.bindings)
 			if tt.wantErr {
-				tassert.Error(t, err)
+				assert.Error(t, err)
 			} else {
-				tassert.NoError(t, err)
+				assert.NoError(t, err)
 			}
-			tassert.Equal(t, tt.want, got)
+			assert.Equal(t, tt.want, got)
 		})
 	}
 }

pkg/core/compilers/compilers.go

@@ -1,16 +1,12 @@
 package compilers
 
 import (
-	"sync"
-
-	"github.com/jmespath-community/go-jmespath/pkg/binding"
 	"github.com/kyverno/kyverno-json/pkg/core/compilers/cel"
 	"github.com/kyverno/kyverno-json/pkg/core/compilers/jp"
 	"github.com/kyverno/kyverno-json/pkg/core/expression"
-	"k8s.io/apimachinery/pkg/util/validation/field"
 )
 
-var DefaultCompiler = Compilers{
+var DefaultCompilers = Compilers{
 	Jp:  jp.NewCompiler(),
 	Cel: cel.NewCompiler(),
 }
@@ -32,40 +28,3 @@ func (c Compilers) Compiler(compiler string) Compiler {
 		return c.Jp
 	}
 }
-
-func (c Compilers) NewBinding(path *field.Path, value any, bindings binding.Bindings, template any, compiler string) binding.Binding {
-	return binding.NewDelegate(
-		sync.OnceValues(
-			func() (any, error) {
-				switch typed := template.(type) {
-				case string:
-					expr := expression.Parse(compiler, typed)
-					if expr.Foreach {
-						return nil, field.Invalid(path.Child("variable"), typed, "foreach is not supported in context")
-					}
-					if expr.Binding != "" {
-						return nil, field.Invalid(path.Child("variable"), typed, "binding is not supported in context")
-					}
-					switch expr.Compiler {
-					case expression.CompilerJP:
-						projected, err := Execute(expr.Statement, value, bindings, c.Jp)
-						if err != nil {
-							return nil, field.InternalError(path.Child("variable"), err)
-						}
-						return projected, nil
-					case expression.CompilerCEL:
-						projected, err := Execute(expr.Statement, value, bindings, c.Cel)
-						if err != nil {
-							return nil, field.InternalError(path.Child("variable"), err)
-						}
-						return projected, nil
-					default:
-						return expr.Statement, nil
-					}
-				default:
-					return typed, nil
-				}
-			},
-		),
-	)
-}

pkg/core/projection/projection.go

@@ -11,7 +11,10 @@ import (
 	reflectutils "github.com/kyverno/kyverno-json/pkg/utils/reflect"
 )
 
-type Handler = func(value any, bindings binding.Bindings) (any, bool, error)
+type (
+	ScalarHandler = func(value any, bindings binding.Bindings) (any, error)
+	MapKeyHandler = func(value any, bindings binding.Bindings) (any, bool, error)
+)
 
 type Info struct {
 	Foreach     bool
@@ -21,10 +24,10 @@ type Info struct {
 
 type Projection struct {
 	Info
-	Handler
+	Handler MapKeyHandler
 }
 
-func Parse(in any, compiler compilers.Compilers, defaultCompiler string) (projection Projection) {
+func ParseMapKey(in any, compiler compilers.Compilers, defaultCompiler string) (projection Projection) {
 	switch typed := in.(type) {
 	case string:
 		// 1. if we have a string, parse the expression
@@ -47,7 +50,7 @@ func Parse(in any, compiler compilers.Compilers, defaultCompiler string) (projec
 				if err != nil {
 					return nil, false, err
 				}
-				return projected, true, err
+				return projected, true, nil
 			}
 		} else {
 			projection.Handler = func(value any, bindings binding.Bindings) (any, bool, error) {
@@ -82,3 +85,40 @@ func Parse(in any, compiler compilers.Compilers, defaultCompiler string) (projec
 	}
 	return
 }
+
+func ParseScalar(in any, compiler compilers.Compilers, defaultCompiler string) (ScalarHandler, error) {
+	switch typed := in.(type) {
+	case string:
+		expr := expression.Parse(defaultCompiler, typed)
+		if expr.Foreach {
+			return nil, errors.New("foreach is not supported in scalar projections")
+		}
+		if expr.Binding != "" {
+			return nil, errors.New("binding is not supported in scalar projections")
+		}
+		if compiler := compiler.Compiler(expr.Compiler); compiler != nil {
+			compile := sync.OnceValues(func() (compilers.Program, error) {
+				return compiler.Compile(expr.Statement)
+			})
+			return func(value any, bindings binding.Bindings) (any, error) {
+				program, err := compile()
+				if err != nil {
+					return nil, err
+				}
+				projected, err := program(value, bindings)
+				if err != nil {
+					return nil, err
+				}
+				return projected, nil
+			}, nil
+		} else {
+			return func(value any, bindings binding.Bindings) (any, error) {
+				return expr.Statement, nil
+			}, nil
+		}
+	default:
+		return func(value any, bindings binding.Bindings) (any, error) {
+			return typed, nil
+		}, nil
+	}
+}

pkg/core/projection/projection_test.go

@@ -6,10 +6,10 @@ import (
 	"github.com/jmespath-community/go-jmespath/pkg/binding"
 	"github.com/kyverno/kyverno-json/pkg/core/compilers"
 	"github.com/kyverno/kyverno-json/pkg/core/expression"
-	tassert "github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/assert"
 )
 
-func TestProjection(t *testing.T) {
+func TestParseMap(t *testing.T) {
 	tests := []struct {
 		name      string
 		key       any
@@ -89,16 +89,16 @@ func TestProjection(t *testing.T) {
 	}}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			compiler := compilers.DefaultCompiler
-			proj := Parse(tt.key, compiler, expression.CompilerJP)
+			compiler := compilers.DefaultCompilers
+			proj := ParseMapKey(tt.key, compiler, expression.CompilerJP)
 			got, found, err := proj.Handler(tt.value, tt.bindings)
 			if tt.wantErr {
-				tassert.Error(t, err)
+				assert.Error(t, err)
 			} else {
-				tassert.NoError(t, err)
+				assert.NoError(t, err)
 			}
-			tassert.Equal(t, tt.wantFound, found)
-			tassert.Equal(t, tt.want, got)
+			assert.Equal(t, tt.wantFound, found)
+			assert.Equal(t, tt.want, got)
 		})
 	}
 }

pkg/json-engine/engine.go

@@ -3,8 +3,10 @@ package jsonengine
 import (
 	"context"
 	"fmt"
+	"sync"
 	"time"
 
+	"github.com/jmespath-community/go-jmespath/pkg/binding"
 	jpbinding "github.com/jmespath-community/go-jmespath/pkg/binding"
 	"github.com/kyverno/kyverno-json/pkg/apis/policy/v1alpha1"
 	"github.com/kyverno/kyverno-json/pkg/core/compilers"
@@ -68,7 +70,7 @@ func New() engine.Engine[Request, Response] {
 		resource any
 		bindings jpbinding.Bindings
 	}
-	compiler := matching.NewCompiler(compilers.DefaultCompiler, 256)
+	compiler := matching.NewCompiler(compilers.DefaultCompilers, 256)
 	ruleEngine := builder.
 		Function(func(ctx context.Context, r ruleRequest) []RuleResponse {
 			bindings := r.bindings.Register("$rule", jpbinding.NewBinding(r.rule))
@@ -82,12 +84,31 @@ func New() engine.Engine[Request, Response] {
 			// TODO: this doesn't seem to be the right path
 			var path *field.Path
 			path = path.Child("context")
-			for i, entry := range r.rule.Context {
+			for _, entry := range r.rule.Context {
 				defaultCompiler := defaultCompiler
 				if entry.Compiler != nil {
 					defaultCompiler = string(*entry.Compiler)
 				}
-				bindings = bindings.Register("$"+entry.Name, compiler.NewBinding(path.Index(i), r.resource, bindings, entry.Variable.Value(), defaultCompiler))
+				bindings = func(variable v1alpha1.Any, bindings jpbinding.Bindings) jpbinding.Bindings {
+					return bindings.Register(
+						"$"+entry.Name,
+						binding.NewDelegate(
+							sync.OnceValues(
+								func() (any, error) {
+									handler, err := variable.Compile(compiler.CompileProjection, defaultCompiler)
+									if err != nil {
+										return nil, field.InternalError(path.Child("variable"), err)
+									}
+									projected, err := handler(r.resource, bindings)
+									if err != nil {
+										return nil, field.InternalError(path.Child("variable"), err)
+									}
+									return projected, nil
+								},
+							),
+						),
+					)
+				}(entry.Variable, bindings)
 			}
 			identifier := ""
 			if r.rule.Identifier != "" {