Add quantity library to CEL (#118803)

* add quantity library to CEL

* add more tests to quantity

* use 1.29 env for quantity

* set CEL default env to 1.28 for 1.28 release

* add compare function

* docs and arith lib

* fixup addInt and subInt overload, add docs

* more tests

* cleanup docs

* remove old comments

* remove unnecessary cast

* add isInteger

* add overflow tests

* boilerplate

* refactor expectedResult for tests

* doc typo fix

* returns bool

* add docs link

* different dos link

* add isInteger true case

* expand iff

* add quantity back to 1.28 version, and revert change to DefaultCompatibilityVersion

* formatting

staging/src/k8s.io/apiserver/pkg/cel/environment/base.go

@@ -78,6 +78,7 @@ var baseOpts = []VersionedOptions{
 		EnvOptions: []cel.EnvOption{
 			cel.CrossTypeNumericComparisons(true),
 			cel.OptionalTypes(),
+			library.Quantity(),
 		},
 	},
 	// TODO: switch to ext.Strings version 2 once format() is fixed to work with HomogeneousAggregateLiterals.

staging/src/k8s.io/apiserver/pkg/cel/library/quantity.go

@@ -0,0 +1,375 @@
+/*
+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 library
+
+import (
+	"errors"
+
+	"github.com/google/cel-go/cel"
+	"github.com/google/cel-go/common/types"
+	"github.com/google/cel-go/common/types/ref"
+	"k8s.io/apimachinery/pkg/api/resource"
+	apiservercel "k8s.io/apiserver/pkg/cel"
+)
+
+// Quantity provides a CEL function library extension of Kubernetes
+// resource.Quantity parsing functions. See `resource.Quantity`
+// documentation for more detailed information about the format itself:
+// https://pkg.go.dev/k8s.io/apimachinery/pkg/api/resource#Quantity
+//
+// quantity
+//
+// Converts a string to a Quantity or results in an error if the string is not a valid Quantity. Refer
+// to resource.Quantity documentation for information on accepted patterns.
+//
+//	quantity(<string>) <Quantity>
+//
+// Examples:
+//
+//	quantity('1.5G') // returns a Quantity
+//	quantity('200k') // returns a Quantity
+//	quantity('200K') // error
+//	quantity('Three') // error
+//	quantity('Mi') // error
+//
+// isQuantity
+//
+// Returns true if a string is a valid Quantity. isQuantity returns true if and
+// only if quantity does not result in error.
+//
+//	isQuantity( <string>) <bool>
+//
+// Examples:
+//
+//	isQuantity('1.3G') // returns true
+//	isQuantity('1.3Gi') // returns true
+//	isQuantity('1,3G') // returns false
+//	isQuantity('10000k') // returns true
+//	isQuantity('200K') // returns false
+//	isQuantity('Three') // returns false
+//	isQuantity('Mi') // returns false
+//
+// Conversion to Scalars:
+//
+//   - isInteger: returns true if and only if asInteger is safe to call without an error
+//
+//   - asInteger: returns a representation of the current value as an int64 if
+//     possible or results in an error if conversion would result in overflow
+//	   or loss of precision.
+//
+//   - asApproximateFloat: returns a float64 representation of the quantity which may
+//     lose precision. If the value of the quantity is outside the range of a float64
+//     +Inf/-Inf will be returned.
+//
+//     <Quantity>.isInteger() <bool>
+//     <Quantity>.asInteger() <int>
+//     <Quantity>.asApproximateFloat() <float>
+//
+// Examples:
+//
+// quantity("50000000G").isInteger() // returns true
+// quantity("50k").isInteger() // returns true
+// quantity("9999999999999999999999999999999999999G").asInteger() // error: cannot convert value to integer
+// quantity("9999999999999999999999999999999999999G").isInteger() // returns false
+// quantity("50k").asInteger() == 50000 // returns true
+// quantity("50k").sub(20000).asApproximateFloat() == 30000 // returns true
+//
+// Arithmetic
+//
+//   - sign: Returns `1` if the quantity is positive, `-1` if it is negative. `0` if it is zero
+//
+//   - add: Returns sum of two quantities or a quantity and an integer
+//
+//   - sub: Returns difference between two quantities or a quantity and an integer
+//
+//     <Quantity>.sign() <int>
+//     <Quantity>.add(<quantity>) <quantity>
+//     <Quantity>.add(<integer>) <quantity>
+//     <Quantity>.sub(<quantity>) <quantity>
+//     <Quantity>.sub(<integer>) <quantity>
+//
+// Examples:
+//
+// quantity("50k").add("20k") == quantity("70k") // returns true
+// quantity("50k").add(20) == quantity("50020") // returns true
+// quantity("50k").sub("20k") == quantity("30k") // returns true
+// quantity("50k").sub(20000) == quantity("30k") // returns true
+// quantity("50k").add(20).sub(quantity("100k")).sub(-50000) == quantity("20") // returns true
+//
+// Comparisons
+//
+//   - isGreaterThan: Returns true if and only if the receiver is greater than the operand
+//
+//   - isLessThan: Returns true if and only if the receiver is less than the operand
+//
+//   - compareTo: Compares receiver to operand and returns 0 if they are equal, 1 if the receiver is greater, or -1 if the receiver is less than the operand
+//
+//
+//     <Quantity>.isLessThan(<quantity>) <bool>
+//     <Quantity>.isGreaterThan(<quantity>) <bool>
+//     <Quantity>.compareTo(<quantity>) <int>
+//
+// Examples:
+//
+// quantity("200M").compareTo(quantity("0.2G")) // returns 0
+// quantity("50M").compareTo(quantity("50Mi")) // returns -1
+// quantity("50Mi").compareTo(quantity("50M")) // returns 1
+// quantity("150Mi").isGreaterThan(quantity("100Mi")) // returns true
+// quantity("50Mi").isGreaterThan(quantity("100Mi")) // returns false
+// quantity("50M").isLessThan(quantity("100M")) // returns true
+// quantity("100M").isLessThan(quantity("50M")) // returns false
+
+func Quantity() cel.EnvOption {
+	return cel.Lib(quantityLib)
+}
+
+var quantityLib = &quantity{}
+
+type quantity struct{}
+
+var quantityLibraryDecls = map[string][]cel.FunctionOpt{
+	"quantity": {
+		cel.Overload("string_to_quantity", []*cel.Type{cel.StringType}, apiservercel.QuantityType, cel.UnaryBinding((stringToQuantity))),
+	},
+	"isQuantity": {
+		cel.Overload("is_quantity_string", []*cel.Type{cel.StringType}, cel.BoolType, cel.UnaryBinding(isQuantity)),
+	},
+	"sign": {
+		cel.Overload("quantity_sign", []*cel.Type{apiservercel.QuantityType}, cel.IntType, cel.UnaryBinding(quantityGetSign)),
+	},
+	"isGreaterThan": {
+		cel.MemberOverload("quantity_is_greater_than", []*cel.Type{apiservercel.QuantityType, apiservercel.QuantityType}, cel.BoolType, cel.BinaryBinding(quantityIsGreaterThan)),
+	},
+	"isLessThan": {
+		cel.MemberOverload("quantity_is_less_than", []*cel.Type{apiservercel.QuantityType, apiservercel.QuantityType}, cel.BoolType, cel.BinaryBinding(quantityIsLessThan)),
+	},
+	"compareTo": {
+		cel.MemberOverload("quantity_compare_to", []*cel.Type{apiservercel.QuantityType, apiservercel.QuantityType}, cel.IntType, cel.BinaryBinding(quantityCompareTo)),
+	},
+	"asApproximateFloat": {
+		cel.MemberOverload("quantity_get_float", []*cel.Type{apiservercel.QuantityType}, cel.DoubleType, cel.UnaryBinding(quantityGetApproximateFloat)),
+	},
+	"asInteger": {
+		cel.MemberOverload("quantity_get_int", []*cel.Type{apiservercel.QuantityType}, cel.IntType, cel.UnaryBinding(quantityGetValue)),
+	},
+	"isInteger": {
+		cel.MemberOverload("quantity_is_integer", []*cel.Type{apiservercel.QuantityType}, cel.BoolType, cel.UnaryBinding(quantityCanValue)),
+	},
+	"add": {
+		cel.MemberOverload("quantity_add", []*cel.Type{apiservercel.QuantityType, apiservercel.QuantityType}, apiservercel.QuantityType, cel.BinaryBinding(quantityAdd)),
+		cel.MemberOverload("quantity_add_int", []*cel.Type{apiservercel.QuantityType, cel.IntType}, apiservercel.QuantityType, cel.BinaryBinding(quantityAddInt)),
+	},
+	"sub": {
+		cel.MemberOverload("quantity_sub", []*cel.Type{apiservercel.QuantityType, apiservercel.QuantityType}, apiservercel.QuantityType, cel.BinaryBinding(quantitySub)),
+		cel.MemberOverload("quantity_sub_int", []*cel.Type{apiservercel.QuantityType, cel.IntType}, apiservercel.QuantityType, cel.BinaryBinding(quantitySubInt)),
+	},
+}
+
+func (*quantity) CompileOptions() []cel.EnvOption {
+	options := make([]cel.EnvOption, 0, len(quantityLibraryDecls))
+	for name, overloads := range quantityLibraryDecls {
+		options = append(options, cel.Function(name, overloads...))
+	}
+	return options
+}
+
+func (*quantity) ProgramOptions() []cel.ProgramOption {
+	return []cel.ProgramOption{}
+}
+
+func isQuantity(arg ref.Val) ref.Val {
+	str, ok := arg.Value().(string)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	_, err := resource.ParseQuantity(str)
+	if err != nil {
+		return types.Bool(false)
+	}
+
+	return types.Bool(true)
+}
+
+func stringToQuantity(arg ref.Val) ref.Val {
+	str, ok := arg.Value().(string)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	q, err := resource.ParseQuantity(str)
+	if err != nil {
+		return types.WrapErr(err)
+	}
+
+	return apiservercel.Quantity{Quantity: &q}
+}
+
+func quantityGetApproximateFloat(arg ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+	return types.Double(q.AsApproximateFloat64())
+}
+
+func quantityCanValue(arg ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+	_, success := q.AsInt64()
+	return types.Bool(success)
+}
+
+func quantityGetValue(arg ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+	v, success := q.AsInt64()
+	if !success {
+		return types.WrapErr(errors.New("cannot convert value to integer"))
+	}
+	return types.Int(v)
+}
+
+func quantityGetSign(arg ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+	return types.Int(q.Sign())
+}
+
+func quantityIsGreaterThan(arg ref.Val, other ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	q2, ok := other.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	return types.Bool(q.Cmp(*q2) == 1)
+}
+
+func quantityIsLessThan(arg ref.Val, other ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	q2, ok := other.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	return types.Bool(q.Cmp(*q2) == -1)
+}
+
+func quantityCompareTo(arg ref.Val, other ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	q2, ok := other.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	return types.Int(q.Cmp(*q2))
+}
+
+func quantityAdd(arg ref.Val, other ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	q2, ok := other.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	copy := *q
+	copy.Add(*q2)
+	return &apiservercel.Quantity{
+		Quantity: &copy,
+	}
+}
+
+func quantityAddInt(arg ref.Val, other ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	q2, ok := other.Value().(int64)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	q2Converted := *resource.NewQuantity(q2, resource.DecimalExponent)
+
+	copy := *q
+	copy.Add(q2Converted)
+	return &apiservercel.Quantity{
+		Quantity: &copy,
+	}
+}
+
+func quantitySub(arg ref.Val, other ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	q2, ok := other.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	copy := *q
+	copy.Sub(*q2)
+	return &apiservercel.Quantity{
+		Quantity: &copy,
+	}
+}
+
+func quantitySubInt(arg ref.Val, other ref.Val) ref.Val {
+	q, ok := arg.Value().(*resource.Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	q2, ok := other.Value().(int64)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(arg)
+	}
+
+	q2Converted := *resource.NewQuantity(q2, resource.DecimalExponent)
+
+	copy := *q
+	copy.Sub(q2Converted)
+	return &apiservercel.Quantity{
+		Quantity: &copy,
+	}
+}

staging/src/k8s.io/apiserver/pkg/cel/library/quantity_test.go

@@ -0,0 +1,295 @@
+/*
+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 library_test
+
+import (
+	"regexp"
+	"testing"
+
+	"github.com/google/cel-go/cel"
+	"github.com/google/cel-go/common"
+	"github.com/google/cel-go/common/types"
+	"github.com/google/cel-go/common/types/ref"
+	"github.com/google/cel-go/ext"
+	"github.com/stretchr/testify/require"
+	"k8s.io/apimachinery/pkg/api/resource"
+	"k8s.io/apimachinery/pkg/util/sets"
+	apiservercel "k8s.io/apiserver/pkg/cel"
+	"k8s.io/apiserver/pkg/cel/library"
+)
+
+func testQuantity(t *testing.T, expr string, expectResult ref.Val, expectRuntimeErrPattern string, expectCompileErrs []string) {
+	env, err := cel.NewEnv(
+		ext.Strings(),
+		library.URLs(),
+		library.Regex(),
+		library.Lists(),
+		library.Quantity(),
+	)
+	if err != nil {
+		t.Fatalf("%v", err)
+	}
+	compiled, issues := env.Compile(expr)
+
+	if len(expectCompileErrs) > 0 {
+		missingCompileErrs := []string{}
+		matchedCompileErrs := sets.New[int]()
+		for _, expectedCompileErr := range expectCompileErrs {
+			compiledPattern, err := regexp.Compile(expectedCompileErr)
+			if err != nil {
+				t.Fatalf("failed to compile expected err regex: %v", err)
+			}
+
+			didMatch := false
+
+			for i, compileError := range issues.Errors() {
+				if compiledPattern.Match([]byte(compileError.Message)) {
+					didMatch = true
+					matchedCompileErrs.Insert(i)
+				}
+			}
+
+			if !didMatch {
+				missingCompileErrs = append(missingCompileErrs, expectedCompileErr)
+			} else if len(matchedCompileErrs) != len(issues.Errors()) {
+				unmatchedErrs := []common.Error{}
+				for i, issue := range issues.Errors() {
+					if !matchedCompileErrs.Has(i) {
+						unmatchedErrs = append(unmatchedErrs, issue)
+					}
+				}
+				require.Empty(t, unmatchedErrs, "unexpected compilation errors")
+			}
+		}
+
+		require.Empty(t, missingCompileErrs, "expected compilation errors")
+		return
+	} else if len(issues.Errors()) > 0 {
+		t.Fatalf("%v", issues.Errors())
+	}
+
+	prog, err := env.Program(compiled)
+	if err != nil {
+		t.Fatalf("%v", err)
+	}
+	res, _, err := prog.Eval(map[string]interface{}{})
+	if len(expectRuntimeErrPattern) > 0 {
+		if err == nil {
+			t.Fatalf("no runtime error thrown. Expected: %v", expectRuntimeErrPattern)
+		} else if matched, regexErr := regexp.MatchString(expectRuntimeErrPattern, err.Error()); regexErr != nil {
+			t.Fatalf("failed to compile expected err regex: %v", regexErr)
+		} else if !matched {
+			t.Fatalf("unexpected err: %v", err)
+		}
+	} else if err != nil {
+		t.Fatalf("%v", err)
+	} else if expectResult != nil {
+		converted := res.Equal(expectResult).Value().(bool)
+		require.True(t, converted, "expectation not equal to output")
+	} else {
+		t.Fatal("expected result must not be nil")
+	}
+
+}
+
+func TestQuantity(t *testing.T) {
+	twelveMi := resource.MustParse("12Mi")
+	trueVal := types.Bool(true)
+	falseVal := types.Bool(false)
+
+	cases := []struct {
+		name               string
+		expr               string
+		expectValue        ref.Val
+		expectedCompileErr []string
+		expectedRuntimeErr string
+	}{
+		{
+			name:        "parse",
+			expr:        `quantity("12Mi")`,
+			expectValue: apiservercel.Quantity{Quantity: &twelveMi},
+		},
+		{
+			name:               "parseInvalidSuffix",
+			expr:               `quantity("10Mo")`,
+			expectedRuntimeErr: "quantities must match the regular expression.*",
+		},
+		{
+			// The above case fails due to a regex check. This case passes the
+			// regex check and fails a suffix check
+			name:               "parseInvalidSuffixPassesRegex",
+			expr:               `quantity("10Mm")`,
+			expectedRuntimeErr: "unable to parse quantity's suffix",
+		},
+		{
+			name:        "isQuantity",
+			expr:        `isQuantity("20")`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "isQuantity_megabytes",
+			expr:        `isQuantity("20M")`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "isQuantity_mebibytes",
+			expr:        `isQuantity("20Mi")`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "isQuantity_invalidSuffix",
+			expr:        `isQuantity("20Mo")`,
+			expectValue: falseVal,
+		},
+		{
+			name:        "isQuantity_passingRegex",
+			expr:        `isQuantity("10Mm")`,
+			expectValue: falseVal,
+		},
+		{
+			name:               "isQuantity_noOverload",
+			expr:               `isQuantity([1, 2, 3])`,
+			expectedCompileErr: []string{"found no matching overload for 'isQuantity' applied to.*"},
+		},
+		{
+			name:        "equality_reflexivity",
+			expr:        `quantity("200M") == quantity("200M")`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "equality_symmetry",
+			expr:        `quantity("200M") == quantity("0.2G") && quantity("0.2G") == quantity("200M")`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "equality_transitivity",
+			expr:        `quantity("2M") == quantity("0.002G") && quantity("2000k") == quantity("2M") && quantity("0.002G") == quantity("2000k")`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "inequality",
+			expr:        `quantity("200M") == quantity("0.3G")`,
+			expectValue: falseVal,
+		},
+		{
+			name:        "quantity_less",
+			expr:        `quantity("50M").isLessThan(quantity("50Mi"))`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "quantity_less_obvious",
+			expr:        `quantity("50M").isLessThan(quantity("100M"))`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "quantity_less_false",
+			expr:        `quantity("100M").isLessThan(quantity("50M"))`,
+			expectValue: falseVal,
+		},
+		{
+			name:        "quantity_greater",
+			expr:        `quantity("50Mi").isGreaterThan(quantity("50M"))`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "quantity_greater_obvious",
+			expr:        `quantity("150Mi").isGreaterThan(quantity("100Mi"))`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "quantity_greater_false",
+			expr:        `quantity("50M").isGreaterThan(quantity("100M"))`,
+			expectValue: falseVal,
+		},
+		{
+			name:        "compare_equal",
+			expr:        `quantity("200M").compareTo(quantity("0.2G"))`,
+			expectValue: types.Int(0),
+		},
+		{
+			name:        "compare_less",
+			expr:        `quantity("50M").compareTo(quantity("50Mi"))`,
+			expectValue: types.Int(-1),
+		},
+		{
+			name:        "compare_greater",
+			expr:        `quantity("50Mi").compareTo(quantity("50M"))`,
+			expectValue: types.Int(1),
+		},
+		{
+			name:        "add_quantity",
+			expr:        `quantity("50k").add(quantity("20")) == quantity("50.02k")`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "add_int",
+			expr:        `quantity("50k").add(20).isLessThan(quantity("50020"))`,
+			expectValue: falseVal,
+		},
+		{
+			name:        "sub_quantity",
+			expr:        `quantity("50k").sub(quantity("20")) == quantity("49.98k")`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "sub_int",
+			expr:        `quantity("50k").sub(20) == quantity("49980")`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "arith_chain_1",
+			expr:        `quantity("50k").add(20).sub(quantity("100k")).asInteger()`,
+			expectValue: types.Int(-49980),
+		},
+		{
+			name:        "arith_chain",
+			expr:        `quantity("50k").add(20).sub(quantity("100k")).sub(-50000).asInteger()`,
+			expectValue: types.Int(20),
+		},
+		{
+			name:        "as_integer",
+			expr:        `quantity("50k").asInteger()`,
+			expectValue: types.Int(50000),
+		},
+		{
+			name:               "as_integer_error",
+			expr:               `quantity("9999999999999999999999999999999999999G").asInteger()`,
+			expectedRuntimeErr: `cannot convert value to integer`,
+		},
+		{
+			name:        "is_integer",
+			expr:        `quantity("9999999999999999999999999999999999999G").isInteger()`,
+			expectValue: falseVal,
+		},
+		{
+			name:        "is_integer",
+			expr:        `quantity("50").isInteger()`,
+			expectValue: trueVal,
+		},
+		{
+			name:        "as_float",
+			expr:        `quantity("50.703k").asApproximateFloat()`,
+			expectValue: types.Double(50703),
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			testQuantity(t, c.expr, c.expectValue, c.expectedRuntimeErr, c.expectedCompileErr)
+		})
+	}
+}

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

@@ -0,0 +1,76 @@
+/*
+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 (
+	"fmt"
+	"reflect"
+
+	"github.com/google/cel-go/cel"
+	"github.com/google/cel-go/checker/decls"
+	"github.com/google/cel-go/common/types"
+	"github.com/google/cel-go/common/types/ref"
+	"k8s.io/apimachinery/pkg/api/resource"
+)
+
+var (
+	QuantityObject    = decls.NewObjectType("kubernetes.Quantity")
+	quantityTypeValue = types.NewTypeValue("kubernetes.Quantity")
+	QuantityType      = cel.ObjectType("kubernetes.Quantity")
+)
+
+// Quantity provdes a CEL representation of a resource.Quantity
+type Quantity struct {
+	*resource.Quantity
+}
+
+func (d Quantity) ConvertToNative(typeDesc reflect.Type) (interface{}, error) {
+	if reflect.TypeOf(d.Quantity).AssignableTo(typeDesc) {
+		return d.Quantity, nil
+	}
+	if reflect.TypeOf("").AssignableTo(typeDesc) {
+		return d.Quantity.String(), nil
+	}
+	return nil, fmt.Errorf("type conversion error from 'Quantity' to '%v'", typeDesc)
+}
+
+func (d Quantity) ConvertToType(typeVal ref.Type) ref.Val {
+	switch typeVal {
+	case typeValue:
+		return d
+	case types.TypeType:
+		return quantityTypeValue
+	default:
+		return types.NewErr("type conversion error from '%s' to '%s'", quantityTypeValue, typeVal)
+	}
+}
+
+func (d Quantity) Equal(other ref.Val) ref.Val {
+	otherDur, ok := other.(Quantity)
+	if !ok {
+		return types.MaybeNoSuchOverloadErr(other)
+	}
+	return types.Bool(d.Quantity.Equal(*otherDur.Quantity))
+}
+
+func (d Quantity) Type() ref.Type {
+	return quantityTypeValue
+}
+
+func (d Quantity) Value() interface{} {
+	return d.Quantity
+}