Merge pull request #74778 from roycaihw/feat/crd-openapi-v3-v2-conversion

staging/publishing/import-restrictions.yaml

@@ -137,6 +137,7 @@
   - k8s.io/client-go
   - k8s.io/component-base
   - k8s.io/klog
+  - k8s.io/kube-openapi
 
 - baseImportPath: "./vendor/k8s.io/kube-openapi/"
   allowedImports:

staging/src/k8s.io/apiextensions-apiserver/BUILD

@@ -47,6 +47,7 @@ filegroup(
         "//staging/src/k8s.io/apiextensions-apiserver/pkg/cmd/server:all-srcs",
         "//staging/src/k8s.io/apiextensions-apiserver/pkg/controller/establish:all-srcs",
         "//staging/src/k8s.io/apiextensions-apiserver/pkg/controller/finalizer:all-srcs",
+        "//staging/src/k8s.io/apiextensions-apiserver/pkg/controller/openapi:all-srcs",
         "//staging/src/k8s.io/apiextensions-apiserver/pkg/controller/status:all-srcs",
         "//staging/src/k8s.io/apiextensions-apiserver/pkg/crdserverscheme:all-srcs",
         "//staging/src/k8s.io/apiextensions-apiserver/pkg/features:all-srcs",

staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/validation/validation.go

@@ -50,8 +50,17 @@ func ValidateCustomResource(customResource interface{}, validator *validate.Sche
 	return nil
 }
 
-// ConvertJSONSchemaProps converts the schema from apiextensions.JSONSchemaPropos to go-openapi/spec.Schema
+// ConvertJSONSchemaProps converts the schema from apiextensions.JSONSchemaPropos to go-openapi/spec.Schema.
 func ConvertJSONSchemaProps(in *apiextensions.JSONSchemaProps, out *spec.Schema) error {
+	return ConvertJSONSchemaPropsWithPostProcess(in, out, nil)
+}
+
+// PostProcessFunc post-processes one node of a spec.Schema.
+type PostProcessFunc func(*spec.Schema) error
+
+// ConvertJSONSchemaPropsWithPostProcess converts the schema from apiextensions.JSONSchemaPropos to go-openapi/spec.Schema
+// and run a post process step on each JSONSchemaProps node.
+func ConvertJSONSchemaPropsWithPostProcess(in *apiextensions.JSONSchemaProps, out *spec.Schema, postProcess PostProcessFunc) error {
 	if in == nil {
 		return nil
 	}
@@ -86,41 +95,43 @@ func ConvertJSONSchemaProps(in *apiextensions.JSONSchemaProps, out *spec.Schema)
 		out.Example = *(in.Example)
 	}
 
-	out.Enum = make([]interface{}, len(in.Enum))
-	for k, v := range in.Enum {
-		out.Enum[k] = v
+	if in.Enum != nil {
+		out.Enum = make([]interface{}, len(in.Enum))
+		for k, v := range in.Enum {
+			out.Enum[k] = v
+		}
 	}
 
-	if err := convertSliceOfJSONSchemaProps(&in.AllOf, &out.AllOf); err != nil {
+	if err := convertSliceOfJSONSchemaProps(&in.AllOf, &out.AllOf, postProcess); err != nil {
 		return err
 	}
-	if err := convertSliceOfJSONSchemaProps(&in.OneOf, &out.OneOf); err != nil {
+	if err := convertSliceOfJSONSchemaProps(&in.OneOf, &out.OneOf, postProcess); err != nil {
 		return err
 	}
-	if err := convertSliceOfJSONSchemaProps(&in.AnyOf, &out.AnyOf); err != nil {
+	if err := convertSliceOfJSONSchemaProps(&in.AnyOf, &out.AnyOf, postProcess); err != nil {
 		return err
 	}
 
 	if in.Not != nil {
 		in, out := &in.Not, &out.Not
 		*out = new(spec.Schema)
-		if err := ConvertJSONSchemaProps(*in, *out); err != nil {
+		if err := ConvertJSONSchemaPropsWithPostProcess(*in, *out, postProcess); err != nil {
 			return err
 		}
 	}
 
 	var err error
-	out.Properties, err = convertMapOfJSONSchemaProps(in.Properties)
+	out.Properties, err = convertMapOfJSONSchemaProps(in.Properties, postProcess)
 	if err != nil {
 		return err
 	}
 
-	out.PatternProperties, err = convertMapOfJSONSchemaProps(in.PatternProperties)
+	out.PatternProperties, err = convertMapOfJSONSchemaProps(in.PatternProperties, postProcess)
 	if err != nil {
 		return err
 	}
 
-	out.Definitions, err = convertMapOfJSONSchemaProps(in.Definitions)
+	out.Definitions, err = convertMapOfJSONSchemaProps(in.Definitions, postProcess)
 	if err != nil {
 		return err
 	}
@@ -135,7 +146,7 @@ func ConvertJSONSchemaProps(in *apiextensions.JSONSchemaProps, out *spec.Schema)
 	if in.AdditionalProperties != nil {
 		in, out := &in.AdditionalProperties, &out.AdditionalProperties
 		*out = new(spec.SchemaOrBool)
-		if err := convertJSONSchemaPropsorBool(*in, *out); err != nil {
+		if err := convertJSONSchemaPropsorBool(*in, *out, postProcess); err != nil {
 			return err
 		}
 	}
@@ -143,7 +154,7 @@ func ConvertJSONSchemaProps(in *apiextensions.JSONSchemaProps, out *spec.Schema)
 	if in.AdditionalItems != nil {
 		in, out := &in.AdditionalItems, &out.AdditionalItems
 		*out = new(spec.SchemaOrBool)
-		if err := convertJSONSchemaPropsorBool(*in, *out); err != nil {
+		if err := convertJSONSchemaPropsorBool(*in, *out, postProcess); err != nil {
 			return err
 		}
 	}
@@ -151,7 +162,7 @@ func ConvertJSONSchemaProps(in *apiextensions.JSONSchemaProps, out *spec.Schema)
 	if in.Items != nil {
 		in, out := &in.Items, &out.Items
 		*out = new(spec.SchemaOrArray)
-		if err := convertJSONSchemaPropsOrArray(*in, *out); err != nil {
+		if err := convertJSONSchemaPropsOrArray(*in, *out, postProcess); err != nil {
 			return err
 		}
 	}
@@ -161,7 +172,7 @@ func ConvertJSONSchemaProps(in *apiextensions.JSONSchemaProps, out *spec.Schema)
 		*out = make(spec.Dependencies, len(*in))
 		for key, val := range *in {
 			newVal := new(spec.SchemaOrStringArray)
-			if err := convertJSONSchemaPropsOrStringArray(&val, newVal); err != nil {
+			if err := convertJSONSchemaPropsOrStringArray(&val, newVal, postProcess); err != nil {
 				return err
 			}
 			(*out)[key] = *newVal
@@ -174,14 +185,20 @@ func ConvertJSONSchemaProps(in *apiextensions.JSONSchemaProps, out *spec.Schema)
 		out.ExternalDocs.URL = in.ExternalDocs.URL
 	}
 
+	if postProcess != nil {
+		if err := postProcess(out); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 
-func convertSliceOfJSONSchemaProps(in *[]apiextensions.JSONSchemaProps, out *[]spec.Schema) error {
+func convertSliceOfJSONSchemaProps(in *[]apiextensions.JSONSchemaProps, out *[]spec.Schema, postProcess PostProcessFunc) error {
 	if in != nil {
 		for _, jsonSchemaProps := range *in {
 			schema := spec.Schema{}
-			if err := ConvertJSONSchemaProps(&jsonSchemaProps, &schema); err != nil {
+			if err := ConvertJSONSchemaPropsWithPostProcess(&jsonSchemaProps, &schema, postProcess); err != nil {
 				return err
 			}
 			*out = append(*out, schema)
@@ -190,25 +207,27 @@ func convertSliceOfJSONSchemaProps(in *[]apiextensions.JSONSchemaProps, out *[]s
 	return nil
 }
 
-func convertMapOfJSONSchemaProps(in map[string]apiextensions.JSONSchemaProps) (map[string]spec.Schema, error) {
+func convertMapOfJSONSchemaProps(in map[string]apiextensions.JSONSchemaProps, postProcess PostProcessFunc) (map[string]spec.Schema, error) {
+	if in == nil {
+		return nil, nil
+	}
+
 	out := make(map[string]spec.Schema)
-	if len(in) != 0 {
-		for k, jsonSchemaProps := range in {
-			schema := spec.Schema{}
-			if err := ConvertJSONSchemaProps(&jsonSchemaProps, &schema); err != nil {
-				return nil, err
-			}
-			out[k] = schema
+	for k, jsonSchemaProps := range in {
+		schema := spec.Schema{}
+		if err := ConvertJSONSchemaPropsWithPostProcess(&jsonSchemaProps, &schema, postProcess); err != nil {
+			return nil, err
 		}
+		out[k] = schema
 	}
 	return out, nil
 }
 
-func convertJSONSchemaPropsOrArray(in *apiextensions.JSONSchemaPropsOrArray, out *spec.SchemaOrArray) error {
+func convertJSONSchemaPropsOrArray(in *apiextensions.JSONSchemaPropsOrArray, out *spec.SchemaOrArray, postProcess PostProcessFunc) error {
 	if in.Schema != nil {
 		in, out := &in.Schema, &out.Schema
 		*out = new(spec.Schema)
-		if err := ConvertJSONSchemaProps(*in, *out); err != nil {
+		if err := ConvertJSONSchemaPropsWithPostProcess(*in, *out, postProcess); err != nil {
 			return err
 		}
 	}
@@ -216,7 +235,7 @@ func convertJSONSchemaPropsOrArray(in *apiextensions.JSONSchemaPropsOrArray, out
 		in, out := &in.JSONSchemas, &out.Schemas
 		*out = make([]spec.Schema, len(*in))
 		for i := range *in {
-			if err := ConvertJSONSchemaProps(&(*in)[i], &(*out)[i]); err != nil {
+			if err := ConvertJSONSchemaPropsWithPostProcess(&(*in)[i], &(*out)[i], postProcess); err != nil {
 				return err
 			}
 		}
@@ -224,24 +243,24 @@ func convertJSONSchemaPropsOrArray(in *apiextensions.JSONSchemaPropsOrArray, out
 	return nil
 }
 
-func convertJSONSchemaPropsorBool(in *apiextensions.JSONSchemaPropsOrBool, out *spec.SchemaOrBool) error {
+func convertJSONSchemaPropsorBool(in *apiextensions.JSONSchemaPropsOrBool, out *spec.SchemaOrBool, postProcess PostProcessFunc) error {
 	out.Allows = in.Allows
 	if in.Schema != nil {
 		in, out := &in.Schema, &out.Schema
 		*out = new(spec.Schema)
-		if err := ConvertJSONSchemaProps(*in, *out); err != nil {
+		if err := ConvertJSONSchemaPropsWithPostProcess(*in, *out, postProcess); err != nil {
 			return err
 		}
 	}
 	return nil
 }
 
-func convertJSONSchemaPropsOrStringArray(in *apiextensions.JSONSchemaPropsOrStringArray, out *spec.SchemaOrStringArray) error {
+func convertJSONSchemaPropsOrStringArray(in *apiextensions.JSONSchemaPropsOrStringArray, out *spec.SchemaOrStringArray, postProcess PostProcessFunc) error {
 	out.Property = in.Property
 	if in.Schema != nil {
 		in, out := &in.Schema, &out.Schema
 		*out = new(spec.Schema)
-		if err := ConvertJSONSchemaProps(*in, *out); err != nil {
+		if err := ConvertJSONSchemaPropsWithPostProcess(*in, *out, postProcess); err != nil {
 			return err
 		}
 	}

staging/src/k8s.io/apiextensions-apiserver/pkg/controller/openapi/BUILD

+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["conversion.go"],
+    importmap = "k8s.io/kubernetes/vendor/k8s.io/apiextensions-apiserver/pkg/controller/openapi",
+    importpath = "k8s.io/apiextensions-apiserver/pkg/controller/openapi",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//staging/src/k8s.io/apiextensions-apiserver/pkg/apis/apiextensions:go_default_library",
+        "//staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/validation:go_default_library",
+        "//vendor/github.com/go-openapi/spec:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["conversion_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//staging/src/k8s.io/apiextensions-apiserver/pkg/apis/apiextensions:go_default_library",
+        "//staging/src/k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/util/diff:go_default_library",
+        "//vendor/github.com/go-openapi/spec:go_default_library",
+        "//vendor/github.com/google/gofuzz:go_default_library",
+        "//vendor/github.com/googleapis/gnostic/OpenAPIv2:go_default_library",
+        "//vendor/github.com/googleapis/gnostic/compiler:go_default_library",
+        "//vendor/gopkg.in/yaml.v2:go_default_library",
+        "//vendor/k8s.io/kube-openapi/pkg/util/proto:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

staging/src/k8s.io/apiextensions-apiserver/pkg/controller/openapi/conversion.go

+/*
+Copyright 2019 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 (
+	"strings"
+
+	"github.com/go-openapi/spec"
+
+	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions"
+	"k8s.io/apiextensions-apiserver/pkg/apiserver/validation"
+)
+
+// ConvertJSONSchemaPropsToOpenAPIv2Schema converts our internal OpenAPI v3 schema
+// (*apiextensions.JSONSchemaProps) to an OpenAPI v2 schema (*spec.Schema).
+func ConvertJSONSchemaPropsToOpenAPIv2Schema(in *apiextensions.JSONSchemaProps) (*spec.Schema, error) {
+	if in == nil {
+		return nil, nil
+	}
+
+	// dirty hack to temporarily set the type at the root. See continuation at the func bottom.
+	// TODO: remove for Kubernetes 1.15
+	oldRootType := in.Type
+	if len(in.Type) == 0 {
+		in.Type = "object"
+	}
+
+	// Remove unsupported fields in OpenAPI v2 recursively
+	out := new(spec.Schema)
+	validation.ConvertJSONSchemaPropsWithPostProcess(in, out, func(p *spec.Schema) error {
+		p.OneOf = nil
+		// TODO(roycaihw): preserve cases where we only have one subtree in AnyOf, same for OneOf
+		p.AnyOf = nil
+		p.Not = nil
+
+		// TODO: drop everything below in 1.15 when we have passed one version skew towards kube-openapi in <1.14, which rejects valid openapi schemata
+
+		if p.Ref.String() != "" {
+			// https://github.com/kubernetes/kube-openapi/pull/143/files#diff-62afddb578e9db18fb32ffb6b7802d92R95
+			p.Properties = nil
+
+			// https://github.com/kubernetes/kube-openapi/pull/143/files#diff-62afddb578e9db18fb32ffb6b7802d92R99
+			p.Type = nil
+
+			// https://github.com/kubernetes/kube-openapi/pull/143/files#diff-62afddb578e9db18fb32ffb6b7802d92R104
+			if !strings.HasPrefix(p.Ref.String(), "#/definitions/") {
+				p.Ref = spec.Ref{}
+			}
+		}
+
+		if len(p.Type) > 1 {
+			// https://github.com/kubernetes/kube-openapi/pull/143/files#diff-62afddb578e9db18fb32ffb6b7802d92R272
+			// We also set Properties to null to enforce parseArbitrary at https://github.com/kubernetes/kube-openapi/blob/814a8073653e40e0e324205d093770d4e7bb811f/pkg/util/proto/document.go#L247
+			p.Type = nil
+			p.Properties = nil
+		} else if len(p.Type) == 1 {
+			switch p.Type[0] {
+			case "null":
+				// https://github.com/kubernetes/kube-openapi/pull/143/files#diff-ce77fea74b9dd098045004410023e0c3R219
+				p.Type = nil
+			case "array":
+				// https://github.com/kubernetes/kube-openapi/pull/143/files#diff-62afddb578e9db18fb32ffb6b7802d92R183
+				// https://github.com/kubernetes/kube-openapi/pull/143/files#diff-62afddb578e9db18fb32ffb6b7802d92R184
+				if p.Items == nil || (p.Items.Schema == nil && len(p.Items.Schemas) != 1) {
+					p.Type = nil
+					p.Items = nil
+				}
+			}
+		} else {
+			// https://github.com/kubernetes/kube-openapi/pull/143/files#diff-62afddb578e9db18fb32ffb6b7802d92R248
+			p.Properties = nil
+		}
+
+		// normalize items
+		if p.Items != nil && len(p.Items.Schemas) == 1 {
+			p.Items = &spec.SchemaOrArray{Schema: &p.Items.Schemas[0]}
+		}
+
+		// general fixups not supported by gnostic
+		p.ID = ""
+		p.Schema = ""
+		p.Definitions = nil
+		p.AdditionalItems = nil
+		p.Dependencies = nil
+		p.PatternProperties = nil
+		if p.ExternalDocs != nil && len(p.ExternalDocs.URL) == 0 {
+			p.ExternalDocs = nil
+		}
+		if p.Items != nil && p.Items.Schemas != nil {
+			p.Items = nil
+		}
+
+		return nil
+	})
+
+	// restore root level type in input, and remove it in output if we had added it
+	// TODO: remove with Kubernetes 1.15
+	in.Type = oldRootType
+	if len(oldRootType) == 0 {
+		out.Type = nil
+	}
+
+	return out, nil
+}

staging/src/k8s.io/apiextensions-apiserver/pkg/controller/openapi/conversion_test.go

+/*
+Copyright 2018 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 (
+	"encoding/json"
+	"fmt"
+	"math"
+	"math/rand"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/go-openapi/spec"
+	"github.com/google/gofuzz"
+	"github.com/googleapis/gnostic/OpenAPIv2"
+	"github.com/googleapis/gnostic/compiler"
+	"gopkg.in/yaml.v2"
+	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions"
+	apiextensionsv1beta1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
+	"k8s.io/apimachinery/pkg/util/diff"
+	"k8s.io/kube-openapi/pkg/util/proto"
+)
+
+func Test_ConvertJSONSchemaPropsToOpenAPIv2Schema(t *testing.T) {
+	var spec = []byte(`description: Foo CRD for Testing
+type: object
+properties:
+  spec:
+    description: Specification of Foo
+    type: object
+    properties:
+      bars:
+        description: List of Bars and their specs.
+        type: array
+        items:
+          type: object
+          required:
+          - name
+          properties:
+            name:
+              description: Name of Bar.
+              type: string
+            age:
+              description: Age of Bar.
+              type: string
+            bazs:
+              description: List of Bazs.
+              items:
+                type: string
+              type: array
+  status:
+    description: Status of Foo
+    type: object
+    properties:
+      bars:
+        description: List of Bars and their statuses.
+        type: array
+        items:
+          type: object
+          properties:
+            name:
+              description: Name of Bar.
+              type: string
+            available:
+              description: Whether the Bar is installed.
+              type: boolean
+            quxType:
+              description: Indicates to external qux type.
+              pattern: in-tree|out-of-tree
+              type: string`)
+
+	specV1beta1 := apiextensionsv1beta1.JSONSchemaProps{}
+	if err := yaml.Unmarshal(spec, &specV1beta1); err != nil {
+		t.Fatal(err)
+	}
+
+	specInternal := apiextensions.JSONSchemaProps{}
+	if err := apiextensionsv1beta1.Convert_v1beta1_JSONSchemaProps_To_apiextensions_JSONSchemaProps(&specV1beta1, &specInternal, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	schema, err := ConvertJSONSchemaPropsToOpenAPIv2Schema(&specInternal)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if _, found := schema.Properties["spec"]; !found {
+		t.Errorf("spec not found")
+	}
+	if _, found := schema.Properties["status"]; !found {
+		t.Errorf("status not found")
+	}
+}
+
+func Test_ConvertJSONSchemaPropsToOpenAPIv2SchemaFuzzing(t *testing.T) {
+	testStr := "test"
+	testStr2 := "test2"
+	testFloat64 := float64(6.4)
+	testInt64 := int64(64)
+	testApiextensionsJSON := apiextensions.JSON(testStr)
+
+	tests := []struct {
+		name     string
+		in       *apiextensions.JSONSchemaProps
+		expected *spec.Schema
+	}{
+		{
+			name: "id",
+			in: &apiextensions.JSONSchemaProps{
+				ID: testStr,
+			},
+			expected: new(spec.Schema),
+			// not supported by gnostic
+			// expected: new(spec.Schema).
+			// 	WithID(testStr),
+		},
+		{
+			name: "$schema",
+			in: &apiextensions.JSONSchemaProps{
+				Schema: "test",
+			},
+			expected: new(spec.Schema),
+			// not supported by gnostic
+			// expected: &spec.Schema{
+			// 	SchemaProps: spec.SchemaProps{
+			// 		Schema: "test",
+			// 	},
+			// },
+		},
+		{
+			name: "$ref",
+			in: &apiextensions.JSONSchemaProps{
+				Ref: &testStr,
+			},
+			expected: new(spec.Schema),
+			// https://github.com/kubernetes/kube-openapi/pull/143/files#diff-62afddb578e9db18fb32ffb6b7802d92R104
+			// expected: spec.RefSchema(testStr),
+		},
+		{
+			name: "description",
+			in: &apiextensions.JSONSchemaProps{
+				Description: testStr,
+			},
+			expected: new(spec.Schema).
+				WithDescription(testStr),
+		},
+		{
+			name: "type and format",
+			in: &apiextensions.JSONSchemaProps{
+				Type:   testStr,
+				Format: testStr2,
+			},
+			expected: new(spec.Schema).
+				Typed(testStr, testStr2),
+		},
+		{
+			name: "title",
+			in: &apiextensions.JSONSchemaProps{
+				Title: testStr,
+			},
+			expected: new(spec.Schema).
+				WithTitle(testStr),
+		},
+		{
+			name: "default",
+			in: &apiextensions.JSONSchemaProps{
+				Default: &testApiextensionsJSON,
+			},
+			expected: new(spec.Schema).
+				WithDefault(testStr),
+		},
+		{
+			name: "maximum and exclusiveMaximum",
+			in: &apiextensions.JSONSchemaProps{
+				Maximum:          &testFloat64,
+				ExclusiveMaximum: true,
+			},
+			expected: new(spec.Schema).
+				WithMaximum(testFloat64, true),
+		},
+		{
+			name: "minimum and exclusiveMinimum",
+			in: &apiextensions.JSONSchemaProps{
+				Minimum:          &testFloat64,
+				ExclusiveMinimum: true,
+			},
+			expected: new(spec.Schema).
+				WithMinimum(testFloat64, true),
+		},
+		{
+			name: "maxLength",
+			in: &apiextensions.JSONSchemaProps{
+				MaxLength: &testInt64,
+			},
+			expected: new(spec.Schema).
+				WithMaxLength(testInt64),
+		},
+		{
+			name: "minLength",
+			in: &apiextensions.JSONSchemaProps{
+				MinLength: &testInt64,
+			},
+			expected: new(spec.Schema).
+				WithMinLength(testInt64),
+		},
+		{
+			name: "pattern",
+			in: &apiextensions.JSONSchemaProps{
+				Pattern: testStr,
+			},
+			expected: new(spec.Schema).
+				WithPattern(testStr),
+		},
+		{
+			name: "maxItems",
+			in: &apiextensions.JSONSchemaProps{
+				MaxItems: &testInt64,
+			},
+			expected: new(spec.Schema).
+				WithMaxItems(testInt64),
+		},
+		{
+			name: "minItems",
+			in: &apiextensions.JSONSchemaProps{
+				MinItems: &testInt64,
+			},
+			expected: new(spec.Schema).
+				WithMinItems(testInt64),
+		},
+		{
+			name: "uniqueItems",
+			in: &apiextensions.JSONSchemaProps{
+				UniqueItems: true,
+			},
+			expected: new(spec.Schema).
+				UniqueValues(),
+		},
+		{
+			name: "multipleOf",
+			in: &apiextensions.JSONSchemaProps{
+				MultipleOf: &testFloat64,
+			},
+			expected: new(spec.Schema).
+				WithMultipleOf(testFloat64),
+		},
+		{
+			name: "enum",
+			in: &apiextensions.JSONSchemaProps{
+				Enum: []apiextensions.JSON{apiextensions.JSON(testStr), apiextensions.JSON(testStr2)},
+			},
+			expected: new(spec.Schema).
+				WithEnum(testStr, testStr2),
+		},
+		{
+			name: "maxProperties",
+			in: &apiextensions.JSONSchemaProps{
+				MaxProperties: &testInt64,
+			},
+			expected: new(spec.Schema).
+				WithMaxProperties(testInt64),
+		},
+		{
+			name: "minProperties",
+			in: &apiextensions.JSONSchemaProps{
+				MinProperties: &testInt64,
+			},
+			expected: new(spec.Schema).
+				WithMinProperties(testInt64),
+		},
+		{
+			name: "required",
+			in: &apiextensions.JSONSchemaProps{
+				Required: []string{testStr, testStr2},
+			},
+			expected: new(spec.Schema).
+				WithRequired(testStr, testStr2),
+		},
+		{
+			name: "items single props",
+			in: &apiextensions.JSONSchemaProps{
+				Items: &apiextensions.JSONSchemaPropsOrArray{
+					Schema: &apiextensions.JSONSchemaProps{
+						Type: "boolean",
+					},
+				},
+			},
+			expected: &spec.Schema{
+				SchemaProps: spec.SchemaProps{
+					Items: &spec.SchemaOrArray{
+						Schema: spec.BooleanProperty(),
+					},
+				},
+			},
+		},
+		{
+			name: "items array props",
+			in: &apiextensions.JSONSchemaProps{
+				Items: &apiextensions.JSONSchemaPropsOrArray{
+					JSONSchemas: []apiextensions.JSONSchemaProps{
+						{Type: "boolean"},
+						{Type: "string"},
+					},
+				},
+			},
+			expected: new(spec.Schema),
+			// https://github.com/kubernetes/kube-openapi/pull/143/files#diff-62afddb578e9db18fb32ffb6b7802d92R272
+			// expected: &spec.Schema{
+			// 	SchemaProps: spec.SchemaProps{
+			// 		Items: &spec.SchemaOrArray{
+			// 			Schemas: []spec.Schema{
+			// 				*spec.BooleanProperty(),
+			// 				*spec.StringProperty(),
+			// 			},
+			// 		},
+			// 	},
+			// },
+		},
+		{
+			name: "allOf",
+			in: &apiextensions.JSONSchemaProps{
+				AllOf: []apiextensions.JSONSchemaProps{
+					{Type: "boolean"},
+					{Type: "string"},
+				},
+			},
+			expected: new(spec.Schema).
+				WithAllOf(*spec.BooleanProperty(), *spec.StringProperty()),
+		},
+		{
+			name: "oneOf",
+			in: &apiextensions.JSONSchemaProps{
+				OneOf: []apiextensions.JSONSchemaProps{
+					{Type: "boolean"},
+					{Type: "string"},
+				},
+			},
+			expected: new(spec.Schema),
+			// not supported by openapi v2
+			// expected: &spec.Schema{
+			// 	SchemaProps: spec.SchemaProps{
+			// 		OneOf: []spec.Schema{
+			// 			*spec.BooleanProperty(),
+			// 			*spec.StringProperty(),
+			// 		},
+			// 	},
+			// },
+		},
+		{
+			name: "anyOf",
+			in: &apiextensions.JSONSchemaProps{
+				AnyOf: []apiextensions.JSONSchemaProps{
+					{Type: "boolean"},
+					{Type: "string"},
+				},
+			},
+			expected: new(spec.Schema),
+			// not supported by openapi v2
+			// expected: &spec.Schema{
+			// 	SchemaProps: spec.SchemaProps{
+			// 		AnyOf: []spec.Schema{
+			// 			*spec.BooleanProperty(),
+			// 			*spec.StringProperty(),
+			// 		},
+			// 	},
+			// },
+		},
+		{
+			name: "not",
+			in: &apiextensions.JSONSchemaProps{
+				Not: &apiextensions.JSONSchemaProps{
+					Type: "boolean",
+				},
+			},
+			expected: new(spec.Schema),
+			// not supported by openapi v2
+			// expected: &spec.Schema{
+			// 	SchemaProps: spec.SchemaProps{
+			// 		Not: spec.BooleanProperty(),
+			// 	},
+			// },
+		},
+		{
+			name: "nested logic",
+			in: &apiextensions.JSONSchemaProps{
+				AllOf: []apiextensions.JSONSchemaProps{
+					{
+						Not: &apiextensions.JSONSchemaProps{
+							Type: "boolean",
+						},
+					},
+					{
+						AnyOf: []apiextensions.JSONSchemaProps{
+							{Type: "boolean"},
+							{Type: "string"},
+						},
+					},
+					{
+						OneOf: []apiextensions.JSONSchemaProps{
+							{Type: "boolean"},
+							{Type: "string"},
+						},
+					},
+					{Type: "string"},
+				},
+				AnyOf: []apiextensions.JSONSchemaProps{
+					{
+						Not: &apiextensions.JSONSchemaProps{
+							Type: "boolean",
+						},
+					},
+					{
+						AnyOf: []apiextensions.JSONSchemaProps{
+							{Type: "boolean"},
+							{Type: "string"},
+						},
+					},
+					{
+						OneOf: []apiextensions.JSONSchemaProps{
+							{Type: "boolean"},
+							{Type: "string"},
+						},
+					},
+					{Type: "string"},
+				},
+				OneOf: []apiextensions.JSONSchemaProps{
+					{
+						Not: &apiextensions.JSONSchemaProps{
+							Type: "boolean",
+						},
+					},
+					{
+						AnyOf: []apiextensions.JSONSchemaProps{
+							{Type: "boolean"},
+							{Type: "string"},
+						},
+					},
+					{
+						OneOf: []apiextensions.JSONSchemaProps{
+							{Type: "boolean"},
+							{Type: "string"},
+						},
+					},
+					{Type: "string"},
+				},
+				Not: &apiextensions.JSONSchemaProps{
+					Not: &apiextensions.JSONSchemaProps{
+						Type: "boolean",
+					},
+					AnyOf: []apiextensions.JSONSchemaProps{
+						{Type: "boolean"},
+						{Type: "string"},
+					},
+					OneOf: []apiextensions.JSONSchemaProps{
+						{Type: "boolean"},
+						{Type: "string"},
+					},
+				},
+			},
+			expected: new(spec.Schema).
+				WithAllOf(spec.Schema{}, spec.Schema{}, spec.Schema{}, *spec.StringProperty()),
+		},
+		{
+			name: "properties",
+			in: &apiextensions.JSONSchemaProps{
+				Properties: map[string]apiextensions.JSONSchemaProps{
+					testStr: {Type: "boolean"},
+				},
+			},
+			expected: new(spec.Schema).
+				SetProperty(testStr, *spec.BooleanProperty()),
+		},
+		{
+			name: "additionalProperties",
+			in: &apiextensions.JSONSchemaProps{
+				AdditionalProperties: &apiextensions.JSONSchemaPropsOrBool{
+					Allows: true,
+					Schema: &apiextensions.JSONSchemaProps{Type: "boolean"},
+				},
+			},
+			expected: &spec.Schema{
+				SchemaProps: spec.SchemaProps{
+					AdditionalProperties: &spec.SchemaOrBool{
+						Allows: true,
+						Schema: spec.BooleanProperty(),
+					},
+				},
+			},
+		},
+		{
+			name: "patternProperties",
+			in: &apiextensions.JSONSchemaProps{
+				PatternProperties: map[string]apiextensions.JSONSchemaProps{
+					testStr: {Type: "boolean"},
+				},
+			},
+			expected: new(spec.Schema),
+			// not supported by gnostic
+			// expected: &spec.Schema{
+			// 	SchemaProps: spec.SchemaProps{
+			// 		PatternProperties: map[string]spec.Schema{
+			// 			testStr: *spec.BooleanProperty(),
+			// 		},
+			// 	},
+			// },
+		},
+		{
+			name: "dependencies schema",
+			in: &apiextensions.JSONSchemaProps{
+				Dependencies: apiextensions.JSONSchemaDependencies{
+					testStr: apiextensions.JSONSchemaPropsOrStringArray{
+						Schema: &apiextensions.JSONSchemaProps{Type: "boolean"},
+					},
+				},
+			},
+			expected: new(spec.Schema),
+			// not supported by gnostic
+			// expected: &spec.Schema{
+			// 	SchemaProps: spec.SchemaProps{
+			// 		Dependencies: spec.Dependencies{
+			// 			testStr: spec.SchemaOrStringArray{
+			// 				Schema: spec.BooleanProperty(),
+			// 			},
+			// 		},
+			// 	},
+			// },
+		},
+		{
+			name: "dependencies string array",
+			in: &apiextensions.JSONSchemaProps{
+				Dependencies: apiextensions.JSONSchemaDependencies{
+					testStr: apiextensions.JSONSchemaPropsOrStringArray{
+						Property: []string{testStr2},
+					},
+				},
+			},
+			expected: new(spec.Schema),
+			// not supported by gnostic
+			// expected: &spec.Schema{
+			// 	SchemaProps: spec.SchemaProps{
+			// 		Dependencies: spec.Dependencies{
+			// 			testStr: spec.SchemaOrStringArray{
+			// 				Property: []string{testStr2},
+			// 			},
+			// 		},
+			// 	},
+			// },
+		},
+		{
+			name: "additionalItems",
+			in: &apiextensions.JSONSchemaProps{
+				AdditionalItems: &apiextensions.JSONSchemaPropsOrBool{
+					Allows: true,
+					Schema: &apiextensions.JSONSchemaProps{Type: "boolean"},
+				},
+			},
+			expected: new(spec.Schema),
+			// not supported by gnostic
+			// expected: &spec.Schema{
+			// 	SchemaProps: spec.SchemaProps{
+			// 		AdditionalItems: &spec.SchemaOrBool{
+			// 			Allows: true,
+			// 			Schema: spec.BooleanProperty(),
+			// 		},
+			// 	},
+			// },
+		},
+		{
+			name: "definitions",
+			in: &apiextensions.JSONSchemaProps{
+				Definitions: apiextensions.JSONSchemaDefinitions{
+					testStr: apiextensions.JSONSchemaProps{Type: "boolean"},
+				},
+			},
+			expected: new(spec.Schema),
+			// not supported by gnostic
+			// expected: &spec.Schema{
+			// 	SchemaProps: spec.SchemaProps{
+			// 		Definitions: spec.Definitions{
+			// 			testStr: *spec.BooleanProperty(),
+			// 		},
+			// 	},
+			// },
+		},
+		{
+			name: "externalDocs",
+			in: &apiextensions.JSONSchemaProps{
+				ExternalDocs: &apiextensions.ExternalDocumentation{
+					Description: testStr,
+					URL:         testStr2,
+				},
+			},
+			expected: new(spec.Schema).
+				WithExternalDocs(testStr, testStr2),
+		},
+		{
+			name: "example",
+			in: &apiextensions.JSONSchemaProps{
+				Example: &testApiextensionsJSON,
+			},
+			expected: new(spec.Schema).
+				WithExample(testStr),
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			out, err := ConvertJSONSchemaPropsToOpenAPIv2Schema(test.in)
+			if err != nil {
+				t.Fatalf("unexpected error in converting openapi schema: %v", err)
+			}
+			if !reflect.DeepEqual(*out, *test.expected) {
+				t.Errorf("unexpected result:\n  want=%v\n   got=%v\n\n%s", *test.expected, *out, diff.ObjectDiff(*test.expected, *out))
+			}
+		})
+	}
+}
+
+// TestKubeOpenapiRejectionFiltering tests that the CRD openapi schema filtering leads to a spec that the
+// kube-openapi/pkg/util/proto model code support in version used in Kubernetes 1.13.
+func TestKubeOpenapiRejectionFiltering(t *testing.T) {
+	for i := 0; i < 10000; i++ {
+		t.Run(fmt.Sprintf("iteration %d", i), func(t *testing.T) {
+			f := fuzz.New()
+			seed := time.Now().UnixNano()
+			randSource := rand.New(rand.NewSource(seed))
+			f.RandSource(randSource)
+			t.Logf("seed = %d", seed)
+
+			fuzzFuncs(f, func(ref *spec.Ref, c fuzz.Continue, visible bool) {
+				var url string
+				if c.RandBool() {
+					url = fmt.Sprintf("http://%d", c.Intn(100000))
+				} else {
+					url = "#/definitions/test"
+				}
+				r, err := spec.NewRef(url)
+				if err != nil {
+					t.Fatalf("failed to fuzz ref: %v", err)
+				}
+				*ref = r
+			})
+
+			// create go-openapi object and fuzz it (we start here because we have the powerful fuzzer already
+			s := &spec.Schema{}
+			f.Fuzz(s)
+
+			// convert to apiextensions v1beta1
+			bs, err := json.Marshal(s)
+			if err != nil {
+				t.Fatal(err)
+			}
+			t.Log(string(bs))
+
+			var schema *apiextensionsv1beta1.JSONSchemaProps
+			if err := json.Unmarshal(bs, &schema); err != nil {
+				t.Fatalf("failed to unmarshal JSON into apiextensions/v1beta1: %v", err)
+			}
+
+			// convert to internal
+			internalSchema := &apiextensions.JSONSchemaProps{}
+			if err := apiextensionsv1beta1.Convert_v1beta1_JSONSchemaProps_To_apiextensions_JSONSchemaProps(schema, internalSchema, nil); err != nil {
+				t.Fatalf("failed to convert from apiextensions/v1beta1 to internal: %v", err)
+			}
+
+			// apply the filter
+			filtered, err := ConvertJSONSchemaPropsToOpenAPIv2Schema(internalSchema)
+			if err != nil {
+				t.Fatalf("failed to filter: %v", err)
+			}
+
+			// create a doc out of it
+			filteredSwagger := &spec.Swagger{
+				SwaggerProps: spec.SwaggerProps{
+					Definitions: spec.Definitions{
+						"test": *filtered,
+					},
+					Info: &spec.Info{
+						InfoProps: spec.InfoProps{
+							Description: "test",
+							Version:     "test",
+							Title:       "test",
+						},
+					},
+					Swagger: "2.0",
+				},
+			}
+
+			// convert to JSON
+			bs, err = json.Marshal(filteredSwagger)
+			if err != nil {
+				t.Fatalf("failed to encode filtered to JSON: %v", err)
+			}
+
+			// unmarshal as yaml
+			var yml yaml.MapSlice
+			if err := yaml.Unmarshal(bs, &yml); err != nil {
+				t.Fatalf("failed to decode filtered JSON by into memory: %v", err)
+			}
+
+			// create gnostic doc
+			doc, err := openapi_v2.NewDocument(yml, compiler.NewContext("$root", nil))
+			if err != nil {
+				t.Fatalf("failed to create gnostic doc: %v", err)
+			}
+
+			// load with kube-openapi/pkg/util/proto
+			if _, err := proto.NewOpenAPIData(doc); err != nil {
+				t.Fatalf("failed to convert to kube-openapi/pkg/util/proto model: %v", err)
+			}
+		})
+	}
+}
+
+// fuzzFuncs is copied from kube-openapi/pkg/aggregator. It fuzzes go-openapi/spec schemata.
+func fuzzFuncs(f *fuzz.Fuzzer, refFunc func(ref *spec.Ref, c fuzz.Continue, visible bool)) {
+	invisible := 0 // == 0 means visible, > 0 means invisible
+	depth := 0
+	maxDepth := 3
+	nilChance := func(depth int) float64 {
+		return math.Pow(0.9, math.Max(0.0, float64(maxDepth-depth)))
+	}
+	updateFuzzer := func(depth int) {
+		f.NilChance(nilChance(depth))
+		f.NumElements(0, max(0, maxDepth-depth))
+	}
+	updateFuzzer(depth)
+	enter := func(o interface{}, recursive bool, c fuzz.Continue) {
+		if recursive {
+			depth++
+			updateFuzzer(depth)
+		}
+
+		invisible++
+		c.FuzzNoCustom(o)
+		invisible--
+	}
+	leave := func(recursive bool) {
+		if recursive {
+			depth--
+			updateFuzzer(depth)
+		}
+	}
+	f.Funcs(
+		func(ref *spec.Ref, c fuzz.Continue) {
+			refFunc(ref, c, invisible == 0)
+		},
+		func(sa *spec.SchemaOrStringArray, c fuzz.Continue) {
+			*sa = spec.SchemaOrStringArray{}
+			if c.RandBool() {
+				c.Fuzz(&sa.Schema)
+			} else {
+				c.Fuzz(&sa.Property)
+			}
+			if sa.Schema == nil && len(sa.Property) == 0 {
+				*sa = spec.SchemaOrStringArray{Schema: &spec.Schema{}}
+			}
+		},
+		func(url *spec.SchemaURL, c fuzz.Continue) {
+			*url = spec.SchemaURL("http://url")
+		},
+		func(s *spec.Dependencies, c fuzz.Continue) {
+			enter(s, false, c)
+			defer leave(false)
+
+			// and nothing with invisible==false
+		},
+		func(p *spec.SimpleSchema, c fuzz.Continue) {
+			// gofuzz is broken and calls this even for *SimpleSchema fields, ignoring NilChance, leading to infinite recursion
+			if c.Float64() > nilChance(depth) {
+				return
+			}
+
+			enter(p, true, c)
+			defer leave(true)
+
+			c.FuzzNoCustom(p)
+
+			// reset JSON fields to some correct JSON
+			if p.Default != nil {
+				p.Default = "42"
+			}
+			if p.Example != nil {
+				p.Example = "42"
+			}
+		},
+		func(s *spec.SchemaProps, c fuzz.Continue) {
+			// gofuzz is broken and calls this even for *SchemaProps fields, ignoring NilChance, leading to infinite recursion
+			if c.Float64() > nilChance(depth) {
+				return
+			}
+
+			enter(s, true, c)
+			defer leave(true)
+
+			c.FuzzNoCustom(s)
+
+			// we don't support multi-type schema props yet in apiextensions/v1beta1
+			if len(s.Type) > 1 {
+				s.Type = s.Type[:1]
+
+				s := apiextensionsv1beta1.JSONSchemaProps{}
+				if reflect.TypeOf(s.Type).String() != "string" {
+					panic(fmt.Errorf("this simplifaction is outdated: apiextensions/v1beta1 types not a single string anymore, but %T", s.Type))
+				}
+			}
+
+			// reset JSON fields to some correct JSON
+			if s.Default != nil {
+				s.Default = "42"
+			}
+			for i := range s.Enum {
+				s.Enum[i] = "42"
+			}
+		},
+		func(i *interface{}, c fuzz.Continue) {
+			// do nothing for examples and defaults. These are free form JSON fields.
+		},
+	)
+}
+
+func max(i, j int) int {
+	if i > j {
+		return i
+	}
+	return j
+}