✨ Generate schema for types with custom JSON marshaling as Any type

Currently controller-gen complains about structs with missing json tags
even when those structs implement custom JSON marshalling.

With this change we check if a type implements custom JSON marshalling and if it
does, we output schema for Any type. This still allows the validation type to
be overriden with a marker.

Author: Slavomir Kaslev

pkg/crd/schema.go

@@ -19,6 +19,7 @@ package crd
 import (
 	"fmt"
 	"go/ast"
+	"go/token"
 	"go/types"
 	"strings"
 
@@ -104,6 +105,11 @@ func (c *schemaContext) requestSchema(pkgPath, typeName string) {
 
 // infoToSchema creates a schema for the type in the given set of type information.
 func infoToSchema(ctx *schemaContext) *apiext.JSONSchemaProps {
+	if obj := ctx.pkg.Types.Scope().Lookup(ctx.info.Name); obj != nil && implementsJSONMarshaler(obj.Type()) {
+		schema := &apiext.JSONSchemaProps{Type: "Any"}
+		applyMarkers(ctx, ctx.info.Markers, schema, ctx.info.RawSpec.Type)
+		return schema
+	}
 	return typeToSchema(ctx, ctx.info.RawSpec.Type)
 }
 
@@ -419,3 +425,16 @@ func builtinToType(basic *types.Basic) (typ string, format string, err error) {
 
 	return typ, format, nil
 }
+
+// Open coded go/types representation of encoding/json.Marshaller
+var jsonMarshaler = types.NewInterfaceType([]*types.Func{
+	types.NewFunc(token.NoPos, nil, "MarshalJSON",
+		types.NewSignature(nil, nil,
+			types.NewTuple(
+				types.NewVar(token.NoPos, nil, "", types.NewSlice(types.Universe.Lookup("byte").Type())),
+				types.NewVar(token.NoPos, nil, "", types.Universe.Lookup("error").Type())), false)),
+}, nil).Complete()
+
+func implementsJSONMarshaler(typ types.Type) bool {
+	return types.Implements(typ, jsonMarshaler) || types.Implements(types.NewPointer(typ), jsonMarshaler)
+}

pkg/crd/testdata/cronjob_types.go

@@ -23,7 +23,9 @@ limitations under the License.
 package cronjob
 
 import (
+	"encoding/json"
 	"fmt"
+	"net/url"
 
 	batchv1beta1 "k8s.io/api/batch/v1beta1"
 	corev1 "k8s.io/api/core/v1"
@@ -190,6 +192,84 @@ func (t *TotallyABool) UnmarshalJSON(in []byte) error {
 	return nil
 }
 
+// +kubebuilder:validation:Type=string
+// URL wraps url.URL.
+// It has custom json marshal methods that enable it to be used in K8s CRDs
+// such that the CRD resource will have the URL but operator code can can work with url.URL struct
+type URL struct {
+	url.URL
+}
+
+func (u *URL) MarshalJSON() ([]byte, error) {
+	return []byte(fmt.Sprintf("%q", u.String())), nil
+}
+
+func (u *URL) UnmarshalJSON(b []byte) error {
+	var ref string
+	if err := json.Unmarshal(b, &ref); err != nil {
+		return err
+	}
+	if ref == "" {
+		*u = URL{}
+		return nil
+	}
+
+	r, err := url.Parse(ref)
+	if err != nil {
+		return err
+	} else if r != nil {
+		*u = URL{*r}
+	} else {
+		*u = URL{}
+	}
+	return nil
+}
+
+func (u *URL) String() string {
+	if u == nil {
+		return ""
+	}
+	return u.URL.String()
+}
+
+// +kubebuilder:validation:Type=string
+// URL2 is an alias of url.URL.
+// It has custom json marshal methods that enable it to be used in K8s CRDs
+// such that the CRD resource will have the URL but operator code can can work with url.URL struct
+type URL2 url.URL
+
+func (u *URL2) MarshalJSON() ([]byte, error) {
+	return []byte(fmt.Sprintf("%q", u.String())), nil
+}
+
+func (u *URL2) UnmarshalJSON(b []byte) error {
+	var ref string
+	if err := json.Unmarshal(b, &ref); err != nil {
+		return err
+	}
+	if ref == "" {
+		*u = URL2{}
+		return nil
+	}
+
+	r, err := url.Parse(ref)
+	if err != nil {
+		return err
+	} else if r != nil {
+		*u = *(*URL2)(r)
+	} else {
+		*u = URL2{}
+	}
+	return nil
+}
+
+func (u *URL2) String() string {
+	if u == nil {
+		return ""
+	}
+	return (*url.URL)(u).String()
+}
+
 // ConcurrencyPolicy describes how the job will be handled.
 // Only one of the following concurrent policies may be specified.
 // If none of the following policies is specified, the default one
@@ -226,6 +306,14 @@ type CronJobStatus struct {
 	// with microsecond precision.
 	// +optional
 	LastScheduleMicroTime *metav1.MicroTime `json:"lastScheduleMicroTime,omitempty"`
+
+	// LastActiveLogURL specifies the logging url for the last started job
+	// +optional
+	LastActiveLogURL *URL `json:"lastActiveLogURL,omitempty"`
+
+	// LastActiveLogURL2 specifies the logging url for the last started job
+	// +optional
+	LastActiveLogURL2 *URL2 `json:"lastActiveLogURL2,omitempty"`
 }
 
 // +kubebuilder:object:root=true

pkg/crd/testdata/testdata.kubebuilder.io_cronjobs.yaml

@@ -5167,6 +5167,14 @@ spec:
                       type: string
                   type: object
                 type: array
+              lastActiveLogURL:
+                description: LastActiveLogURL specifies the logging url for the last
+                  started job
+                type: string
+              lastActiveLogURL2:
+                description: LastActiveLogURL2 specifies the logging url for the last
+                  started job
+                type: string
               lastScheduleMicroTime:
                 description: Information about the last time the job was successfully
                   scheduled, with microsecond precision.