Make validator and defaulter more extensible (#1507)

Co-authored-by: George Pollard <gpollard@microsoft.com>

hack/generated/pkg/genruntime/admissions.go

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT license.
+ */
+
+package genruntime
+
+import (
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+// Validator is similar to controller-runtime/pkg/webhook/admission Validator. Implementing this interface
+// allows you to hook into the code generated validations and add custom handcrafted validations.
+type Validator interface {
+	// CreateValidations returns validation functions that should be run on create.
+	CreateValidations() []func() error
+	// UpdateValidations returns validation functions that should be run on update.
+	UpdateValidations() []func(old runtime.Object) error
+	// DeleteValidations returns validation functions taht should be run on delete.
+	DeleteValidations() []func() error
+}
+
+// Defaulter is similar to controller-runtime/pkg/webhook/admission Defaulter. Implementing this interface
+// allows you to hook into the code generated defaults and add custom handcrafted defaults.
+type Defaulter interface {
+	// CustomDefault performs custom defaults that are run in addition to the code generated defaults.
+	CustomDefault()
+}

hack/generator/pkg/astbuilder/assignments.go

@@ -42,3 +42,26 @@ func SimpleAssignmentWithErr(lhs dst.Expr, tok token.Token, rhs dst.Expr) *dst.A
 		},
 	}
 }
+
+// AssignToInterface performs an assignment of a well-typed variable to an interface{}. This is usually used to
+// perform a type assertion on a concrete type in a subsequent statement (which Go doesn't allow, it only allows type
+// assertions on interface types).
+//	var <lhsVar> interface{} = <rhs>
+func AssignToInterface(lhsVar string, rhs dst.Expr) *dst.DeclStmt {
+	return &dst.DeclStmt{
+		Decl: &dst.GenDecl{
+			Tok: token.VAR,
+			Specs: []dst.Spec{
+				&dst.ValueSpec{
+					Names: []*dst.Ident{
+						dst.NewIdent(lhsVar),
+					},
+					Type: dst.NewIdent("interface{}"),
+					Values: []dst.Expr{
+						dst.Clone(rhs).(dst.Expr),
+					},
+				},
+			},
+		},
+	}
+}

hack/generator/pkg/astbuilder/builder.go

@@ -22,6 +22,20 @@ func CheckErrorAndReturn(otherReturns ...dst.Expr) dst.Stmt {
 	returnValues := append([]dst.Expr{}, cloneExprSlice(otherReturns)...)
 	returnValues = append(returnValues, dst.NewIdent("err"))
 
+	retStmt := &dst.ReturnStmt{
+		Results: returnValues,
+	}
+
+	return CheckErrorAndSingleStatement(retStmt)
+}
+
+// CheckErrorAndSingleStatement checks if the err is non-nil, and if it is executes the provided statement.
+//
+// 	if err != nil {
+// 		<stmt>
+//	}
+func CheckErrorAndSingleStatement(stmt dst.Stmt) dst.Stmt {
+
 	return &dst.IfStmt{
 		Cond: &dst.BinaryExpr{
 			X:  dst.NewIdent("err"),
@@ -30,9 +44,7 @@ func CheckErrorAndReturn(otherReturns ...dst.Expr) dst.Stmt {
 		},
 		Body: &dst.BlockStmt{
 			List: []dst.Stmt{
-				&dst.ReturnStmt{
-					Results: returnValues,
-				},
+				stmt,
 			},
 		},
 	}

hack/generator/pkg/astbuilder/calls.go

@@ -13,7 +13,7 @@ import (
 //
 // <funcName>(<arguments>...)
 //
-func CallFunc(funcName string, arguments ...dst.Expr) dst.Expr {
+func CallFunc(funcName string, arguments ...dst.Expr) *dst.CallExpr {
 	return &dst.CallExpr{
 		Fun:  dst.NewIdent(funcName),
 		Args: cloneExprSlice(arguments),
@@ -25,7 +25,7 @@ func CallFunc(funcName string, arguments ...dst.Expr) dst.Expr {
 //
 // <qualifier>.<funcName>(arguments...)
 //
-func CallQualifiedFunc(qualifier string, funcName string, arguments ...dst.Expr) dst.Expr {
+func CallQualifiedFunc(qualifier string, funcName string, arguments ...dst.Expr) *dst.CallExpr {
 	return &dst.CallExpr{
 		Fun: &dst.SelectorExpr{
 			X:   dst.NewIdent(qualifier),

hack/generator/pkg/astmodel/arm_spec_interface.go

@@ -53,24 +53,27 @@ func NewARMSpecInterfaceImpl(
 	}
 
 	getNameFunc := &objectFunction{
-		name:      "GetName",
-		o:         spec,
-		idFactory: idFactory,
-		asFunc:    getNameFunction,
+		name:             "GetName",
+		o:                spec,
+		idFactory:        idFactory,
+		asFunc:           getNameFunction,
+		requiredPackages: NewPackageReferenceSet(GenRuntimeReference),
 	}
 
 	getTypeFunc := &objectFunction{
-		name:      "GetType",
-		o:         spec,
-		idFactory: idFactory,
-		asFunc:    getTypeFunction,
+		name:             "GetType",
+		o:                spec,
+		idFactory:        idFactory,
+		asFunc:           getTypeFunction,
+		requiredPackages: NewPackageReferenceSet(GenRuntimeReference),
 	}
 
 	getApiVersionFunc := &objectFunction{
-		name:      "GetApiVersion",
-		o:         spec,
-		idFactory: idFactory,
-		asFunc:    getApiVersionFunction,
+		name:             "GetApiVersion",
+		o:                spec,
+		idFactory:        idFactory,
+		asFunc:           getApiVersionFunction,
+		requiredPackages: NewPackageReferenceSet(GenRuntimeReference),
 	}
 
 	result := NewInterfaceImplementation(

hack/generator/pkg/astmodel/file_definition.go

@@ -139,6 +139,7 @@ func (file *FileDefinition) generateImports() *PackageImportSet {
 
 	// TODO: Make this configurable
 	requiredImports.ApplyName(MetaV1PackageReference, "metav1")
+	requiredImports.ApplyName(APIMachineryErrorsReference, "kerrors")
 
 	// Force local imports to have explicit names based on the service
 	for _, imp := range requiredImports.AsSlice() {

hack/generator/pkg/astmodel/function.go

@@ -27,3 +27,93 @@ type Function interface {
 	// Equals determines if this Function is equal to another one
 	Equals(f Function) bool
 }
+
+var _ Function = &objectFunction{}
+
+type objectFunctionHandler func(f *objectFunction, codeGenerationContext *CodeGenerationContext, receiver TypeName, methodName string) *dst.FuncDecl
+
+// objectFunction is a simple helper that implements the Function interface. It is intended for use for functions
+// that only need information about the object they are operating on
+type objectFunction struct {
+	name             string
+	o                *ObjectType
+	idFactory        IdentifierFactory
+	asFunc           objectFunctionHandler
+	requiredPackages *PackageReferenceSet
+}
+
+// Name returns the unique name of this function
+// (You can't have two functions with the same name on the same object or resource)
+func (k *objectFunction) Name() string {
+	return k.name
+}
+
+// RequiredPackageReferences returns the set of required packages for this function
+func (k *objectFunction) RequiredPackageReferences() *PackageReferenceSet {
+	return k.requiredPackages
+}
+
+// References returns the TypeName's referenced by this function
+func (k *objectFunction) References() TypeNameSet {
+	return k.o.References()
+}
+
+// AsFunc renders the current instance as a Go abstract syntax tree
+func (k *objectFunction) AsFunc(codeGenerationContext *CodeGenerationContext, receiver TypeName) *dst.FuncDecl {
+	return k.asFunc(k, codeGenerationContext, receiver, k.name)
+}
+
+// Equals checks if this function is equal to the passed in function
+func (k *objectFunction) Equals(f Function) bool {
+	typedF, ok := f.(*objectFunction)
+	if !ok {
+		return false
+	}
+
+	// TODO: We're not actually checking function structure here
+	return k.o.Equals(typedF.o) && k.name == typedF.name
+}
+
+type resourceFunctionHandler func(f *resourceFunction, codeGenerationContext *CodeGenerationContext, receiver TypeName, methodName string) *dst.FuncDecl
+
+// resourceFunction is a simple helper that implements the Function interface. It is intended for use for functions
+// that only need information about the resource they are operating on
+type resourceFunction struct {
+	name             string
+	resource         *ResourceType
+	idFactory        IdentifierFactory
+	asFunc           resourceFunctionHandler
+	requiredPackages *PackageReferenceSet
+}
+
+// Name returns the unique name of this function
+// (You can't have two functions with the same name on the same object or resource)
+func (r *resourceFunction) Name() string {
+	return r.name
+}
+
+// RequiredPackageReferences returns the set of required packages for this function
+func (r *resourceFunction) RequiredPackageReferences() *PackageReferenceSet {
+	return r.requiredPackages
+}
+
+// References returns the TypeName's referenced by this function
+func (r *resourceFunction) References() TypeNameSet {
+	return r.resource.References()
+}
+
+// AsFunc renders the current instance as a Go abstract syntax tree
+func (r *resourceFunction) AsFunc(codeGenerationContext *CodeGenerationContext, receiver TypeName) *dst.FuncDecl {
+	return r.asFunc(r, codeGenerationContext, receiver, r.name)
+}
+
+// Equals determines if this Function is equal to another one
+func (r *resourceFunction) Equals(f Function) bool {
+	typedF, ok := f.(*resourceFunction)
+	if !ok {
+		return false
+	}
+
+	// TODO: We're not actually checking function structure here
+	return r.resource.Equals(typedF.resource) && r.name == typedF.name
+}