Add new type to OperationConfig so user can implement CustomCheckRequiredFieldsMissingMethod (#112)

Issue #, if available:
[#850](aws-controllers-k8s/community#850)

Description of changes:
Adds new `pkg/generate/config.OperationConfig.CustomCheckRequiredFieldsMissingMethod `field of type *string  so that user can implement a `CustomCheckRequiredFieldsMissingMethod` method as code-generator cannot handle certain cases. 

ex. For the `SageMaker` resource `ModelPackage`. There are versioned `modelPackage` and unversioned `modelPackage`, they both have a different required field being `ModelPackageGroupName` and `ModelPackageName`. `requiredFieldsMissingFromReadOneInput` will by default auto-generate to check for `ModelPackageName` and will infinitely recreate since it will never find the required field when a user attempts to make a versioned `modelPackage` which is `modelPackageGroupName` as it does not contain a `ModelPackageName`. ModelPackage has one or the other for its required field but not both.

This new field allows the user to create their own custom implementation for `requiredFieldsMissingFromReadOneInput`,  `requiredFieldsMissingFromSetAttributesInput`, and  `requiredFieldsMissingFromGetAttributesInput`so that in cases where the auto-generated default required fields do not handle cases where it may be complicated ex: Have an exclusive-or of required fields.


By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Author: ryansteakley

pkg/generate/config/operation.go

@@ -22,8 +22,9 @@ import (
 // OperationConfig represents instructions to the ACK code generator to
 // specify the overriding values for API operation parameters and its custom implementation.
 type OperationConfig struct {
-	CustomImplementation string            `json:"custom_implementation,omitempty"`
-	OverrideValues       map[string]string `json:"override_values"`
+	CustomImplementation                   string            `json:"custom_implementation,omitempty"`
+	CustomCheckRequiredFieldsMissingMethod string            `json:"custom_check_required_fields_missing_method,omitempty"`
+	OverrideValues                         map[string]string `json:"override_values"`
 	// SetOutputCustomMethodName provides the name of the custom method on the
 	// `resourceManager` struct that will set fields on a `resource` struct
 	// depending on the output of the operation.

pkg/model/crd.go

@@ -507,6 +507,24 @@ func (r *CRD) UpdateConditionsCustomMethodName() string {
 	return resGenConfig.UpdateConditionsCustomMethodName
 }
 
+// GetCustomCheckRequiredFieldsMissingMethod returns custom check required fields missing method
+// as string for custom resource, if specified in generator config
+func (r *CRD) GetCustomCheckRequiredFieldsMissingMethod(
+	// The type of operation
+	op *awssdkmodel.Operation,
+) string {
+	if op == nil || r.cfg == nil {
+		return ""
+	}
+
+	operationConfig, found := r.cfg.Operations[op.Name]
+	if !found {
+		return ""
+	}
+
+	return operationConfig.CustomCheckRequiredFieldsMissingMethod
+}
+
 // SpecIdentifierField returns the name of the "Name" or string identifier field
 // in the Spec.
 // This method does not guarantee that the identifier field returned is the
@@ -560,7 +578,7 @@ func (r *CRD) PrintAgeColumn() bool {
 }
 
 // ReconcileRequeuOnSuccessSeconds returns the duration after which to requeue
-// the custom resource as int, if specified in generator config. 
+// the custom resource as int, if specified in generator config.
 func (r *CRD) ReconcileRequeuOnSuccessSeconds() int {
 	if r.cfg == nil {
 		return 0

templates/pkg/resource/sdk_find_get_attributes.go.tpl

@@ -57,7 +57,11 @@ func (rm *resourceManager) sdkFind(
 func (rm *resourceManager) requiredFieldsMissingFromGetAttributesInput(
 	r *resource,
 ) bool {
+{{- if $customCheckMethod := .CRD.GetCustomCheckRequiredFieldsMissingMethod .CRD.Ops.GetAttributes }}
+return rm.{{ $customCheckMethod }}(r)
+{{- else }}
 {{ GoCodeRequiredFieldsMissingFromGetAttributesInput .CRD "r.ko" 1 }}
+{{- end }}
 }
 
 // newGetAttributesRequestPayload returns SDK-specific struct for the HTTP

templates/pkg/resource/sdk_find_read_one.go.tpl

@@ -65,7 +65,11 @@ func (rm *resourceManager) sdkFind(
 func (rm *resourceManager) requiredFieldsMissingFromReadOneInput(
 	r *resource,
 ) bool {
+{{- if $customCheckMethod := .CRD.GetCustomCheckRequiredFieldsMissingMethod .CRD.Ops.ReadOne }}
+return rm.{{ $customCheckMethod }}(r)
+{{- else }}
 {{ GoCodeRequiredFieldsMissingFromReadOneInput .CRD "r.ko" 1 }}
+{{- end }}
 }
 
 // newDescribeRequestPayload returns SDK-specific struct for the HTTP request

templates/pkg/resource/sdk_update_set_attributes.go.tpl

@@ -45,7 +45,11 @@ func (rm *resourceManager) sdkUpdate(
 func (rm *resourceManager) requiredFieldsMissingFromSetAttributesInput(
 	r *resource,
 ) bool {
+{{- if $customCheckMethod := .CRD.GetCustomCheckRequiredFieldsMissingMethod .CRD.Ops.SetAttributes }}
+return rm.{{ $customCheckMethod }}(r)
+{{- else }}
 {{ GoCodeRequiredFieldsMissingFromSetAttributesInput .CRD "r.ko" 1 }}
+{{- end }}
 }
 
 // newSetAttributesRequestPayload returns SDK-specific struct for the HTTP