allow different Go types for input/output shapes

Adds a new SetFieldConfig struct to the code generator config that
allows teams to instruct the code generator to handle the SetResource
generator specially for a particular `pkg/model.OpType`.

This is useful for at least a couple use cases:

1. Different Go types in input and output shapes

When the Go type of a field in the Create Input shape differs from the
Go type of the same-named field in another operation's Output shape, the
code generator doesn't know how to handle this situation and ends up
outputting invalid Go code.

An example of this behaviour is in the RDS controller's DBInstance
resource. The DBSecurityGroups field in the Create Input shape is of
type `[]*string`, but the same field in the Create, ReadMany and Update
output shapes is of type `[]*DBSecurityGroupMembership`. The
`DBSecurityGroupMembership` struct has two fields, `DBSecurityGroupName`
and `Status`. The only part of that struct that is relevant to the
`Spec.DBSecurityGroups` field is the `DBSecurityGroupName` field, which
corresponds to the string identifier of the DB security group provided
by the user in the `CreateDBInstanceRequest.DBSecurityGroups` field.

The code generator ends up calling `pkg/generate/code.SetResource` for
the DBInstance resource, gets to the `Spec.DBSecurityGroups` field and
just doesn't know how to handle the different Go types and so ends up
outputting nothing, which breaks compilation and has caused us to
manually comment out or fix the generated code.  operation.

See: https://github.com/aws-controllers-k8s/rds-controller/blob/dc3271fa7b455fc99c3531ce372ea221c9f5b8e7/pkg/resource/db_instance/sdk.go#L853-L864

In the RDS DBInstance DBSecurityGroups case, we'd add the following to
the RDS generator.yaml file to instruct the code generator how to
transform the response from the DescribeDBInstances Output shape for
setting the value of `Spec.DBSecurityGroups` from the set of
`DBSecurityGroupMembership.DBSecurityGroupName` values:

```yaml
resources:
  DBInstance:
    fields:
      DBSecurityGroups:
        set:
         - on: Create
           from: DBSecurityGroupName
         - on: ReadOne
           from: DBSecurityGroupName
```

2. Ignoring fields in output shapes containing stale data

For some service APIs, the returned value for a field in the Output
shape of an Update operation contains the *originally-set* value instead
of the value of the field that was set in the Update operation itself.

An example of this situation is the ElastiCache ModifyReplicationGroup
API call. If you pass some value for the LogDeliveryConfiguration field
in the Input shape (which comes from the Spec.LogDeliveryConfiguration
field of the ReplicationGroup resource), the value that is returned in
the Output shape's LogDeliveryConfiguration is actually the *old*
(stale) value for the field. The reason for this return of stale data is
because the log delivery configuration is asynchronously mutated.

For these cases, we want to be able to tell the code generator to ignore
these fields when outputting code for the
`pkg/generate/code.SetResource` function, but only for the Update
operation. In this case, we'd add the following to the ElastiCache
generator.yaml file:

```yaml
resources:
  ReplicationGroup:
    fields:
      LogDeliveryConfiguration:
        set:
         - on: Update
           ignore: true
```

Signed-off-by: Jay Pipes <[email protected]>

Author: jaypipes

pkg/generate/ack/controller.go

@@ -21,6 +21,7 @@ import (
 	"github.com/aws-controllers-k8s/code-generator/pkg/generate/code"
 	ackgenconfig "github.com/aws-controllers-k8s/code-generator/pkg/generate/config"
 	"github.com/aws-controllers-k8s/code-generator/pkg/generate/templateset"
+	"github.com/aws-controllers-k8s/code-generator/pkg/model"
 	ackmodel "github.com/aws-controllers-k8s/code-generator/pkg/model"
 	awssdkmodel "github.com/aws/aws-sdk-go/private/model/api"
 )
@@ -102,7 +103,18 @@ var (
 			return code.SetSDKForStruct(r.Config(), r, targetFieldName, targetVarName, targetShapeRef, sourceFieldPath, sourceVarName, indentLevel)
 		},
 		"GoCodeSetResourceForStruct": func(r *ackmodel.CRD, targetFieldName string, targetVarName string, targetShapeRef *awssdkmodel.ShapeRef, sourceVarName string, sourceShapeRef *awssdkmodel.ShapeRef, indentLevel int) string {
-			return code.SetResourceForStruct(r.Config(), r, targetFieldName, targetVarName, targetShapeRef, sourceVarName, sourceShapeRef, indentLevel)
+			f, ok := r.Fields[targetFieldName]
+			if !ok {
+				return ""
+			}
+			// We may have some special instructions for how to handle setting the
+			// field value...
+			setCfg := f.GetSetterConfig(model.OpTypeList)
+
+			if setCfg != nil && setCfg.Ignore {
+				return ""
+			}
+			return code.SetResourceForStruct(r.Config(), r, targetFieldName, targetVarName, targetShapeRef, setCfg, sourceVarName, sourceShapeRef, indentLevel)
 		},
 		"GoCodeCompare": func(r *ackmodel.CRD, deltaVarName string, sourceVarName string, targetVarName string, indentLevel int) string {
 			return code.CompareResource(r.Config(), r, deltaVarName, sourceVarName, targetVarName, indentLevel)

pkg/generate/code/set_resource.go

@@ -181,19 +181,6 @@ func SetResource(
 			continue
 		}
 
-		sourceMemberShapeRef := outputShape.MemberRefs[memberName]
-		if sourceMemberShapeRef.Shape == nil {
-			// Technically this should not happen, so let's bail here if it
-			// does...
-			msg := fmt.Sprintf(
-				"expected .Shape to not be nil for ShapeRef of memberName %s",
-				memberName,
-			)
-			panic(msg)
-		}
-
-		sourceMemberShape := sourceMemberShapeRef.Shape
-
 		// Determine whether the input shape's field is in the Spec or the
 		// Status struct and set the source variable appropriately.
 		var f *model.Field
@@ -219,6 +206,53 @@ func SetResource(
 		}
 
 		targetMemberShapeRef = f.ShapeRef
+
+		// We may have some special instructions for how to handle setting the
+		// field value...
+		setCfg := f.GetSetterConfig(opType)
+
+		if setCfg != nil && setCfg.Ignore {
+			continue
+		}
+
+		sourceMemberShapeRef := outputShape.MemberRefs[memberName]
+		if sourceMemberShapeRef.Shape == nil {
+			// We may have some instructions to specially handle this field by
+			// accessing a different Output shape member.
+			//
+			// As an example, let's say we're dealing with a resource called
+			// Bucket that has a "Name" field. In the Output shape of the
+			// ReadOne resource manager method, the field name is "Bucket",
+			// though. There may be a generator.yaml file that looks like this:
+			//
+			// resources:
+			//   Bucket:
+			//     fields:
+			//       Name:
+			//         set:
+			//          - method: ReadOne
+			//            from: Bucket
+			//
+			// And this would indicate to the code generator that the Spec.Name
+			// field should be set from the value of the Output shape's Bucket
+			// field.
+			var found bool
+			if setCfg != nil && setCfg.From != nil {
+				sourceMemberShapeRef, found = outputShape.MemberRefs[*setCfg.From]
+			}
+			if !found || sourceMemberShapeRef.Shape == nil {
+				// Technically this should not happen, so let's bail here if it
+				// does...
+				msg := fmt.Sprintf(
+					"expected .Shape to not be nil for ShapeRef of memberName %s",
+					memberName,
+				)
+				panic(msg)
+			}
+		}
+
+		sourceMemberShape := sourceMemberShapeRef.Shape
+
 		// fieldVarName is the name of the variable that is used for temporary
 		// storage of complex member field values
 		//
@@ -270,6 +304,7 @@ func SetResource(
 					f.Names.Camel,
 					memberVarName,
 					targetMemberShapeRef,
+					setCfg,
 					sourceAdaptedVarName,
 					sourceMemberShapeRef,
 					indentLevel+1,
@@ -282,6 +317,22 @@ func SetResource(
 				)
 			}
 		default:
+			if setCfg != nil && setCfg.From != nil {
+				// We have some special instructions to pull the value from a
+				// different field or member...
+				sourceAdaptedVarName = sourceVarName + "." + *setCfg.From
+				var found bool
+				sourceMemberShapeRef, found = outputShape.MemberRefs[*setCfg.From]
+				if !found {
+					// This is likely a typo in the generator.yaml file...
+					msg := fmt.Sprintf(
+						"expected to find a member shape of %s called %s",
+						outputShape.ShapeName,
+						*setCfg.From,
+					)
+					panic(msg)
+				}
+			}
 			out += setResourceForScalar(
 				qualifiedTargetVar,
 				sourceAdaptedVarName,
@@ -502,6 +553,14 @@ func setResourceReadMany(
 			continue
 		}
 
+		// We may have some special instructions for how to handle setting the
+		// field value...
+		setCfg := f.GetSetterConfig(model.OpTypeList)
+
+		if setCfg != nil && setCfg.Ignore {
+			continue
+		}
+
 		targetMemberShapeRef = f.ShapeRef
 		out += fmt.Sprintf(
 			"%s\tif %s != nil {\n", indent, sourceAdaptedVarName,
@@ -526,6 +585,7 @@ func setResourceReadMany(
 					f.Names.Camel,
 					memberVarName,
 					targetMemberShapeRef,
+					setCfg,
 					sourceAdaptedVarName,
 					sourceMemberShapeRef,
 					indentLevel+2,
@@ -1100,6 +1160,8 @@ func setResourceForContainer(
 	targetVarName string,
 	// Shape Ref of the target struct field
 	targetShapeRef *awssdkmodel.ShapeRef,
+	// SetFieldConfig of the *target* field
+	targetSetCfg *ackgenconfig.SetFieldConfig,
 	// The struct or struct field that we access our source value from
 	sourceVarName string,
 	// ShapeRef of the source struct field
@@ -1113,6 +1175,7 @@ func setResourceForContainer(
 			targetFieldName,
 			targetVarName,
 			targetShapeRef,
+			targetSetCfg,
 			sourceVarName,
 			sourceShapeRef,
 			indentLevel,
@@ -1123,6 +1186,7 @@ func setResourceForContainer(
 			targetFieldName,
 			targetVarName,
 			targetShapeRef,
+			targetSetCfg,
 			sourceVarName,
 			sourceShapeRef,
 			indentLevel,
@@ -1133,6 +1197,7 @@ func setResourceForContainer(
 			targetFieldName,
 			targetVarName,
 			targetShapeRef,
+			targetSetCfg,
 			sourceVarName,
 			sourceShapeRef,
 			indentLevel,
@@ -1158,6 +1223,8 @@ func SetResourceForStruct(
 	targetVarName string,
 	// Shape Ref of the target struct field
 	targetShapeRef *awssdkmodel.ShapeRef,
+	// SetFieldConfig of the *target* field
+	targetSetCfg *ackgenconfig.SetFieldConfig,
 	// The struct or struct field that we access our source value from
 	sourceVarName string,
 	// ShapeRef of the source struct field
@@ -1199,6 +1266,7 @@ func SetResourceForStruct(
 					cleanNames.Camel,
 					memberVarName,
 					targetMemberShapeRef,
+					nil,
 					sourceAdaptedVarName,
 					memberShapeRef,
 					indentLevel+1,
@@ -1236,6 +1304,8 @@ func setResourceForSlice(
 	targetVarName string,
 	// Shape Ref of the target slice field
 	targetShapeRef *awssdkmodel.ShapeRef,
+	// SetFieldConfig of the *target* field
+	targetSetCfg *ackgenconfig.SetFieldConfig,
 	// The struct or struct field that we access our source value from
 	sourceVarName string,
 	// ShapeRef of the source slice field
@@ -1244,6 +1314,7 @@ func setResourceForSlice(
 ) string {
 	out := ""
 	indent := strings.Repeat("\t", indentLevel)
+
 	sourceShape := sourceShapeRef.Shape
 	targetShape := targetShapeRef.Shape
 	iterVarName := fmt.Sprintf("%siter", targetVarName)
@@ -1257,26 +1328,71 @@ func setResourceForSlice(
 		targetShape.MemberRef.Shape,
 		indentLevel+1,
 	)
-	//  f0elem0 = *f0iter0
+	// We may have some instructions to specially handle this field by
+	// accessing a different Output shape member.
 	//
-	// or
+	// As an example, let's say we're dealing with a resource called
+	// DBInstance that has a "DBSecurityGroups" field of type `[]*string`.
+	// In the Output shape of the ReadOne resource manager method, the
+	// field name is "DBSecurityGroups" of type
+	// `[]*DBSecurityGroupMembership`, though.  This
+	// `DBSecurityGroupMembership` struct contains two fields,
+	// `DBSecurityGroupName` and `DBSecurityGroupStatus` and we wish to
+	// grab only the value of the `DBSecurityGroupName` fields and set the
+	// `Spec.DBSecurityGroups` field to the set of those field values.
 	//
-	//  f0elem0.SetMyField(*f0iter0)
-	containerFieldName := ""
-	if sourceShape.MemberRef.Shape.Type == "structure" {
-		containerFieldName = targetFieldName
+	// There may be a generator.yaml file that looks like this:
+	//
+	// resources:
+	//   DBInstance:
+	//     fields:
+	//       DBSecurityGroups:
+	//         set:
+	//          - method: ReadOne
+	//            from: DBSecurityGroupName
+	//
+	// And this would indicate to the code generator that the
+	// Spec.DBSecurityGroups field should be set from the value of the
+	// Output shape's DBSecurityGroups..DBSecurityGroupName fields.
+	if targetSetCfg != nil && targetSetCfg.From != nil {
+		if sourceMemberShapeRef, found := sourceShape.MemberRef.Shape.MemberRefs[*targetSetCfg.From]; found {
+			out += setResourceForScalar(
+				elemVarName,
+				fmt.Sprintf("*%s.%s", iterVarName, *targetSetCfg.From),
+				sourceMemberShapeRef,
+				indentLevel+1,
+			)
+		} else {
+			// This is a bug in the code generation if this occurs...
+			msg := fmt.Sprintf(
+				"could not find targetSetCfg.From %s in struct member type.",
+				*targetSetCfg.From,
+			)
+			panic(msg)
+		}
+	} else {
+		//  f0elem0 = *f0iter0
+		//
+		// or
+		//
+		//  f0elem0.SetMyField(*f0iter0)
+		containerFieldName := ""
+		if sourceShape.MemberRef.Shape.Type == "structure" {
+			containerFieldName = targetFieldName
+		}
+		out += setResourceForContainer(
+			cfg, r,
+			containerFieldName,
+			elemVarName,
+			&targetShape.MemberRef,
+			targetSetCfg,
+			iterVarName,
+			&sourceShape.MemberRef,
+			indentLevel+1,
+		)
 	}
-	out += setResourceForContainer(
-		cfg, r,
-		containerFieldName,
-		elemVarName,
-		&targetShape.MemberRef,
-		iterVarName,
-		&sourceShape.MemberRef,
-		indentLevel+1,
-	)
 	addressOfVar := ""
-	switch sourceShape.MemberRef.Shape.Type {
+	switch targetShape.MemberRef.Shape.Type {
 	case "structure", "list", "map":
 		break
 	default:
@@ -1299,6 +1415,8 @@ func setResourceForMap(
 	targetVarName string,
 	// Shape Ref of the target map field
 	targetShapeRef *awssdkmodel.ShapeRef,
+	// SetFieldConfig of the *target* field
+	targetSetCfg *ackgenconfig.SetFieldConfig,
 	// The struct or struct field that we access our source value from
 	sourceVarName string,
 	// ShapeRef of the source map field
@@ -1332,6 +1450,7 @@ func setResourceForMap(
 		containerFieldName,
 		valVarName,
 		&targetShape.ValueRef,
+		nil,
 		valIterVarName,
 		&sourceShape.ValueRef,
 		indentLevel+1,