Add a new operation config to override the SetOutput wrapper field (#78)

Issue N/A

In some AWS APIs `Describe` operations output contains the
wanted information in a wrapper field like `TableDescription` and
`GlobalTableDescription` ... However in some other APIs for the same
operation type, the wanted information is wrapped in different nested
object, like `BackupDescription.BackupDetails` for example.

Description of changes:
This patch adds a new operation configuration that instructs the
code-generator to use a specific field path, in order to find the
struct that contains the information we want to set the output from.

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

Author: a-hilaly

pkg/generate/code/set_resource.go

@@ -118,14 +118,29 @@ func SetResource(
 		return ""
 	}
 
+	var err error
 	// We might be in a "wrapper" shape. Unwrap it to find the real object
-	// representation for the CRD's createOp. If there is a single member
-	// shape and that member shape is a structure, unwrap it.
-	if outputShape.UsedAsOutput && len(outputShape.MemberRefs) == 1 {
-		for memberName, memberRef := range outputShape.MemberRefs {
-			if memberRef.Shape.Type == "structure" {
-				sourceVarName += "." + memberName
-				outputShape = memberRef.Shape
+	// representation for the CRD's createOp/DescribeOP.
+
+	// Use the wrapper field path if it's given in the ack-generate config file.
+	wrapperFieldPath := r.GetOutputWrapperFieldPath(op)
+	if wrapperFieldPath != nil {
+		outputShape, err = GetWrapperOutputShape(outputShape, *wrapperFieldPath)
+		if err != nil {
+			msg := fmt.Sprintf("Unable to unwrap the output shape: %v", err)
+			panic(msg)
+		}
+		sourceVarName += "." + *wrapperFieldPath
+	} else {
+		// If the wrapper field path is not specified in the config file and if
+		// there is a single member shape and that member shape is a structure,
+		// unwrap it.
+		if outputShape.UsedAsOutput && len(outputShape.MemberRefs) == 1 {
+			for memberName, memberRef := range outputShape.MemberRefs {
+				if memberRef.Shape.Type == "structure" {
+					sourceVarName += "." + memberName
+					outputShape = memberRef.Shape
+				}
 			}
 		}
 	}
@@ -302,6 +317,41 @@ func SetResource(
 	return out
 }
 
+// GetWrapperOutputShape returns the shape of the last element of a given field
+// Path. It carefully unwraps the output shape and verifies that every element
+// of the field path exists in their correspanding parent shape and that they are
+// structures.
+func GetWrapperOutputShape(
+	shape *awssdkmodel.Shape,
+	fieldPath string,
+) (*awssdkmodel.Shape, error) {
+	if fieldPath == "" {
+		return shape, nil
+	}
+	fieldPathParts := strings.Split(fieldPath, ".")
+	for x, wrapperField := range fieldPathParts {
+		for memberName, memberRef := range shape.MemberRefs {
+			if memberName == wrapperField {
+				if memberRef.Shape.Type != "structure" {
+					// All the mentionned shapes must be structure
+					return nil, fmt.Errorf(
+						"Expected SetOutput.WrapperFieldPath to only contain fields of type 'structure'."+
+							" Found %s of type '%s'",
+						memberName, memberRef.Shape.Type,
+					)
+				}
+				remainPath := strings.Join(fieldPathParts[x+1:], ".")
+				return GetWrapperOutputShape(memberRef.Shape, remainPath)
+			}
+		}
+		return nil, fmt.Errorf(
+			"Incorrect SetOutput.WrapperFieldPath. Could not find %s in Shape %s",
+			wrapperField, shape.ShapeName,
+		)
+	}
+	return shape, nil
+}
+
 func ListMemberNameInReadManyOutput(
 	r *model.CRD,
 ) string {

pkg/generate/code/set_resource_test.go

@@ -14,6 +14,7 @@
 package code_test
 
 import (
+	"fmt"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -22,6 +23,7 @@ import (
 	"github.com/aws-controllers-k8s/code-generator/pkg/generate/code"
 	"github.com/aws-controllers-k8s/code-generator/pkg/model"
 	"github.com/aws-controllers-k8s/code-generator/pkg/testutil"
+	awssdkmodel "github.com/aws/aws-sdk-go/private/model/api"
 )
 
 func TestSetResource_APIGWv2_Route_Create(t *testing.T) {
@@ -153,6 +155,60 @@ func TestSetResource_APIGWv2_Route_ReadOne(t *testing.T) {
 	)
 }
 
+func TestSetResource_DynamoDB_Backup_ReadOne(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	g := testutil.NewGeneratorForService(t, "dynamodb")
+
+	crd := testutil.GetCRDByName(t, g, "Backup")
+	require.NotNil(crd)
+
+	expected := `
+	if ko.Status.ACKResourceMetadata == nil {
+		ko.Status.ACKResourceMetadata = &ackv1alpha1.ResourceMetadata{}
+	}
+	if resp.BackupDescription.BackupDetails.BackupArn != nil {
+		arn := ackv1alpha1.AWSResourceName(*resp.BackupDescription.BackupDetails.BackupArn)
+		ko.Status.ACKResourceMetadata.ARN = &arn
+	}
+	if resp.BackupDescription.BackupDetails.BackupCreationDateTime != nil {
+		ko.Status.BackupCreationDateTime = &metav1.Time{*resp.BackupDescription.BackupDetails.BackupCreationDateTime}
+	} else {
+		ko.Status.BackupCreationDateTime = nil
+	}
+	if resp.BackupDescription.BackupDetails.BackupExpiryDateTime != nil {
+		ko.Status.BackupExpiryDateTime = &metav1.Time{*resp.BackupDescription.BackupDetails.BackupExpiryDateTime}
+	} else {
+		ko.Status.BackupExpiryDateTime = nil
+	}
+	if resp.BackupDescription.BackupDetails.BackupName != nil {
+		ko.Spec.BackupName = resp.BackupDescription.BackupDetails.BackupName
+	} else {
+		ko.Spec.BackupName = nil
+	}
+	if resp.BackupDescription.BackupDetails.BackupSizeBytes != nil {
+		ko.Status.BackupSizeBytes = resp.BackupDescription.BackupDetails.BackupSizeBytes
+	} else {
+		ko.Status.BackupSizeBytes = nil
+	}
+	if resp.BackupDescription.BackupDetails.BackupStatus != nil {
+		ko.Status.BackupStatus = resp.BackupDescription.BackupDetails.BackupStatus
+	} else {
+		ko.Status.BackupStatus = nil
+	}
+	if resp.BackupDescription.BackupDetails.BackupType != nil {
+		ko.Status.BackupType = resp.BackupDescription.BackupDetails.BackupType
+	} else {
+		ko.Status.BackupType = nil
+	}
+`
+	assert.Equal(
+		expected,
+		code.SetResource(crd.Config(), crd, model.OpTypeGet, "resp", "ko", 1, true),
+	)
+}
+
 func TestSetResource_CodeDeploy_Deployment_Create(t *testing.T) {
 	assert := assert.New(t)
 	require := require.New(t)
@@ -2530,3 +2586,62 @@ func TestSetResource_RDS_DBSubnetGroup_ReadMany(t *testing.T) {
 		code.SetResource(crd.Config(), crd, model.OpTypeList, "resp", "ko", 1, false),
 	)
 }
+
+func TestGetWrapperOutputShape(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	g := testutil.NewGeneratorForService(t, "dynamodb")
+
+	crd := testutil.GetCRDByName(t, g, "Backup")
+	require.NotNil(crd)
+
+	op := crd.Ops.ReadOne.OutputRef.Shape
+
+	type args struct {
+		outputShape *awssdkmodel.Shape
+		fieldPath   string
+	}
+	tests := []struct {
+		name          string
+		args          args
+		wantErr       bool
+		wantShapeName string
+	}{
+		{
+			name: "incorrect field path: element not found",
+			args: args{
+				outputShape: op,
+				fieldPath:   "BackupDescription.Something",
+			},
+			wantErr: true,
+		},
+		{
+			name: "incorrect field path: element not of type structure",
+			args: args{
+				outputShape: op,
+				fieldPath:   "BackupDescription.BackupArn",
+			},
+			wantErr: true,
+		},
+		{
+			name: "correct field path",
+			args: args{
+				outputShape: op,
+				fieldPath:   "BackupDescription.BackupDetails",
+			},
+			wantErr:       false,
+			wantShapeName: "BackupDetails",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			outputShape, err := code.GetWrapperOutputShape(tt.args.outputShape, tt.args.fieldPath)
+			if (err != nil) != tt.wantErr {
+				assert.Fail(fmt.Sprintf("GetWrapperOutputShape() error = %v, wantErr %v", err, tt.wantErr))
+			} else if !tt.wantErr {
+				assert.Equal(tt.wantShapeName, outputShape.ShapeName)
+			}
+		})
+	}
+}

pkg/generate/config/operation.go

@@ -28,6 +28,9 @@ type OperationConfig struct {
 	// `resourceManager` struct that will set fields on a `resource` struct
 	// depending on the output of the operation.
 	SetOutputCustomMethodName string `json:"set_output_custom_method_name,omitempty"`
+	// OutputWrapperFieldPath provides the JSON-Path like to the struct field containing
+	// information that will be merged into a `resource` object.
+	OutputWrapperFieldPath string `json:"output_wrapper_field_path,omitempty"`
 	// Override for resource name in case of heuristic failure
 	// An example of this is correcting stutter when the resource logic doesn't properly determine the resource name
 	ResourceName string `json:"resource_name"`

pkg/generate/testdata/models/apis/dynamodb/0000-00-00/generator.yaml

@@ -4,3 +4,12 @@ resources:
       errors:
         404:
           code: ResourceNotFoundException
+operations:
+  DescribeBackup:
+    # DescribeBackupOutput is an unsual shape because it contains information for
+    # the backup it self (BackupDetails), the table details when the backup was
+    # created (SourceTableDetails) and the table features (SourceTableFeatureDetails).
+    # If not specified the code generator will try to determine the wrapper field by
+    # selecting for the output shape that only have a single member, which is incorrect
+    # in this case.
+    output_wrapper_field_path: BackupDescription.BackupDetails

pkg/model/crd.go

@@ -352,6 +352,28 @@ func (r *CRD) SetOutputCustomMethodName(
 	return &resGenConfig.SetOutputCustomMethodName
 }
 
+// GetOutputWrapperFieldPath returns the JSON-Path of the output wrapper field
+// as *string for a given operation, if specified in generator config.
+func (r *CRD) GetOutputWrapperFieldPath(
+	op *awssdkmodel.Operation,
+) *string {
+	if op == nil {
+		return nil
+	}
+	if r.cfg == nil {
+		return nil
+	}
+	opConfig, found := r.cfg.Operations[op.Name]
+	if !found {
+		return nil
+	}
+
+	if opConfig.OutputWrapperFieldPath == "" {
+		return nil
+	}
+	return &opConfig.OutputWrapperFieldPath
+}
+
 // GetCustomImplementation returns custom implementation method name for the
 // supplied operation as specified in generator config
 func (r *CRD) GetCustomImplementation(