Refactor reference resolution into Go code (#417)

Continuation of #401

Refactors the resolveReferenceFor<Field> Go template code into direct Go code. This way we can be more intelligent about nested field references and support unit testing its output.

Breaking change:
The previous Go template produced valid, but ultimately faulty, code for references within lists of structs. These are not supported (see aws-controllers-k8s/community#1291). As such, this update produces a panic when it detects those types of references.

Co-authored-by: Amine <hilalyamine@gmail.com>

pkg/generate/ack/controller.go

@@ -62,6 +62,16 @@ var (
 		"Dereference": func(s *string) string {
 			return *s
 		},
+		"AddToMap": func(m map[string]interface{}, k string, v interface{}) map[string]interface{} {
+			if len(m) == 0 {
+				m = make(map[string]interface{})
+			}
+			m[k] = v
+			return m
+		},
+		"Nil": func() interface{} {
+			return nil
+		},
 		"ResourceExceptionCode": func(r *ackmodel.CRD, httpStatusCode int) string {
 			return r.ExceptionCode(httpStatusCode)
 		},
@@ -183,6 +193,9 @@ var (
 			return code.InitializeNestedStructField(r, sourceVarName, f,
 				apiPkgImportName, indentLevel)
 		},
+		"GoCodeResolveReference": func(f *ackmodel.Field, sourceVarName string, indentLevel int) string {
+			return code.ResolveReferencesForField(f, sourceVarName, indentLevel)
+		},
 	}
 )
 

pkg/generate/code/resource_reference.go

@@ -98,7 +98,7 @@ func ReferenceFieldsValidation(
 			out += fmt.Sprintf("%sif %s.%s != nil"+
 				" && %s.%s != nil {\n", fIndent, pathVarPrefix, field.GetReferenceFieldName().Camel, pathVarPrefix, field.Names.Camel)
 			out += fmt.Sprintf("%s\treturn "+
-				"ackerr.ResourceReferenceAndIDNotSupportedFor(\"%s\", \"%s\")\n",
+				"ackerr.ResourceReferenceAndIDNotSupportedFor(%q, %q)\n",
 				fIndent, field.Path, field.ReferenceFieldPath())
 
 			// Close out all the curly braces with proper indentation
@@ -117,7 +117,7 @@ func ReferenceFieldsValidation(
 					" %s.%s == nil {\n", fIndent, pathVarPrefix,
 					field.ReferenceFieldPath(), pathVarPrefix, field.Path)
 				out += fmt.Sprintf("%s\treturn "+
-					"ackerr.ResourceReferenceOrIDRequiredFor(\"%s\", \"%s\")\n",
+					"ackerr.ResourceReferenceOrIDRequiredFor(%q, %q)\n",
 					fIndent, field.Path, field.ReferenceFieldPath())
 				out += fmt.Sprintf("%s}\n", fIndent)
 			}
@@ -185,6 +185,122 @@ func ReferenceFieldsPresent(
 	return iteratorsOut + returnOut
 }
 
+// ResolveReferencesForField produces Go code for accessing all references that
+// are related to the given concrete field, determining whether its in a valid
+// condition and updating the concrete field with the referenced value.
+// Sample code (resolving a nested singular reference):
+//
+// ```
+//
+//		if ko.Spec.APIRef != nil && ko.Spec.APIRef.From != nil {
+//		arr := ko.Spec.APIRef.From
+//		if arr == nil || arr.Name == nil || *arr.Name == "" {
+//			return fmt.Errorf("provided resource reference is nil or empty: APIRef")
+//		}
+//		obj := &svcapitypes.API{}
+//		if err := getReferencedResourceState_API(ctx, apiReader, obj, *arr.Name, namespace); err != nil {
+//			return err
+//		}
+//		ko.Spec.APIID = (*string)(obj.Status.APIID)
+//	}
+//
+// ```
+func ResolveReferencesForField(field *model.Field, sourceVarName string, indentLevel int) string {
+	r := field.CRD
+	fp := fieldpath.FromString(field.Path)
+
+	outPrefix := ""
+	outSuffix := ""
+
+	fieldAccessPrefix := fmt.Sprintf("%s%s", sourceVarName, r.Config().PrefixConfig.SpecField)
+	targetVarName := fmt.Sprintf("%s.%s", fieldAccessPrefix, field.Path)
+
+	for idx := 0; idx < fp.Size(); idx++ {
+		curFP := fp.CopyAt(idx).String()
+		cur, ok := r.Fields[curFP]
+		if !ok {
+			panic(fmt.Sprintf("unable to find field with path %q. crd: %q", curFP, r.Kind))
+		}
+
+		ref := cur.ShapeRef
+
+		indent := strings.Repeat("\t", indentLevel+idx)
+
+		switch ref.Shape.Type {
+		case ("structure"):
+			fieldAccessPrefix = fmt.Sprintf("%s.%s", fieldAccessPrefix, fp.At(idx))
+
+			outPrefix += fmt.Sprintf("%sif %s != nil {\n", indent, fieldAccessPrefix)
+			outSuffix = fmt.Sprintf("%s}\n%s", indent, outSuffix)
+		case ("list"):
+			if (fp.Size() - idx) > 1 {
+				// TODO(nithomso): add support for structs nested within lists
+				// The logic for structs nested within lists needs to not only
+				// be added here, but also in a custom patching solution since
+				// it isn't supported by `StrategicMergePatch`
+				// see https://github.com/aws-controllers-k8s/community/issues/1291
+				panic(fmt.Errorf("references within lists inside lists aren't supported. crd: %q, path: %q", r.Kind, field.Path))
+			}
+			fieldAccessPrefix = fmt.Sprintf("%s.%s", fieldAccessPrefix, cur.GetReferenceFieldName().Camel)
+
+			iterVarName := fmt.Sprintf("iter%d", idx)
+			aggRefName := fmt.Sprintf("resolved%d", idx)
+
+			// base case for references in a list
+			outPrefix += fmt.Sprintf("%sif len(%s) > 0 {\n", indent, fieldAccessPrefix)
+			outPrefix += fmt.Sprintf("%s\t%s := %s{}\n", indent, aggRefName, field.GoType)
+			outPrefix += fmt.Sprintf("%s\tfor _, %s := range %s {\n", indent, iterVarName, fieldAccessPrefix)
+
+			fieldAccessPrefix = iterVarName
+			outPrefix += fmt.Sprintf("%s\t\tarr := %s.From\n", indent, fieldAccessPrefix)
+			outPrefix += fmt.Sprintf("%s\t\tif arr == nil || arr.Name == nil || *arr.Name == \"\" {\n", indent)
+			outPrefix += fmt.Sprintf("%s\t\t\treturn fmt.Errorf(\"provided resource reference is nil or empty: %s\")\n", indent, field.ReferenceFieldPath())
+			outPrefix += fmt.Sprintf("%s\t\t}\n", indent)
+
+			outPrefix += getReferencedStateForField(field, indentLevel+idx+1)
+
+			outPrefix += fmt.Sprintf("%s\t\t%s = append(%s, (%s)(obj.%s))\n", indent, aggRefName, aggRefName, field.ShapeRef.Shape.MemberRef.GoType(), field.FieldConfig.References.Path)
+			outPrefix += fmt.Sprintf("%s\t}\n", indent)
+			outPrefix += fmt.Sprintf("%s\t%s = %s\n", indent, targetVarName, aggRefName)
+			outPrefix += fmt.Sprintf("%s}\n", indent)
+		case ("map"):
+			panic("references cannot be within a map")
+		default:
+			// base case for single references
+			fieldAccessPrefix = fmt.Sprintf("%s.%s", fieldAccessPrefix, cur.GetReferenceFieldName().Camel)
+
+			outPrefix += fmt.Sprintf("%sif %s != nil && %s.From != nil {\n", indent, fieldAccessPrefix, fieldAccessPrefix)
+			outPrefix += fmt.Sprintf("%s\tarr := %s.From\n", indent, fieldAccessPrefix)
+			outPrefix += fmt.Sprintf("%s\tif arr == nil || arr.Name == nil || *arr.Name == \"\" {\n", indent)
+			outPrefix += fmt.Sprintf("%s\t\treturn fmt.Errorf(\"provided resource reference is nil or empty: %s\")\n", indent, field.ReferenceFieldPath())
+			outPrefix += fmt.Sprintf("%s\t}\n", indent)
+
+			outPrefix += getReferencedStateForField(field, indentLevel+idx)
+
+			outPrefix += fmt.Sprintf("%s\t%s = (%s)(obj.%s)\n", indent, targetVarName, field.GoType, field.FieldConfig.References.Path)
+			outPrefix += fmt.Sprintf("%s}\n", indent)
+		}
+	}
+
+	return outPrefix + outSuffix
+}
+
+func getReferencedStateForField(field *model.Field, indentLevel int) string {
+	out := ""
+	indent := strings.Repeat("\t", indentLevel)
+
+	if field.FieldConfig.References.ServiceName == "" {
+		out += fmt.Sprintf("%s\tobj := &svcapitypes.%s{}\n", indent, field.FieldConfig.References.Resource)
+	} else {
+		out += fmt.Sprintf("%s\tobj := &%sapitypes.%s{}\n", indent, field.ReferencedServiceName(), field.FieldConfig.References.Resource)
+	}
+	out += fmt.Sprintf("%s\tif err := getReferencedResourceState_%s(ctx, apiReader, obj, *arr.Name, namespace); err != nil {\n", indent, field.FieldConfig.References.Resource)
+	out += fmt.Sprintf("%s\t\treturn err\n", indent)
+	out += fmt.Sprintf("%s\t}\n", indent)
+
+	return out
+}
+
 func nestedStructNilCheck(path fieldpath.Path, fieldAccessPrefix string) string {
 	out := ""
 	fieldNamePrefix := ""

pkg/generate/code/resource_reference_test.go

@@ -198,3 +198,160 @@ if ko.Spec.Routes != nil {
 return false || (ko.Spec.VPCRef != nil)`
 	assert.Equal(expected, code.ReferenceFieldsPresent(crd, "ko"))
 }
+
+func Test_ResolveReferencesForField_SingleReference(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	g := testutil.NewModelForServiceWithOptions(t, "apigatewayv2",
+		&testutil.TestingModelOptions{
+			GeneratorConfigFile: "generator-with-reference.yaml",
+		})
+
+	crd := testutil.GetCRDByName(t, g, "Integration")
+	require.NotNil(crd)
+	expected :=
+		`	if ko.Spec.APIRef != nil && ko.Spec.APIRef.From != nil {
+		arr := ko.Spec.APIRef.From
+		if arr == nil || arr.Name == nil || *arr.Name == "" {
+			return fmt.Errorf("provided resource reference is nil or empty: APIRef")
+		}
+		obj := &svcapitypes.API{}
+		if err := getReferencedResourceState_API(ctx, apiReader, obj, *arr.Name, namespace); err != nil {
+			return err
+		}
+		ko.Spec.APIID = (*string)(obj.Status.APIID)
+	}
+`
+
+	field := crd.Fields["APIID"]
+	assert.Equal(expected, code.ResolveReferencesForField(field, "ko", 1))
+}
+
+func Test_ResolveReferencesForField_ReferencingARN(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	g := testutil.NewModelForServiceWithOptions(t, "iam",
+		&testutil.TestingModelOptions{
+			GeneratorConfigFile: "generator.yaml",
+		})
+
+	crd := testutil.GetCRDByName(t, g, "User")
+	require.NotNil(crd)
+	expected :=
+		`	if ko.Spec.PermissionsBoundaryRef != nil && ko.Spec.PermissionsBoundaryRef.From != nil {
+		arr := ko.Spec.PermissionsBoundaryRef.From
+		if arr == nil || arr.Name == nil || *arr.Name == "" {
+			return fmt.Errorf("provided resource reference is nil or empty: PermissionsBoundaryRef")
+		}
+		obj := &svcapitypes.Policy{}
+		if err := getReferencedResourceState_Policy(ctx, apiReader, obj, *arr.Name, namespace); err != nil {
+			return err
+		}
+		ko.Spec.PermissionsBoundary = (*string)(obj.Status.ACKResourceMetadata.ARN)
+	}
+`
+
+	field := crd.Fields["PermissionsBoundary"]
+	assert.Equal(expected, code.ResolveReferencesForField(field, "ko", 1))
+}
+
+func Test_ResolveReferencesForField_SliceOfReferences(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	g := testutil.NewModelForServiceWithOptions(t, "apigatewayv2",
+		&testutil.TestingModelOptions{
+			GeneratorConfigFile: "generator-with-reference.yaml",
+		})
+
+	crd := testutil.GetCRDByName(t, g, "VpcLink")
+	require.NotNil(crd)
+	expected :=
+		`	if len(ko.Spec.SecurityGroupRefs) > 0 {
+		resolved0 := []*string{}
+		for _, iter0 := range ko.Spec.SecurityGroupRefs {
+			arr := iter0.From
+			if arr == nil || arr.Name == nil || *arr.Name == "" {
+				return fmt.Errorf("provided resource reference is nil or empty: SecurityGroupRefs")
+			}
+			obj := &ec2apitypes.SecurityGroup{}
+			if err := getReferencedResourceState_SecurityGroup(ctx, apiReader, obj, *arr.Name, namespace); err != nil {
+				return err
+			}
+			resolved0 = append(resolved0, (*string)(obj.Status.ID))
+		}
+		ko.Spec.SecurityGroupIDs = resolved0
+	}
+`
+
+	field := crd.Fields["SecurityGroupIDs"]
+	assert.Equal(expected, code.ResolveReferencesForField(field, "ko", 1))
+}
+
+func Test_ResolveReferencesForField_NestedSingleReference(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	g := testutil.NewModelForServiceWithOptions(t, "apigatewayv2",
+		&testutil.TestingModelOptions{
+			GeneratorConfigFile: "generator-with-nested-reference.yaml",
+		})
+
+	crd := testutil.GetCRDByName(t, g, "Authorizer")
+	require.NotNil(crd)
+	expected :=
+		`	if ko.Spec.JWTConfiguration != nil {
+		if ko.Spec.JWTConfiguration.IssuerRef != nil && ko.Spec.JWTConfiguration.IssuerRef.From != nil {
+			arr := ko.Spec.JWTConfiguration.IssuerRef.From
+			if arr == nil || arr.Name == nil || *arr.Name == "" {
+				return fmt.Errorf("provided resource reference is nil or empty: JWTConfiguration.IssuerRef")
+			}
+			obj := &svcapitypes.API{}
+			if err := getReferencedResourceState_API(ctx, apiReader, obj, *arr.Name, namespace); err != nil {
+				return err
+			}
+			ko.Spec.JWTConfiguration.Issuer = (*string)(obj.Status.APIID)
+		}
+	}
+`
+
+	field := crd.Fields["JWTConfiguration.Issuer"]
+	assert.Equal(expected, code.ResolveReferencesForField(field, "ko", 1))
+}
+
+func Test_ResolveReferencesForField_SingleReference_DeeplyNested(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	g := testutil.NewModelForServiceWithOptions(t, "s3",
+		&testutil.TestingModelOptions{
+			GeneratorConfigFile: "generator-with-nested-references.yaml",
+		})
+
+	crd := testutil.GetCRDByName(t, g, "Bucket")
+	require.NotNil(crd)
+
+	// the Go template has the appropriate nil checks to ensure the parent path exists
+	expected :=
+		`	if ko.Spec.Logging != nil {
+		if ko.Spec.Logging.LoggingEnabled != nil {
+			if ko.Spec.Logging.LoggingEnabled.TargetBucketRef != nil && ko.Spec.Logging.LoggingEnabled.TargetBucketRef.From != nil {
+				arr := ko.Spec.Logging.LoggingEnabled.TargetBucketRef.From
+				if arr == nil || arr.Name == nil || *arr.Name == "" {
+					return fmt.Errorf("provided resource reference is nil or empty: Logging.LoggingEnabled.TargetBucketRef")
+				}
+				obj := &svcapitypes.Bucket{}
+				if err := getReferencedResourceState_Bucket(ctx, apiReader, obj, *arr.Name, namespace); err != nil {
+					return err
+				}
+				ko.Spec.Logging.LoggingEnabled.TargetBucket = (*string)(obj.Spec.Name)
+			}
+		}
+	}
+`
+
+	field := crd.Fields["Logging.LoggingEnabled.TargetBucket"]
+	assert.Equal(expected, code.ResolveReferencesForField(field, "ko", 1))
+}

pkg/testdata/models/apis/iam/0000-00-00/generator.yaml

@@ -12,7 +12,7 @@ ignore:
    - SAMLProvider
    - ServiceLinkedRole
    - ServiceSpecificCredential
-   - User
+   #- User
    - VirtualMFADevice
 resources:
   Role:
@@ -43,3 +43,28 @@ resources:
         type: "map[string]*bool"
       MyCustomInteger:
         type: "*int64"
+  User:
+    renames:
+      operations:
+        CreateUser:
+          input_fields:
+            UserName: Name
+    fields:
+      PermissionsBoundary:
+        references:
+          resource: Policy
+          path: Status.ACKResourceMetadata.ARN
+        set:
+          # The input and output shapes are different...
+          - from: PermissionsBoundary.PermissionsBoundaryArn
+      # In order to support attaching zero or more policies to a user, we use
+      # custom update code path code that uses the Attach/DetachUserPolicy API
+      # calls to manage the set of PolicyARNs attached to this User.
+      Policies:
+        type: "[]*string"
+        references:
+          resource: Policy
+          path: Status.ACKResourceMetadata.ARN
+      Tags:
+        compare:
+          is_ignored: true