feat!: fromFieldPath and toFieldPath

README.md

@@ -31,7 +31,7 @@ spec:
       spec:
         extraResources:
           - kind: XCluster
-            into: XCluster
+            toFieldPath: XCluster
             apiVersion: example.crossplane.io/v1
             type: Selector
             selector:

example/composition.yaml

@@ -17,7 +17,7 @@ spec:
       spec:
         extraResources:
           - kind: EnvironmentConfig
-            into: envConfs
+            toFieldPath: envConfs
             apiVersion: apiextensions.crossplane.io/v1alpha1
             type: Selector
             selector:
@@ -28,7 +28,7 @@ spec:
                   type: Value
                   value: cluster
           - kind: XCluster
-            into: XCluster
+            toFieldPath: XCluster
             apiVersion: example.crossplane.io/v1
             type: Selector
             selector:

fn.go

@@ -2,11 +2,9 @@ package main
 
 import (
 	"context"
-	"encoding/json"
 	"reflect"
 	"sort"
 
-	"google.golang.org/protobuf/encoding/protojson"
 	"google.golang.org/protobuf/types/known/structpb"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 
@@ -33,6 +31,11 @@ type Function struct {
 	log logging.Logger
 }
 
+type FetchedResult struct {
+	source    v1beta1.ResourceSource
+	resources []interface{}
+}
+
 // RunFunction runs the Function.
 func (f *Function) RunFunction(_ context.Context, req *fnv1.RunFunctionRequest) (*fnv1.RunFunctionResponse, error) {
 	f.log.Info("Running function", "tag", req.GetMeta().GetTag())
@@ -88,27 +91,20 @@ func (f *Function) RunFunction(_ context.Context, req *fnv1.RunFunctionRequest)
 		return rsp, nil
 	}
 
-	// For now cheaply convert to JSON for serializing.
-	//
-	// TODO(reedjosh): look into resources.AsStruct or simlar since unsturctured k8s objects are already almost json.
-	//    structpb.NewList(v []interface{}) should create an array like.
-	//    Combining this and similar structures from the structpb lib should should be done to create
-	//    a map[string][object] container into which the found extra resources can be dumped.
-	//
-	//    The found extra resources should then be directly marhsal-able via:
-	//    obj := &unstructured.Unstructured{}
-	//    obj.MarshalJSON()
-	b, err := json.Marshal(verifiedExtras)
-	if err != nil {
-		response.Fatal(rsp, errors.Errorf("cannot marshal %T: %w", verifiedExtras, err))
-		return rsp, nil
+	out := &unstructured.Unstructured{Object: map[string]interface{}{}}
+	for _, extras := range verifiedExtras {
+		if err := fieldpath.Pave(out.Object).SetValue(extras.source.ToFieldPath, extras.resources); err != nil {
+			response.Fatal(rsp, errors.Wrapf(err, "cannot set nested field path %q", extras.source.ToFieldPath))
+			return rsp, nil
+		}
 	}
-	s := &structpb.Struct{}
-	err = protojson.Unmarshal(b, s)
+
+	s, err := resource.AsStruct(out)
 	if err != nil {
-		response.Fatal(rsp, errors.Errorf("cannot unmarshal %T into %T: %w", extraResources, s, err))
+		response.Fatal(rsp, errors.Wrap(err, "cannot convert unstructured to protobuf Struct well-known type"))
 		return rsp, nil
 	}
+
 	response.SetContextKey(rsp, FunctionContextKeyExtraResources, structpb.NewStructValue(s))
 
 	return rsp, nil
@@ -119,7 +115,7 @@ func (f *Function) RunFunction(_ context.Context, req *fnv1.RunFunctionRequest)
 func buildRequirements(in *v1beta1.Input, xr *resource.Composite) (*fnv1.Requirements, error) { //nolint:gocyclo // Adding non-nil validations increases function complexity.
 	extraResources := make(map[string]*fnv1.ResourceSelector, len(in.Spec.ExtraResources))
 	for _, extraResource := range in.Spec.ExtraResources {
-		extraResName := extraResource.Into
+		extraResName := extraResource.ToFieldPath
 		switch extraResource.Type {
 		case v1beta1.ResourceSourceTypeReference, "":
 			extraResources[extraResName] = &fnv1.ResourceSelector{
@@ -171,14 +167,15 @@ func buildRequirements(in *v1beta1.Input, xr *resource.Composite) (*fnv1.Require
 
 // Verify Min/Max and sort extra resources by field path within a single kind.
 func verifyAndSortExtras(in *v1beta1.Input, extraResources map[string][]resource.Required, //nolint:gocyclo // TODO(reedjosh): refactor
-) (cleanedExtras map[string][]unstructured.Unstructured, err error) {
-	cleanedExtras = make(map[string][]unstructured.Unstructured)
+) ([]FetchedResult, error) {
+	results := []FetchedResult{}
 	for _, extraResource := range in.Spec.ExtraResources {
-		extraResName := extraResource.Into
+		extraResName := extraResource.ToFieldPath
 		resources, ok := extraResources[extraResName]
 		if !ok {
 			return nil, errors.Errorf("cannot find expected extra resource %q", extraResName)
 		}
+
 		switch extraResource.GetType() {
 		case v1beta1.ResourceSourceTypeReference:
 			if len(resources) == 0 {
@@ -190,7 +187,6 @@ func verifyAndSortExtras(in *v1beta1.Input, extraResources map[string][]resource
 			if len(resources) > 1 {
 				return nil, errors.Errorf("expected exactly one extra resource %q, got %d", extraResName, len(resources))
 			}
-			cleanedExtras[extraResName] = append(cleanedExtras[extraResName], *resources[0].Resource)
 
 		case v1beta1.ResourceSourceTypeSelector:
 			selector := extraResource.Selector
@@ -203,12 +199,28 @@ func verifyAndSortExtras(in *v1beta1.Input, extraResources map[string][]resource
 			if selector.MaxMatch != nil && uint64(len(resources)) > *selector.MaxMatch {
 				resources = resources[:*selector.MaxMatch]
 			}
-			for _, r := range resources {
-				cleanedExtras[extraResName] = append(cleanedExtras[extraResName], *r.Resource)
+		}
+
+		result := FetchedResult{source: extraResource}
+		for _, r := range resources {
+			if path := extraResource.FromFieldPath; path != nil {
+				if *path == "" {
+					return nil, errors.New("fromFieldPath cannot be empty, omit the field to get the whole object")
+				}
+
+				// Extract part of the object, from `FromFieldPath`.
+				object, err := fieldpath.Pave(r.Resource.Object).GetValue(*path)
+				if err != nil {
+					return nil, err
+				}
+				result.resources = append(result.resources, object)
+			} else {
+				result.resources = append(result.resources, r.Resource.Object)
 			}
 		}
+		results = append(results, result)
 	}
-	return cleanedExtras, nil
+	return results, nil
 }
 
 // Sort extra resources by field path within a single kind.

fn_test.go

@@ -63,7 +63,7 @@ func TestRunFunction(t *testing.T) {
 									"kind": "EnvironmentConfig",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
 									"type": "Reference",
-									"into": "obj-0",
+									"toFieldPath": "obj-0",
 									"ref": {	
 										"name": "my-env-config"
 									}
@@ -72,7 +72,7 @@ func TestRunFunction(t *testing.T) {
 									"type": "Reference",
 									"kind": "EnvironmentConfig",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
-									"into": "obj-1",
+									"toFieldPath": "obj-1",
 									"ref": {	
 										"name": "my-second-env-config"
 									}
@@ -81,7 +81,7 @@ func TestRunFunction(t *testing.T) {
 									"type": "Selector",
 									"kind": "EnvironmentConfig",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
-									"into": "obj-2",
+									"toFieldPath": "obj-2",
 									"selector": {
 										"matchLabels": [
 											{
@@ -96,7 +96,7 @@ func TestRunFunction(t *testing.T) {
 									"type": "Selector",
 									"kind": "EnvironmentConfig",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
-									"into": "obj-3",
+									"toFieldPath": "obj-3",
 									"selector": {
 										"matchLabels": [
 											{
@@ -111,7 +111,7 @@ func TestRunFunction(t *testing.T) {
 									"type": "Selector",
 									"kind": "EnvironmentConfig",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
-									"into": "obj-4",
+									"toFieldPath": "obj-4",
 									"selector": {
 										"matchLabels": [
 											{
@@ -127,7 +127,7 @@ func TestRunFunction(t *testing.T) {
 									"kind": "Foo",
 									"apiVersion": "test.crossplane.io/v1alpha1",
 									"namespace": "my-namespace",
-									"into": "obj-5",
+									"toFieldPath": "obj-5",
 									"ref": {
 										"name": "my-foo"
 									}
@@ -137,7 +137,7 @@ func TestRunFunction(t *testing.T) {
 									"kind": "Bar",
 									"apiVersion": "test.crossplane.io/v1alpha1",
 									"namespace": "my-namespace",
-									"into": "obj-6",
+									"toFieldPath": "obj-6",
 									"selector": {
 										"matchLabels": [
 											{
@@ -345,7 +345,7 @@ func TestRunFunction(t *testing.T) {
 							"extraResources": [
 								{
 									"type": "Reference",
-									"into": "obj-0",
+									"toFieldPath": "obj-0",
 									"kind": "EnvironmentConfig",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
 									"ref": {
@@ -354,7 +354,7 @@ func TestRunFunction(t *testing.T) {
 								},
 								{
 									"type": "Reference",
-									"into": "obj-1",
+									"toFieldPath": "obj-1",
 									"kind": "EnvironmentConfig",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
 									"ref": {
@@ -363,7 +363,7 @@ func TestRunFunction(t *testing.T) {
 								},
 								{
 									"type": "Selector",
-									"into": "obj-2",
+									"toFieldPath": "obj-2",
 									"kind": "EnvironmentConfig",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
 									"selector": {
@@ -378,7 +378,7 @@ func TestRunFunction(t *testing.T) {
 								},
 								{
 									"type": "Selector",
-									"into": "obj-3",
+									"toFieldPath": "obj-3",
 									"kind": "EnvironmentConfig",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
 									"selector": {
@@ -393,7 +393,7 @@ func TestRunFunction(t *testing.T) {
 								},
 								{
 									"type": "Selector",
-									"into": "obj-4",
+									"toFieldPath": "obj-4",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
 									"kind": "EnvironmentConfig",
 									"selector": {
@@ -565,7 +565,7 @@ func TestRunFunction(t *testing.T) {
 							"extraResources": [
 								{	
 									"type": "Reference",
-									"into": "obj-0",
+									"toFieldPath": "obj-0",
 									"kind": "EnvironmentConfig",
 									"apiVersion": "apiextensions.crossplane.io/v1beta1",
 									"ref": {
@@ -600,6 +600,112 @@ func TestRunFunction(t *testing.T) {
 				},
 			},
 		},
+		"FromFieldPathAndToFieldPath": {
+			reason: "The Function should extract from FromFieldPath and put into ToFieldPath.",
+			args: args{
+				req: &fnv1.RunFunctionRequest{
+					Meta: &fnv1.RequestMeta{Tag: "hello"},
+					Observed: &fnv1.State{
+						Composite: &fnv1.Resource{
+							Resource: resource.MustStructJSON(`{
+								"apiVersion": "test.crossplane.io/v1alpha1",
+								"kind": "XR",
+								"metadata": {
+									"name": "my-xr"
+								}
+							}`),
+						},
+					},
+					RequiredResources: map[string]*fnv1.Resources{
+						"envconfs.names": {
+							Items: []*fnv1.Resource{
+								{
+									Resource: resource.MustStructJSON(`{
+									"apiVersion": "apiextensions.crossplane.io/v1beta1",
+									"kind": "EnvironmentConfig",
+									"metadata": {
+										"name": "first",
+										"labels": {
+											"foo": "bar"
+										}
+									}
+								}`),
+								},
+								{
+									Resource: resource.MustStructJSON(`{
+									"apiVersion": "apiextensions.crossplane.io/v1beta1",
+									"kind": "EnvironmentConfig",
+									"metadata": {
+										"name": "second",
+										"labels": {
+											"foo": "bar"
+										}
+									}
+								}`),
+								},
+							},
+						},
+					},
+					Input: resource.MustStructJSON(`{
+						"apiVersion": "extra-resources.fn.crossplane.io/v1beta1",
+						"kind": "Input",
+						"spec": {
+							"extraResources": [
+								{
+									"kind": "EnvironmentConfig",
+									"apiVersion": "apiextensions.crossplane.io/v1beta1",
+									"fromFieldPath": "metadata.name",
+									"toFieldPath": "envconfs.names",
+									"type": "Selector",
+									"selector": {
+										"matchLabels": [
+											{
+												"type": "Value",
+												"key": "foo",
+												"value": "bar"
+											}
+										]
+									}
+								}
+							]
+						}
+					}`),
+				},
+			},
+			want: want{
+				rsp: &fnv1.RunFunctionResponse{
+					Meta:    &fnv1.ResponseMeta{Tag: "hello", Ttl: durationpb.New(response.DefaultTTL)},
+					Results: []*fnv1.Result{},
+					Requirements: &fnv1.Requirements{
+						Resources: map[string]*fnv1.ResourceSelector{
+							"envconfs.names": {
+								ApiVersion: "apiextensions.crossplane.io/v1beta1",
+								Kind:       "EnvironmentConfig",
+								Match: &fnv1.ResourceSelector_MatchLabels{
+									MatchLabels: &fnv1.MatchLabels{
+										Labels: map[string]string{
+											"foo": "bar",
+										},
+									},
+								},
+							},
+						},
+					},
+					Context: &structpb.Struct{
+						Fields: map[string]*structpb.Value{
+							"apiextensions.crossplane.io/extra-resources": structpb.NewStructValue(resource.MustStructJSON(`{
+									"envconfs": {
+											"names": [
+													"first",
+													"second"
+											]
+									}
+							}`)),
+						},
+					},
+				},
+			},
+		},
 	}
 
 	for name, tc := range cases {