fix for #3515 Allowing Kptfile pipeline functions to be referenced by…

internal/fnruntime/runner.go

@@ -574,6 +574,42 @@ func newFnConfig(fsys filesys.FileSystem, f *kptfilev1.Function, pkgPath types.U
 
 	var node *yaml.RNode
 	switch {
+	case f.ResourceRef != nil:
+		// Handle resource reference
+		resources, err := fsys.ReadFile(string(pkgPath))
+		if err != nil {
+			return nil, errors.E(op, fn,
+				fmt.Errorf("failed to read package resources: %w", err))
+		}
+
+		nodes, err := yaml.Parse(string(resources))
+		if err != nil {
+			return nil, errors.E(op, fn,
+				fmt.Errorf("failed to parse package resources: %w", err))
+		}
+
+		// Find the referenced resource
+		elements, err := nodes.Elements()
+		if err != nil {
+			return nil, errors.E(op, fn, err)
+		}
+
+		for _, res := range elements {
+			meta, err := res.GetMeta()
+			if err != nil {
+				continue
+			}
+
+			if meta.Name == f.ResourceRef.Name &&
+				meta.Namespace == f.ResourceRef.Namespace &&
+				meta.Kind == f.ResourceRef.Kind {
+				return res, nil
+			}
+		}
+		return nil, errors.E(op, fn,
+			fmt.Errorf("resource not found: %s/%s/%s",
+				f.ResourceRef.Kind, f.ResourceRef.Namespace, f.ResourceRef.Name))
+
 	case f.ConfigPath != "":
 		path := filepath.Join(string(pkgPath), f.ConfigPath)
 		file, err := fsys.Open(path)

pkg/api/kptfile/v1/types.go

@@ -266,6 +266,14 @@ type Pipeline struct {
 	Validators []Function `yaml:"validators,omitempty" json:"validators,omitempty"`
 }
 
+// ResourceReference allows referencing a resource in the package
+type ResourceReference struct {
+    Name      string `json:"name,omitempty" yaml:"name,omitempty"`
+    Namespace string `json:"namespace,omitempty" yaml:"namespace,omitempty"`
+	Kind      string `json:"kind,omitempty" yaml:"kind,omitempty"`
+}
+
+
 // String returns the string representation of Pipeline struct
 // The string returned is the struct content in Go default format.
 func (p *Pipeline) String() string {
@@ -327,6 +335,8 @@ type Function struct {
 	// `Exclude` are used to specify resources on which the function should NOT be executed.
 	// If not specified, all resources selected by `Selectors` are selected.
 	Exclusions []Selector `yaml:"exclude,omitempty" json:"exclude,omitempty"`
+
+	ResourceRef *ResourceReference `json:"resourceRef,omitempty" yaml:"resourceRef,omitempty"`
 }
 
 // Selector specifies the selection criteria

pkg/api/kptfile/v1/validation.go

@@ -65,7 +65,6 @@ func (p *Pipeline) validate(fsys filesys.FileSystem, pkgPath types.UniquePath) e
 	}
 	return nil
 }
-
 func (f *Function) validate(fsys filesys.FileSystem, fnType string, idx int, pkgPath types.UniquePath) error {
 	if f.Image == "" && f.Exec == "" {
 		return &ValidateError{
@@ -89,7 +88,34 @@ func (f *Function) validate(fsys filesys.FileSystem, fnType string, idx int, pkg
 			}
 		}
 	}
-	// TODO(droot): validate the exec
+
+	// Validate ResourceRef
+	if f.ResourceRef != nil {
+		if f.ConfigPath != "" {
+			return &ValidateError{
+				Field:  fmt.Sprintf("pipeline.%s[%d]", fnType, idx),
+				Reason: "resourceRef cannot be specified with configPath",
+			}
+		}
+		if len(f.ConfigMap) != 0 {
+			return &ValidateError{
+				Field:  fmt.Sprintf("pipeline.%s[%d]", fnType, idx),
+				Reason: "resourceRef cannot be specified with configMap",
+			}
+		}
+		if f.ResourceRef.Name == "" {
+			return &ValidateError{
+				Field:  fmt.Sprintf("pipeline.%s[%d].resourceRef", fnType, idx),
+				Reason: "name is required",
+			}
+		}
+		if f.ResourceRef.Kind == "" {
+			return &ValidateError{
+				Field:  fmt.Sprintf("pipeline.%s[%d].resourceRef", fnType, idx),
+				Reason: "kind is required",
+			}
+		}
+	}
 
 	if len(f.ConfigMap) != 0 && f.ConfigPath != "" {
 		return &ValidateError{

pkg/api/kptfile/v1/validation_test.go

@@ -149,6 +149,93 @@ func TestKptfileValidate(t *testing.T) {
 			},
 			valid: false,
 		},
+		{
+			name: "pipeline: valid resource reference",
+			kptfile: KptFile{
+				Pipeline: &Pipeline{
+					Mutators: []Function{
+						{
+							Image: "gcr.io/kpt-fn/set-labels:v0.1",
+							ResourceRef: &ResourceReference{
+								Name: "my-config",
+								Kind: "ConfigMap",
+							},
+						},
+					},
+				},
+			},
+			valid: true,
+		},
+		{
+			name: "pipeline: resource ref missing name",
+			kptfile: KptFile{
+				Pipeline: &Pipeline{
+					Mutators: []Function{
+						{
+							Image: "gcr.io/kpt-fn/set-labels:v0.1",
+							ResourceRef: &ResourceReference{
+								Kind: "ConfigMap",
+							},
+						},
+					},
+				},
+			},
+			valid: false,
+		},
+		{
+			name: "pipeline: resource ref missing kind",
+			kptfile: KptFile{
+				Pipeline: &Pipeline{
+					Mutators: []Function{
+						{
+							Image: "gcr.io/kpt-fn/set-labels:v0.1",
+							ResourceRef: &ResourceReference{
+								Name: "my-config",
+							},
+						},
+					},
+				},
+			},
+			valid: false,
+		},
+		{
+			name: "pipeline: resource ref with configPath",
+			kptfile: KptFile{
+				Pipeline: &Pipeline{
+					Mutators: []Function{
+						{
+							Image:      "gcr.io/kpt-fn/set-labels:v0.1",
+							ConfigPath: "config.yaml",
+							ResourceRef: &ResourceReference{
+								Name: "my-config",
+								Kind: "ConfigMap",
+							},
+						},
+					},
+				},
+			},
+			valid: false,
+		},
+		{
+			name: "pipeline: resource ref with configMap",
+			kptfile: KptFile{
+				Pipeline: &Pipeline{
+					Mutators: []Function{
+						{
+							Image: "gcr.io/kpt-fn/set-labels:v0.1",
+							ConfigMap: map[string]string{
+								"key": "value",
+							},
+							ResourceRef: &ResourceReference{
+								Name: "my-config",
+								Kind: "ConfigMap",
+							},
+						},
+					},
+				},
+			},
+			valid: false,
+		},
 	}
 
 	for _, c := range cases {