wip

functions/go/set-namespace/transformer/namespace.go

@@ -15,6 +15,7 @@ package transformer
 
 import (
 	"fmt"
+	"reflect"
 	"regexp"
 	"strings"
 
@@ -55,6 +56,11 @@ func SetNamespace(rl *fn.ResourceList) error {
 		rl.Results = append(rl.Results, fn.ErrorConfigObjectResult(err, rl.FunctionConfig))
 		return nil
 	}
+
+	if !tc.Validate(rl.Items) {
+		rl.Results = append(rl.Results,fn.GeneralResult(strings.Join(tc.Errors, "\n"), fn.Error))
+		return nil
+	}
 	// Update "namespace" to the proper resources.
 	tc.Transform(rl.Items)
 	var result *fn.Result
@@ -69,26 +75,29 @@ func SetNamespace(rl *fn.ResourceList) error {
 }
 
 type NamespaceTransformer struct {
-	Namespace    string
+	CurrentNamespace string
+	NewNamespace    string
 	DependsOnMap map[string]bool
 	Errors       []string
 }
 
 func (p *NamespaceTransformer) Config(o *fn.KubeObject) error {
 	switch {
 	case o.IsGVK("v1", "ConfigMap"):
-		p.Namespace = o.GetStringOrDie("data", "namespace")
-		if p.Namespace == "" {
+		p.NewNamespace = o.GetStringOrDie("data", "namespace")
+		if p.NewNamespace == "" {
 			return fmt.Errorf("`data.namespace` should not be empty")
 		}
+		p.CurrentNamespace = o.GetStringOrDie("data", "namespace_selector")
 	case o.IsGVK(fnConfigAPIVersion, fnConfigKind):
-		p.Namespace = o.GetStringOrDie("namespace")
-		if p.Namespace == "" {
+		p.NewNamespace = o.GetStringOrDie("namespace")
+		if p.NewNamespace == "" {
 			return fmt.Errorf("`namespace` should not be empty")
 		}
+		p.CurrentNamespace = o.GetStringOrDie("selector")
 	case o.IsGVK("v1", "ConfigMap") && o.GetName() == "kptfile.kpt.dev":
-		p.Namespace = o.GetStringOrDie("data", "name")
-		if p.Namespace == "" {
+		p.NewNamespace = o.GetStringOrDie("data", "name")
+		if p.NewNamespace == "" {
 			return fmt.Errorf("`data.name` should not be empty")
 		}
 	default:
@@ -98,6 +107,49 @@ func (p *NamespaceTransformer) Config(o *fn.KubeObject) error {
 	return nil
 }
 
+func (p *NamespaceTransformer) Validate(objects []*fn.KubeObject) bool {
+	// Gather all namespace objects
+	nsMap := map[string]bool{}
+	for _, o := range objects {
+		if o.IsGVK("v1", "Namespace") {
+			nsMap[o.GetName()] = true
+		}
+	}
+	existingNamespaces := reflect.ValueOf(nsMap).MapKeys()
+	// Check no more than one namespace object exists.
+	if len(existingNamespaces) > 1 {
+		msg := fmt.Sprintf("accept no more than one namespace object but found %v: %v",
+			len(existingNamespaces), existingNamespaces)
+		p.Errors = append(p.Errors, msg)
+		return false
+	}
+	// Use the namespace object value as namespace selector.
+	if len(existingNamespaces) == 1 {
+		currentNamespace := existingNamespaces[0].String()
+		if p.CurrentNamespace == "" {
+			p.CurrentNamespace = currentNamespace
+		} else if p.CurrentNamespace != currentNamespace {
+			msg := fmt.Sprintf("detect namespace object %v mismatching to namespace selector %v",
+				currentNamespace, p.CurrentNamespace)
+			p.Errors = append(p.Errors, msg)
+			return false
+		}
+	}
+
+	// no namespace object
+	if p.CurrentNamespace != "" {
+		return true
+	}
+
+	for _, o := range objects {
+		if o.IsGVK("v1", "Namespace") {
+			nsMap[o.GetName()] = true
+		}
+	}
+
+	return true
+}
+
 func (p *NamespaceTransformer) Transform(objects []*fn.KubeObject) {
 	p.SetDependsOnMap(objects)
 	for _, o := range objects {