Merge "Add kyaml Label selector to document plugins"

pkg/document/plugin/kyamlutils/document_selector.go

@@ -18,6 +18,7 @@ import (
 	"fmt"
 	"strings"
 
+	"k8s.io/apimachinery/pkg/labels"
 	"sigs.k8s.io/kustomize/kyaml/kio"
 	"sigs.k8s.io/kustomize/kyaml/kio/filters"
 	"sigs.k8s.io/kustomize/kyaml/yaml"
@@ -84,6 +85,17 @@ func (f DocumentSelector) ByNamespace(ns string) DocumentSelector {
 	return f
 }
 
+// ByLabel adds filter to filter by labelSelector.
+// For more details about syntax for labelSelector refer to Parse() function description from
+// https://github.com/kubernetes/apimachinery/blob/master/pkg/labels/selector.go
+func (f DocumentSelector) ByLabel(labelSelector string) DocumentSelector {
+	if labelSelector != "" {
+		f.filters = append(f.filters, &LabelFilter{MatchExpression: labelSelector})
+		return f
+	}
+	return f
+}
+
 // Filter RNode objects
 func (f DocumentSelector) Filter(items []*yaml.RNode) (result []*yaml.RNode, err error) {
 	result = items
@@ -95,3 +107,35 @@ func (f DocumentSelector) Filter(items []*yaml.RNode) (result []*yaml.RNode, err
 	}
 	return result, nil
 }
+
+var _ kio.Filter = &LabelFilter{}
+
+// LabelFilter allows to filter labels based on label Selectors
+// Uses kubernetes label selector library from apimachinery package undreneath
+// For syntax for MatchExpression, please refer to description of Parse() function at
+// https://github.com/kubernetes/apimachinery/blob/master/pkg/labels/selector.go
+type LabelFilter struct {
+	MatchExpression string
+}
+
+// Filter implements RNode filter interface
+func (lf *LabelFilter) Filter(input []*yaml.RNode) ([]*yaml.RNode, error) {
+	var output kio.ResourceNodeSlice
+	selector, err := labels.Parse(lf.MatchExpression)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, node := range input {
+		nodeLabels, err := node.GetLabels()
+		if err != nil {
+			return nil, err
+		}
+
+		if selector.Matches(labels.Set(nodeLabels)) {
+			output = append(output, node)
+		}
+	}
+
+	return output, nil
+}

pkg/document/plugin/kyamlutils/document_selector_test.go

@@ -33,6 +33,8 @@ func documents(t *testing.T) []*yaml.RNode {
 apiVersion: v1
 kind: Pod
 metadata:
+  labels:
+    app: pod1
   name: p1
   namespace: capi
 ---
@@ -69,6 +71,8 @@ func TestFilter(t *testing.T) {
 			expectedDocs: `apiVersion: v1
 kind: Pod
 metadata:
+  labels:
+    app: pod1
   name: p1
   namespace: capi`,
 		},
@@ -78,6 +82,8 @@ metadata:
 			expectedDocs: `apiVersion: v1
 kind: Pod
 metadata:
+  labels:
+    app: pod1
   name: p1
   namespace: capi
 ---
@@ -114,6 +120,8 @@ metadata:
 			expectedDocs: `apiVersion: v1
 kind: Pod
 metadata:
+  labels:
+    app: pod1
   name: p1
   namespace: capi
 ---
@@ -139,12 +147,70 @@ kind: Deployment
 metadata:
   name: p1`,
 		},
+		{
+			name:     "Get by label exact match",
+			selector: kyamlutils.DocumentSelector{}.ByLabel("app=pod1"),
+			expectedDocs: `apiVersion: v1
+kind: Pod
+metadata:
+  labels:
+    app: pod1
+  name: p1
+  namespace: capi`,
+		},
+		{
+			name:     "Get by empty label",
+			selector: kyamlutils.DocumentSelector{}.ByLabel(""),
+			expectedDocs: `apiVersion: v1
+kind: Pod
+metadata:
+  labels:
+    app: pod1
+  name: p1
+  namespace: capi
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: p2
+  namespace: capi
+---
+apiVersion: v1beta1
+kind: Deployment
+metadata:
+  name: p1`,
+		},
+		{
+			name:     "Get by label not equal",
+			selector: kyamlutils.DocumentSelector{}.ByLabel("app!=pod1"),
+			expectedDocs: `apiVersion: v1
+kind: Pod
+metadata:
+  name: p2
+  namespace: capi
+---
+apiVersion: v1beta1
+kind: Deployment
+metadata:
+  name: p1`,
+		},
+		{
+			name:     "Get by label inclusion",
+			selector: kyamlutils.DocumentSelector{}.ByLabel("app in (pod1)"),
+			expectedDocs: `apiVersion: v1
+kind: Pod
+metadata:
+  labels:
+    app: pod1
+  name: p1
+  namespace: capi`,
+		},
 	}
 	for _, tc := range testCases {
 		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			filteredDocs, err := tc.selector.Filter(docs)
-			assert.Equal(t, err, tc.expectedErr)
+			assert.Equal(t, tc.expectedErr, err)
 
 			buf := &bytes.Buffer{}
 			err = kio.ByteWriter{Writer: buf}.Write(filteredDocs)