add replacement filter to support replacmenttransformer

2026-06-14 02:20:53 +00:00 · 2021-03-17 13:51:31 -07:00
parent 710db98dbf
commit fa0b237178
14 changed files with 722 additions and 103 deletions
--- a/api/filters/replacement/doc.go
+++ b/api/filters/replacement/doc.go
@@ -0,0 +1,4 @@
+// Package replacement contains a kio.Filter implementation of the kustomize
+// replacement transformer (accepts sources and looks for targets to replace
+// their values with values from the sources).
+package replacement
--- a/api/filters/replacement/example_test.go
+++ b/api/filters/replacement/example_test.go
@@ -0,0 +1,68 @@
+// Copyright 2021 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package replacement
+
+import (
+	"bytes"
+	"log"
+	"os"
+
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+func ExampleFilter() {
+	f := Filter{}
+	err := yaml.Unmarshal([]byte(`
+replacements:
+- source:
+    kind: Foo2
+    fieldPath: spec.replicas
+  targets:
+  - select:
+      kind: Foo1
+    fieldPaths: 
+    - spec.replicas`), &f)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = kio.Pipeline{
+		Inputs: []kio.Reader{&kio.ByteReader{Reader: bytes.NewBufferString(`
+apiVersion: example.com/v1
+kind: Foo1
+metadata:
+  name: instance
+spec:
+  replicas: 3
+---
+apiVersion: example.com/v1
+kind: Foo2
+metadata:
+  name: instance
+spec:
+  replicas: 99
+`)}},
+		Filters: []kio.Filter{f},
+		Outputs: []kio.Writer{kio.ByteWriter{Writer: os.Stdout}},
+	}.Execute()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Output:
+	// apiVersion: example.com/v1
+	// kind: Foo1
+	// metadata:
+	//   name: instance
+	// spec:
+	//   replicas: 99
+	// ---
+	// apiVersion: example.com/v1
+	// kind: Foo2
+	// metadata:
+	//   name: instance
+	// spec:
+	//   replicas: 99
+}
--- a/api/filters/replacement/replacement.go
+++ b/api/filters/replacement/replacement.go
@@ -0,0 +1,123 @@
+// Copyright 2021 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package replacement
+
+import (
+	"fmt"
+	"strings"
+
+	"sigs.k8s.io/kustomize/api/resid"
+	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+type Filter struct {
+	Replacements []types.Replacement
+}
+
+// Filter replaces values of targets with values from sources
+// TODO (#3492): Connect this to a replacement transformer plugin
+func (f Filter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
+	for _, r := range f.Replacements {
+		if r.Source == nil || r.Targets == nil {
+			return nil, fmt.Errorf("replacements must specify a source and at least one target")
+		}
+		value, err := getReplacement(nodes, &r)
+		if err != nil {
+			return nil, err
+		}
+		nodes, err = applyReplacement(nodes, value, r.Targets)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return nodes, nil
+}
+
+func applyReplacement(nodes []*yaml.RNode, value *yaml.RNode, targets []*types.TargetSelector) ([]*yaml.RNode, error) {
+	for _, t := range targets {
+		if len(t.FieldPaths) == 0 {
+			t.FieldPaths = []string{types.DefaultReplacementFieldPath}
+		}
+		for _, n := range nodes {
+			// TODO (#3492): Don't include matches listed in the `reject` field
+			if t.Select.KrmId.Match(getKrmId(n)) {
+				err := applyToNode(n, value, t)
+				if err != nil {
+					return nil, err
+				}
+			}
+		}
+	}
+	return nodes, nil
+}
+
+func applyToNode(node *yaml.RNode, value *yaml.RNode, target *types.TargetSelector) error {
+	if target.Select == nil {
+		return fmt.Errorf("target must specify resources to select")
+	}
+	for _, fp := range target.FieldPaths {
+		fieldPath := strings.Split(fp, ".")
+		// TODO (#3492): Add tests for map keys in the fieldPath (e.g. .spec.containers[name=nginx])
+		t, err := node.Pipe(yaml.Lookup(fieldPath...))
+		if err != nil {
+			return err
+		}
+		if t != nil {
+			// TODO (#3492): Use the field options to refine interpretation of the field
+			t.SetYNode(value.YNode())
+		}
+	}
+	return nil
+}
+
+func getReplacement(nodes []*yaml.RNode, r *types.Replacement) (*yaml.RNode, error) {
+	source, err := selectSourceNode(nodes, r.Source)
+	if err != nil {
+		return nil, err
+	}
+
+	if r.Source.FieldPath == "" {
+		r.Source.FieldPath = types.DefaultReplacementFieldPath
+	}
+	fieldPath := strings.Split(r.Source.FieldPath, ".")
+
+	// TODO (#3492): Add tests for map keys in the fieldPath (e.g. .spec.containers[name=nginx])
+	rn, err := source.Pipe(yaml.Lookup(fieldPath...))
+	if err != nil {
+		return nil, err
+	}
+	// TODO (#3492): Use the field options to refine interpretation of the field
+	return rn, nil
+}
+
+// selectSourceNode finds the node that matches the selector, returning
+// an error if multiple or none are found
+func selectSourceNode(nodes []*yaml.RNode, selector *types.SourceSelector) (*yaml.RNode, error) {
+	var matches []*yaml.RNode
+	for _, n := range nodes {
+		if selector.KrmId.Match(getKrmId(n)) {
+			if len(matches) > 0 {
+				return nil, fmt.Errorf("more than one match for source %v", selector)
+			}
+			matches = append(matches, n)
+		}
+	}
+	if len(matches) == 0 {
+		return nil, fmt.Errorf("found no matches for source %v", selector)
+	}
+	return matches[0], nil
+}
+
+func getKrmId(n *yaml.RNode) *types.KrmId {
+	ns, _ := n.GetNamespace()
+	apiVersion := yaml.GetValue(n.Field(yaml.APIVersionField).Value)
+	group, version := resid.ParseGroupVersion(apiVersion)
+
+	return &types.KrmId{
+		Gvk:       resid.Gvk{Group: group, Version: version, Kind: n.GetKind()},
+		Name:      n.GetName(),
+		Namespace: ns,
+	}
+}
--- a/api/filters/replacement/replacement_test.go
+++ b/api/filters/replacement/replacement_test.go
@@ -0,0 +1,336 @@
+// Copyright 2021 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package replacement
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	filtertest "sigs.k8s.io/kustomize/api/testutils/filtertest"
+	"sigs.k8s.io/yaml"
+)
+
+func TestFilter(t *testing.T) {
+	testCases := map[string]struct {
+		input        string
+		replacements string
+		expected     string
+		expectedErr  bool
+	}{
+		"simple": {
+			input: `apiVersion: v1
+kind: Deployment
+metadata:
+  name: deploy1
+spec:
+  template:
+    spec:
+      containers:
+      - image: nginx:1.7.9
+        name: nginx-tagged
+      - image: postgres:1.8.0
+        name: postgresdb
+---
+apiVersion: v1
+kind: Deployment
+metadata:
+  name: deploy2
+spec:
+  template:
+    spec:
+      containers:
+      - image: nginx:1.7.9
+        name: nginx-tagged
+      - image: postgres:1.8.0
+        name: postgresdb
+`,
+			replacements: `replacements:
+- source:
+    kind: Deployment
+    name: deploy2
+    fieldPath: spec.template.spec.containers.0.image
+  targets:
+  - select:
+      kind: Deployment
+      name: deploy1
+    fieldPaths: 
+    - spec.template.spec.containers.1.image
+`,
+			expected: `apiVersion: v1
+kind: Deployment
+metadata:
+  name: deploy1
+spec:
+  template:
+    spec:
+      containers:
+      - image: nginx:1.7.9
+        name: nginx-tagged
+      - image: nginx:1.7.9
+        name: postgresdb
+---
+apiVersion: v1
+kind: Deployment
+metadata:
+  name: deploy2
+spec:
+  template:
+    spec:
+      containers:
+      - image: nginx:1.7.9
+        name: nginx-tagged
+      - image: postgres:1.8.0
+        name: postgresdb
+`,
+		},
+		"complex type": {
+			input: `apiVersion: v1
+kind: Pod
+metadata:
+  name: pod
+spec:
+  containers:
+  - image: busybox
+    name: myapp-container
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deploy2
+spec:
+  template:
+    spec:
+      containers: {}
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deploy3
+spec:
+  template:
+    spec:
+      containers: {}
+`,
+			replacements: `replacements:
+- source:
+    kind: Pod
+    name: pod
+    fieldPath: spec.containers
+  targets:
+  - select:
+      kind: Deployment
+    fieldPaths: 
+    - spec.template.spec.containers
+`,
+			expected: `apiVersion: v1
+kind: Pod
+metadata:
+  name: pod
+spec:
+  containers:
+  - image: busybox
+    name: myapp-container
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deploy2
+spec:
+  template:
+    spec:
+      containers:
+      - image: busybox
+        name: myapp-container
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deploy3
+spec:
+  template:
+    spec:
+      containers:
+      - image: busybox
+        name: myapp-container
+`,
+		},
+		"from ConfigMap": {
+			input: `apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deploy
+  labels:
+    foo: bar
+spec:
+  template:
+    metadata:
+      labels:
+        foo: bar
+    spec:
+      containers:
+        - name: command-demo-container
+          image: debian
+          command: ["printenv"]
+          args:
+            - HOSTNAME
+            - PORT
+        - name: busybox
+          image: busybox:latest
+          args:
+            - echo
+            - HOSTNAME
+            - PORT
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cm
+data:
+  HOSTNAME: example.com
+  PORT: 8080
+`,
+			replacements: `replacements:
+- source:
+    kind: ConfigMap
+    name: cm
+    fieldPath: data.HOSTNAME
+  targets:
+  - select:
+      kind: Deployment
+    fieldPaths:
+    - spec.template.spec.containers.0.args.0
+    - spec.template.spec.containers.1.args.1
+- source:
+    kind: ConfigMap
+    name: cm
+    fieldPath: data.PORT
+  targets:
+  - select:
+      kind: Deployment
+    fieldPaths:
+    - spec.template.spec.containers.0.args.1
+    - spec.template.spec.containers.1.args.2
+`,
+			expected: `apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deploy
+  labels:
+    foo: bar
+spec:
+  template:
+    metadata:
+      labels:
+        foo: bar
+    spec:
+      containers:
+      - name: command-demo-container
+        image: debian
+        command: ["printenv"]
+        args:
+        - example.com
+        - 8080
+      - name: busybox
+        image: busybox:latest
+        args:
+        - echo
+        - example.com
+        - 8080
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cm
+data:
+  HOSTNAME: example.com
+  PORT: 8080
+`,
+		},
+		"multiple matches for source select": {
+			input: `apiVersion: v1
+kind: Deployment
+metadata:
+  name: deploy1
+spec:
+  template:
+    spec:
+      containers:
+      - image: nginx:1.7.9
+        name: nginx-tagged
+      - image: postgres:1.8.0
+        name: postgresdb
+---
+apiVersion: v1
+kind: Deployment
+metadata:
+  name: deploy2
+spec:
+  template:
+    spec:
+      containers:
+      - image: nginx:1.7.9
+        name: nginx-tagged
+      - image: postgres:1.8.0
+        name: postgresdb
+---
+apiVersion: v1
+kind: Deployment
+metadata:
+  name: deploy3
+spec:
+  template:
+    spec:
+      containers:
+      - image: nginx:1.7.9
+        name: nginx-tagged
+      - image: postgres:1.8.0
+        name: postgresdb
+`,
+			replacements: `replacements:
+- source:
+    kind: Deployment
+  targets:
+  - select:
+      kind: Deployment
+`,
+			expectedErr: true,
+		},
+		"replacement has no source": {
+			input: `apiVersion: v1
+kind: Deployment
+metadata:
+  name: deploy
+spec:
+  template:
+    spec:
+      containers:
+      - image: nginx:1.7.9
+        name: nginx-tagged
+      - image: postgres:1.8.0
+        name: postgresdb
+`,
+			replacements: `replacements:
+- targets:
+  - select:
+      kind: Deployment
+`,
+			expectedErr: true,
+		},
+	}
+
+	for tn, tc := range testCases {
+		t.Run(tn, func(t *testing.T) {
+			f := Filter{}
+			err := yaml.Unmarshal([]byte(tc.replacements), &f)
+			assert.NoError(t, err)
+			actual, err := filtertest.RunFilterE(t, tc.input, f)
+			assert.Equal(t, tc.expectedErr, err != nil)
+			if !tc.expectedErr &&
+				!assert.Equal(t, strings.TrimSpace(tc.expected), strings.TrimSpace(actual)) {
+				t.FailNow()
+			}
+		})
+	}
+}