Function framework support for patching containers

kyaml/fn/framework/containers.go

@@ -0,0 +1,60 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package framework
+
+import (
+	"bytes"
+	"text/template"
+
+	"sigs.k8s.io/kustomize/kyaml/errors"
+	"sigs.k8s.io/kustomize/kyaml/sets"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+	"sigs.k8s.io/kustomize/kyaml/yaml/merge2"
+)
+
+// PatchTemplateContainers executes t as a template and patches each container in each resource
+// with the result.
+func PatchTemplateContainers(resources []*yaml.RNode, t string, input interface{}, containers ...string) error {
+	resourcePatch := template.Must(template.New("containers").Parse(t))
+	var b bytes.Buffer
+	if err := resourcePatch.Execute(&b, input); err != nil {
+		return errors.Wrap(err)
+	}
+	patch, err := yaml.Parse(b.String())
+	if err != nil {
+		return errors.WrapPrefixf(err, b.String())
+	}
+	return PatchContainers(resources, patch, containers...)
+}
+
+// PatchContainers applies patch to each container in each resource.
+func PatchContainers(resources []*yaml.RNode, patch *yaml.RNode, containers ...string) error {
+	names := sets.String{}
+	names.Insert(containers...)
+
+	for i := range resources {
+		containers, err := resources[i].Pipe(yaml.Lookup("spec", "template", "spec", "containers"))
+		if err != nil {
+			return errors.Wrap(err)
+		}
+		if containers == nil {
+			continue
+		}
+		err = containers.VisitElements(func(node *yaml.RNode) error {
+			f := node.Field("name")
+			if f == nil {
+				return nil
+			}
+			if names.Len() > 0 && !names.Has(yaml.GetValue(f.Value)) {
+				return nil
+			}
+			_, err := merge2.Merge(patch, node, yaml.MergeOptions{})
+			return errors.Wrap(err)
+		})
+		if err != nil {
+			return errors.Wrap(err)
+		}
+	}
+	return nil
+}

kyaml/fn/framework/example_test.go

@@ -6,12 +6,14 @@ package framework_test
 import (
 	"bytes"
 	"fmt"
+	"log"
 	"os"
 	"path/filepath"
 	"text/template"
 
 	"github.com/spf13/pflag"
 	"sigs.k8s.io/kustomize/kyaml/fn/framework"
+	"sigs.k8s.io/kustomize/kyaml/kio"
 	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
@@ -890,3 +892,226 @@ metadata:
 	//     key: bar
 	//     config.kubernetes.io/index: '1'
 }
+
+// ExamplePatchTemplateContainers_names patches all containers.
+func ExamplePatchTemplateContainers() {
+	resources, err := kio.ParseAll(`
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: foo
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: a
+      - name: bar
+        image: b
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: foo
+spec:
+  selector:
+    foo: bar
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: bar
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: a
+      - name: baz
+        image: b
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: bar
+spec:
+  selector:
+    foo: bar
+`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	input := struct{ Value string }{Value: "new-value"}
+	err = framework.PatchTemplateContainers(resources, `
+env:
+  KEY: {{ .Value }}
+`, input)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println(kio.StringAll(resources))
+
+	// Output:
+	// apiVersion: apps/v1
+	// kind: Deployment
+	// metadata:
+	//   name: foo
+	// spec:
+	//   template:
+	//     spec:
+	//       containers:
+	//       - name: foo
+	//         image: a
+	//         env:
+	//           KEY: new-value
+	//       - name: bar
+	//         image: b
+	//         env:
+	//           KEY: new-value
+	// ---
+	// apiVersion: v1
+	// kind: Service
+	// metadata:
+	//   name: foo
+	// spec:
+	//   selector:
+	//     foo: bar
+	// ---
+	// apiVersion: apps/v1
+	// kind: Deployment
+	// metadata:
+	//   name: bar
+	// spec:
+	//   template:
+	//     spec:
+	//       containers:
+	//       - name: foo
+	//         image: a
+	//         env:
+	//           KEY: new-value
+	//       - name: baz
+	//         image: b
+	//         env:
+	//           KEY: new-value
+	// ---
+	// apiVersion: v1
+	// kind: Service
+	// metadata:
+	//   name: bar
+	// spec:
+	//   selector:
+	//     foo: bar
+	//  <nil>
+}
+
+// ExamplePatchTemplateContainers_names patches containers matching
+// a specific name.
+func ExamplePatchTemplateContainers_names() {
+	resources, err := kio.ParseAll(`
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: foo
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: a
+      - name: bar
+        image: b
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: foo
+spec:
+  selector:
+    foo: bar
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: bar
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: a
+      - name: baz
+        image: b
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: bar
+spec:
+  selector:
+    foo: bar
+`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	input := struct{ Value string }{Value: "new-value"}
+	err = framework.PatchTemplateContainers(resources, `
+env:
+  KEY: {{ .Value }}
+`, input, "foo")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println(kio.StringAll(resources))
+
+	// Output:
+	// apiVersion: apps/v1
+	// kind: Deployment
+	// metadata:
+	//   name: foo
+	// spec:
+	//   template:
+	//     spec:
+	//       containers:
+	//       - name: foo
+	//         image: a
+	//         env:
+	//           KEY: new-value
+	//       - name: bar
+	//         image: b
+	// ---
+	// apiVersion: v1
+	// kind: Service
+	// metadata:
+	//   name: foo
+	// spec:
+	//   selector:
+	//     foo: bar
+	// ---
+	// apiVersion: apps/v1
+	// kind: Deployment
+	// metadata:
+	//   name: bar
+	// spec:
+	//   template:
+	//     spec:
+	//       containers:
+	//       - name: foo
+	//         image: a
+	//         env:
+	//           KEY: new-value
+	//       - name: baz
+	//         image: b
+	// ---
+	// apiVersion: v1
+	// kind: Service
+	// metadata:
+	//   name: bar
+	// spec:
+	//   selector:
+	//     foo: bar
+	//  <nil>
+}

kyaml/kio/byteio_reader.go

@@ -78,6 +78,20 @@ func (rw *ByteReadWriter) Write(nodes []*yaml.RNode) error {
 	}.Write(nodes)
 }
 
+// ParseAll reads all of the inputs into resources
+func ParseAll(inputs ...string) ([]*yaml.RNode, error) {
+	return (&ByteReader{
+		Reader: bytes.NewBufferString(strings.Join(inputs, "\n---\n")),
+	}).Read()
+}
+
+// StringAll writes all of the resources to a string
+func StringAll(resources []*yaml.RNode) (string, error) {
+	var b bytes.Buffer
+	err := (&ByteWriter{Writer: &b}).Write(resources)
+	return b.String(), err
+}
+
 // ByteReader decodes ResourceNodes from bytes.
 // By default, Read will set the config.kubernetes.io/index annotation on each RNode as it
 // is read so they can be written back in the same order.