Support for FieldSpec based operations on kyaml objects

api/filters/fsslice/doc.go

@@ -0,0 +1,6 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package fsslice contains a yaml.Filter to modify a resource using an
+// FsSlice to identify fields to be updated within the resource.
+package fsslice

api/filters/fsslice/example_test.go

@@ -0,0 +1,62 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package fsslice_test
+
+import (
+	"bytes"
+	"log"
+	"os"
+
+	"sigs.k8s.io/kustomize/api/filters/fsslice"
+	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+func ExampleFilter() {
+	in := &kio.ByteReader{
+		Reader: bytes.NewBufferString(`
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance
+---
+apiVersion: example.com/v1
+kind: Bar
+metadata:
+  name: instance
+`),
+	}
+	fltr := fsslice.Filter{
+		CreateKind: yaml.ScalarNode,
+		SetValue:   fsslice.SetScalar("green"),
+		FsSlice: []types.FieldSpec{
+			{Path: "a/b", CreateIfNotPresent: true},
+		},
+	}
+
+	err := kio.Pipeline{
+		Inputs:  []kio.Reader{in},
+		Filters: []kio.Filter{kio.FilterAll(fltr)},
+		Outputs: []kio.Writer{kio.ByteWriter{Writer: os.Stdout}},
+	}.Execute()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Output:
+	// apiVersion: example.com/v1
+	// kind: Foo
+	// metadata:
+	//   name: instance
+	// a:
+	//   b: green
+	// ---
+	// apiVersion: example.com/v1
+	// kind: Bar
+	// metadata:
+	//   name: instance
+	// a:
+	//   b: green
+}

api/filters/fsslice/fieldspec_filter.go

@@ -0,0 +1,145 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package fsslice
+
+import (
+	"strings"
+
+	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/errors"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+// fieldSpecFilter applies a single fieldSpec to a single object
+// fieldSpecFilter stores internal state and should not be reused
+type fieldSpecFilter struct {
+	// FieldSpec contains the path to the value to set.
+	FieldSpec types.FieldSpec `yaml:"fieldSpec"`
+
+	// Set the field using this function
+	SetValue SetFn
+
+	// CreateKind defines the type of node to create if the field is not found
+	CreateKind yaml.Kind
+
+	// path keeps internal state about the current path
+	path []string
+}
+
+func (fltr fieldSpecFilter) Filter(obj *yaml.RNode) (*yaml.RNode, error) {
+	// check if the FieldSpec applies to the object
+	if match, err := isMatchGVK(fltr.FieldSpec, obj); !match || err != nil {
+		return obj, errors.Wrap(err)
+	}
+	fltr.path = strings.Split(fltr.FieldSpec.Path, "/")
+	if err := fltr.filter(obj); err != nil {
+		s, _ := obj.String()
+		return nil, errors.WrapPrefixf(err,
+			"obj %v at path %v", s, fltr.FieldSpec.Path)
+	}
+	return obj, nil
+}
+
+func (fltr fieldSpecFilter) filter(obj *yaml.RNode) error {
+	if len(fltr.path) == 0 {
+		// found the field -- set its value
+		return fltr.SetValue(obj)
+	}
+	switch obj.YNode().Kind {
+	case yaml.SequenceNode:
+		return fltr.seq(obj)
+	case yaml.MappingNode:
+		return fltr.field(obj)
+	}
+	// not found -- this might be an error since the type doesn't match
+
+	return errors.Errorf("unsupported yaml node")
+}
+
+// field calls filter on the field matching the next path element
+func (fltr fieldSpecFilter) field(obj *yaml.RNode) error {
+	fieldName, isSeq := isSequenceField(fltr.path[0])
+
+	// lookup the field matching the next path element
+	var lookupField yaml.Filter
+	switch {
+	case !fltr.FieldSpec.CreateIfNotPresent || fltr.CreateKind == 0 || isSeq:
+		// dont' create the field if we don't find it
+		lookupField = yaml.Lookup(fieldName)
+	case len(fltr.path) <= 1:
+		// create the field if it is missing: use the provided node kind
+		lookupField = yaml.LookupCreate(fltr.CreateKind, fieldName)
+	default:
+		// create the field if it is missing: must be a mapping node
+		lookupField = yaml.LookupCreate(yaml.MappingNode, fieldName)
+	}
+
+	// locate (or maybe create) the field
+	field, err := obj.Pipe(lookupField)
+	if err != nil || field == nil {
+		return errors.WrapPrefixf(err, "fieldName: %s", fieldName)
+	}
+
+	// copy the current fltr and change the path on the copy
+	var next = fltr
+	// call filter for the next path element on the matching field
+	next.path = fltr.path[1:]
+	return next.filter(field)
+}
+
+// seq calls filter on all sequence elements
+func (fltr fieldSpecFilter) seq(obj *yaml.RNode) error {
+	if err := obj.VisitElements(func(node *yaml.RNode) error {
+		// recurse on each element -- re-allocating a fieldSpecFilter is
+		// not strictly required, but is more consistent with field
+		// and less likely to have side effects
+		// keep the entire path -- it does not contain parts for sequences
+		return fltr.filter(node)
+	}); err != nil {
+		return errors.WrapPrefixf(err,
+			"visit traversal on path: %v", fltr.path)
+	}
+
+	return nil
+}
+
+// isSequenceField returns true if the path element is for a sequence field.
+// isSequence also returns the path element with the '[]' suffix trimmed
+func isSequenceField(name string) (string, bool) {
+	isSeq := strings.HasSuffix(name, "[]")
+	name = strings.TrimSuffix(name, "[]")
+	return name, isSeq
+}
+
+// isMatchGVK returns true if the fs.GVK matches the obj GVK.
+func isMatchGVK(fs types.FieldSpec, obj *yaml.RNode) (bool, error) {
+	meta, err := obj.GetMeta()
+	if err != nil {
+		return false, err
+	}
+	if fs.Kind != "" && fs.Kind != meta.Kind {
+		// kind doesn't match
+		return false, err
+	}
+
+	// parse the group and version from the apiVersion field
+	var group, version string
+	parts := strings.SplitN(meta.APIVersion, "/", 2)
+	group = parts[0]
+	if len(parts) > 1 {
+		version = parts[1]
+	}
+
+	if fs.Group != "" && fs.Group != group {
+		// group doesn't match
+		return false, nil
+	}
+
+	if fs.Version != "" && fs.Version != version {
+		// version doesn't match
+		return false, nil
+	}
+
+	return true, nil
+}

api/filters/fsslice/fsslice.go

@@ -0,0 +1,78 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package fsslice
+
+import (
+	"strings"
+
+	"sigs.k8s.io/kustomize/api/resid"
+	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+// SetFn sets a value
+type SetFn func(*yaml.RNode) error
+
+// SetScalar returns a SetFn to set a scalar value
+func SetScalar(value string) SetFn {
+	return func(node *yaml.RNode) error {
+		return node.PipeE(yaml.FieldSetter{StringValue: value})
+	}
+}
+
+// SetEntry returns a SetFn to set an entry in a map
+func SetEntry(key, value string) SetFn {
+	return func(node *yaml.RNode) error {
+		return node.PipeE(yaml.FieldSetter{
+			Name: key, StringValue: value})
+	}
+}
+
+var _ yaml.Filter = Filter{}
+
+// Filter uses an FsSlice to modify fields on a single object
+type Filter struct {
+	// FieldSpecList list of FieldSpecs to set
+	FsSlice types.FsSlice `yaml:"fsSlice"`
+
+	// SetValue is called on each field that matches one of the FieldSpecs
+	SetValue SetFn
+
+	// CreateKind is used to create fields that do not exist
+	CreateKind yaml.Kind
+}
+
+func (fltr Filter) Filter(obj *yaml.RNode) (*yaml.RNode, error) {
+	for i := range fltr.FsSlice {
+		// apply this FieldSpec
+		// create a new filter for each iteration because they
+		// store internal state about the field paths
+		_, err := (&fieldSpecFilter{
+			FieldSpec:  fltr.FsSlice[i],
+			SetValue:   fltr.SetValue,
+			CreateKind: fltr.CreateKind,
+		}).Filter(obj)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return obj, nil
+}
+
+// GetGVK parses the metadata into a GVK
+func GetGVK(meta yaml.ResourceMeta) resid.Gvk {
+	// parse the group and version from the apiVersion field
+	var group, version string
+	parts := strings.SplitN(meta.APIVersion, "/", 2)
+	group = parts[0]
+	if len(parts) > 1 {
+		version = parts[1]
+	}
+
+	return resid.Gvk{
+		Group:   group,
+		Version: version,
+		Kind:    meta.Kind,
+	}
+}

api/filters/fsslice/fsslice_test.go

@@ -0,0 +1,354 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package fsslice_test
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"sigs.k8s.io/kustomize/api/filters/fsslice"
+	"sigs.k8s.io/kustomize/api/resid"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+type TestCase struct {
+	name     string
+	input    string
+	expected string
+	filter   fsslice.Filter
+	fsSlice  string
+	error    string
+}
+
+var tests = []TestCase{
+	{
+		name: "update",
+		fsSlice: `
+- path: a/b
+  group: foo
+  kind: Bar
+`,
+		input: `
+apiVersion: foo/v1beta1
+kind: Bar
+a:
+  b: c
+`,
+		expected: `
+apiVersion: foo/v1beta1
+kind: Bar
+a:
+  b: e
+`,
+		filter: fsslice.Filter{
+			SetValue: fsslice.SetScalar("e"),
+		},
+	},
+
+	{
+		name: "update-kind-not-match",
+		fsSlice: `
+- path: a/b
+  group: foo
+  kind: Bar1
+`,
+		input: `
+apiVersion: foo/v1beta1
+kind: Bar2
+a:
+  b: c
+`,
+		expected: `
+apiVersion: foo/v1beta1
+kind: Bar2
+a:
+  b: c
+`,
+		filter: fsslice.Filter{
+			SetValue: fsslice.SetScalar("e"),
+		},
+	},
+
+	{
+		name: "update-group-not-match",
+		fsSlice: `
+- path: a/b
+  group: foo1
+  kind: Bar
+`,
+		input: `
+apiVersion: foo2/v1beta1
+kind: Bar
+a:
+  b: c
+`,
+		expected: `
+apiVersion: foo2/v1beta1
+kind: Bar
+a:
+  b: c
+`,
+		filter: fsslice.Filter{
+			SetValue: fsslice.SetScalar("e"),
+		},
+	},
+
+	{
+		name: "update-version-not-match",
+		fsSlice: `
+- path: a/b
+  group: foo
+  version: v1beta1
+  kind: Bar
+`,
+		input: `
+apiVersion: foo/v1beta2
+kind: Bar
+a:
+  b: c
+`,
+		expected: `
+apiVersion: foo/v1beta2
+kind: Bar
+a:
+  b: c
+`,
+		filter: fsslice.Filter{
+			SetValue: fsslice.SetScalar("e"),
+		},
+	},
+
+	{
+		name: "bad-version",
+		fsSlice: `
+- path: a/b
+  group: foo
+  version: v1beta1
+  kind: Bar
+`,
+		input: `
+apiVersion: foo/v1beta2/something
+kind: Bar
+a:
+  b: c
+`,
+		expected: `
+apiVersion: foo/v1beta2/something
+kind: Bar
+a:
+  b: c
+`,
+		filter: fsslice.Filter{
+			SetValue: fsslice.SetScalar("e"),
+		},
+	},
+
+	{
+		name: "bad-meta",
+		fsSlice: `
+- path: a/b
+  group: foo
+  version: v1beta1
+  kind: Bar
+`,
+		input: `
+a:
+  b: c
+`,
+		filter: fsslice.Filter{
+			SetValue: fsslice.SetScalar("e"),
+		},
+		error: "missing Resource metadata",
+	},
+
+	{
+		name: "miss-match-type",
+		fsSlice: `
+- path: a/b/c
+  kind: Bar
+`,
+		input: `
+kind: Bar
+a:
+  b: a
+`,
+		error: "obj kind: Bar\na:\n  b: a\n at path a/b/c: unsupported yaml node",
+		filter: fsslice.Filter{
+			SetValue: fsslice.SetScalar("e"),
+		},
+	},
+
+	{
+		name: "add",
+		fsSlice: `
+- path: a/b/c/d
+  group: foo
+  create: true
+  kind: Bar
+`,
+		input: `
+apiVersion: foo/v1beta1
+kind: Bar
+a: {}
+`,
+		expected: `
+apiVersion: foo/v1beta1
+kind: Bar
+a: {b: {c: {d: e}}}
+`,
+		filter: fsslice.Filter{
+			SetValue:   fsslice.SetScalar("e"),
+			CreateKind: yaml.ScalarNode,
+		},
+	},
+
+	{
+		name: "update-in-sequence",
+		fsSlice: `
+- path: a/b[]/c/d
+  group: foo
+  kind: Bar
+`,
+		input: `
+apiVersion: foo/v1beta1
+kind: Bar
+a:
+  b:
+  - c:
+      d: a
+`,
+		expected: `
+apiVersion: foo/v1beta1
+kind: Bar
+a:
+  b:
+  - c:
+      d: e
+`,
+		filter: fsslice.Filter{
+			SetValue: fsslice.SetScalar("e"),
+		},
+	},
+
+	// Don't create a sequence
+	{
+		name: "empty-sequence-no-create",
+		fsSlice: `
+- path: a/b[]/c/d
+  group: foo
+  create: true
+  kind: Bar
+`,
+		input: `
+apiVersion: foo/v1beta1
+kind: Bar
+a: {}
+`,
+		expected: `
+apiVersion: foo/v1beta1
+kind: Bar
+a: {}
+`,
+		filter: fsslice.Filter{
+			SetValue:   fsslice.SetScalar("e"),
+			CreateKind: yaml.ScalarNode,
+		},
+	},
+
+	// Create a new field for an element in a sequence
+	{
+		name: "empty-sequence-create",
+		fsSlice: `
+- path: a/b[]/c/d
+  group: foo
+  create: true
+  kind: Bar
+`,
+		input: `
+apiVersion: foo/v1beta1
+kind: Bar
+a:
+  b:
+  - c: {}
+`,
+		expected: `
+apiVersion: foo/v1beta1
+kind: Bar
+a:
+  b:
+  - c: {d: e}
+`,
+		filter: fsslice.Filter{
+			SetValue:   fsslice.SetScalar("e"),
+			CreateKind: yaml.ScalarNode,
+		},
+	},
+}
+
+func TestFilter_Filter(t *testing.T) {
+	for i := range tests {
+		test := tests[i]
+		t.Run(test.name, func(t *testing.T) {
+			err := yaml.Unmarshal([]byte(test.fsSlice), &test.filter.FsSlice)
+			if !assert.NoError(t, err) {
+				t.FailNow()
+			}
+
+			out := &bytes.Buffer{}
+			rw := &kio.ByteReadWriter{
+				Reader:                bytes.NewBufferString(test.input),
+				Writer:                out,
+				OmitReaderAnnotations: true,
+			}
+
+			// run the filter
+			err = kio.Pipeline{
+				Inputs:  []kio.Reader{rw},
+				Filters: []kio.Filter{kio.FilterAll(test.filter)},
+				Outputs: []kio.Writer{rw},
+			}.Execute()
+			if test.error != "" {
+				if !assert.EqualError(t, err, test.error) {
+					t.FailNow()
+				}
+				// stop rest of test
+				return
+			}
+
+			if !assert.NoError(t, err) {
+				t.FailNow()
+			}
+
+			// check results
+			if !assert.Equal(t,
+				strings.TrimSpace(test.expected),
+				strings.TrimSpace(out.String())) {
+				t.FailNow()
+			}
+		})
+	}
+}
+
+func TestGetGVK(t *testing.T) {
+	obj, err := yaml.Parse(`
+apiVersion: apps/v1
+kind: Deployment
+`)
+	if !assert.NoError(t, err) {
+		t.FailNow()
+	}
+	meta, err := obj.GetMeta()
+	if !assert.NoError(t, err) {
+		t.FailNow()
+	}
+
+	gvk := fsslice.GetGVK(meta)
+	expected := resid.Gvk{Group: "apps", Version: "v1", Kind: "Deployment"}
+	if !assert.Equal(t, expected, gvk) {
+		t.FailNow()
+	}
+}