Add set-default-name function

functions/go/gcp-set-default-name/Dockerfile

@@ -0,0 +1,15 @@
+FROM golang:1.17-alpine3.13
+ENV CGO_ENABLED=0
+WORKDIR /go/src/
+
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+RUN go build -o /usr/local/bin/function ./
+
+#############################################
+
+FROM alpine:3.13
+COPY --from=0 /usr/local/bin/function /usr/local/bin/function
+ENTRYPOINT ["function"]

functions/go/gcp-set-default-name/README.md

@@ -0,0 +1,19 @@
+# set-default-name
+
+### Feature
+`set-default-name` sets two types of default name values:
+
+- It sets the `metadata.name` fields for white listed KRM resources.
+- It sets custom field specs to their referred `metadata.name` fields.  
+
+In case one, you use `ConfigMap` to set the name. The ConfigMap should
+contain a `.data.name` field and be provided as input resource. If the KRM 
+resources are not listed, their `'metadata.name` won't be updated. 
+The white list can be found in `./fieldspec/name.go`.
+
+In case two, you can find the nameReferences whiteliest in `./fieldspec/nameref.go`
+A `nameReference` contains a GVK and a list of referrals. The GVK gives 
+the resources' `metadata.data` to read, the `referral` lists the resource 
+field spec to update. This is different from kustomize nameReference, which 
+only updates referrals metadata.name field and requires the referrals and 
+referror have the same `metadata.name`.  

functions/go/gcp-set-default-name/fieldspec/name.go

@@ -0,0 +1,28 @@
+package fieldspec
+
+/* CustomNameFieldSpecs list should be adjusted actively before we get a variant constructor solution.
+ */
+
+const (
+	CustomNameFieldSpecs = `
+customMetaName:
+- path: metadata/name 
+  group: storage.cnrm.cloud.google.com
+
+- path: metadata/name 
+  group: serviceusage.cnrm.cloud.google.com
+
+- path: metadata/name 
+  group: redis.cnrm.cloud.google.com
+
+- path: metadata/name 
+  group: spanner.cnrm.cloud.google.com
+
+# A fieldSpec object under customMetaName. 
+# - path: <fieldspec>
+#   group: <API Group Name> if ignored, matches all 
+#   version: <API Version> if ignored, matches all
+#   kind: <Kind> if ignored, matches all
+#   create: [true|false] default to false, if set to true, create the field path in resource. 
+`
+)

functions/go/gcp-set-default-name/fieldspec/nameref.go

@@ -0,0 +1,30 @@
+package fieldspec
+
+const (
+	NameReferenceFieldSpecs = `
+nameReference:
+# Blueprint redis-bucket
+- kind: RedisInstance
+  group: redis.cnrm.cloud.google.com
+  version: v1beta1
+  fieldSpecs:
+  - path: spec/displayName
+    kind: RedisInstance
+    group: redis.cnrm.cloud.google.com
+    version: v1beta1
+
+# Blueprint spanner
+- kind: SpannerInstance
+  group: spanner.cnrm.cloud.google.com
+  version: v1beta1
+  fieldSpecs:
+  - path: spec/displayName
+    kind: SpannerInstance
+    group: spanner.cnrm.cloud.google.com
+    version: v1beta1
+  - path: spec/instanceRef/name
+    kind: SpannerDatabase
+    group: spanner.cnrm.cloud.google.com
+    version: v1beta1
+`
+)

functions/go/gcp-set-default-name/go.mod

@@ -0,0 +1,36 @@
+module github.com/GoogleContainerTools/kpt-functions-catalog/functions/go/gcp-set-default-name
+
+go 1.17
+
+require (
+	sigs.k8s.io/kustomize/api v0.10.0
+	sigs.k8s.io/kustomize/kyaml v0.13.1-0.20211202184144-fe551be87b8d
+
+// sigs.k8s.io/kustomize/api v0.8.11-0.20210614195535-7e8ba62e9fd9
+// sigs.k8s.io/kustomize/kyaml v0.10.21
+)
+
+require (
+	github.com/PuerkitoBio/purell v1.1.1 // indirect
+	github.com/PuerkitoBio/urlesc v0.0.0-20170810143723-de5bf2ad4578 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-errors/errors v1.0.1 // indirect
+	github.com/go-openapi/jsonpointer v0.19.3 // indirect
+	github.com/go-openapi/jsonreference v0.19.3 // indirect
+	github.com/go-openapi/swag v0.19.5 // indirect
+	github.com/inconshreveable/mousetrap v1.0.0 // indirect
+	github.com/mailru/easyjson v0.7.0 // indirect
+	github.com/monochromegane/go-gitignore v0.0.0-20200626010858-205db1a8cc00 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/spf13/cobra v1.2.1 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/stretchr/testify v1.7.0 // indirect
+	github.com/xlab/treeprint v0.0.0-20181112141820-a009c3971eca // indirect
+	golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4 // indirect
+	golang.org/x/text v0.3.5 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
+	k8s.io/kube-openapi v0.0.0-20210421082810-95288971da7e // indirect
+	sigs.k8s.io/yaml v1.2.0 // indirect
+)

functions/go/gcp-set-default-name/main.go

@@ -0,0 +1,58 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"sigs.k8s.io/kustomize/api/hasher"
+	"sigs.k8s.io/kustomize/api/resmap"
+	"sigs.k8s.io/kustomize/api/resource"
+	"sigs.k8s.io/kustomize/kyaml/fn/framework"
+	"sigs.k8s.io/kustomize/kyaml/fn/framework/command"
+)
+
+type Processor struct {}
+
+func newResMapFactory() *resmap.Factory {
+	resourceFactory := resource.NewFactory(&hasher.Hasher{})
+	resourceFactory.IncludeLocalConfigs = true
+	return resmap.NewFactory(resourceFactory)
+}
+
+func (p *Processor) Process(resourceList *framework.ResourceList) error {
+	err := func() error{
+		trans := &CustomNameTransformer{}
+		err := trans.Config(resourceList.FunctionConfig)
+		if err != nil {
+			return err
+		}
+		resmapFactory := newResMapFactory()
+		resMap, err := resmapFactory.NewResMapFromRNodeSlice(resourceList.Items)
+		if err != nil {
+			return fmt.Errorf("failed to convert items to resource map: %w", err)
+		}
+		if err := trans.Transform(resMap); err != nil {
+			return err
+		}
+		resourceList.Items = resMap.ToRNodeSlice()
+		return nil
+	}()
+	if err != nil {
+		resourceList.Results = framework.Results{
+			&framework.Result{
+				Message:  err.Error(),
+				Severity: framework.Error,
+			},
+		}
+		return resourceList.Results
+	}
+	return nil
+}
+
+func main() {
+	cmd := command.Build(&Processor{}, command.StandaloneEnabled, false)
+	if err := cmd.Execute(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}

functions/go/gcp-set-default-name/namereference/filter.go

@@ -0,0 +1,96 @@
+package namereference
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+	"sigs.k8s.io/kustomize/api/filters/fieldspec"
+	"sigs.k8s.io/kustomize/api/resmap"
+	"sigs.k8s.io/kustomize/api/resource"
+	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/resid"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+type UnlimitedNameRefFilter struct {
+	Referrer *resource.Resource
+	NameFieldToUpdate types.FieldSpec
+	ReferralTarget resid.Gvk
+	ReferralCandidates resmap.ResMap
+
+}
+
+func (f UnlimitedNameRefFilter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
+	return kio.FilterAll(yaml.FilterFunc(f.run)).Filter(nodes)
+}
+
+func (f UnlimitedNameRefFilter) run(node *yaml.RNode) (*yaml.RNode, error) {
+	if node.GetNamespace() != f.Referrer.GetNamespace() {
+		return nil, fmt.Errorf("not in the same namespace")
+	}
+	if err := node.PipeE(fieldspec.Filter{
+		FieldSpec: f.NameFieldToUpdate,
+		SetValue:  f.updateName,
+	}); err != nil {
+		return nil, errors.Wrapf(
+			err, "updating name reference in '%s' field of '%s'",
+			f.NameFieldToUpdate.Path, f.Referrer.CurId().String())
+	}
+	return node, nil
+}
+
+func (f UnlimitedNameRefFilter) updateName(node *yaml.RNode) error {
+	if yaml.IsMissingOrNull(node) {
+		return nil
+	}
+	candidates := f.ReferralCandidates.Resources()
+	candidates = doSieve(candidates, previousIdSelectedByGvk(&f.ReferralTarget))
+	candidates = doSieve(candidates, f.sameCurrentNamespaceAsReferrer())
+	if len(candidates) == 0 {
+		return nil
+	}
+	referral := candidates[0]
+	return node.PipeE(yaml.FieldSetter{StringValue: referral.GetName()})
+}
+
+type sieveFunc func(*resource.Resource) bool
+
+func doSieve(list []*resource.Resource, fn sieveFunc) (s []*resource.Resource) {
+	for _, r := range list {
+		if fn(r) {
+			s = append(s, r)
+		}
+	}
+	return
+}
+
+func previousIdSelectedByGvk(gvk *resid.Gvk) sieveFunc {
+	return func(r *resource.Resource) bool {
+		if r.OrgId().IsSelected(gvk) {
+			return true
+		}
+		return false
+	}
+}
+
+func (f UnlimitedNameRefFilter) sameCurrentNamespaceAsReferrer() sieveFunc {
+	referrerCurId := f.Referrer.CurId()
+	if referrerCurId.IsClusterScoped() {
+		// If the referrer is cluster-scoped, let anything through.
+		return func(_ *resource.Resource) bool {return true}
+	}
+	return func(r *resource.Resource) bool {
+		if r.CurId().IsClusterScoped() {
+			// Allow cluster-scoped through.
+			return true
+		}
+		if r.GetKind() == "ServiceAccount" {
+			// Allow service accounts through, even though they
+			// are in a namespace.  A RoleBinding in another namespace
+			// can reference them.
+			return true
+		}
+		return referrerCurId.IsNsEquals(r.CurId())
+	}
+}

functions/go/gcp-set-default-name/namereference/transformer.go

@@ -0,0 +1,67 @@
+package namereference
+
+import (
+	"log"
+
+	"sigs.k8s.io/kustomize/api/resmap"
+	"sigs.k8s.io/kustomize/api/resource"
+	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/resid"
+)
+
+type nameReferenceTransformer struct {
+	backRefs []NameBackReferences
+}
+
+type NameBackReferences struct {
+	resid.Gvk `json:",inline,omitempty" yaml:",inline,omitempty"`
+	Referrers types.FsSlice `json:"fieldSpecs,omitempty" yaml:"fieldSpecs,omitempty"`
+}
+
+type NbrSlice []NameBackReferences
+
+var _ resmap.Transformer = &nameReferenceTransformer{}
+
+type filterMap map[*resource.Resource][]UnlimitedNameRefFilter
+
+func NewNameReferenceTransformer(
+	br []NameBackReferences) resmap.Transformer {
+	if br == nil {
+		log.Fatal("backrefs not expected to be nil")
+	}
+	return &nameReferenceTransformer{backRefs: br}
+}
+
+func (t *nameReferenceTransformer) Transform(m resmap.ResMap) error {
+	fMap := t.determineFilters(m.Resources())
+	for r, fList := range fMap {
+		c := m.SubsetThatCouldBeReferencedByResource(r)
+		for _, f := range fList {
+			f.Referrer = r
+			f.ReferralCandidates = c
+			if err := f.Referrer.ApplyFilter(f); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (t *nameReferenceTransformer) determineFilters(
+	resources []*resource.Resource) (fMap filterMap) {
+	// We cache the resource OrgId values because they don't change and otherwise are very visible in a memory pprof
+	fMap = make(filterMap)
+	for _, backReference := range t.backRefs {
+		for _, referrerSpec := range backReference.Referrers {
+			for _, res := range resources {
+				if res.OrgId().IsSelected(&referrerSpec.Gvk) {
+						fMap[res] = append(fMap[res], UnlimitedNameRefFilter{
+							NameFieldToUpdate: referrerSpec,
+							ReferralTarget: backReference.Gvk,
+						})
+				}
+			}
+		}
+	}
+	return fMap
+}