Make the replica transformer kind aware.

The previous implementation had a bug and poorly handled
types that should not have a `spec: replica:` field.

Documentation is updated to reflect the change in behavior,
and better highlights the cases where a patch should be
used instead of this shorthand.

docs/fields.md

@@ -355,6 +355,7 @@ Replicas modified the number of replicas for a resource.
 E.g. Given this kubernetes Deployment fragment:
 
 ```
+kind: Deployment
 metadata:
   name: deployment-name
 spec:
@@ -374,6 +375,17 @@ This field accepts a list, so many resources can
 be modified at the same time.
 
 
+#### Limitation
+As this declaration does not take in a `kind:` nor a `group:`
+it will match any `group` and `kind` that has a matching name and
+that is one of:
+- `Deployment`
+- `ReplicationController`
+- `ReplicaSet`
+- `StatefulSet`
+
+For more complex use cases, revert to using a patch.
+
 
 ### resources
 

pkg/target/kusttarget_configplugin.go

@@ -239,10 +239,12 @@ func (kt *KustTarget) configureBuiltinReplicaCountTransformer(
 	tConfig *config.TransformerConfig) (
 	result []transformers.Transformer, err error) {
 	var c struct {
-		Replica types.Replica
+		Replica    types.Replica
+		FieldSpecs []config.FieldSpec
 	}
 	for _, args := range kt.kustomization.Replicas {
 		c.Replica = args
+		c.FieldSpecs = tConfig.Replicas
 		p := builtin.NewReplicaCountTransformerPlugin()
 		err = kt.configureBuiltinPlugin(p, c, "replica")
 		if err != nil {

pkg/transformers/config/defaultconfig/defaultconfig.go

@@ -32,6 +32,7 @@ func GetDefaultFieldSpecs() []byte {
 		[]byte(varReferenceFieldSpecs),
 		[]byte(nameReferenceFieldSpecs),
 		[]byte(imagesFieldSpecs),
+		[]byte(replicasFieldSpecs),
 	}
 	return bytes.Join(configData, []byte("\n"))
 }
@@ -47,5 +48,6 @@ func GetDefaultFieldSpecsAsMap() map[string]string {
 	result["varreference"] = varReferenceFieldSpecs
 	result["namereference"] = nameReferenceFieldSpecs
 	result["images"] = imagesFieldSpecs
+	result["replicas"] = replicasFieldSpecs
 	return result
 }

pkg/transformers/config/defaultconfig/replicas.go

@@ -0,0 +1,20 @@
+package defaultconfig
+
+const replicasFieldSpecs = `
+replicas:
+- path: spec/replicas
+  create: true
+  kind: Deployment
+
+- path: spec/replicas
+  create: true
+  kind: ReplicationController
+
+- path: spec/replicas
+  create: true
+  kind: ReplicaSet
+
+- path: spec/replicas
+  create: true
+  kind: StatefulSet
+`

pkg/transformers/config/transformerconfig.go

@@ -35,6 +35,7 @@ type TransformerConfig struct {
 	NameReference     nbrSlice `json:"nameReference,omitempty" yaml:"nameReference,omitempty"`
 	VarReference      fsSlice  `json:"varReference,omitempty" yaml:"varReference,omitempty"`
 	Images            fsSlice  `json:"images,omitempty" yaml:"images,omitempty"`
+	Replicas          fsSlice  `json:"replicas,omitempty" yaml:"replicas,omitempty"`
 }
 
 // MakeEmptyConfig returns an empty TransformerConfig object
@@ -61,6 +62,7 @@ func (t *TransformerConfig) sortFields() {
 	sort.Sort(t.NameReference)
 	sort.Sort(t.VarReference)
 	sort.Sort(t.Images)
+	sort.Sort(t.Replicas)
 }
 
 // AddPrefixFieldSpec adds a FieldSpec to NamePrefix
@@ -135,6 +137,10 @@ func (t *TransformerConfig) Merge(input *TransformerConfig) (
 	if err != nil {
 		return nil, err
 	}
+	merged.Replicas, err = t.Replicas.mergeAll(input.Replicas)
+	if err != nil {
+		return nil, err
+	}
 	merged.sortFields()
 	return merged, nil
 }

pkg/types/kustomization.go

@@ -369,5 +369,5 @@ type Replica struct {
 	Name string `json:"name,omitempty" yaml:"name,omitempty"`
 
 	// The number of replicas required.
-	Count uint `json:"count,omitempty" yaml:"count,omitempty"`
+	Count int64 `json:"count,omitempty" yaml:"count,omitempty"`
 }

plugin/builtin/ReplicaCountTransformer.go

@@ -7,19 +7,17 @@ import (
 	"sigs.k8s.io/kustomize/pkg/ifc"
 	"sigs.k8s.io/kustomize/pkg/resid"
 	"sigs.k8s.io/kustomize/pkg/resmap"
+	"sigs.k8s.io/kustomize/pkg/transformers"
+	"sigs.k8s.io/kustomize/pkg/transformers/config"
 	"sigs.k8s.io/kustomize/pkg/types"
 	"sigs.k8s.io/yaml"
 )
 
-const (
-	fldReplica = "replicas"
-	fldSpec    = "spec"
-)
-
 // Find matching replicas declarations and replace the count.
 // Eases the kustomization configuration of replica changes.
 type ReplicaCountTransformerPlugin struct {
-	Replica types.Replica `json:"replica,omitempty" yaml:"replica,omitempty"`
+	Replica    types.Replica      `json:"replica,omitempty" yaml:"replica,omitempty"`
+	FieldSpecs []config.FieldSpec `json:"fieldSpecs,omitempty" yaml:"fieldSpecs,omitempty"`
 }
 
 //noinspection GoUnusedGlobalVariable
@@ -31,30 +29,46 @@ func (p *ReplicaCountTransformerPlugin) Config(
 	ldr ifc.Loader, rf *resmap.Factory, c []byte) (err error) {
 
 	p.Replica = types.Replica{}
+	p.FieldSpecs = nil
 	return yaml.Unmarshal(c, p)
 }
 
 func (p *ReplicaCountTransformerPlugin) Transform(m resmap.ResMap) error {
-	matcher := func(r resid.ResId) bool {
-		return r.Name == p.Replica.Name
-	}
-
-	for _, r := range m.GetMatchingResourcesByOriginalId(matcher) {
-		kMap := r.Map()
-
-		specInterface, ok := kMap[fldSpec]
-		if !ok {
-			return fmt.Errorf("object %s missing field %s, cannot update %s",
-				p.Replica.Name, fldSpec, fldReplica)
-		}
-
-		if spec, ok := specInterface.(map[string]interface{}); ok {
-			spec[fldReplica] = p.Replica.Count
-			kMap[fldSpec] = spec
-		} else {
-			return fmt.Errorf("object %s has a malformed %s", p.Replica.Name, fldSpec)
+	for i, replicaSpec := range p.FieldSpecs {
+		for _, res := range m.GetMatchingResourcesByOriginalId(p.createMatcher(i)) {
+			err := transformers.MutateField(
+				res.Map(), replicaSpec.PathSlice(),
+				replicaSpec.CreateIfNotPresent, p.addReplicas)
+			if err != nil {
+				return err
+			}
 		}
 	}
 
 	return nil
 }
+
+// Match Replica.Name and FieldSpec
+func (p *ReplicaCountTransformerPlugin) createMatcher(i int) resmap.IdMatcher {
+	return func(r resid.ResId) bool {
+		return r.Name == p.Replica.Name &&
+			r.Gvk.IsSelected(&p.FieldSpecs[i].Gvk)
+	}
+}
+
+func (p *ReplicaCountTransformerPlugin) addReplicas(in interface{}) (interface{}, error) {
+	switch m := in.(type) {
+	case int64:
+		// Was already in the field.
+	case map[string]interface{}:
+		if len(m) != 0 {
+			// A map was already in the replicas field, don't want to
+			// discard this data silently.
+			return nil, fmt.Errorf("%#v is expected to be %T", in, m)
+		}
+		// Just got added, default type is map, but we can return anything.
+	default:
+		return nil, fmt.Errorf("%#v is expected to be %T", in, m)
+	}
+	return p.Replica.Count, nil
+}

plugin/builtin/replicacounttransformer/ReplicaCountTransformer.go

@@ -10,19 +10,17 @@ import (
 	"sigs.k8s.io/kustomize/pkg/ifc"
 	"sigs.k8s.io/kustomize/pkg/resid"
 	"sigs.k8s.io/kustomize/pkg/resmap"
+	"sigs.k8s.io/kustomize/pkg/transformers"
+	"sigs.k8s.io/kustomize/pkg/transformers/config"
 	"sigs.k8s.io/kustomize/pkg/types"
 	"sigs.k8s.io/yaml"
 )
 
-const (
-	fldReplica = "replicas"
-	fldSpec    = "spec"
-)
-
 // Find matching replicas declarations and replace the count.
 // Eases the kustomization configuration of replica changes.
 type plugin struct {
-	Replica types.Replica `json:"replica,omitempty" yaml:"replica,omitempty"`
+	Replica    types.Replica      `json:"replica,omitempty" yaml:"replica,omitempty"`
+	FieldSpecs []config.FieldSpec `json:"fieldSpecs,omitempty" yaml:"fieldSpecs,omitempty"`
 }
 
 //noinspection GoUnusedGlobalVariable
@@ -32,30 +30,46 @@ func (p *plugin) Config(
 	ldr ifc.Loader, rf *resmap.Factory, c []byte) (err error) {
 
 	p.Replica = types.Replica{}
+	p.FieldSpecs = nil
 	return yaml.Unmarshal(c, p)
 }
 
 func (p *plugin) Transform(m resmap.ResMap) error {
-	matcher := func(r resid.ResId) bool {
-		return r.Name == p.Replica.Name
-	}
-
-	for _, r := range m.GetMatchingResourcesByOriginalId(matcher) {
-		kMap := r.Map()
-
-		specInterface, ok := kMap[fldSpec]
-		if !ok {
-			return fmt.Errorf("object %s missing field %s, cannot update %s",
-				p.Replica.Name, fldSpec, fldReplica)
-		}
-
-		if spec, ok := specInterface.(map[string]interface{}); ok {
-			spec[fldReplica] = p.Replica.Count
-			kMap[fldSpec] = spec
-		} else {
-			return fmt.Errorf("object %s has a malformed %s", p.Replica.Name, fldSpec)
+	for i, replicaSpec := range p.FieldSpecs {
+		for _, res := range m.GetMatchingResourcesByOriginalId(p.createMatcher(i)) {
+			err := transformers.MutateField(
+				res.Map(), replicaSpec.PathSlice(),
+				replicaSpec.CreateIfNotPresent, p.addReplicas)
+			if err != nil {
+				return err
+			}
 		}
 	}
 
 	return nil
 }
+
+// Match Replica.Name and FieldSpec
+func (p *plugin) createMatcher(i int) resmap.IdMatcher {
+	return func(r resid.ResId) bool {
+		return r.Name == p.Replica.Name &&
+			r.Gvk.IsSelected(&p.FieldSpecs[i].Gvk)
+	}
+}
+
+func (p *plugin) addReplicas(in interface{}) (interface{}, error) {
+	switch m := in.(type) {
+	case int64:
+		// Was already in the field.
+	case map[string]interface{}:
+		if len(m) != 0 {
+			// A map was already in the replicas field, don't want to
+			// discard this data silently.
+			return nil, fmt.Errorf("%#v is expected to be %T", in, m)
+		}
+		// Just got added, default type is map, but we can return anything.
+	default:
+		return nil, fmt.Errorf("%#v is expected to be %T", in, m)
+	}
+	return p.Replica.Count, nil
+}

plugin/builtin/replicacounttransformer/ReplicaCountTransformer_test.go

@@ -24,26 +24,130 @@ apiVersion: builtin
 kind: ReplicaCountTransformer
 metadata:
   name: notImportantHere
+
 replica:
-  name: deploy1
+  name: myapp
   count: 23
+fieldSpecs:
+- path: spec/replicas
+  create: true
+  kind: Deployment
+
+- path: spec/replicas
+  create: true
+  kind: ReplicationController
+
+- path: spec/replicas
+  create: true
+  kind: ReplicaSet
+
+- path: spec/replicas
+  create: true
+  kind: StatefulSet
 `, `
-group: apps
-apiVersion: v1
+apiVersion: builtin
+kind: Service
+metadata:
+  name: myapp
+spec:
+  ports:
+  - port: 1111
+  targetport: 1111
+---
+apiVersion: builtin
 kind: Deployment
 metadata:
-  name: deploy1
+  name: otherapp
 spec:
-  replicas: 1
+  replicas: 5
+---
+apiVersion: builtin
+kind: Deployment
+metadata:
+  name: myapp
+spec:
+  replicas: 5
+---
+apiVersion: builtin
+kind: StatefulSet
+metadata:
+  name: myapp
+spec:
+  selector:
+    matchLabels:
+      app: app
+---
+apiVersion: builtin
+kind: ReplicaSet
+metadata:
+  name: myapp
+spec:
+  selector:
+    matchLabels:
+      app: app
+---
+apiVersion: builtin
+kind: ReplicationController
+metadata:
+  name: myapp
+spec:
+  selector:
+    matchLabels:
+      app: app
 `)
 
 	th.AssertActualEqualsExpected(rm, `
-apiVersion: v1
-group: apps
+apiVersion: builtin
+kind: Service
+metadata:
+  name: myapp
+spec:
+  ports:
+  - port: 1111
+  targetport: 1111
+---
+apiVersion: builtin
 kind: Deployment
 metadata:
-  name: deploy1
+  name: myapp
 spec:
   replicas: 23
+---
+apiVersion: builtin
+kind: Deployment
+metadata:
+  name: otherapp
+spec:
+  replicas: 5
+---
+apiVersion: builtin
+kind: StatefulSet
+metadata:
+  name: myapp
+spec:
+  replicas: 23
+  selector:
+    matchLabels:
+      app: app
+---
+apiVersion: builtin
+kind: ReplicaSet
+metadata:
+  name: myapp
+spec:
+  replicas: 23
+  selector:
+    matchLabels:
+      app: app
+---
+apiVersion: builtin
+kind: ReplicationController
+metadata:
+  name: myapp
+spec:
+  replicas: 23
+  selector:
+    matchLabels:
+      app: app
 `)
 }