Update Transformer to accept blank source string

ADD: return condition for blank source string.
ADD: test case 26 for example.
CHG: Updated source value variable type

Closes: #620
Change-Id: Id2bac427cd0570eac3e87b98ded665d70613d2d6

pkg/api/v1alpha1/replacement_plugin_types.go

@@ -85,7 +85,7 @@ type Replacement struct {
 type ReplSource struct {
 	ObjRef   *Target `json:"objref,omitempty" yaml:"objref,omitempty"`
 	FieldRef string  `json:"fieldref,omitempty" yaml:"fiedldref,omitempty"`
-	Value    string  `json:"value,omitempty" yaml:"value,omitempty"`
+	Value    *string `json:"value,omitempty" yaml:"value,omitempty"`
 }
 
 // ReplTarget defines where a substitution is to.

pkg/api/v1alpha1/zz_generated.deepcopy.go

@@ -1481,6 +1481,11 @@ func (in *ReplSource) DeepCopyInto(out *ReplSource) {
 		*out = new(Target)
 		**out = **in
 	}
+	if in.Value != nil {
+		in, out := &in.Value, &out.Value
+		*out = new(string)
+		**out = **in
+	}
 }
 
 // DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new ReplSource.

pkg/document/plugin/replacement/transformer.go

@@ -62,9 +62,12 @@ func New(obj map[string]interface{}) (kio.Filter, error) {
 		if r.Target != nil && r.Targets != nil {
 			return nil, ErrBadConfiguration{Msg: "only target OR targets is allowed in one replacement, not both"}
 		}
-		if r.Source.ObjRef != nil && r.Source.Value != "" {
+		if r.Source.ObjRef != nil && r.Source.Value != nil {
 			return nil, ErrBadConfiguration{Msg: "only one of fieldref and value is allowed in one replacement"}
 		}
+		if r.Source.ObjRef == nil && r.Source.Value == nil {
+			return nil, ErrBadConfiguration{Msg: "no source value or source objectref value was given"}
+		}
 	}
 	return p, nil
 }
@@ -91,9 +94,10 @@ func (p *plugin) Filter(items []*yaml.RNode) ([]*yaml.RNode, error) {
 }
 
 func getValue(items []*yaml.RNode, source *airshipv1.ReplSource) (*yaml.RNode, error) {
-	if source.Value != "" {
+	if source.Value != nil {
-		return yaml.NewScalarRNode(source.Value), nil
+		return yaml.NewScalarRNode(*source.Value), nil
 	}
+
 	sources, err := kyamlutils.DocumentSelector{}.
 		ByAPIVersion(source.ObjRef.APIVersion).
 		ByGVK(source.ObjRef.Group, source.ObjRef.Version, source.ObjRef.Kind).

pkg/document/plugin/replacement/transformer_test.go

@@ -1360,6 +1360,58 @@ spec:
         name: nginx-sha256
       - image: alpine:1.8.0
         name: init-alpine
+`,
+	},
+	{
+		cfg: `
+apiVersion: airshipit.org/v1alpha1
+kind: ReplacementTransformer
+metadata:
+  name: Test_Case_26_Empty_Source_String
+replacements:
+- source:
+    value: ""
+  target:
+    objref:
+      kind: Deployment
+      name: source-controller
+    fieldrefs: ["spec.template.spec.containers[name=manager].env[name=http_proxy].value%REPLACEMENT_HTTP_PROXY%"]
+`,
+
+		in: `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: source-controller
+spec:
+  template:
+    spec:
+      containers:
+      - name: manager
+        env:
+        - name: http_proxy
+          value: REPLACEMENT_HTTP_PROXY
+        - name: https_proxy
+          value: REPLACEMENT_HTTPS_PROXY
+        - name: no_proxy
+          value: REPLACEMENT_NO_PROXY
+`,
+		expectedOut: `apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: source-controller
+spec:
+  template:
+    spec:
+      containers:
+      - name: manager
+        env:
+        - name: http_proxy
+          value: ""
+        - name: https_proxy
+          value: REPLACEMENT_HTTPS_PROXY
+        - name: no_proxy
+          value: REPLACEMENT_NO_PROXY
 `,
 	},
 }