Drain the top level internal.

api/internal/accumulator/refvartransformer.go

@@ -0,0 +1,110 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package accumulator
+
+import (
+	"fmt"
+
+	expansion2 "sigs.k8s.io/kustomize/v3/api/internal/accumulator/expansion"
+
+	"sigs.k8s.io/kustomize/v3/api/resmap"
+	"sigs.k8s.io/kustomize/v3/api/transform"
+	"sigs.k8s.io/kustomize/v3/api/types"
+)
+
+type refVarTransformer struct {
+	varMap            map[string]interface{}
+	replacementCounts map[string]int
+	fieldSpecs        []types.FieldSpec
+	mappingFunc       func(string) interface{}
+}
+
+// newRefVarTransformer returns a new refVarTransformer
+// that replaces $(VAR) style variables with values.
+// The fieldSpecs are the places to look for occurrences of $(VAR).
+func newRefVarTransformer(
+	varMap map[string]interface{}, fs []types.FieldSpec) *refVarTransformer {
+	return &refVarTransformer{
+		varMap:     varMap,
+		fieldSpecs: fs,
+	}
+}
+
+// replaceVars accepts as 'in' a string, or string array, which can have
+// embedded instances of $VAR style variables, e.g. a container command string.
+// The function returns the string with the variables expanded to their final
+// values.
+func (rv *refVarTransformer) replaceVars(in interface{}) (interface{}, error) {
+	switch vt := in.(type) {
+	case []interface{}:
+		var xs []interface{}
+		for _, a := range in.([]interface{}) {
+			xs = append(xs, expansion2.Expand(a.(string), rv.mappingFunc))
+		}
+		return xs, nil
+	case map[string]interface{}:
+		inMap := in.(map[string]interface{})
+		xs := make(map[string]interface{}, len(inMap))
+		for k, v := range inMap {
+			s, ok := v.(string)
+			if !ok {
+				// This field not contain a $(VAR) since it is not
+				// of string type. For instance .spec.replicas: 3 in
+				// a Deployment object
+				xs[k] = v
+			} else {
+				// This field can potentially contains a $(VAR) since it is
+				// of string type. For instance .spec.replicas: $(REPLICAS)
+				// in a Deployment object
+				xs[k] = expansion2.Expand(s, rv.mappingFunc)
+			}
+		}
+		return xs, nil
+	case interface{}:
+		s, ok := in.(string)
+		if !ok {
+			// This field not contain a $(VAR) since it is not of string type.
+			return in, nil
+		}
+		// This field can potentially contain a $(VAR) since it is
+		// of string type.
+		return expansion2.Expand(s, rv.mappingFunc), nil
+	case nil:
+		return nil, nil
+	default:
+		return "", fmt.Errorf("invalid type encountered %T", vt)
+	}
+}
+
+// UnusedVars returns slice of Var names that were unused
+// after a Transform run.
+func (rv *refVarTransformer) UnusedVars() []string {
+	var unused []string
+	for k := range rv.varMap {
+		_, ok := rv.replacementCounts[k]
+		if !ok {
+			unused = append(unused, k)
+		}
+	}
+	return unused
+}
+
+// Transform replaces $(VAR) style variables with values.
+func (rv *refVarTransformer) Transform(m resmap.ResMap) error {
+	rv.replacementCounts = make(map[string]int)
+	rv.mappingFunc = expansion2.MappingFuncFor(
+		rv.replacementCounts, rv.varMap)
+	for _, res := range m.Resources() {
+		for _, fieldSpec := range rv.fieldSpecs {
+			if res.OrgId().IsSelected(&fieldSpec.Gvk) {
+				if err := transform.MutateField(
+					res.Map(), fieldSpec.PathSlice(),
+					false, rv.replaceVars); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}