Files
kustomize/api/internal/accumulator/refvartransformer.go
2019-10-21 13:30:31 -07:00

111 lines
3.1 KiB
Go

// Copyright 2019 The Kubernetes Authors.
// SPDX-License-Identifier: Apache-2.0
package accumulator
import (
"fmt"
expansion2 "sigs.k8s.io/kustomize/api/internal/accumulator/expansion"
"sigs.k8s.io/kustomize/api/resmap"
"sigs.k8s.io/kustomize/api/transform"
"sigs.k8s.io/kustomize/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
}