✨ Manage encoding when replacing values

There is an unused option in kustomize `ReplacementTransformer`
 named `encoding`. We make this option usable an provide 3 encodings:

 - base64
 - hex
 - bcrypt

 This is useful to have values in plain text in replacement sources
 and encode them in the destination.

 The `bcrypt` option may provide some issues has the value would
 change for each run.

main.go

@@ -114,7 +114,7 @@ func main() {
 
 	cmd := command.Build(processor, command.StandaloneDisabled, false)
 	command.AddGenerateDockerfile(cmd)
-	cmd.Version = "v0.4.1" // <---VERSION--->
+	cmd.Version = "v0.4.2" // <---VERSION--->
 
 	if err := cmd.Execute(); err != nil {
 		os.Exit(1)

pkg/extras/encoding.go

@@ -0,0 +1,85 @@
+package extras
+
+import (
+	"encoding/base64"
+	"encoding/hex"
+	"fmt"
+	"strings"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+// EncodingType enumerates the existing encoding types.
+//
+//go:generate go run golang.org/x/tools/cmd/stringer -type=EncodingType
+type EncodingType int
+
+const (
+	UnknownEncoding EncodingType = iota
+	Base64Encoding
+	BCryptEncoding
+	HexEncoding
+)
+
+var stringToEncodingTypeMap map[string]EncodingType
+
+func init() { //nolint:gochecknoinits
+	stringToEncodingTypeMap = makeStringToEncodingTypeMap()
+}
+
+// makeStringToEncodingTypeMap makes a map to get the appropriate
+// [EncodingType] given its name.
+func makeStringToEncodingTypeMap() (result map[string]EncodingType) {
+	result = make(map[string]EncodingType, 3)
+	for k := range EncoderFactories {
+		result[strings.Replace(strings.ToLower(k.String()), "encoding", "", 1)] = k
+	}
+	return
+}
+
+// getEncodingType returns the appropriate [EncodingType] for the passed
+// encoding type name
+func getEncodingType(n string) EncodingType {
+	result, ok := stringToEncodingTypeMap[strings.ToLower(n)]
+	if ok {
+		return result
+	}
+	return UnknownEncoding
+}
+
+// Encoder is an encoder function
+type Encoder func(value string) (string, error)
+
+// EncodeBase64 encodes value in base64
+func EncodeBase64(value string) (string, error) {
+	return base64.StdEncoding.EncodeToString([]byte(value)), nil
+}
+
+// EncodeBcrypt generates the bcrypt hash of value.
+func EncodeBcrypt(value string) (string, error) {
+	encoded, err := bcrypt.GenerateFromPassword([]byte(value), 10)
+
+	return string(encoded), err
+}
+
+// EncodeHex returns the hex string of value
+func EncodeHex(value string) (string, error) {
+	return hex.EncodeToString([]byte(value)), nil
+}
+
+// EncoderFactories register the [Encoder] factory functions for each
+// [EncoderType].
+var EncoderFactories = map[EncodingType]Encoder{
+	Base64Encoding: EncodeBase64,
+	BCryptEncoding: EncodeBcrypt,
+	HexEncoding:    EncodeHex,
+}
+
+func GetEncodedValue(value string, encoding string) (string, error) {
+	et := getEncodingType(encoding)
+	if f, ok := EncoderFactories[et]; ok {
+		return f(value)
+	}
+
+	return "", fmt.Errorf("encoding %s is unknown (%d)", encoding, et)
+}

pkg/extras/replacement.go

@@ -96,18 +96,27 @@ func selectSourceNode(nodes []*yaml.RNode, selector *types.SourceSelector) (*yam
 }
 
 func getRefinedValue(options *types.FieldOptions, rn *yaml.RNode) (*yaml.RNode, error) {
-	if options == nil || options.Delimiter == "" {
+	if options == nil || (options.Delimiter == "" && options.Encoding == "") {
 		return rn, nil
 	}
 	if rn.YNode().Kind != yaml.ScalarNode {
-		return nil, fmt.Errorf("delimiter option can only be used with scalar nodes")
-	}
-	value := strings.Split(yaml.GetValue(rn), options.Delimiter)
-	if options.Index >= len(value) || options.Index < 0 {
-		return nil, fmt.Errorf("options.index %d is out of bounds for value %s", options.Index, yaml.GetValue(rn))
+		return nil, fmt.Errorf("delimiter or encoding option can only be used with scalar nodes")
 	}
 	n := rn.Copy()
-	n.YNode().Value = value[options.Index]
+	if options.Delimiter != "" {
+		value := strings.Split(yaml.GetValue(rn), options.Delimiter)
+		if options.Index >= len(value) || options.Index < 0 {
+			return nil, fmt.Errorf("options.index %d is out of bounds for value %s", options.Index, yaml.GetValue(rn))
+		}
+
+		n.YNode().Value = value[options.Index]
+	} else {
+		value, err := GetEncodedValue(yaml.GetValue(rn), options.Encoding)
+		if err != nil {
+			return nil, errors.Wrapf(err, "while encoding value")
+		}
+		n.YNode().Value = value
+	}
 	return n, nil
 }
 

tests/sourced-replacement/expected/argocd-cm.yaml

@@ -34,3 +34,4 @@ data:
           teamNameField: slug
           orgs:
             - name: thisisfakeorganization
+  b64encoded: VGhpcyBpcyB0aGUgdmFsdWUgdG8gZW5jb2RlIGluIGJhc2U2NA==

tests/sourced-replacement/functions/argocd-values-replacements.yaml

@@ -26,3 +26,14 @@ replacements:
           name: argocd-cm
         fieldPaths:
           - data.dex\.config.!!yaml.connectors.[id=github].config.orgs.0.name
+  - source:
+      name: autocloud-values
+      fieldPath: data.to_encode
+      options:
+        encoding: base64
+    targets:
+      - select:
+          kind: ConfigMap
+          name: argocd-cm
+        fieldPaths:
+          - data.b64encoded

tests/sourced-replacement/original/argocd-cm.yaml

@@ -34,3 +34,4 @@ data:
           teamNameField: slug
           orgs:
             - name: johndoe
+  b64encoded: dGhpc2lzZmFrZXZhbHVl

tests/sourced-replacement/values/properties.yaml

@@ -9,3 +9,4 @@ data:
     repo: antoinemartin/autocloud
     email: [email protected]
     clientID: thisisfakeclientid
+  to_encode: This is the value to encode in base64