helm-convert: Enable capturegroup default substitution

Signed-off-by: Jim Ramsay <[email protected]>

addon-tools/helm-convert/README.md

@@ -100,6 +100,46 @@ service:
       k8s-app: {}
 ```
 
+### Capturegroup default substitution
+
+The helm-convert tool supports a mechanism to substitute capturegroup default
+values if required.  If the defaults.yaml contains a section called
+`captureGroup_defaults`, and the YAML in question contains one or more
+captureGroups using either the `regex` or `capturegroup` inlineDiff mechanism,
+all capturegroups with a default in the `captureGroup_defaults` section will be
+replaced by the default value when converting the reference template to helm
+chart template.
+
+For example, if you have a CR like this:
+
+```yaml
+apiVersion: v1
+Kind: Foo
+spec:
+  value: |-
+    Something with (?<blee>.*) in it,
+    And another capturegroup (?<bar>.*) with no default.
+```
+
+With this in the values.yaml:
+
+```yaml
+Foo:
+- captureGroup_defaults:
+    blee: 42
+```
+
+The resulting Helm template will look like this:
+
+```yaml
+apiVersion: v1
+Kind: Foo
+spec:
+  value: |-
+    Something with 42 in it,
+    And another capturegroup (?<bar>.*) with no default.
+```
+
 ## Auto Extracting of default values from Existing CRs
 
 another feature that can help in initial building of values.yaml files is extracting default values from existing CRs,

addon-tools/helm-convert/convert/convert.go

@@ -59,6 +59,7 @@ type Options struct {
 func convertToHelm(o *Options) error {
 	helmTemplates := make(map[string]string)
 	helmValues := make(map[string]any)
+	var preValues map[string]any
 	crsWithDefaults := make(map[string]map[string]interface{})
 
 	cfs, err := compare.GetRefFS(o.refPath)
@@ -79,12 +80,19 @@ func convertToHelm(o *Options) error {
 		}
 	}
 
+	if o.valuesPath != "" {
+		preValues, err = loadValues(o.valuesPath)
+		if err != nil {
+			return err
+		}
+	}
+
 	for _, t := range templates {
 
 		visitor := ExpectedValuesFinder{}
 		Inspect(t.GetTemplateTree().Root, visitor.Visit())
 
-		helmTemplate, err := convertToHelmTemplate(cfs, t)
+		helmTemplate, err := convertToHelmTemplate(cfs, t, preValues)
 		if err != nil {
 			return err
 		}
@@ -107,11 +115,7 @@ func convertToHelm(o *Options) error {
 		}
 	}
 
-	if o.valuesPath != "" {
-		preValues, err := loadValues(o.valuesPath)
-		if err != nil {
-			return err
-		}
+	if preValues != nil {
 		merged, err := compare.MergeManifests(&unstructured.Unstructured{Object: preValues}, &unstructured.Unstructured{Object: helmValues})
 		if err != nil {
 			return fmt.Errorf("failed to merge given values with generated values %w", err)
@@ -177,7 +181,26 @@ func loadYAMLFiles(root string) (map[string]map[string]interface{}, error) {
 	return filesMapping, nil
 }
 
-func convertToHelmTemplate(cfs fs.FS, t compare.ReferenceTemplate) (string, error) {
+func cgDefaultsFor(compName string, helmValues map[string]any) (map[string]any, error) {
+	if values, ok := helmValues[compName].([]any); ok && len(values) > 0 {
+		if section, ok := values[0].(map[string]any); ok && len(section) > 0 {
+			if dflts, ok := section["captureGroup_defaults"].(map[string]any); ok && len(dflts) > 0 {
+				return dflts, nil
+			}
+		}
+	}
+	return nil, fmt.Errorf("no captureGroup_defaults found for %s", compName)
+}
+
+func removeCgDefaults(compName string, helmValues map[string]any) {
+	if values, ok := helmValues[compName].([]any); ok && len(values) > 0 {
+		if section, ok := values[0].(map[string]any); ok && len(section) > 0 {
+			delete(section, "captureGroup_defaults")
+		}
+	}
+}
+
+func convertToHelmTemplate(cfs fs.FS, t compare.ReferenceTemplate, helmValues map[string]any) (string, error) {
 	var templateStructure = `{{- $values := list (dict)}}
 {{- if .Values.%v}}
 {{- $values = .Values.%v }}
@@ -187,12 +210,43 @@ func convertToHelmTemplate(cfs fs.FS, t compare.ReferenceTemplate) (string, erro
 %v 
 {{ end -}}
 `
-	content, err := fs.ReadFile(cfs, t.GetIdentifier())
+	data, err := fs.ReadFile(cfs, t.GetIdentifier())
 	if err != nil {
 		return "", fmt.Errorf("failed to read template named: %s %w", t.GetIdentifier(), err)
 	}
+
 	compName := getCompName(t.GetIdentifier())
-	helmTemplate := fmt.Sprintf(templateStructure, compName, compName, string(content))
+
+	content := string(data)
+
+	if len(t.GetConfig().GetInlineDiffFuncs()) > 0 {
+		if dflts, err := cgDefaultsFor(compName, helmValues); err == nil {
+			cgs := compare.CapturegroupIndex(content)
+			contentBuilder := strings.Builder{}
+			idx := 0
+			for _, group := range cgs {
+				if idx < group.Start {
+					contentBuilder.WriteString(content[idx:group.Start])
+				}
+				if dflt, ok := dflts[group.Name]; ok {
+					fmt.Fprintf(os.Stderr, "  %s replacing CaptureGroup (?<%s>...) at [%d:%d] with default: %v\n", compName, group.Name, group.Start, group.End, dflt)
+					contentBuilder.WriteString(fmt.Sprintf("%v", dflt))
+				} else {
+					contentBuilder.WriteString(content[group.Start:group.End])
+				}
+				idx = group.End
+			}
+			if idx < len(content) {
+				contentBuilder.WriteString(content[idx:])
+			}
+			content = contentBuilder.String()
+			// Now that we've fully consumed the defaults, strip them so they don't appear in the Helm chart...
+			removeCgDefaults(compName, helmValues)
+		}
+	}
+
+	helmTemplate := fmt.Sprintf(templateStructure, compName, compName, content)
+
 	return helmTemplate, nil
 }
 

addon-tools/helm-convert/convert/convert_test.go

@@ -81,6 +81,10 @@ func TestConvert(t *testing.T) {
 			name:           "Values Contain Keys With Dots",
 			passDefaultDir: true,
 		},
+		{
+			name:           "Capturegroup Defaults",
+			passValuesFile: true,
+		},
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {

addon-tools/helm-convert/convert/testdata/CapturegroupDefaults/reference/metadata.yaml

@@ -0,0 +1,12 @@
+apiVersion: v2
+parts:
+  - name: ExamplePart
+    components:
+      - name: DemonSets
+        allOf:
+          - path: sa.yaml
+            config:
+              perField:
+              - pathToKey: spec.value
+                inlineDiffFunc: capturegroups
+          - path: secret.yaml

addon-tools/helm-convert/convert/testdata/CapturegroupDefaults/reference/sa.yaml

@@ -0,0 +1,11 @@
+apiVersion: {{ .apiVersion }}
+kind: ServiceAccount
+metadata:
+  labels:
+    k8s-app: kubernetes-dashboard
+  name: {{ .metadata.name }}
+  namespace: kubernetes-dashboard
+spec:
+  value: |-
+    Long string with (?<one>[a-z0-9]*) capturegroup
+    And another (?<two>[a-z0-9]*) capturegorup

addon-tools/helm-convert/convert/testdata/CapturegroupDefaults/reference/secret.yaml

@@ -0,0 +1,10 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  labels:
+    k8s-app: kubernetes-dashboard
+  name: {{ .metadata.name }}
+  namespace: kubernetes-dashboard
+type: Opaque
+{{ if .data }}data:
+  {{ .data | toYaml }}{{ end }}

addon-tools/helm-convert/convert/testdata/CapturegroupDefaults/result/Chart.yaml

@@ -0,0 +1,3 @@
+description: This Helm Chart was generated from a kube-compare reference
+name: Capturegroup Defaults
+version: "1"

addon-tools/helm-convert/convert/testdata/CapturegroupDefaults/result/templates/sa.yaml

@@ -0,0 +1,19 @@
+{{- $values := list (dict)}}
+{{- if .Values.sa}}
+{{- $values = .Values.sa }}
+{{- end }}
+{{- range $values -}}
+---
+apiVersion: {{ .apiVersion }}
+kind: ServiceAccount
+metadata:
+  labels:
+    k8s-app: kubernetes-dashboard
+  name: {{ .metadata.name }}
+  namespace: kubernetes-dashboard
+spec:
+  value: |-
+    Long string with 100 capturegroup
+    And another (?<two>[a-z0-9]*) capturegorup
+ 
+{{ end -}}

addon-tools/helm-convert/convert/testdata/CapturegroupDefaults/result/templates/secret.yaml

@@ -0,0 +1,18 @@
+{{- $values := list (dict)}}
+{{- if .Values.secret}}
+{{- $values = .Values.secret }}
+{{- end }}
+{{- range $values -}}
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  labels:
+    k8s-app: kubernetes-dashboard
+  name: {{ .metadata.name }}
+  namespace: kubernetes-dashboard
+type: Opaque
+{{ if .data }}data:
+  {{ .data | toYaml }}{{ end }}
+
+{{ end -}}

addon-tools/helm-convert/convert/testdata/CapturegroupDefaults/result/values.yaml

@@ -0,0 +1,8 @@
+sa:
+- apiVersion: v1
+  metadata:
+    name: kubernetes-dashboard
+secret:
+- data: {}
+  metadata:
+    name: {}

addon-tools/helm-convert/convert/testdata/CapturegroupDefaults/values.yaml

@@ -0,0 +1,6 @@
+sa:
+- apiVersion: v1
+  metadata:
+    name: kubernetes-dashboard
+  captureGroup_defaults:
+    one: 100