feat: add prefix and suffix options to replacements for targeting con...

api/filters/replacement/replacement.go

@@ -229,6 +229,15 @@ func fieldRetrievalError(fieldPath string, isCreate bool) string {
 
 func setFieldValue(options *types.FieldOptions, targetField *yaml.RNode, value *yaml.RNode) error {
 	value = value.Copy()
+
+	// Handle prefix/suffix matching for sequence nodes (e.g., container args)
+	// Only apply prefix/suffix matching if the target field is a sequence and
+	// prefix/suffix options are specified
+	if targetField.YNode().Kind == yaml.SequenceNode && options != nil && (options.Prefix != "" || options.Suffix != "") {
+		return setFieldValueInSequence(options, targetField, value)
+	}
+
+	// Handle delimiter option for scalar nodes
 	if options != nil && options.Delimiter != "" {
 		if targetField.YNode().Kind != yaml.ScalarNode {
 			return fmt.Errorf("delimiter option can only be used with scalar nodes")
@@ -247,6 +256,24 @@ func setFieldValue(options *types.FieldOptions, targetField *yaml.RNode, value *
 		value.YNode().Value = strings.Join(tv, options.Delimiter)
 	}
 
+	// Handle prefix/suffix matching for scalar nodes
+	if options != nil && (options.Prefix != "" || options.Suffix != "") {
+		if targetField.YNode().Kind != yaml.ScalarNode {
+			return fmt.Errorf("prefix/suffix options can only be used with scalar or sequence nodes")
+		}
+		targetValue := targetField.YNode().Value
+		newValue := yaml.GetValue(value)
+
+		// Only modify if the target matches both prefix and suffix
+		if !matchesPrefixAndSuffix(targetValue, options.Prefix, options.Suffix) {
+			return nil
+		}
+
+		// Preserve prefix and suffix in the result
+		result := options.Prefix + newValue + options.Suffix
+		value.YNode().Value = result
+	}
+
 	if targetField.YNode().Kind == yaml.ScalarNode {
 		// For scalar, only copy the value (leave any type intact to auto-convert int->string or string->int)
 		targetField.YNode().Value = value.YNode().Value
@@ -257,6 +284,43 @@ func setFieldValue(options *types.FieldOptions, targetField *yaml.RNode, value *
 	return nil
 }
 
+// setFieldValueInSequence handles setting values in sequence nodes (string arrays)
+// when prefix and/or suffix options are specified
+func setFieldValueInSequence(options *types.FieldOptions, targetField *yaml.RNode, value *yaml.RNode) error {
+	elements, err := targetField.Elements()
+	if err != nil {
+		return err
+	}
+
+	newValue := yaml.GetValue(value)
+
+	for _, elem := range elements {
+		if elem.YNode().Kind != yaml.ScalarNode {
+			continue
+		}
+
+		elemValue := elem.YNode().Value
+		if matchesPrefixAndSuffix(elemValue, options.Prefix, options.Suffix) {
+			// Replace the value portion while preserving prefix and suffix
+			result := options.Prefix + newValue + options.Suffix
+			elem.YNode().Value = result
+		}
+	}
+
+	return nil
+}
+
+// matchesPrefixAndSuffix checks if a string has the specified prefix and suffix
+func matchesPrefixAndSuffix(s, prefix, suffix string) bool {
+	if prefix != "" && !strings.HasPrefix(s, prefix) {
+		return false
+	}
+	if suffix != "" && !strings.HasSuffix(s, suffix) {
+		return false
+	}
+	return true
+}
+
 // setValueInStructuredData handles setting values within structured data (JSON/YAML) in scalar fields
 func setValueInStructuredData(target *yaml.RNode, value *yaml.RNode, fieldPath string, createKind yaml.Kind) error {
 	pathParts := kyaml_utils.SmarterPathSplitter(fieldPath, ".")

api/filters/replacement/replacement_test.go

@@ -5005,6 +5005,289 @@ data:
     labels: {app: "my-awesome-app", version: "1.0.0", env: "production"}
     spec: {replicas: 3, selector: {matchLabels: {app: "my-awesome-app"}}}`,
 		},
+		"prefix option on scalar field": {
+			input: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: source
+  namespace: production
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: target
+data:
+  config: "--namespace=default"
+`,
+			replacements: `replacements:
+- source:
+    kind: ConfigMap
+    name: source
+    fieldPath: metadata.namespace
+  targets:
+  - select:
+      kind: ConfigMap
+      name: target
+    fieldPaths:
+    - data.config
+    options:
+      prefix: "--namespace="
+`,
+			expected: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: source
+  namespace: production
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: target
+data:
+  config: "--namespace=production"
+`,
+		},
+		"prefix option on sequence field (container args)": {
+			input: `apiVersion: v1
+kind: Namespace
+metadata:
+  name: my-namespace
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: cert-manager
+spec:
+  template:
+    spec:
+      containers:
+      - name: cert-manager
+        image: quay.io/jetstack/cert-manager-controller:v1.2.0
+        args:
+        - --v=2
+        - --default-issuer-kind=ClusterIssuer
+        - --leader-election-namespace=kube-system
+`,
+			replacements: `replacements:
+- source:
+    kind: Namespace
+    name: my-namespace
+    fieldPath: metadata.name
+  targets:
+  - select:
+      kind: Deployment
+    fieldPaths:
+    - spec.template.spec.containers.[name=cert-manager].args
+    options:
+      prefix: "--leader-election-namespace="
+`,
+			expected: `apiVersion: v1
+kind: Namespace
+metadata:
+  name: my-namespace
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: cert-manager
+spec:
+  template:
+    spec:
+      containers:
+      - name: cert-manager
+        image: quay.io/jetstack/cert-manager-controller:v1.2.0
+        args:
+        - --v=2
+        - --default-issuer-kind=ClusterIssuer
+        - --leader-election-namespace=my-namespace
+`,
+		},
+		"prefix option on sequence field with multiple matches": {
+			input: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: source
+  namespace: staging
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: app
+spec:
+  template:
+    spec:
+      containers:
+      - name: app
+        args:
+        - --namespace=default
+        - --other-namespace=default
+        - --namespace=other
+`,
+			replacements: `replacements:
+- source:
+    kind: ConfigMap
+    name: source
+    fieldPath: metadata.namespace
+  targets:
+  - select:
+      kind: Deployment
+    fieldPaths:
+    - spec.template.spec.containers.[name=app].args
+    options:
+      prefix: "--namespace="
+`,
+			expected: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: source
+  namespace: staging
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: app
+spec:
+  template:
+    spec:
+      containers:
+      - name: app
+        args:
+        - --namespace=staging
+        - --other-namespace=default
+        - --namespace=staging
+`,
+		},
+		"suffix option on scalar field": {
+			input: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: source
+data:
+  port: "8080"
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: target
+data:
+  url: "3000/api"
+`,
+			replacements: `replacements:
+- source:
+    kind: ConfigMap
+    name: source
+    fieldPath: data.port
+  targets:
+  - select:
+      kind: ConfigMap
+      name: target
+    fieldPaths:
+    - data.url
+    options:
+      suffix: "/api"
+`,
+			expected: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: source
+data:
+  port: "8080"
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: target
+data:
+  url: "8080/api"
+`,
+		},
+		"prefix and suffix options combined": {
+			input: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: source
+data:
+  value: "myvalue"
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: target
+data:
+  config: "prefix_oldvalue_suffix"
+`,
+			replacements: `replacements:
+- source:
+    kind: ConfigMap
+    name: source
+    fieldPath: data.value
+  targets:
+  - select:
+      kind: ConfigMap
+      name: target
+    fieldPaths:
+    - data.config
+    options:
+      prefix: "prefix_"
+      suffix: "_suffix"
+`,
+			expected: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: source
+data:
+  value: "myvalue"
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: target
+data:
+  config: "prefix_myvalue_suffix"
+`,
+		},
+		"prefix option no match on scalar field": {
+			input: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: source
+  namespace: production
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: target
+data:
+  config: "--other=value"
+`,
+			replacements: `replacements:
+- source:
+    kind: ConfigMap
+    name: source
+    fieldPath: metadata.namespace
+  targets:
+  - select:
+      kind: ConfigMap
+      name: target
+    fieldPaths:
+    - data.config
+    options:
+      prefix: "--namespace="
+`,
+			expected: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: source
+  namespace: production
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: target
+data:
+  config: "--other=value"
+`,
+		},
 	}
 
 	for tn := range testCases {

api/types/replacement.go

@@ -127,11 +127,21 @@ type FieldOptions struct {
 
 	// If field missing, add it.
 	Create bool `json:"create,omitempty" yaml:"create,omitempty"`
+
+	// Prefix is used to select elements in a list that start with this prefix.
+	// When set, only elements starting with this prefix will be modified.
+	// The prefix is preserved in the resulting value.
+	Prefix string `json:"prefix,omitempty" yaml:"prefix,omitempty"`
+
+	// Suffix is used to select elements in a list that end with this suffix.
+	// When set, only elements ending with this suffix will be modified.
+	// The suffix is preserved in the resulting value.
+	Suffix string `json:"suffix,omitempty" yaml:"suffix,omitempty"`
 }
 
 func (fo *FieldOptions) String() string {
-	if fo == nil || (fo.Delimiter == "" && !fo.Create) {
+	if fo == nil || (fo.Delimiter == "" && !fo.Create && fo.Prefix == "" && fo.Suffix == "") {
 		return ""
 	}
-	return fmt.Sprintf("%s(%d), create=%t", fo.Delimiter, fo.Index, fo.Create)
+	return fmt.Sprintf("%s(%d), create=%t, prefix=%q, suffix=%q", fo.Delimiter, fo.Index, fo.Create, fo.Prefix, fo.Suffix)
 }