new-function

name	new-function
description	Add a new template function to jhelm (Helm or Sprig)
disable-model-invocation	true
argument-hint	["function-name"]

Add a new template function

Guided workflow for adding a new template function named $ARGUMENTS.

Step 1: Determine the category

Helm functions (in jhelm-gotemplate/src/main/java/.../helm/):

• conversion/ConversionFunctions.java — YAML/JSON conversion (toYaml, fromJson, etc.)
• template/TemplateFunctions.java — Template inclusion (include, tpl, required)
• kubernetes/KubernetesFunctions.java — Kubernetes integration (lookup)
• chart/ChartFunctions.java — Chart utilities (semverCompare, certificate generation)

Sprig functions (in jhelm-gotemplate/src/main/java/.../sprig/):

• strings/StringFunctions.java — String manipulation
• collections/CollectionFunctions.java — List/dict operations
• logic/LogicFunctions.java — default, empty, coalesce, ternary
• math/MathFunctions.java — Arithmetic operations
• encoding/EncodingFunctions.java — Base64, SHA, etc.
• crypto/CryptoFunctions.java — UUID, random, encryption
• date/DateFunctions.java — Date formatting/manipulation
• reflection/ReflectionFunctions.java — Type checking
• network/NetworkFunctions.java — DNS lookup
• semver/SemverFunctions.java — Semantic versioning

Step 2: Implement the function

1. Add the function to the appropriate category class
2. Follow existing patterns in that class (method signature, error handling)
3. Use @Slf4j for logging if needed
4. For strict variants, create a must* version that throws on error

Step 3: Registration

The function auto-registers via the coordinator:

• Helm functions: HelmFunctions.java → getFunctionCategories()
• Sprig functions: SprigFunctionsRegistry.java → getFunctionCategories()

If adding a new category, update getFunctionCategories() in the appropriate coordinator.

Step 4: Add tests

Add tests in the corresponding test class (e.g., Helm4FunctionsTest.java, or the test class for the Sprig category).

Step 5: Verify

Run the relevant module tests:

./mvnw test -pl jhelm-gotemplate