yaml-to-kotlin

YAML to Kotlin Gradle Plugin

Tired of writing Kotlin data classes by hand? Let YAML do the heavy lifting! This Gradle plugin automatically generates type-safe Kotlin data classes, complete with validation, from your YAML schema definitions.

Why YAML to Kotlin?

• Readability: YAML’s clean syntax makes it easy to define complex data structures.
• Type Safety: Generated Kotlin data classes provide compile-time checks for data integrity.
• Less Boilerplate: Say goodbye to tedious, manual data class creation.
• Maintainability: Keep your data models in sync with your YAML schemas effortlessly.

Key Features

• Effortless Data Modeling: Craft your data models in human-readable YAML.
• Automatic Code Generation: Generate Kotlin data classes with a single Gradle task.
• Basic Validation: Start with built-in validation rules, or add your own.
• Customization: Configure output directories, package names, and more.
• Future-Proof: Stay tuned for upcoming features like advanced validation and Kotlinx.serialization support!

Installation

plugins {
    id("io.github.noodlemind.yaml-to-kotlin") version "1.1.0"
}

Usage

1. Place your YAML schema files in the src/main/resources/schemas directory.
2. Configure the plugin in your build.gradle.kts:

    kotlin yamlToKotlin { inputDir.set(file("src/main/resources/schemas")) outputDir.set(file("build/generated/source/yaml-to-kotlin")) packageName = "com.example.generated" }
   

3. Run the Gradle task:

   ./gradlew generateKotlinFromYaml
   

YAML Schema Standards

Your YAML schemas should follow these standards & structure:

Base Structure:

ObjectName:
  type: object
  properties:
    propertyName:
      type: string|integer|number|boolean
      required: true|false
      validate:
        - pattern: isLetter|isNumeric|minLength|maxLength|regex
          value: <validation-value>

Standards / Options:

Section	Attribute	Type	Description	Required
types	base	string	Base type (e.g., integer, string, boolean)	Yes
types	minimum	number	Minimum value for numeric types	No
types	maximum	number	Maximum value for numeric types	No
types	minLength	integer	Minimum length for string types	No
types	maxLength	integer	Maximum length for string types	No
types	pattern	string	Regex pattern for string types	No
entities	properties	object	Map of property names to their definitions	Yes
entities.properties	type	string	Type of the property (can be custom type)	Yes
entities.properties	required	boolean	Whether the property is required	No
entities.properties	references	object	For defining relationships between entities	No
entities.properties.references	entity	string	Name of the referenced entity	Yes (if references is used)
entities.properties.references	property	string	Name of the property in the referenced entity	Yes (if references is used)
validations	name	string	Name of the custom validation	Yes
validations	params	array of strings	Parameters for the custom validation	No

Configuration Options

Option	Description	Default
inputDir	Directory containing YAML schema files	src/main/resources/schemas
outputDir	Directory for generated Kotlin files	build/generated/source/yaml-to-kotlin
packageName	Package name for generated classes	com.example.generated
schemaFileExtension	File extension for YAML schemas	yaml
generateValidations	Generate validation code	true
generateDataClasses	Generate data classes	true
generateSealedClasses	Generate sealed classes	false
addKotlinxSerializationAnnotations	Add kotlinx.serialization annotations	false

Examples

Employee Data Class

Template: 'v1.0.0'
Metadata:
   name: 'Complex Employee Data Template'
   description: 'Schema for detailed employee information'

Components:
   Schemas:
      Email:
         type: string
         format: email

      Department:
         type: string
         enum:
            - SALES
            - MARKETING
            - HR
            - IT
            - FINANCE

      Address:
         type: object
         properties:
            street:
               type: string
               validate:
                  - pattern: minLength
                    value: 2
            zipCode:
               type: string
               validate:
                  - pattern: isNumeric
            country:
               type: string
               validate:
                  - pattern: isLetter

      Employee:
         type: object
         properties:
            firstName:
               type: string
               required: true
               validate:
                  - pattern: isLetter
            lastName:
               type: string
               required: true
               validate:
                  - pattern: isLetter
            email:
               $ref: '#/Components/Schemas/Email'
            departmentName:
               $ref: '#/Components/Schemas/Department'
            jobTitle:
               type: string
               validate:
                  - pattern: isLetter
            reportsTo:
               $ref: '#/Components/Schemas/Email'
            phoneNumber:
               type: string
               validate:
                  - pattern: regex
                    value: '^[0-9]{10}$'
            AddressDetails:
               type: object
               properties:
                  HomeAddress:
                     $ref: '#/Components/Schemas/Address'
                  OfficeAddress:
                     $ref: '#/Components/Schemas/Address'

Contributing

We welcome contributions! Please see our Contributing Guidelines for more details.

License

This project is licensed under the MIT License—see the LICENSE file for details.

Let’s write cleaner, safer, and more maintainable Kotlin code together.

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