Metadata Model Extensions

This directory contains community-contributed extensions to DataHub's metadata model. These extensions include custom validators, plugins, and other components that extend DataHub's core functionality.

What Goes Here

Custom Validators: Aspect payload validators that enforce business rules on metadata
Model Plugins: Extensions that add new functionality to the metadata model
Custom Aspects: Additional metadata aspects for specific use cases
Entity Extensions: Modifications to existing entity types

Structure

Each extension should be in its own subdirectory with:

README.md - Documentation for the extension
build.gradle - Build configuration
src/ - Source code
Tests and examples as appropriate

Current Extensions

datahub-demo-dataset-governance-validator - Demo validator that shows how to validate that logical datasets have required governance metadata (ownership, tags, domain)

Building Extensions

Extensions in this directory are self-contained and work independently. To build an extension:

# From the extension directory (recommended)
cd datahub-demo-dataset-governance-validator
./gradlew build

# Create deployable plugin structure
./gradlew createModelPlugin

# Deploy to local DataHub instance
./gradlew deployPlugin

Prerequisites:

If building from within the DataHub repository, first build required DataHub components:

# From DataHub root directory
./gradlew :entity-registry:build :li-utils:build :metadata-models:build

Extensions automatically detect and use DataHub JARs when available

Contributing

See the main CONTRIBUTING.md for general contribution guidelines.

For metadata model extensions specifically:

Self-contained design - Extensions should work independently without modifying core DataHub files
Smart dependency detection - Use the build pattern that automatically detects DataHub JARs
Follow the existing directory structure pattern
Include comprehensive documentation
Add tests for your extension
Update this README to list your extension

Standalone Usage

Extensions can be moved to standalone repositories and still work by:

Copying the extension directory
Providing required DataHub JAR files in a libs/ directory
Updating the build.gradle to reference the JAR files