KurrentDB Schema Registry Examples

A collection of Node.js examples demonstrating KurrentDB Schema Registry functionality.

Prerequisites

Requirements

• KurrentDB: Version 25.1 or above (required for Schema Registry support)
• Node.js Client: @kurrent/kurrentdb-client version 1.2.0 or above (required for Schema Registry API)

Start KurrentDB Server

Before running the examples, you need to have KurrentDB running. The easiest way is using Docker:

docker run --name kurrentdb-node -it -p 2113:2113 docker.kurrent.io/kurrent-latest/kurrentdb:25.1.1 --insecure --run-projections=All --enable-atom-pub-over-http --start-standard-projections

Note: The command above is shown as a single line for compatibility across all terminals and operating systems. If your terminal supports multi-line commands, you can split it for better readability.

This will start KurrentDB on port 2113 and run in insecure mode (no TLS and no credientials required to login)

Managing the container:

# Stop the server
docker stop kurrentdb-node

# Restart the server
docker start kurrentdb-node

# Remove the container
docker rm kurrentdb-node

Setup

1. Install dependencies:

npm install

2. Make sure KurrentDB is running on localhost:2113 (or update the endpoint in the example files)

Examples

1. Simple Schema Example (simple-schema-example.js)

A quick start guide showing basic schema operations:

• Create a schema with unique UUID-based name
• Retrieve schema metadata
• Check compatibility
• Register new versions
• List versions

Note: Uses unique schema names (with UUID suffix) for each run.

npm run simple

2. Comprehensive Schema Demo (schema-registry-demo.js)

Complete demonstration of all schema registry features:

• Create schemas with initial versions and unique UUID-based names
• Get schema metadata and versions
• Check schema compatibility
• Register new schema versions
• List schemas and versions
• Update schema metadata
• Get versions by ID
• Test incompatible changes
• Cleanup operations (commented out by default)

Note: Uses unique schema names (with UUID suffix) for each run.

npm run demo

3. Multi-Format Examples (multi-format-example.js)

Demonstrates different schema formats:

• JSON Schema - Standard JSON schema validation
• Protobuf - Protocol Buffers schema definition
• Avro - Apache Avro schema format
• Bytes - Custom binary schema format
• Compatibility modes explained
• Listing schemas by format

Note: All schemas created with unique UUID-based names.

npm run formats

Schema Registry Features Demonstrated

Schema Management

• ✓ Create schemas with different data formats (JSON, Protobuf, Avro, Bytes)
• ✓ Update schema metadata (description, tags)
• ✓ Delete schemas and versions
• ✓ List all schemas with filtering

Version Management

• ✓ Register new schema versions
• ✓ Get specific versions by number or ID
• ✓ List all versions for a schema
• ✓ Delete specific versions

Compatibility Checking

• ✓ Check if a new schema is compatible
• ✓ Different compatibility modes (backward, forward, full, etc.)
• ✓ Detect incompatible changes
• ✓ Error details for compatibility issues

Data Formats

• ✓ JSON Schema
• ✓ Protocol Buffers (Protobuf)
• ✓ Apache Avro
• ✓ Custom Bytes format

Compatibility Modes

• backward - New schema can read old data
• forward - Old schema can read new data
• full - Both backward and forward compatible
• backward-all - Compatible with all previous versions
• forward-all - All previous versions compatible with new
• full-all - Fully compatible with all versions
• none - No compatibility checking

Configuration

You can modify the connection settings in each example file:

• endpoint: KurrentDB connection string (default: localhost:2113)
• tls: Whether to use TLS (default: false)

API Reference

All examples use the @kurrent/kurrentdb-client package (v1.2.0-alpha.0).

Key methods demonstrated:

• createSchema() - Create a new schema
• getSchema() - Get schema metadata
• updateSchema() - Update schema metadata
• deleteSchema() - Delete a schema
• listSchemas() - List all schemas
• registerSchemaVersion() - Add a new version
• getSchemaVersion() - Get a specific version
• getSchemaVersionById() - Get version by ID
• listSchemaVersions() - List all versions
• deleteSchemaVersions() - Delete specific versions
• checkSchemaCompatibility() - Check compatibility
• listRegisteredSchemas() - List schemas with definitions
• lookupSchemaName() - Look up schema by version ID