xrcg 0.9.3.dev0

A command-line tool for xRegistry with code generation for messaging and eventing applications

xRegistry Code Generation CLI

Generate production-ready, type-safe messaging SDKs from xRegistry message catalog definitions. One command gives you compile-ready producer/consumer code with tests, dependency management, and protocol-specific bindings.

Quick Start

1. Install (Docker or pip):

# Docker (recommended - no Python needed)
docker pull ghcr.io/xregistry/codegen/xrcg:latest

# Or via pip
pip install git+https://github.com/xregistry/codegen.git

2. Generate a Kafka producer from a sample definition:

# Using Docker (Linux/macOS)
docker run --rm -v $(pwd):/work ghcr.io/xregistry/codegen/xrcg:latest \
  generate --projectname PrinterEvents --language py --style kafkaproducer \
  --definitions https://raw.githubusercontent.com/xregistry/codegen/main/samples/message-definitions/inkjet.xreg.json \
  --output ./generated

# Using Docker (Windows PowerShell)
docker run --rm -v ${PWD}:/work ghcr.io/xregistry/codegen/xrcg:latest `
  generate --projectname PrinterEvents --language py --style kafkaproducer `
  --definitions https://raw.githubusercontent.com/xregistry/codegen/main/samples/message-definitions/inkjet.xreg.json `
  --output ./generated

# Or with pip install (any platform)
xrcg generate --projectname PrinterEvents --language py --style kafkaproducer \
  --definitions https://raw.githubusercontent.com/xregistry/codegen/main/samples/message-definitions/inkjet.xreg.json \
  --output ./generated

This produces a complete Python project with:

• Type-safe producer classes for each message type
• Strongly-typed data classes generated from Avro schema
• Integration tests using Testcontainers
• Ready to use: cd generated && pip install -e . && pytest

3. Or generate for a different platform — same definition, different target:

xrcg generate --projectname ContosoEvents --language cs --style ehproducer \
  --definitions ./contoso-erp.xreg.json --output ./generated   # C# Event Hubs

xrcg generate --projectname ContosoEvents --language ts --style mqttclient \
  --definitions ./contoso-erp.xreg.json --output ./generated   # TypeScript MQTT

xrcg generate --projectname ContosoEvents --language py --style kafkaconsumer \
  --definitions ./contoso-erp.xreg.json --output ./generated   # Python Kafka

What You Get

Unlike snippet generators, this tool produces complete SDK-like projects:

Feature	What's Generated
Type-safe clients	Producer/consumer classes with strongly-typed methods per message
Data classes	Schema-derived classes via Avrotize (JSON Schema, Avro, Protobuf)
Build files	pom.xml, .csproj, package.json, pyproject.toml with correct dependencies
Integration tests	Docker-based tests using Testcontainers for Kafka, MQTT, AMQP brokers
Project structure	Language-idiomatic layout ready for IDE import

Supported Languages: Java 21+, C# (.NET 6+), Python 3.9+, TypeScript/JavaScript

Supported Protocols: Apache Kafka, MQTT 5.0, AMQP 1.0, Azure Event Hubs, Azure Service Bus, Azure Event Grid, HTTP/CloudEvents

Generating Code

For complete command documentation, see Command Reference.

The Generate Command

xrcg generate --projectname <name> --language <lang> --style <style> \
  --definitions <file-or-url> --output <dir>

Option	Description
--projectname	Project/namespace name for generated code
--language	Target language: java, cs, py, ts, asyncapi, openapi
--style	Protocol binding: kafkaproducer, ehconsumer, mqttclient, etc.
--definitions	Path or URL to xRegistry JSON/YAML definition
--output	Output directory (will be created/overwritten)
--templates	Custom template directory (optional)
--template-args	Extra args as key=value (optional)

Available Templates

Run xrcg list to see all available language/style combinations:

├── java: Java 21+
│   ├── kafkaproducer, kafkaconsumer     # Apache Kafka
│   ├── ehproducer, ehconsumer           # Azure Event Hubs  
│   ├── sbproducer, sbconsumer           # Azure Service Bus
│   ├── amqpproducer, amqpconsumer       # AMQP 1.0 (RabbitMQ 4+, Artemis, Qpid)
│   └── mqttclient                       # MQTT 5.0
├── cs: C# / .NET 6.0+
│   ├── kafkaproducer, kafkaconsumer
│   ├── ehproducer, ehconsumer, ehazfn   # Event Hubs + Azure Functions
│   ├── sbproducer, sbconsumer, sbazfn
│   ├── egproducer, egazfn               # Event Grid
│   ├── amqpproducer, amqpconsumer
│   └── mqttclient
├── py: Python 3.9+
│   ├── kafkaproducer, kafkaconsumer
│   ├── ehproducer, ehconsumer
│   └── mqttclient
├── ts: TypeScript
│   ├── kafkaproducer, kafkaconsumer
│   ├── ehproducer, ehconsumer
│   ├── sbproducer, sbconsumer
│   ├── egproducer, amqpproducer, amqpconsumer
│   └── mqttclient
├── asyncapi: AsyncAPI 3.0 definitions
└── openapi: OpenAPI 3.0 definitions

Protocol-Specific Examples

AMQP 1.0 (RabbitMQ, Artemis, Qpid)

# Generate Java producer
xrcg generate --language java --style amqpproducer \
  --projectname MyProducer --definitions ./catalog.json --output ./out

# Generate C# consumer  
xrcg generate --language cs --style amqpconsumer \
  --projectname MyConsumer --definitions ./catalog.json --output ./out

See RabbitMQ AMQP 1.0 Setup Guide for broker configuration.

AsyncAPI / OpenAPI Generation

# Generate AsyncAPI producer definition
xrcg generate --language asyncapi --style producer \
  --projectname MyAPI --definitions ./catalog.json --output ./out

# With binary CloudEvents mode
xrcg generate --language asyncapi --style producer \
  --projectname MyAPI --definitions ./catalog.json --output ./out \
  --template-args ce_content_mode=binary

# Generate OpenAPI for HTTP producer
xrcg generate --language openapi --style producer \
  --projectname MyAPI --definitions ./catalog.json --output ./out

Custom Templates

Override built-in templates or add new language/style combinations:

xrcg generate --templates ./my-templates --language java --style myproducer ...

Template directory structure mirrors the built-in templates. See Authoring Templates.

Installation Details

Docker (Recommended)

docker pull ghcr.io/xregistry/codegen/xrcg:latest

Create a shell alias for convenience:

# Linux/macOS (.bashrc or .zshrc)
alias xrcg='docker run --rm -v $(pwd):/work ghcr.io/xregistry/codegen/xrcg:latest'

# Windows PowerShell (profile)
function xrcg { docker run --rm -v ${PWD}:/work ghcr.io/xregistry/codegen/xrcg:latest $args }

Note: File paths must be relative to your current directory due to Docker volume mapping.

Python Package

Requires Python 3.10+:

pip install git+https://github.com/xregistry/codegen.git

For development setup, see Development Environment.

Working with xRegistry Definitions

The generator consumes xRegistry message catalog documents—JSON/YAML files that describe schemas, messages, and endpoints. You can:

• Use existing definition files (see samples/message-definitions/)
• Create definitions manually following the xRegistry spec
• Manage definitions using the CLI's manifest or catalog commands

Sample Definitions

Sample	Description
contoso-erp.xreg.json	ERP system events (orders, payments, inventory)
fabrikam-motorsports.xreg.json	Motorsports telemetry stream
inkjet.xreg.json	IoT printer events

Managing Definitions with CLI

Manifest Mode (Local Files)

Work with local JSON files for version-controlled, offline workflows:

# Create a message group
xrcg manifest messagegroup add --manifest=./catalog.json --id=orders --envelope=CloudEvents/1.0

# Add a message definition
xrcg manifest message add --manifest=./catalog.json --messagegroupid=orders \
  --id=OrderPlaced --description="Order was placed"

# Validate the file
xrcg validate --definitions ./catalog.json

Catalog Mode (Remote Registry)

Interact with a remote xRegistry HTTP API for team collaboration:

# Configure registry connection
xrcg config set registry.base_url https://registry.example.com
xrcg config set registry.auth_token <token>

# Work with remote registry
xrcg catalog messagegroup add --id=orders ...
xrcg catalog message list --messagegroupid=orders

Currently supports xrserver registry.

Validate Command

Check definition files for errors:

xrcg validate --definitions ./catalog.json
xrcg validate --definitions https://example.com/catalog.json

Configuration

Store defaults to avoid repetition:

xrcg config set defaults.language java
xrcg config set defaults.output_dir ./generated
xrcg config list

Config location: ~/.config/xrcg/config.json (Linux), %APPDATA%\xrcg\config.json (Windows)

What is xRegistry?

xRegistry is a CNCF project defining a standard format for describing messaging and eventing infrastructure. A message catalog document contains:

• Schema groups — Payload schemas (JSON Schema, Avro, Protobuf)
• Message groups — Message definitions with CloudEvents envelope metadata
• Endpoints — Protocol bindings (Kafka topics, AMQP queues, HTTP endpoints)

The code generator follows references between these elements to produce cohesive, type-safe SDKs.

Community

• Slack: #cloudevents on CNCF Slack
• Mailing list: [e-mail]
• Governance: GOVERNANCE.md
• Contributing: CONTRIBUTING.md

License

Apache 2.0