MegaBrain RAG Pipeline

Scalable, self-hosted, intelligent code knowledge platform that indexes multi-language source code from various repositories and provides precise semantic search and natural language Q&A through a modern, reactive architecture.

Documentation

• Complete documentation
• Deployment & user setup

Technology Stack

• Backend Framework: Quarkus 3.15+ (RESTEasy Reactive)
• Language: Java 22+
• Build Tool: Maven 3.8+
• Code Parsing: JavaParser 3.x, Tree-sitter (java-tree-sitter)
• Search: Apache Lucene 9.x
• Graph Database: Neo4j Java Driver 5.x
• LLM Integration: Quarkus LangChain4j Extension (Ollama, OpenAI, Anthropic)
• Git Operations: JGit
• CLI: Picocli with Quarkus Integration
• Scheduling: Quartz Scheduler
• Database: PostgreSQL

Project Structure

megabrain/
├── backend/                      # Java/Quarkus backend
│   ├── pom.xml                  # Maven project configuration
│   └── src/
│       ├── main/
│       │   ├── java/
│       │   │   └── io/megabrain/
│       │   │       ├── api/          # REST endpoints
│       │   │       ├── cli/          # CLI commands
│       │   │       ├── config/       # Configuration classes
│       │   │       ├── core/         # Core services
│       │   │       ├── ingestion/   # Code ingestion services
│       │   │       ├── rag/          # RAG services
│       │   │       └── search/      # Search services
│       │   └── resources/
│       │       └── application.properties
│       └── test/
│           ├── java/
│           └── resources/
├── frontend/                     # Angular 20 frontend
│   ├── package.json             # npm dependencies
│   ├── angular.json             # Angular CLI configuration
│   ├── tsconfig.json             # TypeScript configuration
│   └── src/
│       ├── app/                  # Angular components
│       ├── assets/               # Static assets
│       └── environments/         # Environment configuration
├── features/                     # Feature specifications
│   ├── epics/                    # Epic definitions
│   └── user-stories/            # User stories and tasks
└── README.md

Getting Started

Prerequisites

Backend:

• Java 22 or higher
• Maven 3.8 or higher

Frontend:

• Node.js 18+ and npm
• Angular CLI 20 (install globally: npm install -g @angular/cli@20)

Build and Run Backend

cd backend

# Compile the project
mvn clean compile

# Run tests
mvn test

# Start in development mode
mvn quarkus:dev

# Build native executable (requires GraalVM)
mvn clean package -Pnative

Build and Run Frontend

cd frontend

# Install dependencies
npm install

# Start development server (with API proxy)
npm start
# or
ng serve

# Build for production
npm run build

The frontend development server runs on http://localhost:4200 and proxies API requests to http://localhost:8080.

Health Check

Once the application is running, check the health endpoint:

curl http://localhost:8080/q/health

Configuration

Backend Configuration

Edit backend/src/main/resources/application.properties to configure:

• Database connections (PostgreSQL, Neo4j)
• LLM provider settings (Ollama, OpenAI, Anthropic)
• Lucene index directory
• Grammar cache directory

Frontend Configuration

Edit frontend/src/environments/environment.ts for development or frontend/src/environments/environment.prod.ts for production to configure:

• API base URL
• Feature flags
• Other environment-specific settings

Development

This project follows the MegaBrain feature specification organized by epics:

• EPIC-00: Project Infrastructure Setup (this setup)
• EPIC-01: Code Ingestion & Indexing
• EPIC-02: Hybrid Search & Retrieval
• EPIC-03: RAG Answer Generation
• EPIC-04: REST API & CLI
• EPIC-05: Web Dashboard
• EPIC-06: Dependency Graph Analysis
• EPIC-07: Documentation Intelligence
• EPIC-08: MCP Tool Server

See features/ directory for detailed user stories and task breakdowns.

License

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