RulEuler Rule Engine¶

RulEuler is an open-source rule engine built on the Rete algorithm. It separates business rules from application code, enabling rule management through both visual editors and text expressions, with hot-reload support.

What Problem Does It Solve¶

Business systems are often cluttered with if-else logic for risk control, approval workflows, pricing strategies, and resource allocation. Every change requires code modifications, testing, and redeployment. RulEuler lets business users configure rules directly in the admin console — changes take effect immediately, no code changes needed.

Use Cases¶

Risk decisions — credit scoring, anti-fraud rules, credit limit approval
Business approvals — multi-level approval workflows, conditional routing
Dynamic pricing — promotion rules, discount strategies, tiered pricing
Resource allocation — gate assignment, ticket dispatching, load balancing
Compliance checks — data validation rules, regulatory compliance

Background¶

RulEuler is a fork of URule 2.1.6 (Bstek open-source edition). URule has a solid core engine, but its JCR storage model is not intuitive for most developers, and some capabilities needed improvement. RulEuler keeps the core engine intact and adds the following:

Area	URule Open Source	RulEuler
Storage	JCR (Jackrabbit) only	Added MySQL relational storage, per-project selection
Runtime	Spring Boot 2.x	Spring Boot 3.x + JDK 21
Admin UI	jQuery + Bootstrap 3	Added React 18 + Ant Design 5 modern admin
Rule editing	Tedious wizard-only	Added REA text expression editor
Variable definition	Requires Java POJO	GeneralEntity dynamic type, just field name + type
Access control	None	RBAC users/roles/permissions
Auto testing	None	Path coverage + MC/DC auto-generated test cases
Authentication	None	JWT authentication

Key Features¶

Visual rule editing — decision tables, decision trees, rule flows, scorecards
REA text editor — write rules in natural-language-style expressions
Rete algorithm — efficient pattern matching for high-volume rule execution
Multiple rule types — rule sets, decision tables, decision trees, rule flows, scorecards
Hot reload — rules update automatically after saving, no restart needed
Auto testing — auto-generate test cases with regression comparison
RBAC — user, role, and project-level access control

Architecture¶

graph LR
    Browser --> Admin[Admin Console :16009]
    App[Business App] --> Client[Rule Execution :16001]
    Admin --> DB[(MySQL)]
    Client --> DB

Admin console (ruleuler-server + ruleuler-admin) — rule editing, project management, access control
Rule execution (ruleuler-client) — loads knowledge packages, executes rule flows, exposes REST API
Two services deployed independently, sharing rule data via MySQL

REA Expression Editor

Auto Testing

Quick Start¶

git clone https://github.com/sibosend/ruleuler.git
cd ruleuler
cp .env.example .env
docker compose up -d --build

Once started, visit http://localhost:16009/admin/. Default credentials: admin / asdfg@1234.

Invoke Rules¶

curl -X POST http://localhost:16001/process/airport_gate_allocation_db/gate_pkg/gate_allocation_flow \
  -H 'Content-Type: application/json' \
  -d '{
  "FlightInfo": {
    "aircraft_type": "A380",
    "arrival_time": 8,
    "is_international": true,
    "passenger_count": 260
  },
  "GateResult": {}
}'