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ERP Plus System Blueprint

This document is the master blueprint of ERP Plus, combining architecture, engines, data flow, and system design into a single mental model.

What is ERP Plus?

ERP Plus is a:

Modular multi-account ERP platform built as a Rails modular monolith using Engines.

System Identity

ERP Plus is NOT:

  • ❌ a monolith legacy app
  • ❌ a microservices system
  • ❌ a collection of independent engines

ERP Plus IS:

a single coordinated system composed of isolated domain engines with strict contracts and controlled data flow.

Delivery Blueprint

ERP Plus operates through three coordinated systems:

Planning
    ↓
Implementation
    ↓
Deployment

Planning System

Managed in Taiga.

Contains:

  • Epics
  • User Stories
  • Tasks
  • Issues
  • Sprint planning

Implementation System

Managed in GitHub.

Contains:

  • repositories
  • branches
  • commits
  • pull requests

Deployment System

Managed through:

  • GitHub Actions
  • Docker
  • Kamal

Delivery Architecture

Taiga
  ↓
GitHub
  ↓
CI/CD
  ↓
Production

This delivery architecture is part of the ERP Plus system blueprint.

Global Architecture Map

ERP Plus System
│
├── 🌐 Entry Layer (Requests)
│   └── API / Web / Frontend
│
├── 🔐 Identity Layer
│   ├── erp_core (authentication)
│   └── erp_accounts (accounts)
│
├── ⚙️ Domain Layer (Engines)
│   ├── erp_users
│   ├── erp_inventory
│   ├── erp_workers
│   └── others
│
├── 🔁 Execution Layer
│   └── erp_workers (background jobs)
│
└── 📡 Infrastructure Layer
    ├── PostgreSQL
    ├── Solid Stack
    ├── Docker
    ├── Kamal
    └── GitHub Actions CI/CD

System Flow (Unified Model)

Every action in ERP Plus follows this pattern:

Request
  → Authentication (erp_core)
  → Account Resolution (erp_accounts)
  → Authorization Layer
  → Domain Engine Execution
  → Optional Background Jobs (erp_workers)
  → Response

Engine System Model

Each engine behaves as:

a bounded context inside a controlled monolith

Engine Responsibilities

Each engine MUST:

  • own its domain logic
  • expose public services
  • avoid internal leakage
  • respect account boundaries

Engine Isolation Model

erp_inventory ❌ cannot access erp_users internals
erp_workers ❌ cannot modify domain logic
erp_core ✔ shared utilities only

Communication Model

Engines communicate ONLY via:

1. Public Services

ErpInventory::ProductService.create(...)

2. Domain Interfaces

Defined explicitly per engine.

3. Future: Domain Events

Planned evolution toward:

  • event-driven architecture
  • async cross-engine communication

Multi-Account Model

ERP Plus is account-first:

Every request is scoped by:

  • organization
  • account
  • account context
User → Account → Data Scope → Engine Logic

Execution Model

Domain logic is executed inside engines:

  • synchronous for simple operations
  • asynchronous via workers for heavy tasks

Background System

erp_workers handles:

  • async jobs
  • retries
  • scheduled tasks
  • heavy computations

Flow:

Engine → Job → Queue → Worker → Side Effect → Persistence

Security Model

Security is enforced at multiple layers:

  • authentication (erp_core)
  • account isolation (erp_accounts)
  • authorization layer
  • engine-level rules
  • CI security scanning

Infrastructure Layer

ERP Plus runs on a managed infrastructure platform documented in the Operations section.

The blueprint focuses on logical architecture rather than deployment implementation details.

System Design Principles

ERP Plus follows:

1. Isolation

Engines are independent bounded contexts.

2. Explicit Communication

No hidden coupling between engines.

3. Account-first Design

Everything is multi-account by default.

4. Infrastructure Awareness

System is designed for real production deployment.

5. Security by Default

Security is built into every layer.

Mental Model (MOST IMPORTANT)

Think of ERP Plus as:

A single system composed of isolated domain engines connected through controlled flows and strict contracts.

Scaling Model

ERP Plus scales by:

  • adding new engines
  • not modifying existing ones
  • extending via services
  • keeping strict boundaries

Final System View

User → Identity → Account → Domain Engine → Worker → Response

Why this blueprint exists

This file is the:

  • 🧠 architectural truth
  • 📐 system map
  • 🔌 engine coordination model
  • 🚀 scaling guide
  • 📚 onboarding reference

Final Statement

ERP Plus is:

a controlled modular ecosystem where every engine behaves like a mini-product inside a single governed platform.