Architecture

ERD Online uses a frontend/backend split monolith:

┌─────────────┐  HTTP :9502       ┌──────────────────────────┐
│  Frontend   │ ────────────────▶ │   Backend (Spring Boot)   │
│ React/Umi   │ /auth /syst /ncnb │  Single-process Monolith  │
│ (Nginx)     │ SocketIO :9092    │  + netty-socketio         │
└─────────────┘  /project/erd     │  (presence, ADR-0009)     │
                                  │  ┌─────────────────────┐  │
                                  │  │ auth  (JWT + ticket)│  │
                                  │  │ system(users/perms) │  │
                                  │  │ erd   (model core)  │  │
                                  │  │ common(shared libs) │  │
                                  │  └─────────────────────┘  │
                                  └────────┬─────────┬────────┘
                                           │         │
                                     ┌─────▼───┐ ┌───▼────┐
                                     │ MySQL 8 │ │ Redis  │
                                     │ erd +   │ │ token/ │
                                     │ martin  │ │ ticket │
                                     └─────────┘ └────────┘

The frontend keeps legacy gateway path prefixes /auth, /syst, /ncnb. The backend GatewayPrefixStripFilter strips them in-process (equivalent to gateway StripPrefix=1) — no standalone gateway needed. Collaboration Presence uses port 9092 (ticket auth, see ADR-0009), not the HTTP proxy.

Official hosting (no VPS): sole docs URL https://doc.erdonline.com (Cloudflare Pages); static demo → Cloudflare Pages; runtime image → GHCR; data plane self-hosted only. See ADR-0018 and Deployment.

Backend modules (business packages inside the monolith)

Package	Responsibility	Origin
com.erdonline.auth	OAuth2 authorization + resource server (same process)	Former martin-biz-auth
com.erdonline.system	Users / roles / menus / dictionaries	Former martin-biz-system
com.erdonline.erd	ERD modeling core, SQL, versions, collaboration	Former martin-extension-ncnb
com.erdonline.erd.reverse	Multi-DB reverse Dialect SPI (index dictionary + FK/associations + Generic fallback); dbReverseMeta exposes capabilities/schema	ADR-0006
com.erdonline.common	core/bean/data/log/security/vip/websocket/oss/swagger	Former martin-common-*
com.erdonline.config	Security / CORS / Swagger / MyBatis / WebSocket config	Merged new

Key changes from microservices to monolith

• Service discovery (Nacos): removed; config inlined in application.yml
• API gateway: removed; auth / CORS logic merged into monolith Security filter chain
• Feign remote calls: replaced with in-process Spring Bean injection
• OAuth2: authorization and resource servers merged; same RedisTokenStore for local issue/validate
• Sentinel / Skywalking: removed

Project model source of truth (projectJSON)

Tables/fields/associations/canvas layout for ERD projects live in JSON column project.projectJSON (not normalized relational tables). Public spec and machine-validatable schema:

• Docs: data-format (additive compatibility only, credential discipline)
• Schema: schema/projectjson.schema.json
• Validation: node scripts/validate-projectjson.mjs

JDBC secrets do not go in projectJSON (ADR-0008); connections live in data_sources.

Data storage

Uses a single business database erd (ADR-0020). Historical dual DB (martin/erd) merged; stub tables in old erd dump that duplicated auth were dropped.

• Tables in one DB: system/auth (users, roles, menus, OAuth, QRTZ…) and modeling metadata (projects, versions, shares, data_sources…) coexist.
• Dual SqlSessionFactory (transitional): MartinDataSourceConfig / ErdDataSourceConfig still route by mapper package, but JDBC both point at the same MYSQLDATABASE (default erd).
• Redis: OAuth token storage (RedisTokenStore) and cache.
• Bootstrap: db/init only CREATE DATABASE + CREATE TABLE; seeds / demo / E2E written by classpath:db/migration/erd (ErdFlywayConfig).