Architecture Decision Records (ADR)

[q-soriarty]

Architecture Decision Records

This thread serves as the index for architecture decisions. Before proposing a significant technical change, review existing decisions and discuss alternatives here.

Current Decisions

Decision	Choice	Rationale
Authentication	Keycloak (OIDC)	Single abstraction for local users, LDAP, and external SSO. Backend validates JWT only.
Data Source of Truth	Git (GitHub)	Each project is a repo with flow JSON + generated PLC solution. PostgreSQL for metadata only.
Frontend Framework	React + React Flow	MIT-licensed node editor with active community
Backend Framework	ASP.NET Core	Strong typing, SignalR for real-time, EF Core for data access
PLC Communication	ADS over MQTT	Centralized broker, no per-server ADS route config
Build/Deploy Separation	Separate operations	Deploy implies Build permission. Both executed by build server.
Real-time Updates	SignalR	Build status push, monitor data streaming
Build Queue	PostgreSQL + MQTT	FOR UPDATE SKIP LOCKED for job claiming, MQTT for wake-up signals
Container Orchestration	docker-socket-proxy	Filtered Docker API access for monitor container lifecycle
Reverse Proxy	Traefik v3	Auto-discovery via Docker labels, zero-config routing

How to Propose a Change

1. Open a new discussion in Ideas with the prefix [ADR]
2. Describe the problem, options considered, and recommended approach
3. Reference the relevant milestone or issue
4. After consensus, update the Decision Log

Full documentation: ARCHITECTURE.md | DECISION_LOG.md | TECH_DECISIONS.md