# Architecture Requirements

Phase: design
Enforcement: informational

## ARCH-001: No Cross-Cloud Dependencies

Services MUST NOT import cloud-provider-specific SDKs directly. All cloud interactions go through the platform abstraction layer.

**Rule:** No direct imports of `com.amazonaws.*`, `com.google.cloud.*`, or `com.azure.*` in service code. Use the platform's cloud-agnostic interfaces. If your service runs on AWS today, it must be deployable to GCP tomorrow without code changes.

**Test:** Scan imports for cloud-provider SDK packages outside the platform abstraction layer.

## ARCH-002: No Cross-Service Database Access

Services MUST NOT directly query another service's database. All cross-service data access goes through APIs or events.

**Rule:** Each service owns its schema. No shared database connections, no cross-schema joins, no direct table access outside your service boundary. If you need data from another service, call its API or consume its events.

**Test:** Scan datasource configs and SQL for references to schemas/tables outside the service's declared ownership.

## ARCH-003: No Hardcoded Tenant or Environment Configuration

Services MUST NOT contain hardcoded tenant IDs, environment URLs, or deployment-specific configuration in source code.

**Rule:** All tenant and environment config comes from the platform config plane (environment variables, config service, or Helm values). No `if (tenant == "acme")` logic. No `https://prod.reltio.com` literals.

**Test:** Scan for URL literals matching known environment patterns, hardcoded tenant identifiers, environment-switching conditionals.

## ARCH-004: API Contract Versioning

All public API changes MUST maintain backward compatibility or follow the deprecation protocol (minimum 30-day dual-support window).

**Rule:** No removed fields, renamed endpoints, or changed response shapes without a versioned migration path. Breaking changes require a new API version.

**Test:** Diff OpenAPI specs between branches. Flag removed paths, removed required fields, or changed response types.