Ekklesia/docs/architecture/platform-architecture.md

Platform architecture

Ekklesia is a long-lived platform from which churches can compose many applications and user experiences. It begins as a modular monolith so contracts can stabilize before distribution is introduced.

Dependency model

The arrows below mean "depends on." Presentation and composition depend on stable lower-level contracts; infrastructure never learns individual feature names.

Surface Builder configuration -> Surfaces -> public capability contracts
                                      ^
                                      |
                         HTTP/API and client contracts
                                      |
Feature Modules -> Module SDK / platform contracts <- Core implementations

The four ownership layers are:

1. Core orchestrates generic platform infrastructure: startup, identity, permissions, configuration, database connectivity, storage, events, jobs, module discovery, and lifecycle.
2. Modules own backend domain behavior, data schemas, resources, actions, routes, events, permissions, and jobs.
3. Surfaces own every presentation concern: components, renderers, layout, navigation, accessibility, interaction, branding, and client state.
4. Surface Builder stores validated declarative composition. It selects capabilities and surface-owned renderers but contains neither executable code nor module business logic.

Modules do not own UI. For example, Calendar data, actions, and permissions will live in modules/calendar; Calendar renderers for a dashboard or public website will live in those surfaces.

Stable seams

• Modules use public SDK ports and injected Core services, never undocumented Core internals.
• Modules do not import another module's schema or private code. Integrations use public service contracts, capabilities, events, or APIs.
• Surfaces consume API/client and capability contracts, never feature-module packages.
• Core discovers feature modules generically. It contains no feature-specific imports or conditional branches.
• Deployable apps are thin composition roots and do not become domain-logic owners.
• Generated bootstrap artifacts may connect discovered entry points at the application edge; they do not become manually maintained Core registries.

Security invariants

• Authorization is enforced server-side.
• Secrets are isolated from public configuration and logs.
• Authentication tokens, private form content, prayer requests, and pastoral information are not logged.
• Sensitive actions are designed for auditability without copying sensitive content into audit records.
• Private objects use signed access and namespaced storage paths.
• Every network service starts from least-privilege and local-only development defaults.

Current implementation status

Implemented now: the Phase 1 repository and infrastructure foundation plus public module contracts, static versioned manifests, independent capability versions and dependency ranges, automatic filesystem discovery, compiled server loading, runtime-definition verification, staged capability registration, dependency-ordered startup and reverse shutdown, rollback, and a backend-only module template. Optional compiled schema entrypoints now contribute validated, namespaced module-owned Drizzle tables to a deterministic aggregate without connecting to a database. Optional module-owned Drizzle migration directories now produce an atomic dependency-ordered offline inventory with validated metadata, explicit destructive-change declarations, and exact SHA-256 checksums. Core can now compare that inventory with its fixed PostgreSQL history table, produce a read-only plan, and apply the complete pending batch under a session advisory lock and one transaction. Destructive migrations require an exact externally supplied approval bound to module, identity, and checksum. Hermetic integration coverage now exercises those contracts through the production adapter against the pinned PostgreSQL container, including real DDL rollback and advisory-lock concurrency. The Core-owned Doctor composes those existing services into a deterministic terminal readiness report: static module, schema, and migration validation always run when their prerequisites succeed, while PostgreSQL history planning runs only when configured. Schema inspection evaluates compiled schema definition entrypoints, which the module contract requires to be side-effect-free; Doctor never imports or starts module server entrypoints. It does not apply migrations or modify PostgreSQL, and it honestly skips object storage because no production Core storage service exists yet.

Phase 4A added the Core identity foundation. Core owns a Better Auth-backed identity schema (ekklesia_core_user, ekklesia_core_session, ekklesia_core_account, ekklesia_core_verification) reachable only through Ekklesia-owned contracts and an explicit Core-owned Better Auth construction boundary; modules never import Better Auth or receive a raw database client. That schema ships as a first-class Core-owned migration source that reuses the exact migration format, checksum rule, planner, and transactional runner Phase 3 already established, ordered before module migrations in the same aggregate. See ADR 0010.

Phase 4B adds identity HTTP transport: a minimal Hono-based apps/api composition root mounts Better Auth at /api/auth/* and exposes one Ekklesia-owned route, GET /api/v1/principal, behind Core's own Fetch-compatible identity runtime (@ekklesia/core/identity) — Core still does not depend on Hono. Public email/password registration is the intended eventual product policy — every account receives identical lowest-privilege baseline status, and signup order never grants elevation — but is disabled by default as of Phase 5D pass 1, below. See ADR 0011 and the API guide, and the identity development guide for the underlying schema and contracts. It is now possible to publicly register, sign in, resolve a principal, and sign out.

Phase 4C is complete: Core's authorization foundation — a schema, evaluator, and store for platform owners, explicit grants, and relationship-derived grants, plus an immutable permission registry — and an explicit, single-use, auditable platform-owner bootstrap command, plus reusable Hono enforcement and an /api/v1/grants HTTP API in apps/api. See ADR 0013 and the authorization guide.

Phase 5A wired module-declared permissions into that same authorization system — a version-3 manifest, one composed platform permission registry spanning Core's own declarations and every installed module's, enforced through the identical middleware Core's own routes use. Phase 5B let a module mount its own framework-neutral HTTP routes in production, under /api/v1/modules/<module-id>, enforced and response-sanitized exactly like Core's own routes. This branch completes Phase 5C: typed module database access (context.services.database) for a module's lifecycle hooks and authorized HTTP handlers, over the platform's one existing PostgreSQL pool. See ADR 0014, ADR 0015, ADR 0016, and the repository root README for the complete, current status of every phase.

Phase 5D pass 1 of 5 hardens the public request perimeter against an independent security audit of the Phase 5C checkpoint: a server-owned client-address resolution boundary (direct mode by default, explicit trusted-proxy mode otherwise) replaces trusting a caller-controlled forwarded header for the authentication rate limiter; public sign-up is disabled by default behind an explicit typed opt-in; every public route — Better Auth, Core's grant mutation, and every module route via a new required maxBodyBytes field on the executable route contract — has an explicit, enforced request-body ceiling with one sanitized 413 contract; and the Node HTTP server has finite header/request timeouts. See ADR 0017. This pass does not add distributed rate limiting or durable signup-abuse control, and Phase 5D itself is not complete — passes 2–5 and a final independent re-audit remain before Phase 6 may begin.

The project continues finishing the module platform's backend foundations before Phase 6 Surface work begins. Target architecture not yet implemented includes production approval-provider composition, physical storage-bucket provisioning, jobs/workflow automation, richer public resource and action contracts, a Dashboard, a Builder, and reference feature modules; none of these are scheduled by this document.