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feat: define the module UI authoring model and host contract
ADR 0021 established that a module may own UI and added a statically
validated, never-executed `entrypoints.ui` path, but deliberately left
five questions open: what the artifact exports, what a host provides,
how one artifact runs under both Ekklesia and a standalone host, what
the browser-side trust model is, and how module UI avoids being welded
to a Dashboard that does not exist. This answers them.

React and TypeScript are the supported module UI authoring model. The
repository already leaned this way: `packages/typescript-config` ships a
`browser.json` preset and a `react-native.json` preset with
`"jsx": "react-jsx"`, and ADR 0002 names browser and React Native
configurations. One framework is supported; every other stays rejected.

React is deliberately not part of the contract. A module's compiled
artifact default-exports `defineModuleUi({ id, version, mount })`, and
`mount(container, context)` takes a DOM element and returns an unmount
function. `id` and `version` are build-artifact identity markers a host
verifies against the manifest, mirroring `defineModuleRuntime` exactly.
A host needs an element and a context, never a matching rendering
library, so a module's framework, a host's framework, and the platform
boundary between them stay independent.

The contract lives in a new `@ekklesia/module-ui-sdk` rather than in
`@ekklesia/module-sdk`, for a concrete reason: that package re-exports
all of `@ekklesia/contracts`, so routing module UI through it would drag
Zod, Drizzle, and semver into every browser bundle. The new package has
no runtime dependencies, and its one dependency on contracts is
type-only — the emitted `host-context.js` is `export {};`, and a test
pins that so it cannot regress.

The host context is four members: `moduleId`, `api`, `principal`, and
`permissions`. Navigation, theme, module configuration, organization
context, and diagnostics are deliberately absent; each needs a design
that does not exist. Module UI reaches its backend through
`api.request(path)` with a path relative to its own API root and never
constructs `/api/v1/modules/<id>/...`, which is Ekklesia's private
deployment detail — a module that builds that URL is silently unhostable
anywhere else. One fixture artifact is mounted under two hosts with
different origins and URL shapes to prove it.

Client-side permission hints are presentation only, and both the docs
and a test say so plainly: a denied hint does not stop the module from
calling its API, because server-side `requirePermission` is the only
authority. Module UI is trusted code in the host's own browser realm —
no iframe, no sandbox — which matches the backend model rather than
overstating it, since a module's server half already holds the API's
database authority.

The boundary guard is narrowed precisely, not removed: `.tsx`, `react`,
and `react-dom` are un-denied and modules may depend on the new
`module-ui-sdk` role. `.jsx`, `.css`, every other framework,
`react-router-dom`, `react-native`, and `@vitejs/plugin-react` stay
denied, layer rules are untouched, and an unsupported framework aliased
behind an allowed name (`"react": "npm:vue@3"`) is resolved and rejected
by its real target. Fixtures prove each case, including that module UI
source still cannot import Core.

Core, apps/api, and the manifest contract are untouched. Discovery still
validates the `entrypoints.ui` path and never evaluates it; hosts
perform their own dynamic import and validate the result with
`parseModuleUiExport`. No Dashboard shell, UI runtime, navigation,
grouping, standalone host, build or styling pipeline, installer,
hot-loading, or feature module is added.

Co-Authored-By: Claude Opus 5 <[email protected]>
2026-08-21 20:52:47 -05:00

207 lines
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Markdown

# 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.
> **Trust boundary.** Installed modules are trusted compiled code, not sandboxed plugins: a module
> runs arbitrary JavaScript in the API process and shares its PostgreSQL role. The layering
> described below is a correctness and ownership boundary, not hostile-code isolation. A module that
> ships its own UI ([ADR 0021](decisions/0021-modules-as-hostable-products.md)) is exactly as
> trusted as one that does not. See
> [Security model and deployment trust boundaries](../development/security.md).
## Dependency model
The arrows below mean "depends on." Presentation and composition depend on stable lower-level
contracts; infrastructure never learns individual feature names.
```text
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 domain behavior, data schemas, resources, actions, routes, events, permissions,
jobs — and, per [ADR 0021](decisions/0021-modules-as-hostable-products.md), their own UI, authored
in React against `@ekklesia/module-ui-sdk`
([ADR 0022](decisions/0022-module-ui-authoring-and-host-contract.md)). A module
is an independently versioned product, not only a backend capability. It does not own the
containing application shell or any platform policy.
3. **Surfaces** own the presentation concerns a module does not: the containing application shell,
layout, navigation, accessibility, interaction, branding, and client state — including the shell
that hosts a module's own UI.
4. **Surface Builder** stores validated declarative composition. It selects capabilities and
surface-owned renderers but contains neither executable code nor module business logic.
A module owns its own product experience. Calendar data, actions, permissions, and its own
management UI live in `modules/calendar`; the dashboard or public-website shell that hosts it —
navigation, theme, layout, and platform chrome — lives in a surface. The module supplies the screen
for its feature; the surface supplies the application around it.
Modules are flat peers. `video`, `livestream`, `announcements`, and `calendar` are independent
first-class modules with no parent/child relationship. A Dashboard may group them into folders such
as `Media` or `Sunday Production`, but those groups are presentation configuration an administrator
can reorganize, never module ownership and never a dependency. Genuine module and capability
dependencies remain the only way one module may require another.
## 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](decisions/0010-core-identity-and-better-auth-adoption.md).
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](decisions/0011-identity-http-transport-and-public-enrollment.md) and
[the API guide](../development/api.md), and
[the identity development guide](../development/identity.md) 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](decisions/0013-core-authorization-and-owner-bootstrap.md) and
[the authorization guide](../development/authorization.md).
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. Phase
5C added 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](decisions/0014-module-permission-declarations-and-platform-registry.md),
[ADR 0015](decisions/0015-static-module-http-routing-and-runtime-lifecycle.md),
[ADR 0016](decisions/0016-module-database-access.md), and the repository root
[README](../../README.md#current-status) for the complete, current status of every phase.
**Phase 5D is complete.** Five passes hardened the platform against an independent security audit of
the Phase 5C checkpoint, and an independent whole-repository re-audit closed the phase:
1. the public request perimeter — a server-owned client-address resolution boundary for the
authentication rate limiter, public sign-up disabled by default behind an explicit typed opt-in,
an enforced request-body ceiling on every public route (including a module route's own declared
contract), and finite Node header/request timeouts;
2. identity session resolution, and a mandatory certificate- **and** hostname-verified PostgreSQL
transport with no plaintext or `rejectUnauthorized: false` exception;
3. durable authorization history that survives user deletion, a one-time owner bootstrap that
deleting a user cannot reopen, and bounded, unambiguous explicit-grant management;
4. module route-overlap rejection at registration, finite startup rollback and shutdown deadlines,
and hardened migration command timeouts and SQL execution;
5. deployment and supply-chain closure plus the final re-audit.
See [ADR 0017](decisions/0017-public-request-perimeter-hardening.md),
[ADR 0018](decisions/0018-identity-session-resolution-and-database-transport.md),
[ADR 0019](decisions/0019-durable-authorization-history-and-grant-management.md), and
[ADR 0020](decisions/0020-module-runtime-and-migration-execution-hardening.md).
These guarantees hold under a **trusted-contributor, not-yet-deployed** threat model. The remaining
limitations are operational rather than architectural: CI is a trusted-code-only boundary whose
runner topology and job-token authority are unverified, and Ekklesia is not deployed, so the origin,
proxy, and throttling properties a public launch requires are unproven. Neither set of requirements
blocks Phase 6. Read
[Security model and deployment trust boundaries](../development/security.md) for what each boundary
does and does not protect against, and the repository root
[README](../../README.md#current-status) for the current status of every phase.
**Phase 6A established the module product contract.**
[ADR 0021](decisions/0021-modules-as-hostable-products.md) replaces the backend-only module model:
a module is an independently versioned product that may own its own UI, hostable inside Ekklesia and
— later, from the same implementation — as a standalone application. Core keeps the host shell and
every platform policy, the module graph stays flat, and Dashboard grouping stays presentation
configuration.
What that pass implemented is the **static contract only**: `manifestVersion: 4` adds one optional
`entrypoints.ui` field, validated during discovery exactly like the server and schema entrypoints —
package-relative, inside the package, compiled ESM. Discovery remains inert; nothing imports, mounts,
or renders that entrypoint.
**Phase 6B pass 1 defines the module UI authoring model and host contract.**
[ADR 0022](decisions/0022-module-ui-authoring-and-host-contract.md) selects React and TypeScript as
the supported way to author module UI, and defines what a compiled `entrypoints.ui` artifact exports
and what a host provides it. React is the authoring model but deliberately not the contract: an
artifact default-exports `defineModuleUi({ id, version, mount })`, and `mount(container, context)`
takes a DOM element and returns an unmount function, so a module's framework and a host's stay
independent.
The contract lives in `@ekklesia/module-ui-sdk`, a browser-safe shared package with no runtime
dependencies, consumed by module authors and hosts alike. Its host context is four members —
`moduleId`, `api`, `principal`, `permissions`. Module UI reaches its own backend through
`api.request(path)` with a path relative to the module's own API root, never by constructing
Ekklesia's `/api/v1/modules/<module-id>` prefix, which is what keeps a standalone host possible.
Client-side permission hints are presentation only; server-side enforcement remains the sole
authority. Module UI is trusted code in the host's browser realm — there is no sandbox, matching the
backend trust model rather than overstating it.
Core is untouched by this: discovery still validates the `entrypoints.ui` path and never evaluates
it, and hosts perform their own dynamic import. The Dashboard shell, a UI runtime, the module UI
build and styling pipeline, the standalone host, and every feature module remain future work.
Restart-based discovery, explicit operator-invoked migrations, and the trusted compiled-module model
are all unchanged.
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.