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  Sync Impact Report
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  Version change: (new) -> 1.0.0
  Modified principles: N/A (initial ratification)
  Added sections:
    - Core Principles (5 principles)
    - Technology Stack & Constraints
    - Development Workflow
    - Governance
  Removed sections: N/A
  Templates requiring updates:
    - .specify/templates/plan-template.md — ✅ no changes needed (Constitution Check section is generic)
    - .specify/templates/spec-template.md — ✅ no changes needed
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    - .specify/templates/checklist-template.md — ✅ no changes needed
    - .specify/templates/agent-file-template.md — ✅ no changes needed
  Follow-up TODOs: None
-->

# ImageApi Constitution

## Core Principles

### I. Layered Architecture

All features MUST follow the established layered architecture:

- **HTTP Layer** (`main.rs`, feature modules): Route handlers, request
  parsing, response formatting. No direct database access.
- **Service Layer** (`files.rs`, `exif.rs`, `memories.rs`, etc.): Business
  logic. No HTTP-specific types.
- **DAO Layer** (`database/` trait definitions): Trait-based data access
  contracts. Every DAO MUST be defined as a trait to enable mock
  implementations for testing.
- **Database Layer** (Diesel ORM, `schema.rs`): Concrete `Sqlite*Dao`
  implementations. All queries traced with OpenTelemetry.

New features MUST NOT bypass layers (e.g., HTTP handlers MUST NOT
execute raw SQL). Actix actors are permitted for long-running async
work (video processing, file watching) but MUST interact with the
DAO layer through the established trait interfaces.

### II. Path Safety (NON-NEGOTIABLE)

All user-supplied file paths MUST be validated against `BASE_PATH`
using `is_valid_full_path()` before any filesystem operation. This
prevents directory traversal attacks.

- Paths stored in the database MUST be relative to `BASE_PATH`.
- Paths passed to external tools (ffmpeg, image processing) MUST be
  fully resolved absolute paths.
- Extension detection MUST use the centralized helpers in
  `file_types.rs` (case-insensitive). Manual string matching on
  extensions is prohibited.

### III. Trait-Based Testability

All data access MUST go through trait-based DAOs so that every
handler and service can be tested with mock implementations.

- Each DAO trait MUST be defined in `src/database/` and require
  `Sync + Send`.
- Mock DAOs for testing MUST live in `src/testhelpers.rs`.
- Integration tests against real SQLite MUST use in-memory databases
  via `in_memory_db_connection()` from `database::test`.
- Handler tests MUST use `actix_web::test` utilities with JWT token
  injection (using `Claims::valid_user()` and the `test_key` secret).
- New DAO implementations MUST include a `#[cfg(test)]` constructor
  (e.g., `from_connection`) accepting an injected connection.

### IV. Environment-Driven Configuration

Server behavior MUST be controlled through environment variables
loaded from `.env` files. Hard-coded paths, URLs, or secrets are
prohibited.

- Required variables MUST call `.expect()` with a clear message at
  startup so misconfiguration fails fast.
- Optional variables MUST use `.unwrap_or_else()` with sensible
  defaults and be documented in `README.md`.
- Any new environment variable MUST be added to the README
  environment section before the feature is considered complete.

### V. Observability

All database operations and HTTP handlers MUST be instrumented
with OpenTelemetry spans via the `trace_db_call` helper or
equivalent tracing macros.

- Release builds export traces to the configured OTLP endpoint.
- Debug builds use the basic logger.
- Prometheus metrics (`imageserver_image_total`,
  `imageserver_video_total`) MUST be maintained for key counters.
- Errors MUST be logged at `error!` level with sufficient context
  for debugging without reproducing the issue.

## Technology Stack & Constraints

- **Language**: Rust (stable toolchain, Cargo build system)
- **HTTP Framework**: Actix-web 4
- **ORM**: Diesel 2.2 with SQLite backend
- **Auth**: JWT (HS256) via `jsonwebtoken` crate, bcrypt password
  hashing
- **Video Processing**: ffmpeg/ffprobe (CLI, must be on PATH)
- **Image Processing**: `image` crate for thumbnails, `kamadak-exif`
  for EXIF extraction
- **Tracing**: OpenTelemetry with OTLP export (release),
  basic logger (debug)
- **Testing**: `cargo test`, `actix_web::test`, in-memory SQLite

External dependencies (ffmpeg, Ollama) are optional runtime
requirements. The server MUST start and serve core functionality
(images, thumbnails, tags) without them. Features that depend on
optional services MUST degrade gracefully with logged warnings,
not panics.

## Development Workflow

- `cargo fmt` MUST pass before committing.
- `cargo clippy` warnings MUST be resolved or explicitly suppressed
  with a justification comment.
- `cargo test` MUST pass with all tests green before merging to
  master.
- Database schema changes MUST use Diesel migrations
  (`diesel migration generate`), with hand-written SQL in `up.sql`
  and `down.sql`, followed by `diesel print-schema` to regenerate
  `schema.rs`.
- Features MUST be developed on named branches
  (`###-feature-name`) and merged to master via pull request.
- File uploads MUST preserve existing files (append timestamp on
  conflict, never overwrite).

## Governance

This constitution defines the non-negotiable architectural and
development standards for the ImageApi project. All code changes
MUST comply with these principles.

- **Amendments**: Any change to this constitution MUST be documented
  with a version bump, rationale, and updated Sync Impact Report.
- **Versioning**: MAJOR for principle removals/redefinitions, MINOR
  for new principles or material expansions, PATCH for wording
  clarifications.
- **Compliance**: Pull request reviews SHOULD verify adherence to
  these principles. The CLAUDE.md file provides runtime development
  guidance and MUST remain consistent with this constitution.

**Version**: 1.0.0 | **Ratified**: 2026-02-26 | **Last Amended**: 2026-02-26