# clean-axum

Axum scaffold with clean architecture.

You probably don't need [Rust on Rails](https://github.com/loco-rs/loco).

Refer to [this post](https://kigawas.me/posts/rustacean-clean-architecture-approach/) for rationale and background.

## Features

- [Axum](https://github.com/tokio-rs/axum) framework
- [SeaORM](https://github.com/SeaQL/sea-orm) domain models
- Completely separated API routers and DB-related logic (named "persistence" layer)
- Completely separated input parameters, queries and output schemas
- OpenAPI documentation ([Swagger UI](https://clean-axum.shuttleapp.rs/docs) and [Scalar](https://clean-axum.shuttleapp.rs/scalar)) powered by [Utoipa](https://github.com/juhaku/utoipa)
- Error handling with [Anyhow](https://github.com/dtolnay/anyhow)
- Custom parameter validation with [validator](https://github.com/Keats/validator)
- Optional [Shuttle](https://www.shuttle.rs/) runtime
- Optional [prefork](https://docs.rs/prefork/latest/prefork/) workers for maximizing performance on Linux

## Module hierarchy

### API logic

- `api::routers`: Axum endpoints
- `api::error`: Models and traits for error handling
- `api::extractor` Custom Axum extractors
  - `api::extractor::json`: `Json` for bodies and responses
  - `api::extractor::valid`: `Valid` for JSON body validation
- `api::validation`: JSON validation model based on `validator`
- `api::models`: Non domain model API models
  - `api::models::response`: JSON error response

### OpenAPI documentation

- `doc`: Utoipa doc declaration

### API-agonistic application logic

Main concept: Web framework is replaceable.

All modules here should not include any specific API web framework logic.

- `app::persistence`: DB manipulation (CRUD) functions
- `app::config`: DB or API server configuration
- `app::state`: APP state, e.g. DB connection
- `app::error`: APP errors used by `api::error`. e.g. "User not found"

### DB/API-agnostic domain models

Main concept: Database (Sqlite/MySQL/PostgreSQL) is replaceable.

Except `models::domains` and `migration`, all modules are ORM library agnostic.

- `models::domains`: SeaORM domain models
- `models::params`: Serde input parameters for creating/updating domain models in DB
- `models::schemas`: Serde output schemas for combining different domain models
- `models::queries`: Serde queries for filtering domain models
- `migration`: SeaORM migration files

### Unit and integration tests

- `tests::api`: API integration tests. Hierarchy is the same as `api::routers`
- `tests::app::persistence`: DB/ORM-related unit tests. Hierarchy is the same as `app::persistence`

### Others

- `utils`: Utility functions
- `main`: Tokio and Shuttle conditional entry point

## Run

### Start server

```bash
cp .env.example .env
# touch dev.db
# cargo install sea-orm-cli
# sea-orm-cli migrate up
cargo run

# or for production
cargo run --release
```

### Call API

```bash
curl -X POST http://localhost:3000/users -H "Content-Type: application/json" -d '{"username":"aaa"}'
curl -X POST http://localhost:3000/users -H "Content-Type: application/json" -d '{"username":"abc"}'
curl http://localhost:3000/users\?username\=a
```

### OpenAPI doc (Swagger UI/Scalar)

```bash
open http://localhost:3000/docs
open http://localhost:3000/scalar
```

## Start Shuttle local server

```bash
# cargo install cargo-shuttle
cargo shuttle run
```

Make sure docker engine is running, otherwise:

```bash
brew install colima docker
colima start
sudo ln -sf $HOME/.colima/default/docker.sock /var/run/docker.sock
```

## Shuttle deployment

```bash
cargo shuttle login
cargo shuttle deploy
```

## Benchmark

```bash
# edit .env to use Postgres
cargo run --release
wrk --latency -t20 -c50 -d10s http://localhost:3000/users\?username\=
```