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Powerful SQL migration toolkit for Rust.

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Refinery strives to make running migrations for different databases as easy as possible.
It works by running your migrations on a provided database connection, either by embedding them on your Rust code, or via the [refinery_cli].

Currently [`postgres`](https://crates.io/crates/postgres), [`tokio-postgres`](https://crates.io/crates/tokio-postgres) , [`mysql`](https://crates.io/crates/mysql), [`mysql_async`](https://crates.io/crates/mysql_async), [`rusqlite`](https://crates.io/crates/rusqlite) and [`tiberius`](https://github.com/prisma/tiberius) are supported.
If you are using a driver that is not yet supported, namely [`SQLx`](https://github.com/launchbadge/sqlx) you can run migrations providing a [`Config`](https://docs.rs/refinery/latest/refinery/config/struct.Config.html) instead of the connection type, as `Config` impl's `Migrate`. You will still need to provide the `postgres`/`mysql`/`rusqlite`/`tiberius` driver as a feature for [`Runner::run`](https://docs.rs/refinery/latest/refinery/struct.Runner.html#method.run) and `tokio-postgres`/`mysql_async` for [`Runner::run_async`](https://docs.rs/refinery/latest/refinery/struct.Runner.html#method.run_async).
`refinery` works best with [`Barrel`](https://crates.io/crates/barrel) but you can also have your migrations in `.sql` files or use any other Rust crate for schema generation.

## Usage

- Add refinery to your Cargo.toml dependencies with the selected driver as feature eg: `refinery = { version = "0.8", features = ["rusqlite"]}`
- Migrations can be defined in .sql files or Rust modules that must have a function called `migration` that returns a [`String`](https://doc.rust-lang.org/std/string/struct.String.html).
- Migrations can be strictly versioned by prefixing the file with `V` or not strictly versioned by prefixing the file with `U`.
- Migrations, both .sql files and Rust modules must be named in the format `[U|V]{1}__{2}.sql` or `[U|V]{1}__{2}.rs`, where `{1}` represents the migration version and `{2}` the name.
- Migrations can be run either by embedding them in your Rust code with `embed_migrations` macro, or via [refinery_cli].

### Example: Library
```rust,no_run
use rusqlite::Connection;

mod embedded {
    use refinery::embed_migrations;
    embed_migrations!("./tests/sql_migrations");
}

fn main() {
    let mut conn = Connection::open_in_memory().unwrap();
    embedded::migrations::runner().run(&mut conn).unwrap();
}
```

For more library examples, refer to the [`examples`](https://github.com/rust-db/refinery/tree/main/examples).
### Example: CLI

NOTE: 

- Contiguous (adjacent) migration version numbers are restricted to `u32` (unsigned, 32-bit integers).
- Non-contiguous (not adjacent) migration version numbers are restricted to `u32` (unsigned, 32-bit integers).

```bash
export DATABASE_URL="postgres://postgres:secret@localhost:5432/your-db"
pushd migrations
    # Runs ./src/V1__*.rs or ./src/V1__*.sql 
    refinery migrate -e DATABASE_URL -p ./src -t 1
popd
```

### Example: Deadpool

```rust
let mut conn = pool.get().await?;
let client = conn.deref_mut().deref_mut();
let report = embedded::migrations::runner().run_async(client).await?;
```

### Example: bb8

```rust
let mut client = pool.dedicated_connection().await?;
let report = embedded::migrations::runner().run_async(&mut client).await?;
```

### Non-contiguous VS Contiguous migrations

Depending on how your project/team has been structured will define whether you want to use contiguous (adjacent) migrations `V{1}__{2}.[sql|rs]` or non-contiguous (not adjacent) migrations `U{1}__{2}.[sql|rs]`.
If migration sequential numbering reflects the order they were developed and, they are deployed in the order they are numbered, you won't run into any problems using contiguous migrations.
This is because you can be sure the next migration being run is _always_ going to have a version number greater than the previous.

With non-contiguous migrations there is more flexibility in the order that the migrations can be created and deployed.
If developer 1 creates a PR with a migration today `U11__update_cars_table.sql`, but it is reviewed for a week.
Meanwhile, developer 2 creates a PR with migration `U12__create_model_tags.sql` that is much simpler and gets merged and deployed immediately.
This would stop developer 1's migration from ever running if you were using contiguous migrations because the next migration would need to be > 12.

## Implementation details

refinery works by creating a table that keeps all the applied migrations' versions and their metadata. When you [run](https://docs.rs/refinery/latest/refinery/struct.Runner.html#method.run) the migrations `Runner`, refinery compares the applied migrations with the ones to be applied, checking for [divergent](https://docs.rs/refinery/latest/refinery/struct.Runner.html#method.set_abort_divergent) and [missing](https://docs.rs/refinery/latest/refinery/struct.Runner.html#method.set_abort_missing) and executing unapplied migrations.\
By default, refinery runs each migration in a single transaction. Alternatively, you can also configure refinery to wrap the entire execution of all migrations in a single transaction by setting [set_grouped](https://docs.rs/refinery/latest/refinery/struct.Runner.html#method.set_grouped) to true.

### Rollback

refinery's design was based on [flyway](https://flywaydb.org/) and so, it shares its earlier [philosophy](https://web.archive.org/web/20191226033347/https://flywaydb.org/documentation/command/undo#important-notes) on undo/rollback migrations. 
Flyway has since changed it's opinion but refinery hasn't. To undo/rollback a migration, you have to generate a new one and write specifically what you want to undo.

## Support for Additional Database Drivers

While initially it seemed beneficial to support as many aditional drivers as possible in this repo, with the current bandwidth available by the maintainers it's preferable to create them and maintain them on external repositories (see [here](https://github.com/rust-db/refinery/pull/264#issuecomment-1419198667) for context).

Notable external database drivers:

- [Klickhouse](https://github.com/Protryon/klickhouse) ([Clickhouse](https://clickhouse.tech/docs/en/) database driver with refinery support)


## MSRV

refinery aims to support stable Rust, the previous Rust version, and nightly.

## Contributing

:balloon: Thanks for your help to improve the project!
No contribution is too small and all contributions are valued, feel free to open Issues and submit Pull Requests.

## License

This project is licensed under the [MIT license](LICENSE).

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in refinery by you, shall be licensed as MIT, without any additional
terms or conditions.

[refinery_cli]: https://crates.io/crates/refinery_cli
