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//! Traits, utilities, and a macro for easy database connection pooling. //! //! # Overview //! //! This crate provides traits, utilities, and a procedural macro for //! configuring and accessing database connection pools in Rocket. A _database //! connection pool_ is a data structure that maintains active database //! connections for later use in the application. This implementation is backed //! by [`r2d2`] and exposes connections through request guards. //! //! Databases are individually configured through Rocket's regular configuration //! mechanisms. Connecting a Rocket application to a database using this library //! occurs in three simple steps: //! //! 1. Configure your databases in `Rocket.toml`. //! (see [Configuration](#configuration)) //! 2. Associate a request guard type and fairing with each database. //! (see [Guard Types](#guard-types)) //! 3. Use the request guard to retrieve a connection in a handler. //! (see [Handlers](#handlers)) //! //! For a list of supported databases, see [Provided Databases](#provided). This //! support can be easily extended by implementing the [`Poolable`] trait. See //! [Extending](#extending) for more. //! //! ## Example //! //! Before using this library, the feature corresponding to your database type //! in `rocket_sync_db_pools` must be enabled: //! //! ```toml //! [dependencies.rocket_sync_db_pools] //! version = "0.1.0-rc.1" //! features = ["diesel_sqlite_pool"] //! ``` //! //! See [Provided](#provided) for a list of supported database and their //! associated feature name. //! //! In whichever configuration source you choose, configure a `databases` //! dictionary with an internal dictionary for each database, here `sqlite_logs` //! in a TOML source: //! //! ```toml //! [default.databases] //! sqlite_logs = { url = "/path/to/database.sqlite" } //! ``` //! //! In your application's source code, one-time: //! //! ```rust //! # #[macro_use] extern crate rocket; //! # #[cfg(feature = "diesel_sqlite_pool")] //! # mod test { //! use rocket_sync_db_pools::{database, diesel}; //! //! #[database("sqlite_logs")] //! struct LogsDbConn(diesel::SqliteConnection); //! //! #[launch] //! fn rocket() -> _ { //! rocket::build().attach(LogsDbConn::fairing()) //! } //! # } fn main() {} //! ``` //! //! Whenever a connection to the database is needed: //! //! ```rust //! # #[macro_use] extern crate rocket; //! # #[macro_use] extern crate rocket_sync_db_pools; //! # //! # #[cfg(feature = "diesel_sqlite_pool")] //! # mod test { //! # use rocket_sync_db_pools::diesel; //! # //! # #[database("sqlite_logs")] //! # struct LogsDbConn(diesel::SqliteConnection); //! # //! # type Logs = (); //! # type Result<T> = std::result::Result<T, ()>; //! # //! #[get("/logs/<id>")] //! async fn get_logs(conn: LogsDbConn, id: usize) -> Result<Logs> { //! # /* //! conn.run(|c| Logs::by_id(c, id)).await //! # */ //! # Ok(()) //! } //! # } fn main() {} //! ``` //! //! # Usage //! //! ## Configuration //! //! Databases can be configured as any other values. Using the default //! configuration provider, either via `Rocket.toml` or environment variables. //! You can also use a custom provider. //! //! ### `Rocket.toml` //! //! To configure a database via `Rocket.toml`, add a table for each database //! to the `databases` table where the key is a name of your choice. The table //! should have a `url` key and, optionally, a `pool_size` key. This looks as //! follows: //! //! ```toml //! # Option 1: //! [global.databases] //! sqlite_db = { url = "db.sqlite" } //! //! # Option 2: //! [global.databases.my_db] //! url = "postgres://root:root@localhost/my_db" //! //! # With a `pool_size` key: //! [global.databases] //! sqlite_db = { url = "db.sqlite", pool_size = 20 } //! ``` //! //! The table _requires_ one key: //! //! * `url` - the URl to the database //! //! Additionally, all configurations accept the following _optional_ keys: //! //! * `pool_size` - the size of the pool, i.e., the number of connections to //! pool (defaults to the configured number of workers * 4) //! //! Additional options may be required or supported by other adapters. //! //! ### Procedurally //! //! Databases can also be configured procedurally via `rocket::custom()`. //! The example below does just this: //! //! ```rust //! # #[cfg(feature = "diesel_sqlite_pool")] { //! # use rocket::launch; //! use rocket::figment::{value::{Map, Value}, util::map}; //! //! #[launch] //! fn rocket() -> _ { //! let db: Map<_, Value> = map! { //! "url" => "db.sqlite".into(), //! "pool_size" => 10.into() //! }; //! //! let figment = rocket::Config::figment() //! .merge(("databases", map!["my_db" => db])); //! //! rocket::custom(figment) //! } //! # rocket(); //! # } //! ``` //! //! ### Environment Variables //! //! Lastly, databases can be configured via environment variables by specifying //! the `databases` table as detailed in the [Environment Variables //! configuration //! guide](https://rocket.rs/v0.5-rc/guide/configuration/#environment-variables): //! //! ```bash //! ROCKET_DATABASES='{my_db={url="db.sqlite"}}' //! ``` //! //! Multiple databases can be specified in the `ROCKET_DATABASES` environment variable //! as well by comma separating them: //! //! ```bash //! ROCKET_DATABASES='{my_db={url="db.sqlite"},my_pg_db={url="postgres://root:root@localhost/my_pg_db"}}' //! ``` //! //! ## Guard Types //! //! Once a database has been configured, the `#[database]` attribute can be used //! to tie a type in your application to a configured database. The database //! attribute accepts a single string parameter that indicates the name of the //! database. This corresponds to the database name set as the database's //! configuration key. //! //! The macro generates a [`FromRequest`] implementation for the decorated type, //! allowing the type to be used as a request guard. This implementation //! retrieves a connection from the database pool or fails with a //! `Status::ServiceUnavailable` if connecting to the database times out. //! //! The macro also generates two inherent methods on the decorated type: //! //! * `fn fairing() -> impl Fairing` //! //! Returns a fairing that initializes the associated database connection //! pool. //! //! * `async fn get_one<P: Phase>(&Rocket<P>) -> Option<Self>` //! //! Retrieves a connection wrapper from the configured pool. Returns `Some` //! as long as `Self::fairing()` has been attached. //! //! The attribute can only be applied to unit-like structs with one type. The //! internal type of the structure must implement [`Poolable`]. //! //! ```rust //! # #[macro_use] extern crate rocket_sync_db_pools; //! # #[cfg(feature = "diesel_sqlite_pool")] //! # mod test { //! use rocket_sync_db_pools::diesel; //! //! #[database("my_db")] //! struct MyDatabase(diesel::SqliteConnection); //! # } //! ``` //! //! Other databases can be used by specifying their respective [`Poolable`] //! type: //! //! ```rust //! # #[macro_use] extern crate rocket_sync_db_pools; //! # #[cfg(feature = "postgres_pool")] //! # mod test { //! use rocket_sync_db_pools::postgres; //! //! #[database("my_pg_db")] //! struct MyPgDatabase(postgres::Client); //! # } //! ``` //! //! The fairing returned from the generated `fairing()` method _must_ be //! attached for the request guard implementation to succeed. Putting the pieces //! together, a use of the `#[database]` attribute looks as follows: //! //! ```rust //! # #[macro_use] extern crate rocket; //! # #[macro_use] extern crate rocket_sync_db_pools; //! # //! # #[cfg(feature = "diesel_sqlite_pool")] { //! # use rocket::figment::{value::{Map, Value}, util::map}; //! use rocket_sync_db_pools::diesel; //! //! #[database("my_db")] //! struct MyDatabase(diesel::SqliteConnection); //! //! #[launch] //! fn rocket() -> _ { //! # let db: Map<_, Value> = map![ //! # "url" => "db.sqlite".into(), "pool_size" => 10.into() //! # ]; //! # let figment = rocket::Config::figment().merge(("databases", map!["my_db" => db])); //! rocket::custom(figment).attach(MyDatabase::fairing()) //! } //! # } //! ``` //! //! ## Handlers //! //! Finally, use your type as a request guard in a handler to retrieve a //! connection wrapper for the database: //! //! ```rust //! # #[macro_use] extern crate rocket; //! # #[macro_use] extern crate rocket_sync_db_pools; //! # //! # #[cfg(feature = "diesel_sqlite_pool")] //! # mod test { //! # use rocket_sync_db_pools::diesel; //! #[database("my_db")] //! struct MyDatabase(diesel::SqliteConnection); //! //! #[get("/")] //! fn my_handler(conn: MyDatabase) { //! // ... //! } //! # } //! ``` //! //! A connection can be retrieved and used with the `run()` method: //! //! ```rust //! # #[macro_use] extern crate rocket; //! # #[macro_use] extern crate rocket_sync_db_pools; //! # //! # #[cfg(feature = "diesel_sqlite_pool")] //! # mod test { //! # use rocket_sync_db_pools::diesel; //! # type Data = (); //! #[database("my_db")] //! struct MyDatabase(diesel::SqliteConnection); //! //! fn load_from_db(conn: &diesel::SqliteConnection) -> Data { //! // Do something with connection, return some data. //! # () //! } //! //! #[get("/")] //! async fn my_handler(mut conn: MyDatabase) -> Data { //! conn.run(|c| load_from_db(c)).await //! } //! # } //! ``` //! //! # Database Support //! //! Built-in support is provided for many popular databases and drivers. Support //! can be easily extended by [`Poolable`] implementations. //! //! ## Provided //! //! The list below includes all presently supported database adapters and their //! corresponding [`Poolable`] type. //! // Note: Keep this table in sync with site/guite/6-state.md //! | Kind | Driver | Version | `Poolable` Type | Feature | //! |----------|-----------------------|-----------|--------------------------------|------------------------| //! | MySQL | [Diesel] | `1` | [`diesel::MysqlConnection`] | `diesel_mysql_pool` | //! | Postgres | [Diesel] | `1` | [`diesel::PgConnection`] | `diesel_postgres_pool` | //! | Postgres | [Rust-Postgres] | `0.19` | [`postgres::Client`] | `postgres_pool` | //! | Sqlite | [Diesel] | `1` | [`diesel::SqliteConnection`] | `diesel_sqlite_pool` | //! | Sqlite | [`Rusqlite`] | `0.24` | [`rusqlite::Connection`] | `sqlite_pool` | //! | Memcache | [`memcache`] | `0.15` | [`memcache::Client`] | `memcache_pool` | //! //! [Diesel]: https://diesel.rs //! [`rusqlite::Connection`]: https://docs.rs/rusqlite/0.23.0/rusqlite/struct.Connection.html //! [`diesel::SqliteConnection`]: http://docs.diesel.rs/diesel/prelude/struct.SqliteConnection.html //! [`postgres::Client`]: https://docs.rs/postgres/0.19/postgres/struct.Client.html //! [`diesel::PgConnection`]: http://docs.diesel.rs/diesel/pg/struct.PgConnection.html //! [`diesel::MysqlConnection`]: http://docs.diesel.rs/diesel/mysql/struct.MysqlConnection.html //! [`Rusqlite`]: https://github.com/jgallagher/rusqlite //! [Rust-Postgres]: https://github.com/sfackler/rust-postgres //! [`diesel::PgConnection`]: http://docs.diesel.rs/diesel/pg/struct.PgConnection.html //! [`memcache`]: https://github.com/aisk/rust-memcache //! [`memcache::Client`]: https://docs.rs/memcache/0.15/memcache/struct.Client.html //! //! The above table lists all the supported database adapters in this library. //! In order to use particular `Poolable` type that's included in this library, //! you must first enable the feature listed in the "Feature" column. The //! interior type of your decorated database type should match the type in the //! "`Poolable` Type" column. //! //! ## Extending //! //! Extending Rocket's support to your own custom database adapter (or other //! database-like struct that can be pooled by `r2d2`) is as easy as //! implementing the [`Poolable`] trait. See the documentation for [`Poolable`] //! for more details on how to implement it. //! //! [`FromRequest`]: rocket::request::FromRequest //! [request guards]: rocket::request::FromRequest //! [`Poolable`]: crate::Poolable #![doc(html_root_url = "https://api.rocket.rs/v0.5-rc/rocket_sync_db_pools")] #![doc(html_favicon_url = "https://rocket.rs/images/favicon.ico")] #![doc(html_logo_url = "https://rocket.rs/images/logo-boxed.png")] #[doc(hidden)] #[macro_use] pub extern crate rocket; #[cfg(any( feature = "diesel_sqlite_pool", feature = "diesel_postgres_pool", feature = "diesel_mysql_pool" ))] pub use diesel; #[cfg(feature = "postgres_pool")] pub use postgres; #[cfg(feature = "postgres_pool")] pub use r2d2_postgres; #[cfg(feature = "sqlite_pool")] pub use rusqlite; #[cfg(feature = "sqlite_pool")] pub use r2d2_sqlite; #[cfg(feature = "memcache_pool")] pub use memcache; #[cfg(feature = "memcache_pool")] pub use r2d2_memcache; pub use r2d2; mod poolable; mod config; mod error; mod connection; pub use self::poolable::{Poolable, PoolResult}; pub use self::config::Config; pub use self::error::Error; pub use rocket_sync_db_pools_codegen::*; pub use self::connection::*;