| # r2d2 |
| [](https://circleci.com/gh/sfackler/r2d2) |
| |
| A generic connection pool for Rust. |
| |
| [Documentation](https://docs.rs/r2d2) |
| |
| Opening a new database connection every time one is needed is both inefficient |
| and can lead to resource exhaustion under high traffic conditions. A connection |
| pool maintains a set of open connections to a database, handing them out for |
| repeated use. |
| |
| r2d2 is agnostic to the connection type it is managing. Implementors of the |
| `ManageConnection` trait provide the database-specific logic to create and |
| check the health of connections. |
| |
| A (possibly not exhaustive) list of adaptors for different backends: |
| |
| Backend | Adaptor Crate |
| ---------------------------------------------------------------------- | ------------- |
| [rust-postgres](https://github.com/sfackler/rust-postgres) | [r2d2-postgres](https://github.com/sfackler/r2d2-postgres) |
| [redis-rs](https://github.com/mitsuhiko/redis-rs) | use `r2d2` feature of [redis-rs](https://github.com/mitsuhiko/redis-rs) |
| [rust-memcache](https://github.com/aisk/rust-memcache) | [r2d2-memcache](https://github.com/megumish/r2d2-memcache) |
| [rust-mysql-simple](https://github.com/blackbeam/rust-mysql-simple) | [r2d2-mysql](https://github.com/outersky/r2d2-mysql) |
| [rusqlite](https://github.com/jgallagher/rusqlite) | [r2d2-sqlite](https://github.com/ivanceras/r2d2-sqlite) |
| [rusted-cypher](https://github.com/livioribeiro/rusted-cypher) | [r2d2-cypher](https://github.com/flosse/r2d2-cypher) |
| [diesel](https://github.com/sgrif/diesel) | [diesel::r2d2](https://github.com/diesel-rs/diesel/blob/master/diesel/src/r2d2.rs) ([docs](https://docs.diesel.rs/diesel/r2d2/)) |
| [couchdb](https://github.com/chill-rs/chill) | [r2d2-couchdb](https://github.com/scorphus/r2d2-couchdb) |
| [mongodb (archived)](https://github.com/mongodb-labs/mongo-rust-driver-prototype)<br>use official [mongodb](https://github.com/mongodb/mongo-rust-driver) driver instead | [r2d2-mongodb](https://gitlab.com/petoknm/r2d2-mongodb)<br>(deprecated: official driver handles pooling internally) |
| [odbc](https://github.com/Koka/odbc-rs) | [r2d2-odbc](https://github.com/Koka/r2d2-odbc) |
| [jfs](https://github.com/flosse/rust-json-file-store) | [r2d2-jfs](https://github.com/flosse/r2d2-jfs) |
| [oracle](https://github.com/kubo/rust-oracle) | [r2d2-oracle](https://github.com/rursprung/r2d2-oracle) |
| |
| # Example |
| |
| Using an imaginary "foodb" database. |
| |
| ```rust |
| use std::thread; |
| |
| extern crate r2d2; |
| extern crate r2d2_foodb; |
| |
| fn main() { |
| let manager = r2d2_foodb::FooConnectionManager::new("localhost:1234"); |
| let pool = r2d2::Pool::builder() |
| .max_size(15) |
| .build(manager) |
| .unwrap(); |
| |
| for _ in 0..20 { |
| let pool = pool.clone(); |
| thread::spawn(move || { |
| let conn = pool.get().unwrap(); |
| // use the connection |
| // it will be returned to the pool when it falls out of scope. |
| }) |
| } |
| } |
| ``` |
| |
| ## License |
| |
| Licensed under either of |
| * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0) |
| * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) |
| |
| at your option. |
| |
| ### Contribution |
| |
| Unless you explicitly state otherwise, any contribution intentionally submitted |
| for inclusion in the work by you shall be dual licensed as above, without any |
| additional terms or conditions. |
