bb8

A full-featured connection pool, designed for asynchronous connections (using tokio). Originally based on 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.

bb8 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 adapters for different backends:

Backend | Adapter Crate ------- | ------------- tokio-postgres | bb8-postgres (in-tree) redis | bb8-redis (in-tree) redis_cluster_async | bb8-redis-cluster rsmq | rsmq_async bolt-client | bb8-bolt diesel | diesel_async tiberius | bb8-tiberius nebula-client | bb8-nebula memcache-async | bb8-memcached lapin | bb8-lapin arangors | bb8-arangodb tonic | bb8-tonic

Example

Using an imaginary "foodb" database.

#[tokio::main]
async fn main() {
    let manager = bb8_foodb::FooConnectionManager::new("localhost:1234");
    let pool = bb8::Pool::builder()
        .max_size(15)
        .build(manager)
        .await
        .unwrap();

    for _ in 0..20 {
        let pool = pool.clone();
        tokio::spawn(async move {
            let conn = pool.get().await.unwrap();
            // use the connection
            // it will be returned to the pool when it falls out of scope.
        });
    }
}

License

Licensed under the MIT license (LICENSE).

Contribution

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