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	bb8-diesel
tiberius	bb8-tiberius
nebula-client	bb8-nebula
memcache-async	bb8-memcached
lapin	bb8-lapin
arangors	bb8-arangodb

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.