Module deadpool::managed

Available on crate feature managed only.

Managed version of the pool.

“Managed” means that it requires a Manager which is responsible for creating and recycling objects as they are needed.

Example

use deadpool::managed;

#[derive(Debug)]
enum Error { Fail }

struct Computer {}

impl Computer {
    async fn get_answer(&self) -> i32 {
        42
    }
}

struct Manager {}

impl managed::Manager for Manager {
    type Type = Computer;
    type Error = Error;

    async fn create(&self) -> Result<Computer, Error> {
        Ok(Computer {})
    }
    async fn recycle(&self, conn: &mut Computer, _: &managed::Metrics) -> managed::RecycleResult<Error> {
        Ok(())
    }
}

type Pool = managed::Pool<Manager>;

#[tokio::main]
async fn main() {
    let mgr = Manager {};
    let pool = Pool::builder(mgr).max_size(16).build().unwrap();
    let mut conn = pool.get().await.unwrap();
    let answer = conn.get_answer().await;
    assert_eq!(answer, 42);
}

For a more complete example please see deadpool-postgres crate.

Re-exports

• pub use crate::Status;

Modules

• reexports
  This module contains all things that should be reexported by backend implementations in order to avoid direct dependencies on the deadpool crate itself.

Structs

• Metrics
  Statistics regarding an object returned by the pool
• Object
  Wrapper around the actual pooled object which implements Deref, DerefMut and Drop traits.
• Pool
  Generic object and connection pool.
• PoolBuilder
  Builder for Pools.
• PoolConfig
  Pool configuration.
• Timeouts
  Timeouts when getting Objects from a Pool.

Enums

• BuildError
  Possible errors returned when PoolBuilder::build() fails to build a Pool.
• CreatePoolError
  This error is used when building pools via the config create_pool methods.
• Hook
  Wrapper for hook functions
• HookError
  Error which is returned by pre_create, pre_recycle and post_recycle hooks.
• PoolError
  Possible errors returned by Pool::get() method.
• QueueMode
  Mode for dequeuing Objects from a Pool.
• RecycleError
  Possible errors returned by the Manager::recycle() method.
• TimeoutType
  Possible steps causing the timeout in an error returned by Pool::get() method.

Traits

• Manager
  Manager responsible for creating new Objects or recycling existing ones.

Type Aliases

• HookFuture
  The boxed future that should be returned by async hooks
• HookResult
  The result returned by hooks
• RecycleResult
  Result type of the Manager::recycle() method.