Module managed

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 async_trait::async_trait;
use deadpool::managed;

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

struct Computer {}

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

struct Manager {}

#[async_trait]
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::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.

syncDeprecated

Helpers for writing pools for objects that don’t support async and need to be run inside a thread.

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 structure which which can abort the creation and recycling of objects.

HookErrorCause

Possible errors returned by hooks

PoolError

Possible errors returned by Pool::get() method.

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.