Trait diesel::r2d2::ManageConnection

source ·
pub trait ManageConnection: Send + Sync + 'static {
    type Connection: Send + 'static;
    type Error: Error + 'static;

    // Required methods
    fn connect(&self) -> Result<Self::Connection, Self::Error>;
    fn is_valid(&self, conn: &mut Self::Connection) -> Result<(), Self::Error>;
    fn has_broken(&self, conn: &mut Self::Connection) -> bool;
Available on crate feature r2d2 only.
Expand description

A trait which provides connection-specific functionality.

Required Associated Types§


type Connection: Send + 'static

The connection type this manager deals with.


type Error: Error + 'static

The error type returned by Connections.

Required Methods§


fn connect(&self) -> Result<Self::Connection, Self::Error>

Attempts to create a new connection.


fn is_valid(&self, conn: &mut Self::Connection) -> Result<(), Self::Error>

Determines if the connection is still connected to the database.

A standard implementation would check if a simple query like SELECT 1 succeeds.


fn has_broken(&self, conn: &mut Self::Connection) -> bool

Quickly determines if the connection is no longer usable.

This will be called synchronously every time a connection is returned to the pool, so it should not block. If it returns true, the connection will be discarded.

For example, an implementation might check if the underlying TCP socket has disconnected. Implementations that do not support this kind of fast health check may simply return false.



impl<T> ManageConnection for ConnectionManager<T>
where T: R2D2Connection + Send + 'static,


type Connection = T


type Error = Error