crablog/src/pg_pool.rs
2018-09-14 00:35:12 +08:00

42 lines
1.4 KiB
Rust

use diesel::pg::PgConnection;
use r2d2;
use diesel::r2d2::ConnectionManager;
type ManagedPgConn = ConnectionManager<PgConnection>;
type Pool = r2d2::Pool<ManagedPgConn>;
use rocket::http::Status;
use rocket::request::{self, FromRequest};
use rocket::{Outcome, Request, State};
use std::ops::Deref;
/// Db Connection request guard type: wrapper around r2d2 pooled connection
pub struct DbConn(pub r2d2::PooledConnection<ManagedPgConn>);
/// Attempts to retrieve a single connection from the managed database pool. If
/// no pool is currently managed, fails with an `InternalServerError` status. If
/// no connections are available, fails with a `ServiceUnavailable` status.
impl<'a, 'r> FromRequest<'a, 'r> for DbConn {
type Error = ();
fn from_request(request: &'a Request<'r>) -> request::Outcome<DbConn, ()> {
let pool = request.guard::<State<Pool>>()?;
match pool.get() {
Ok(conn) => Outcome::Success(DbConn(conn)),
Err(_) => Outcome::Failure((Status::ServiceUnavailable, ())),
}
}
}
// For the convenience of using an &DbConn as an &SqliteConnection.
impl Deref for DbConn {
type Target = PgConnection;
fn deref(&self) -> &Self::Target {
&self.0
}
}
pub fn init(database_url: &str) -> Pool {
let manager = ConnectionManager::<PgConnection>::new(database_url);
r2d2::Pool::new(manager).expect("Failed to create pool.")
}