Rust/Rocket/Diesel - How can I query a MySqlDatabase using rocket_sync_db_pools

Question

When trying to call load on my prices schema created by diesel in a Rocket app, I get the error the trait LoadConnection is not implemented for &mut rocket_sync_db_pools::diesel::MysqlConnection

I've looked at a few tutorials, and have followed the examples on github and on rocket's documentation, as well as Diesel's documentation.

I've tried implementing the DbConn with diesel::MySqlConnection instead of rocket_sync_db_pools, but I get an error saying the trait bound diesel::MysqlConnection: Poolable is not satisfied

Would love some help!

My code can be found below. [main.rs]

#[macro_use] extern crate rocket;
#[macro_use] extern crate diesel;
#[macro_use] extern crate diesel_migrations;
#[macro_use] extern crate rocket_sync_db_pools;


mod schema;
mod db_utils;

use rocket::{Rocket, Build};
use rocket::fairing::AdHoc;
use rocket::request::FlashMessage;
use rocket::serde::Serialize;
use rocket::form::Form;
use rocket::fs::{FileServer, relative};
use diesel::prelude::*;


#[database("my_db")]
pub struct DbConn(rocket_sync_db_pools::diesel::MysqlConnection);


#[get("/")]
fn index(conn: DbConn) {

    conn.run(|c| self::schema::prices::dsl::prices.load(&mut c));

}



#[launch]
fn rocket() -> _ {
    rocket::build()
        .attach(DbConn::fairing())
        .mount("/", routes![index])
}

And [schema.rs]

// @generated automatically by Diesel CLI.

diesel::table! {
    prices (id) {
        id -> Integer,
        date -> Text,
        ticker -> Text,
        price -> Float,
    }
}

and [db_utils/models.rs]

use diesel::prelude::*;


#[derive(Queryable)]
pub struct Price {
  pub id: i32,
  pub date: String,
  pub ticker: String,
  pub price: f32
}

Answer 1

Your question is missing important information about your dependency versions. The error message and the code examples suggest that you depend on rocket 0.5.0-rc.2 and diesel 2.0.0. These versions are not compatible, as rocket_sync_db_pools only contains support for diesel 1.4. You either need to use a compatible diesel version their or provide your own rocket integration for diesel 2.0