You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: main.rs
    path of file: ./repos/examples/databases/mysql/src
    
    the code of the file until where you have to start completion: use std::{env, io};

use actix_web::{web, App, HttpServer};

mod models;
mod persistence;
mod routes;

fn get_conn_builder(
    db_user: String,
    db_password: String,
    db_host: String,
    db_port: u16,
    db_name: String,
) -> mysql::OptsBuilder {
    mysql::OptsBuilder::new()
        .ip_or_hostname(Some(db_host))
        .tcp_port(db_port)
        .db_name(Some(db_name))
        .user(Some(db_user))
        .pass(Some(db_password))
}

#[actix_web::main]
async fn main() -> io::Result<()> {
    // initialize environment
    dotenvy::dotenv().ok();

    // initialize logger
    env_logger::init_from_env(env_logger::Env::new().default_filter_or("info"));

    log::info!("setting up app from environment");

    let db_user = env::var("MYSQL_USER").expect("MYSQL_USER is not set in .env file");
    let db_password = env::var("MYSQL_PASSWORD").expect("MYSQL_PASSWORD is not set in .env file");
    let db_host = env::var("MYSQL_HOST").expect("MYSQL_HOST is not set in .env file");
    let db_port = env::var("MYSQL_PORT").expect("MYSQL_PORT is not set in .env file");
    let db_name = env::var("MYSQL_DBNAME").expect("MYSQL_DBNAM
    
async fn main() -> io::Result<()> {
    // initialize environment
    dotenvy::dotenv().ok();

    // initialize logger
    env_logger::init_from_env(env_logger::Env::new().default_filter_or("info"));

    log::info!("setting up app from environment");

    let db_user = env::var("MYSQL_USER").expect("MYSQL_USER is not set in .env file");
    let db_password = env::var("MYSQL_PASSWORD").expect("MYSQL_PASSWORD is not set in .env file");
    let db_host = env::var("MYSQL_HOST").expect("MYSQL_HOST is not set in .env file");
    let db_port = env::var("MYSQL_PORT").expect("MYSQL_PORT is not set in .env file");
    let db_name = env::var("MYSQL_DBNAME").expect("MYSQL_DBNAME is not set in .env file");
    let db_port = db_port.parse().unwrap();

    let builder = get_conn_builder(db_user, db_password, db_host, db_port, db_name);

    log::info!("initializing database connection");

    let pool = mysql::Pool::new(builder).unwrap();

    let shared_data = web::Data::new(pool);

    log::info!("starting HTTP server at http://localhost:8080");

    HttpServer::new(move || {
        App::new()
            .app_data(shared_data.clone())
            .service(routes::index)
            .service(routes::add_bank)
            .service(routes::add_branch)
            .service(routes::add_teller)
            .service(routes::add_customer)
            .service(routes::get_bank)
            .service(routes::get_branch)
            .service(routes::get_teller)
            .service(routes::get_customer)
    })
    .bind(("127.0.0.1", 8080))?
    .workers(2)
    .run()
    .await
}