How do I keep a global Postgres connection? - postgresql

Question

I want to store the Postgres connection on global scope to access from any function in a module. Here is an example:
use postgres::{Client, NoTls};
static mut client: Option<Client> = None;
pub fn get_player(id: i32) {
// Use global client connection object:
for row in client.unwrap().query("SELECT * FROM public.\"User\" WHERE \"accountID\"=$1;",&[&id]).unwrap(){
let id: i32 = row.get(0);
let name: &str = row.get(1);
println!("found player: {} {}", id, name);
}
}
pub fn init() {
let mut connection = Client::connect("host=localhost user=postgres", NoTls);
match connection {
Ok(cli) => {
println!("Database connected.");
client = Some(cli);
}
Err(_) => println!("Database ERROR while connecting."),
}
}
It is not compiling & working as intended and I don't know how to make this in Rust.

Answer 1

Here is an example with lazy_static and r2d2_postgres that provides a database connection pool:
use r2d2_postgres::postgres::{NoTls, Client};
use r2d2_postgres::PostgresConnectionManager;
#[macro_use]
extern crate lazy_static;
lazy_static! {
static ref POOL: r2d2::Pool<PostgresConnectionManager<NoTls>> = {
let manager = PostgresConnectionManager::new(
// TODO: PLEASE MAKE SURE NOT TO USE HARD CODED CREDENTIALS!!!
"host=localhost user=postgres password=password".parse().unwrap(),
NoTls,
);
r2d2::Pool::new(manager).unwrap()
};
}
pub fn get_player(id: i32) {
// Use global client connection object:
let mut client = POOL.get().unwrap();
for row in client.query("SELECT * FROM public.\"User\" WHERE \"accountID\"=$1;",&[&id]).unwrap(){
let id: i32 = row.get(0);
let name: &str = row.get(1);
println!("found player: {} {}", id, name);
}
}