affluence/src/db/mod.rs

mod schema;
pub mod users;

use diesel::connection::SimpleConnection;
use diesel::r2d2::{ConnectionManager, Pool};
use diesel::sqlite::{Sqlite, SqliteConnection};
use std::error::Error;

use diesel_migrations::{embed_migrations, EmbeddedMigrations, MigrationHarness};
pub const MIGRATIONS: EmbeddedMigrations = embed_migrations!("migrations");

type DbError = Box<dyn Error + Send + Sync + 'static>;

fn run_migrations(connection: &mut impl MigrationHarness<Sqlite>) -> Result<(), DbError> {
    // This will run the necessary migrations.
    //
    // See the documentation for `MigrationHarness` for
    // all available methods.
    connection.run_pending_migrations(MIGRATIONS)?;

    Ok(())
}

fn initialize_db(conn: &mut SqliteConnection) -> Result<(), DbError> {
    // Enable WAL mode and enforce foreign keys
    conn.batch_execute(
        "PRAGMA journal_mode = WAL; PRAGMA synchronous = NORMAL; PRAGMA foreign_keys = ON;",
    )?;
    run_migrations(conn)?;

    Ok(())
}

pub fn initialize_pool(url: &str) -> Result<Pool<ConnectionManager<SqliteConnection>>, DbError> {
    let manager = ConnectionManager::new(url);

    let pool = Pool::builder()
        .test_on_check_out(true)
        .build(manager)
        .expect("oops");

    let mut conn = pool.get()?;
    initialize_db(&mut conn)?;

    Ok(pool)
}