pg_task 1.0.0

Resumable state machine based Postgres tasks
Documentation 
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use anyhow::Result;
use sqlx::PgPool;
use tracing_subscriber::{EnvFilter, FmtSubscriber};

pub async fn init() -> Result<PgPool> {
    dotenv::dotenv().ok();
    init_logging()?;
    connect().await
}

async fn connect() -> Result<PgPool> {
    let db = sqlx::PgPool::connect(&std::env::var("DATABASE_URL")?).await?;
    sqlx::migrate!().run(&db).await?;
    Ok(db)
}

fn init_logging() -> Result<()> {
    let subscriber = FmtSubscriber::builder()
        .with_env_filter(EnvFilter::from_default_env())
        .finish();
    tracing::subscriber::set_global_default(subscriber)?;
    Ok(())
}

// Make `cargo check --examples` happy
#[allow(dead_code)]
fn main() {}

#[cfg(test)]
mod tests {
    use super::*;

    #[sqlx::test(migrations = "./migrations")]
    async fn init_connects_and_runs_migrations(pool: PgPool) {
        let db_name: String = sqlx::query_scalar!(r#"SELECT current_database() AS "db_name!""#)
            .fetch_one(&pool)
            .await
            .unwrap();

        std::env::set_var("DATABASE_URL", current_database_url(&db_name));
        std::env::remove_var("RUST_LOG");

        let db = init().await.unwrap();
        let current_db: String = sqlx::query_scalar!(r#"SELECT current_database() AS "db_name!""#)
            .fetch_one(&db)
            .await
            .unwrap();

        assert_eq!(current_db, db_name);
        sqlx::query!("SELECT id FROM pg_task LIMIT 1")
            .fetch_optional(&db)
            .await
            .unwrap();
    }

    // Point DATABASE_URL at the database created by sqlx::test while keeping
    // the original host, user, password, and query parameters. CI connects over
    // TCP with password auth, so postgres:///{db_name} would lose credentials.
    fn current_database_url(db_name: &str) -> String {
        let database_url = std::env::var("DATABASE_URL").expect("DATABASE_URL must be set");
        let (url, query) = database_url
            .split_once('?')
            .map_or((database_url.as_str(), None), |(url, query)| {
                (url, Some(query))
            });
        let (prefix, _) = url.rsplit_once('/').unwrap();
        let mut current_database_url = format!("{prefix}/{db_name}");
        if let Some(query) = query {
            current_database_url.push('?');
            current_database_url.push_str(query);
        }
        current_database_url
    }
}