atrg-db

Database layer for at-rust-go: SQLite and PostgreSQL connection pooling and migrations.

Part of at-rust-go (atrg) — a batteries-included AT Protocol backend framework for Rust.

What this crate provides

• DbPool — enum wrapping either sqlx::SqlitePool or sqlx::PgPool, the primary database handle used throughout atrg
• connect(url) — create a connection pool, dispatching by URL scheme (sqlite://, sqlite::memory:, postgres://, postgresql://)
• run_internal_migrations(pool) — apply atrg's own embedded migrations (sessions table, etc.) using the dialect matching the pool variant; idempotent on every startup
• run_user_migrations(pool, dir) — discover and apply application-specific .sql migrations from a directory, silently skipping if the directory is missing or empty

The crate does not provide an ORM. Write SQL with sqlx.

Cargo features

At least one of sqlite or postgres must be enabled (a compile_error! fires otherwise). Enabling both is supported; connect() picks the backend at runtime from the URL scheme.

Usage

[dependencies]
# SQLite only (default)
atrg-db = "0.1"

# PostgreSQL only
atrg-db = { version = "0.1", default-features = false, features = ["postgres"] }

# Both backends — let `connect()` choose at runtime
atrg-db = { version = "0.1", features = ["postgres"] }

use atrg_db::DbPool;

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    // Pick the backend from the URL scheme
    let pool: DbPool = atrg_db::connect("sqlite://atrg.db").await?;
    // or: let pool = atrg_db::connect("postgres://user:pass@host/db").await?;

    // Run atrg internal migrations (sessions, OAuth state, etc.)
    atrg_db::run_internal_migrations(&pool).await?;

    // Run your app's migrations from the migrations/ directory
    atrg_db::run_user_migrations(&pool, std::path::Path::new("./migrations")).await?;

    // Borrow the underlying sqlx pool to run queries
    if let Some(sqlite) = pool.as_sqlite() {
        let row: (i32,) = sqlx::query_as("SELECT 1").fetch_one(sqlite).await?;
        assert_eq!(row.0, 1);
    }

    Ok(())
}

Connection defaults

SQLite

PostgreSQL

Migration conventions

atrg's internal migrations live in this crate under migrations/sqlite/ and migrations/postgres/. The set matching the active DbPool variant is run automatically. User migrations live in your project's migrations/ directory and are applied in filename order against the same backend:

migrations/
├── 0001_create_posts.sql
└── 0002_create_follows.sql

License

LGPL-3.0-only — see LICENSE.