migrant_lib

Embeddable migration management

migrant_lib allows defining and embedding management of migrations in your compiled application.

• Migrations can be defined as files or functions.
• File migrations can be either read from files at runtime or embedded in your executable at compile time.
• Migration tags must all be unique and may only contain the characters [a-z0-9-].
• Function migrations must have the signature fn(DbConn) -> Result<(), Box<std::error::Error>>. See the embedded_programmable example for a working sample of function migrations.
• When working with embedded and function migrations, the respective database feature must be enabled (postgresql / sqlite).
• When database features are enabled, the entirety of the database-specific connection library will be re-exported in the types module.

fn up(_: DbConn) -> Result<(), Box<std::error::Error>> {
    print!(" Up!");
    Ok(())
}

fn down(_: DbConn) -> Result<(), Box<std::error::Error>> {
    print!(" Down!");
    Ok(())
}

config.use_migrations(vec![
    FileMigration::with_tag("initial")?
        .up("migrations/embedded/initial/up.sql")?
        .down("migrations/embedded/initial/down.sql")?
        .boxed(),
    EmbeddedMigration::with_tag("second")?
        .up(include_str!("../migrations/embedded/second/up.sql"))
        .down(include_str!("../migrations/embedded/second/down.sql"))
        .boxed(),
    FnMigration::with_tag("custom")?
        .up(up)
        .down(down)
        .boxed(),
])?;

Migrations management identical to the migrant cli tool can also be embedded. This method only supports file-based migrations and those migration files must be generated by migrant_lib::new (or the migrant cli). This is required because migration order is implied by file names which must follow a specific format and contain a valid timestamp.

See the migrant_cli_compatible example for a working sample.

License: MIT