Crate migrant_lib

Embeddable migration management

Also see migrant CLI

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

Available Features:

Feature	Backend
d-postgres	Enable postgres connectivity
d-sqlite	Enable sqlite connectivity
d-mysql	Enable mysql connectivity
d-all	Enable all backends

Note: No features are enabled by default

---

• 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 (d-postgres / d-sqlite / d-mysql).
• 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.

Reexports

pub use errors::*;

pub use config::Config;

pub use config::Settings;

pub use migration::FileMigration;

pub use migration::EmbeddedMigration;

pub use migration::FnMigration;

Modules

config	Configuration structs
errors	Error types
migration	Embedded / programmable migrations
types	Re-exported database-specific drivers

Structs

DbConn	Database connection wrapper
Migrator	Migration applicator

Enums

DbKind	Database type being used
Direction	Represents direction to apply migrations. Up -> up.sql Down -> down.sql

Traits

Migratable

A type that can be used to define database migrations

Functions

edit	Open a migration file containing tag in its name
list	List the currently applied and available migrations under migration_location
new	Create a new migration with the given tag
search_for_settings_file	Search for a Migrant.toml file in the current and parent directories
shell	Open a repl connection to the given Config settings