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use crate::acquire::Acquire;
use crate::migrate::{AppliedMigration, Migrate, MigrateError, Migration, MigrationSource};
use std::borrow::Cow;
use std::collections::{HashMap, HashSet};
use std::ops::Deref;
use std::slice;
#[derive(Debug)]
pub struct Migrator {
pub migrations: Cow<'static, [Migration]>,
pub ignore_missing: bool,
pub locking: bool,
}
fn validate_applied_migrations(
applied_migrations: &[AppliedMigration],
migrator: &Migrator,
) -> Result<(), MigrateError> {
if migrator.ignore_missing {
return Ok(());
}
let migrations: HashSet<_> = migrator.iter().map(|m| m.version).collect();
for applied_migration in applied_migrations {
if !migrations.contains(&applied_migration.version) {
return Err(MigrateError::VersionMissing(applied_migration.version));
}
}
Ok(())
}
impl Migrator {
/// Creates a new instance with the given source.
///
/// # Examples
///
/// ```rust,no_run
/// # use sqlx_core_oldapi::migrate::MigrateError;
/// # fn main() -> Result<(), MigrateError> {
/// # sqlx_rt::block_on(async move {
/// # use sqlx_core_oldapi::migrate::Migrator;
/// use std::path::Path;
///
/// // Read migrations from a local folder: ./migrations
/// let m = Migrator::new(Path::new("./migrations")).await?;
/// # Ok(())
/// # })
/// # }
/// ```
/// See [MigrationSource] for details on structure of the `./migrations` directory.
pub async fn new<'s, S>(source: S) -> Result<Self, MigrateError>
where
S: MigrationSource<'s>,
{
Ok(Self {
migrations: Cow::Owned(source.resolve().await.map_err(MigrateError::Source)?),
ignore_missing: false,
locking: true,
})
}
/// Specify whether applied migrations that are missing from the resolved migrations should be ignored.
pub fn set_ignore_missing(&mut self, ignore_missing: bool) -> &Self {
self.ignore_missing = ignore_missing;
self
}
/// Specify whether or not to lock database during migration. Defaults to `true`.
///
/// ### Warning
/// Disabling locking can lead to errors or data loss if multiple clients attempt to apply migrations simultaneously
/// without some sort of mutual exclusion.
///
/// This should only be used if the database does not support locking, e.g. CockroachDB which talks the Postgres
/// protocol but does not support advisory locks used by SQLx's migrations support for Postgres.
pub fn set_locking(&mut self, locking: bool) -> &Self {
self.locking = locking;
self
}
/// Get an iterator over all known migrations.
pub fn iter(&self) -> slice::Iter<'_, Migration> {
self.migrations.iter()
}
/// Run any pending migrations against the database; and, validate previously applied migrations
/// against the current migration source to detect accidental changes in previously-applied migrations.
///
/// # Examples
///
/// ```rust,no_run
/// # #[cfg(feature = "sqlite")]
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # sqlx_rt::block_on(async move {
/// # use sqlx_core_oldapi::migrate::Migrator;
/// let m = Migrator::new(std::path::Path::new("./migrations")).await?;
/// let pool = sqlx_core_oldapi::sqlite::SqlitePoolOptions::new().connect("sqlite::memory:").await?;
/// m.run(&pool).await?;
/// # Ok(())
/// # })
/// # }
/// ```
pub async fn run<'a, A>(&self, migrator: A) -> Result<(), MigrateError>
where
A: Acquire<'a>,
<A::Connection as Deref>::Target: Migrate,
{
let mut conn = migrator
.acquire()
.await
.map_err(MigrateError::AcquireConnection)?;
self.run_direct(&mut *conn).await
}
// Getting around the annoying "implementation of `Acquire` is not general enough" error
#[doc(hidden)]
pub async fn run_direct<C>(&self, conn: &mut C) -> Result<(), MigrateError>
where
C: Migrate,
{
// lock the database for exclusive access by the migrator
if self.locking {
conn.lock().await.map_err(MigrateError::AcquireConnection)?;
}
// creates [_migrations] table only if needed
// eventually this will likely migrate previous versions of the table
conn.ensure_migrations_table()
.await
.map_err(MigrateError::AccessMigrationMetadata)?;
let version = conn
.dirty_version()
.await
.map_err(MigrateError::AccessMigrationMetadata)?;
if let Some(version) = version {
return Err(MigrateError::Dirty(version));
}
let applied_migrations = conn
.list_applied_migrations()
.await
.map_err(MigrateError::AccessMigrationMetadata)?;
validate_applied_migrations(&applied_migrations, self)?;
let applied_migrations: HashMap<_, _> = applied_migrations
.into_iter()
.map(|m| (m.version, m))
.collect();
for migration in self.iter() {
if migration.migration_type.is_down_migration() {
continue;
}
match applied_migrations.get(&migration.version) {
Some(applied_migration) => {
if migration.checksum != applied_migration.checksum {
return Err(MigrateError::VersionMismatch(migration.version));
}
}
None => {
conn.apply(migration)
.await
.map_err(|e| MigrateError::Execute(migration.version, e))?;
}
}
}
// unlock the migrator to allow other migrators to run
// but do nothing as we already migrated
if self.locking {
conn.unlock()
.await
.map_err(MigrateError::AcquireConnection)?;
}
Ok(())
}
/// Run down migrations against the database until a specific version.
///
/// # Examples
///
/// ```rust,no_run
/// # #[cfg(feature = "sqlite")]
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # sqlx_rt::block_on(async move {
/// # use sqlx_core_oldapi::migrate::Migrator;
/// let m = Migrator::new(std::path::Path::new("./migrations")).await?;
/// let pool = sqlx_core_oldapi::sqlite::SqlitePoolOptions::new().connect("sqlite::memory:").await?;
/// m.undo(&pool, 4).await?;
/// # Ok(())
/// # })
/// # }
/// ```
pub async fn undo<'a, A>(&self, migrator: A, target: i64) -> Result<(), MigrateError>
where
A: Acquire<'a>,
<A::Connection as Deref>::Target: Migrate,
{
let mut conn = migrator
.acquire()
.await
.map_err(MigrateError::AcquireConnection)?;
// lock the database for exclusive access by the migrator
if self.locking {
conn.lock().await.map_err(MigrateError::AcquireConnection)?;
}
// creates [_migrations] table only if needed
// eventually this will likely migrate previous versions of the table
conn.ensure_migrations_table()
.await
.map_err(MigrateError::AccessMigrationMetadata)?;
let version = conn
.dirty_version()
.await
.map_err(MigrateError::AccessMigrationMetadata)?;
if let Some(version) = version {
return Err(MigrateError::Dirty(version));
}
let applied_migrations = conn
.list_applied_migrations()
.await
.map_err(MigrateError::AccessMigrationMetadata)?;
validate_applied_migrations(&applied_migrations, self)?;
let applied_migrations: HashMap<_, _> = applied_migrations
.into_iter()
.map(|m| (m.version, m))
.collect();
for migration in self
.iter()
.rev()
.filter(|m| m.migration_type.is_down_migration())
.filter(|m| applied_migrations.contains_key(&m.version))
.filter(|m| m.version > target)
{
conn.revert(migration)
.await
.map_err(|e| MigrateError::Execute(migration.version, e))?;
}
// unlock the migrator to allow other migrators to run
// but do nothing as we already migrated
if self.locking {
conn.unlock()
.await
.map_err(MigrateError::AcquireConnection)?;
}
Ok(())
}
}