Plume/plume-models/src/migrations.rs

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Rust
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use Connection;
use Error;
use Result;
use diesel::connection::{Connection as Conn, SimpleConnection};
use migrations_internals::{setup_database, MigrationConnection};
use std::path::Path;
#[allow(dead_code)] //variants might not be constructed if not required by current migrations
enum Action {
Sql(&'static str),
Function(&'static Fn(&Connection, &Path) -> Result<()>),
}
impl Action {
fn run(&self, conn: &Connection, path: &Path) -> Result<()> {
match self {
Action::Sql(sql) => conn.batch_execute(sql).map_err(Error::from),
Action::Function(f) => f(conn, path),
}
}
}
struct ComplexMigration {
name: &'static str,
up: &'static [Action],
down: &'static [Action],
}
impl ComplexMigration {
fn run(&self, conn: &Connection, path: &Path) -> Result<()> {
println!("Running migration {}", self.name);
for step in self.up {
step.run(conn, path)?
}
Ok(())
}
fn revert(&self, conn: &Connection, path: &Path) -> Result<()> {
println!("Reverting migration {}", self.name);
for step in self.down {
step.run(conn, path)?
}
Ok(())
}
}
pub struct ImportedMigrations(&'static [ComplexMigration]);
impl ImportedMigrations {
pub fn run_pending_migrations(&self, conn: &Connection, path: &Path) -> Result<()> {
use diesel::dsl::sql;
use diesel::sql_types::Bool;
use diesel::{select, RunQueryDsl};
#[cfg(feature = "postgres")]
let schema_exists: bool = select(sql::<Bool>(
"EXISTS \
(SELECT 1 \
FROM information_schema.tables \
WHERE table_name = '__diesel_schema_migrations')",
))
.get_result(conn)?;
#[cfg(feature = "sqlite")]
let schema_exists: bool = select(sql::<Bool>(
"EXISTS \
(SELECT 1 \
FROM sqlite_master \
WHERE type = 'table' \
AND name = '__diesel_schema_migrations')",
))
.get_result(conn)?;
if !schema_exists {
setup_database(conn)?;
}
let latest_migration = conn.latest_run_migration_version()?;
let latest_id = if let Some(migration) = latest_migration {
self.0
.binary_search_by_key(&migration.as_str(), |mig| mig.name)
.map(|id| id + 1)
.map_err(|_| Error::NotFound)?
} else {
0
};
let to_run = &self.0[latest_id..];
for migration in to_run {
conn.transaction(|| {
migration.run(conn, path)?;
conn.insert_new_migration(migration.name)
.map_err(Error::from)
})?;
}
Ok(())
}
pub fn is_pending(&self, conn: &Connection) -> Result<bool> {
let latest_migration = conn.latest_run_migration_version()?;
if let Some(migration) = latest_migration {
Ok(self.0.last().expect("no migrations found").name != migration)
} else {
Ok(true)
}
}
pub fn rerun_last_migration(&self, conn: &Connection, path: &Path) -> Result<()> {
let latest_migration = conn.latest_run_migration_version()?;
let id = latest_migration
.and_then(|m| self.0.binary_search_by_key(&m.as_str(), |m| m.name).ok())?;
let migration = &self.0[id];
conn.transaction(|| {
migration.revert(conn, path)?;
migration.run(conn, path)
})
}
}
pub const IMPORTED_MIGRATIONS: ImportedMigrations = {
import_migrations! {}
};