This commit is contained in:
Dull Bananas 2024-05-04 14:00:39 +00:00
parent f2a6d73682
commit 691bce0e71
4 changed files with 24 additions and 14 deletions

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@ -9,15 +9,6 @@ const MIGRATIONS: EmbeddedMigrations = embed_migrations!();
/// This SQL code sets up the `r` schema, which contains things that can be safely dropped and replaced
/// instead of being changed using migrations. It may not create or modify things outside of the `r` schema
/// (indicated by `r.` before the name), unless a comment says otherwise.
///
/// Currently, this code is only run after the server starts and there's at least 1 pending migration
/// to run. This means every time you change something here, you must also create a migration (a blank
/// up.sql file works fine). This behavior will be removed when we implement a better way to avoid
/// useless schema updates and locks.
///
/// If you add something that depends on something (such as a table) created in a new migration, then down.sql
/// must use `CASCADE` when dropping it. This doesn't need to be fixed in old migrations because the
/// "replaceable-schema" migration runs `DROP SCHEMA IF EXISTS r CASCADE` in down.sql.
const REPLACEABLE_SCHEMA: &[&str] = &[
"DROP SCHEMA IF EXISTS r CASCADE;",
"CREATE SCHEMA r;",
@ -26,17 +17,25 @@ const REPLACEABLE_SCHEMA: &[&str] = &[
];
pub fn run(db_url: &str) -> Result<(), LemmyError> {
let test_enabled = std::env::var("LEMMY_TEST_MIGRATIONS")
.map(|s| !s.is_empty())
.unwrap_or(false);
// Migrations don't support async connection
let mut conn = PgConnection::establish(db_url).with_context(|| "Error connecting to database")?;
// Run all pending migrations except for the newest one, then run the newest one in the same transaction
// as `REPLACEABLE_SCHEMA`. This code will be becone less hacky when the conditional setup of things in
// `REPLACEABLE_SCHEMA` is done without using the number of pending migrations.
info!("Running Database migrations (This may take a long time)...");
let migrations = conn
let unfiltered_migrations = conn
.pending_migrations(MIGRATIONS)
.map_err(|e| anyhow::anyhow!("Couldn't determine pending migrations: {e}"))?;
for migration in migrations.iter().rev().skip(1).rev() {
// Does not include the "forbid_diesel_cli" migration
let migrations = unfiltered_migrations.iter().filter(|m| m.name().version() != "000000000000000".into());
conn.transaction::<_, LemmyError, _>(|conn|) // left off here
for migration in migrations.clone() {
conn
.run_migration(migration)
.map_err(|e| anyhow::anyhow!("Couldn't run DB Migrations: {e}"))?;

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@ -0,0 +1,6 @@
DO $$
BEGIN
RAISE NOTICE 'migrations must be managed using lemmy_server instead of diesel CLI';
END
$$;

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@ -0,0 +1 @@
drop table previously_run_sql;

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@ -0,0 +1,4 @@
drop schema if exists r cascade;
create table previously_run_sql (content text primary key);
insert into previously_run_sql (content) values ('');