stuff

Author: dullbananas

crates/diesel_utils/src/schema_setup/mod.rs

@@ -10,15 +10,17 @@ use diesel::{
   RunQueryDsl,
   connection::SimpleConnection,
   dsl::exists,
-  migration::{Migration, MigrationVersion},
+  migration::{Migration, MigrationSource, MigrationVersion},
   pg::Pg,
   select,
   update,
 };
-use diesel_migrations::MigrationHarness;
+use diesel_migrations::{EmbeddedMigrations, MigrationHarness};
 use std::time::Instant;
 use tracing::debug;
 
+// TODO: add duration logging to diesel
+
 diesel::table! {
   pg_namespace (nspname) {
     nspname -> Text,
@@ -32,10 +34,62 @@ diesel::table! {
   }
 }
 
-fn migrations() -> diesel_migrations::EmbeddedMigrations {
-  // Using `const` here is required by the borrow checker
-  const MIGRATIONS: diesel_migrations::EmbeddedMigrations = diesel_migrations::embed_migrations!();
-  MIGRATIONS
+struct MigrationWrapper {
+  embedded_migration: Box<dyn Migration<Pg>>,
+}
+
+impl Migration<Pg> for MigrationWrapper {
+  fn run(
+    &self,
+    conn: &mut dyn diesel::connection::BoxableConnection<Pg>,
+  ) -> diesel::migration::Result<()> {
+    // Drop `r` schema, so migrations don't need to be made to work both with and without things in
+    // it existing
+    revert_replaceable_schema(conn)?;
+
+    self.embedded_migration.run(conn)
+  }
+
+  fn revert(
+    &self,
+    conn: &mut dyn diesel::connection::BoxableConnection<Pg>,
+  ) -> diesel::migration::Result<()> {
+    // Drop `r` schema, so migrations don't need to be made to work both with and without things in
+    // it existing
+    revert_replaceable_schema(conn)?;
+
+    self.embedded_migration.revert(conn)
+  }
+
+  fn metadata(&self) -> &dyn diesel::migration::MigrationMetadata {
+    self.embedded_migration.metadata()
+  }
+
+  fn name(&self) -> &dyn diesel::migration::MigrationName {
+    self.embedded_migration.name()
+  }
+}
+
+struct LemmyMigrations;
+
+impl MigrationSource<Pg> for LemmyMigrations {
+  fn migrations(&self) -> diesel::migration::Result<Vec<Box<dyn Migration<Pg>>>> {
+    // Using `const` here is required by the borrow checker
+    const MIGRATIONS: diesel_migrations::EmbeddedMigrations =
+      diesel_migrations::embed_migrations!();
+
+    Ok(
+      MIGRATIONS
+        .migrations()?
+        .into_iter()
+        .map(|migration| -> Box<dyn Migration<Pg>> {
+          Box::new(MigrationWrapper {
+            embedded_migration: migration,
+          })
+        })
+        .collect(),
+    )
+  }
 }
 
 /// This SQL code sets up the `r` schema, which contains things that can be safely dropped and
@@ -192,7 +246,7 @@ pub fn run(options: Options, db_url: &str) -> anyhow::Result<Branch> {
     && options.run
     && options.limit.is_none()
     && !conn
-      .has_pending_migration(migrations())
+      .has_pending_migration(LemmyMigrations)
       .map_err(convert_err)?
   {
     // The condition above implies that the migration that creates the previously_run_sql table was
@@ -211,6 +265,7 @@ pub fn run(options: Options, db_url: &str) -> anyhow::Result<Branch> {
   // Block concurrent attempts to run migrations until `conn` is closed, and disable the
   // trigger that prevents the Diesel CLI from running migrations
   options.print("Waiting for lock...");
+  // TODO: maybe make diesel do something similar, and disable the trigger in some other way:
   conn.batch_execute("SELECT pg_advisory_lock(0);")?;
   options.print("Running Database migrations (This may take a long time)...");
 
@@ -271,7 +326,7 @@ fn run_replaceable_schema(conn: &mut PgConnection) -> anyhow::Result<()> {
   })
 }
 
-fn revert_replaceable_schema(conn: &mut PgConnection) -> anyhow::Result<()> {
+fn revert_replaceable_schema(conn: &mut (impl SimpleConnection + ?Sized)) -> anyhow::Result<()> {
   conn
     .batch_execute("DROP SCHEMA IF EXISTS r CASCADE;")
     .with_context(|| format!("Failed to revert SQL files in {REPLACEABLE_SCHEMA_PATH}"))?;