Support alternative read-replica PgPool (#4374)

* Add ReadOnlyPgPool

* Clippy, fmt

apps/labrinth/tests/common/database.rs

@@ -1,4 +1,6 @@
-use labrinth::{database::redis::RedisPool, search};
+use labrinth::database::ReadOnlyPgPool;
+use labrinth::database::redis::RedisPool;
+use labrinth::search;
 use sqlx::{PgPool, postgres::PgPoolOptions};
 use std::time::Duration;
 use url::Url;
@@ -36,6 +38,7 @@ const TEMPLATE_DATABASE_NAME: &str = "labrinth_tests_template";
 #[derive(Clone)]
 pub struct TemporaryDatabase {
     pub pool: PgPool,
+    pub ro_pool: ReadOnlyPgPool,
     pub redis_pool: RedisPool,
     pub search_config: labrinth::search::SearchConfig,
     pub database_name: String,
@@ -74,6 +77,8 @@ impl TemporaryDatabase {
             .await
             .expect("Connection to temporary database failed");
 
+        let ro_pool = ReadOnlyPgPool::from(pool.clone());
+
         println!("Running migrations on temporary database");
 
         // Performs migrations
@@ -90,6 +95,7 @@ impl TemporaryDatabase {
             search::SearchConfig::new(Some(temp_database_name.clone()));
         Self {
             pool,
+            ro_pool,
             database_name: temp_database_name,
             redis_pool,
             search_config,
@@ -184,6 +190,7 @@ impl TemporaryDatabase {
                     let name = generate_random_name("test_template_");
                     let db = TemporaryDatabase {
                         pool: pool.clone(),
+                        ro_pool: ReadOnlyPgPool::from(pool.clone()),
                         database_name: TEMPLATE_DATABASE_NAME.to_string(),
                         redis_pool: RedisPool::new(Some(name.clone())),
                         search_config: search::SearchConfig::new(Some(name)),

apps/labrinth/tests/common/mod.rs

@@ -26,6 +26,7 @@ pub async fn setup(db: &database::TemporaryDatabase) -> LabrinthConfig {
     }
 
     let pool = db.pool.clone();
+    let ro_pool = db.ro_pool.clone();
     let redis_pool = db.redis_pool.clone();
     let search_config = db.search_config.clone();
     let file_host: Arc<dyn file_hosting::FileHost + Send + Sync> =
@@ -40,6 +41,7 @@ pub async fn setup(db: &database::TemporaryDatabase) -> LabrinthConfig {
 
     labrinth::app_setup(
         pool.clone(),
+        ro_pool.clone(),
         redis_pool.clone(),
         search_config,
         &mut clickhouse,