refactor(drainer): removed router dependency from drainer (#209)

crates/drainer/src/connection.rs

@@ -0,0 +1,34 @@
+use async_bb8_diesel::ConnectionManager;
+use bb8::PooledConnection;
+use diesel::PgConnection;
+
+use crate::settings::Database;
+
+pub type PgPool = bb8::Pool<async_bb8_diesel::ConnectionManager<PgConnection>>;
+
+pub async fn redis_connection(
+    conf: &crate::settings::Settings,
+) -> redis_interface::RedisConnectionPool {
+    redis_interface::RedisConnectionPool::new(&conf.redis).await
+}
+
+#[allow(clippy::expect_used)]
+pub async fn diesel_make_pg_pool(database: &Database, _test_transaction: bool) -> PgPool {
+    let database_url = format!(
+        "postgres://{}:{}@{}:{}/{}",
+        database.username, database.password, database.host, database.port, database.dbname
+    );
+    let manager = async_bb8_diesel::ConnectionManager::<PgConnection>::new(database_url);
+    let pool = bb8::Pool::builder().max_size(database.pool_size);
+
+    pool.build(manager)
+        .await
+        .expect("Failed to create PostgreSQL connection pool")
+}
+
+#[allow(clippy::expect_used)]
+pub async fn pg_connection(pool: &PgPool) -> PooledConnection<ConnectionManager<PgConnection>> {
+    pool.get()
+        .await
+        .expect("Couldn't retrieve PostgreSQL connection")
+}