automatically remove expired auth sessions

backend/src/lib/outbound/postgres/auth.rs

@@ -1,3 +1,5 @@
+use std::time::Duration;
+
 use anyhow::{Context as _, anyhow};
 use argon2::{
     Argon2, PasswordHash, PasswordVerifier as _,
@@ -7,7 +9,8 @@ use argon2::{
     },
 };
 use chrono::Utc;
-use sqlx::{Acquire as _, PgConnection};
+use sqlx::{Acquire as _, PgConnection, PgPool};
+use tokio::task::JoinHandle;
 use uuid::Uuid;
 
 use crate::domain::warren::{
@@ -340,6 +343,44 @@ impl AuthRepository for Postgres {
 }
 
 impl Postgres {
+    pub(super) fn start_session_cleanup_task(pool: PgPool, interval: Duration) -> JoinHandle<()> {
+        tokio::spawn(async move {
+            loop {
+                {
+                    let Ok(mut connection) = pool.acquire().await else {
+                        break;
+                    };
+
+                    if let Ok(count) = Self::delete_expired_auth_sessions(&mut connection).await {
+                        tracing::debug!("Removed {count} expired auth session(s)");
+                    }
+                }
+
+                tokio::time::sleep(interval).await;
+            }
+
+            tracing::debug!("Session cleanup task stopped");
+        })
+    }
+
+    async fn delete_expired_auth_sessions(
+        connection: &mut PgConnection,
+    ) -> Result<u64, sqlx::Error> {
+        let delete_count = sqlx::query(
+            "
+            DELETE FROM
+                auth_sessions
+            WHERE
+                expires_at <= CURRENT_TIMESTAMP
+            ",
+        )
+        .execute(connection)
+        .await?
+        .rows_affected();
+
+        Ok(delete_count)
+    }
+
     async fn create_user(
         &self,
         connection: &mut PgConnection,

backend/src/lib/outbound/postgres/mod.rs

@@ -1,11 +1,10 @@
-use std::str::FromStr as _;
+use std::{str::FromStr as _, time::Duration};
 
 use anyhow::Context as _;
 use sqlx::{
     ConnectOptions as _, Connection as _, PgConnection, PgPool,
     postgres::{PgConnectOptions, PgPoolOptions},
 };
-
 pub mod auth;
 pub mod warrens;
 
@@ -58,6 +57,9 @@ impl Postgres {
             .await?;
         sqlx::migrate!("./migrations").run(&pool).await?;
 
+        // 3600 seconds = 1 hour
+        Self::start_session_cleanup_task(pool.clone(), Duration::from_secs(3600));
+
         Ok(Self { pool })
     }
 }