Add database health check for ping handler

Signed-off-by: JmPotato <[email protected]>

src/handlers.rs

@@ -464,6 +464,20 @@ pub async fn handler_delete_post<T: Editable>(
     .into_response()
 }
 
-pub async fn handler_ping() -> impl IntoResponse {
-    "pong"
+pub async fn handler_ping(State(state): State<Arc<AppState>>) -> impl IntoResponse {
+    // Check if the database connection is alive.
+    if state.db.is_closed() {
+        return (
+            StatusCode::INTERNAL_SERVER_ERROR,
+            "Database connection is closed".to_string(),
+        );
+    }
+    // Check if the database read can be performed.
+    if let Err(err) = User::try_check_initialization(&state.db).await {
+        return (
+            StatusCode::INTERNAL_SERVER_ERROR,
+            format!("Failed to read from the database: {:?}", err),
+        );
+    }
+    (StatusCode::OK, "pong".to_string())
 }

src/models/users.rs

@@ -46,4 +46,12 @@ impl User {
             .await?;
         Ok(())
     }
+
+    pub async fn try_check_initialization(db: &sqlx::MySqlPool) -> Result<(), Error> {
+        sqlx::query("SELECT * FROM users LIMIT 1")
+            .fetch_one(db)
+            .await
+            .map_err(|e| e.into())
+            .map(|_| ())
+    }
 }