[BE] Fixes #21: Attempt to connect to DB on each query, if no connection is present

backend/src/controller/person/mod.rs

@@ -10,7 +10,7 @@ use crate::{db, model::person::Person};
 
 #[get("/person/<dni>")]
 pub async fn get_by_dni(dni: i32) -> (Status, Json<JsonResult<Person>>) {
-    let db = db();
+    let db = db().await;
     info!("get person with dni {}", dni);
 
     /*

backend/src/main.rs

@@ -1,5 +1,6 @@
 use cors::Cors;
 use once_cell::sync::OnceCell;
+use rocket::tokio;
 use sqlx::mysql::MySqlPoolOptions;
 use sqlx::{MySql, Pool};
 use std::env;
@@ -17,17 +18,29 @@ pub mod json_result;
 static DB: OnceCell<Pool<MySql>> = OnceCell::new();
 
 /// Returns a global reference to the database pool
-/// This MUST be called after the DB pool has been initialized,
+/// 
-/// otherwise it will panic
+/// If the database pool has not been initialized, this function will attempt to initialize it
-pub fn db() -> &'static Pool<MySql> {
+/// up to 3 times
-    DB.get().expect("DB not initialized")
+/// 
+/// If the database pool fails to initialize, this function will panic.
+pub async fn db() -> &'static Pool<MySql> {
+    let attempts = 3;
+
+    for _ in 0..attempts {
+        match DB.get() {
+            Some(db) => return db,
+            None => {
+                log::info!("DB not initialized, initializing from db()");
+                init_db().await;
+            }
+        }
+    };
+
+    log::error!("Failed to initialize DB after {} attempts", attempts);
+    panic!("DB not initialized");
 }
 
-#[launch]
+pub async fn init_db() {
-async fn rocket() -> _ {
-    dotenvy::dotenv().expect("Failed to load .env file");
-    env_logger::init();
-
     /*
        Init DB and set it as a global variable
     */
@@ -41,6 +54,14 @@ async fn rocket() -> _ {
         Ok(pool) => DB.set(pool).expect("Failed to set DB pool"),
         Err(e) => log::error!("Error connecting to DB: {}", e),
     }
+}
+
+#[launch]
+async fn rocket() -> _ {
+    dotenvy::dotenv().expect("Failed to load .env file");
+    env_logger::init();
+
+    init_db().await;
 
     /* Init Rocket */
     rocket::build().attach(Cors {}).mount(

backend/src/model/course.rs

@@ -28,7 +28,7 @@ pub struct Course {
 
 impl Course {
     pub async fn get_all() -> Result<Vec<Course>, sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         let results = sqlx::query!("SELECT * FROM course")
             .fetch_all(db)
@@ -47,7 +47,7 @@ impl Course {
     }
 
     pub async fn get_course_name(course_id: i32) -> Option<String> {
-        let db = db();
+        let db = db().await;
 
         let res = sqlx::query!(
             "SELECT course_name FROM course WHERE course_id = ?",

backend/src/model/custom_label.rs

@@ -9,7 +9,7 @@ pub struct CustomLabel {
 
 impl CustomLabel {
     pub async fn get_all() -> Result<Vec<CustomLabel>, sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         let result = sqlx::query_as::<_, CustomLabel>(
             r#"
@@ -24,7 +24,7 @@ impl CustomLabel {
     }
 
     pub async fn get_id_by_value(value: &String) -> Result<i32, sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         let result = sqlx::query!(
             "SELECT custom_label_id FROM custom_label WHERE custom_label_value = ?",
@@ -43,7 +43,7 @@ impl CustomLabel {
     }
 
     pub async fn create(value: &String) -> Result<i32, sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         sqlx::query!(
             "INSERT INTO custom_label (custom_label_value) VALUES (?)",

backend/src/model/person.rs

@@ -32,7 +32,7 @@ pub struct Person {
 
 impl Person {
     pub async fn get_by_dni(dni: i32) -> Result<Person, sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         let result = sqlx::query_as!(Person, "SELECT * FROM person WHERE person_dni = ?", dni)
             .fetch_one(db)
@@ -58,7 +58,7 @@ pub struct PersonCreate {
 
 impl PersonCreate {
     pub async fn create(&self) -> Result<(), sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         sqlx::query!(
             "INSERT INTO person (person_dni, person_names, person_paternal_surname, person_maternal_surname) VALUES (?, ?, ?, ?)", 
@@ -84,7 +84,7 @@ pub struct PersonLink {
 impl PersonLink {
     /// Links a person to a user in the online classroom
     pub async fn insert(&self) -> Result<(), String> {
-        let db = db();
+        let db = db().await;
 
         let res = sqlx::query!(
             "UPDATE person SET person_classroom_id = ?, person_classroom_username = ? WHERE person_id = ?",

backend/src/model/register.rs

@@ -32,7 +32,7 @@ pub struct RegisterCreate {
 impl RegisterCreate {
     /// Registers a new certificate
     pub async fn create(&self) -> Result<(), sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         // Get custom_label_id from db based of self.custom_label
         let custom_label_id = {
@@ -82,7 +82,7 @@ impl RegisterCreate {
     }
 
     async fn get_next_register_code(course_id: i32) -> Result<i32, sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         let course_name = Course::get_course_name(course_id).await;
 
@@ -140,7 +140,7 @@ pub struct Register {
 
 impl Register {
     pub async fn get_by_dni(dni: String) -> Result<Vec<Register>, sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         let res = sqlx::query!(
             "SELECT * FROM register 
@@ -166,7 +166,7 @@ impl Register {
     }
 
     pub async fn delete(register_id: i32) -> Result<(), sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         let _ = sqlx::query!("DELETE FROM register WHERE register_id = ?", register_id)
             .execute(db)
@@ -179,7 +179,7 @@ impl Register {
         register_id_list: String,
         person_dni_list: String,
     ) -> Result<Vec<ScanData>, sqlx::Error> {
-        let db = db();
+        let db = db().await;
 
         let sql = format!(
             "