feat: retry mongodb connection (ping) on start up to 50 times

Signed-off-by: Stefano Cappa <[email protected]>

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ks89-register"
-version = "1.0.0"
+version = "1.1.0"
 edition = "2021"
 resolver = "2"
 

README.md

@@ -21,6 +21,7 @@ GitHub releases [HERE](https://github.com/home-anthill/register/releases)
 
 Versions:
 
+- 20/08/2024 - 1.1.0
 - 19/08/2024 - 1.0.2
 - 19/05/2024 - 1.0.1
 - 19/05/2024 - 1.0.0

src/db/mod.rs

@@ -1,5 +1,6 @@
 use crate::config::Env;
 use std::env;
+use std::future::Future;
 use log::{error, info, warn};
 use mongodb::bson::doc;
 use mongodb::options::{ClientOptions, ServerApi, ServerApiVersion};
@@ -31,7 +32,6 @@ async fn connect(env_config: Env) -> mongodb::error::Result<Database> {
     };
 
     let mut client_options = ClientOptions::parse(mongo_uri).await?;
-
     // Set the server_api field of the client_options object to Stable API version 1
     let server_api = ServerApi::builder().version(ServerApiVersion::V1).build();
     client_options.server_api = Some(server_api);
@@ -43,9 +43,29 @@ async fn connect(env_config: Env) -> mongodb::error::Result<Database> {
     let database = client.database(mongo_db_name.as_str());
 
     info!(target: "app", "Pinging MongoDB server...");
-    database.run_command(doc! { "ping": 1 }).await?;
-
-    info!(target: "app", "MongoDB connected!");
+    retry_connect_mongodb(|| async { database.run_command(doc! { "ping": 1 }).await }, 50).await?;
 
     Ok(database)
 }
+
+async fn retry_connect_mongodb<T, E, Fut, F>(mut f: F, retries: usize) -> Result<T, E>
+where
+    F: FnMut() -> Fut,
+    Fut: Future<Output=Result<T, E>>,
+{
+    let mut count = 0;
+    loop {
+        let result = f().await;
+        if result.is_ok() {
+            info!(target: "app", "MongoDB connected!");
+            return result;
+        } else {
+            if count >= retries {
+                error!(target: "app", "Cannot connect to MongoDB, max tries reached");
+                return result;
+            }
+            count += 1;
+            warn!(target: "app", "MongoDB ping failed (count={}), retrying...", count);
+        }
+    }
+}