Auto restart database connection

src/server/tmdb.js

@@ -19,12 +19,35 @@ module.exports = {
 
 const mysql = require("mysql");
 
-let connection = mysql.createConnection({
+let db_config = {
   host: process.env.DB_HOST,
   user: process.env.DB_USER,
   password: process.env.DB_PASSWORD,
   database: process.env.DB_DATABASE
-});
+};
+let connection
+// https://stackoverflow.com/a/20211143
+function handleDisconnect() {
+  connection = mysql.createConnection(db_config); // Recreate the connection
+  
+  connection.connect(function(err) {
+    if(err) {                                    
+      console.log('error when connecting to db:', err);
+      setTimeout(handleDisconnect, 2000); // We introduce a delay before attempting to reconnect,
+    }                                     // to avoid a hot loop, and to allow our node script to
+  });                                     // process asynchronous requests in the meantime.
+  // If you're also serving http, display a 503 error.
+  connection.on('error', function(err) {
+    console.log('db error', err);
+    if(err.code === 'PROTOCOL_CONNECTION_LOST') { // Connection to the MySQL server is usually
+      handleDisconnect();                         // lost due to either server restart, or a
+    } else {                                      // connnection idle timeout (the wait_timeout
+      throw err;                                  // server variable configures this)
+    }
+  });
+}
+
+handleDisconnect(); //Start the auto-restarting connection
 
 function escapeString(str) {
   // return mysql.escape(str);