database separated and stability improved, celebrate argument parse added, fastest session server search added, session server work check added, session server websocket get added, error handling improved, overal stability improved, overal scalability improved, everything refactored

src/controllers/session.js

@@ -0,0 +1,60 @@
+const database = require('../database/database')
+const not_found_error = require('../../lib/src/http/errors/not_found_error')
+const {get_fastest_session_server, run_session} = require('../modules/session_server')
+
+const create_session = async (req, res, next) => {
+    const {title} = req.body
+
+    var free_servers = await database.get_free_session_servers(title)
+
+    if (!free_servers) {
+        next(new not_found_error('no free session server or title not exists'))
+        return
+    }
+
+    var session_server = await get_fastest_session_server(free_servers)
+    
+    if (!session_server) {
+        next(new not_found_error('all session servers are not available'))
+        return
+    }
+
+    var session_id = await database.generate_session_id()
+    if (!session_id) {
+        next(new not_found_error('can not generate session id'))
+        return
+    }
+
+    var websocket_url = await run_session(session_server.url, session_id, title)
+
+    if (!websocket_url) {
+        next(new not_found_error('websocket_url not valid'))
+        return
+    }
+    
+    var add_active_session_result = await database.add_active_session(session_server.url, session_id, websocket_url)
+
+    if (!add_active_session_result) {
+        next(new not_found_error('add_active_session error'))
+        return
+    }
+    res.json({session_id:session_id})
+}
+
+const connect_session = async (req, res, next) => {
+    var websocket_url = await database.get_session_websocket_url(req.query.session_id)
+    if (!websocket_url) {
+        next(new not_found_error('session not exists'))
+        return
+    }
+    res.json({websocket_url:websocket_url})
+}
+
+const schedule_session = async (req, res, next) => {
+}
+
+module.exports = {
+    create_session,
+    schedule_session,
+    connect_session
+}