process kill updated to invisible, webrtc_timeout increased, port allocation changed for high concurrency, port information added to database, app process kill added if webrtc not started

src/modules/session_observer.js

@@ -3,6 +3,7 @@ const database = require('../database/database')
 const {is_proc_running, kill_proc} = require('./run_process')
 const coordinator = require('./coordinator')
 const wait_list = require('./wait_list')
+const {free_app_port, free_webrtc_port} = require('./port_alloc')
 
 const observer_timeout = 100
 var pending_list = new wait_list([])
@@ -34,12 +35,15 @@ const check_sessions = async (sessions) => {
             // kill process if running
             kill_proc(session.webrtc_pid)
             kill_proc(session.app_pid)
+            // free ports allocated for processes
+            free_webrtc_port(session.webrtc_port)
+            free_app_port(session.app_port)
             
             var close_session_result = await coordinator.close_session(session.session_id)
             if (close_session_result) {
                 await database.remove_running_session(session.session_id)
             } else {
-                console.log('can not connect to coordinator')
+                console.error('can not connect to coordinator')
             }
             pending_list.remove(session.session_id)
         }