Improve lock handling

api/resources/root.py

@@ -1,25 +1,26 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
-from threading import Lock
-
 import falcon
 from engine import evaluate_solution
+from threading import Lock
+from typing import Dict
+import logging
 
 
 class RootResource:
     def __init__(self):
         self.main_lock = Lock()
-        self.task_locks = {}
+        self.task_locks: Dict[str, Lock] = {}
+        self.max_tasks = 5
 
     def on_get(self, request, response):
-        response.text = 'HESS v1.2409.0'
+        response.text = 'HES Server v1.2410.0'
 
     def on_post(self, request, response):
         payload = request.media
 
-        bad_request = ('task_id' not in payload or 'solution' not in payload)
-        if bad_request:
+        if 'task_id' not in payload or 'solution' not in payload:
             response.status = falcon.HTTP_400
             response.media = {
                 'error': 'task_id or solution are missing',
@@ -29,11 +30,21 @@ class RootResource:
         task_id = payload['task_id']
         solution = payload['solution']
 
-        with self.main_lock:
-            if task_id not in self.task_locks:
-                self.task_locks[task_id] = Lock()
+        try:
+            with self.main_lock:
+                if len(self.task_locks) >= self.max_tasks:
+                    # Remove the oldest task lock if we've reached the limit
+                    oldest_task = next(iter(self.task_locks))
+                    del self.task_locks[oldest_task]
+
+                if task_id not in self.task_locks:
+                    self.task_locks[task_id] = Lock()
 
-        with self.task_locks[task_id]:
-            passed = evaluate_solution(task_id, solution)
+            with self.task_locks[task_id]:
+                passed = evaluate_solution(task_id, solution)
 
-        response.media = {'passed': passed}
+            response.media = {'passed': passed}
+        except Exception as e:
+            logging.error('Error processing request: {}'.format(str(e)))
+            response.status = falcon.HTTP_500
+            response.media = {'error': 'Internal server error'}