WebHost: allow setting a generation time limit (#1209)

* WebHost: allow setting a generation time limit.

WebHostLib/__init__.py

@@ -31,8 +31,10 @@ app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
 app.config['MAX_CONTENT_LENGTH'] = 64 * 1024 * 1024  # 64 megabyte limit
 # if you want to deploy, make sure you have a non-guessable secret key
 app.config["SECRET_KEY"] = bytes(socket.gethostname(), encoding="utf-8")
-# at what amount of worlds should scheduling be used, instead of rolling in the webthread
+# at what amount of worlds should scheduling be used, instead of rolling in the web-thread
 app.config["JOB_THRESHOLD"] = 2
+# after what time in seconds should generation be aborted, freeing the queue slot. Can be set to None to disable.
+app.config["JOB_TIME"] = 600
 app.config['SESSION_PERMANENT'] = True
 
 # waitress uses one thread for I/O, these are for processing of views that then get sent

WebHostLib/generate.py

@@ -4,6 +4,7 @@ import pickle
 import random
 import tempfile
 import zipfile
+import concurrent.futures
 from collections import Counter
 from typing import Dict, Optional, Any
 
@@ -98,7 +99,7 @@ def gen_game(gen_options, meta: Optional[Dict[str, Any]] = None, owner=None, sid
     meta.setdefault("server_options", {}).setdefault("hint_cost", 10)
     race = meta.setdefault("race", False)
 
-    try:
+    def task():
         target = tempfile.TemporaryDirectory()
         playercount = len(gen_options)
         seed = get_seed()
@@ -138,6 +139,23 @@ def gen_game(gen_options, meta: Optional[Dict[str, Any]] = None, owner=None, sid
         ERmain(erargs, seed, baked_server_options=meta["server_options"])
 
         return upload_to_db(target.name, sid, owner, race)
+    thread_pool = concurrent.futures.ThreadPoolExecutor(max_workers=1)
+    thread = thread_pool.submit(task)
+
+    try:
+        return thread.result(app.config["JOB_TIME"])
+    except concurrent.futures.TimeoutError as e:
+        if sid:
+            with db_session:
+                gen = Generation.get(id=sid)
+                if gen is not None:
+                    gen.state = STATE_ERROR
+                    meta = json.loads(gen.meta)
+                    meta["error"] = (
+                            "Allowed time for Generation exceeded, please consider generating locally instead. " +
+                            e.__class__.__name__ + ": " + str(e))
+                    gen.meta = json.dumps(meta)
+                    commit()
     except BaseException as e:
         if sid:
             with db_session: