- check_answer no longer blocks the tornado event_loop.

Miguel Barão
1 parent 6deb4a4f
Showing 5 changed files with 31 additions and 17 deletions Show diff stats
BUGS.md
demo/solar_system/questions.yaml
learnapp.py
serve.py
templates/topic.html
 # BUGS
-- generators e correct scripts que durem muito tempo bloqueiam o eventloop do tornado.
-- change password modal nao aparece no ipad (safari e firefox)
 - on start topic, logs show questionhandler.get() twice.
+- change password modal nao aparece no ipad (safari e firefox)
 - detect questions in questions.yaml without ref -> error ou generate default.
-- Criar outra estrutura organizada em capítulos (conjuntos de tópicos). Permitir capítulos de capítulos, etc. talvez usar grafos de grafos...
-- generators not working: bcrypt (ver blog)
 - tabelas nas perguntas radio/checkbox não ocupam todo o espaço como em question.
 # TODO
-- session management. close after inactive time.
+- Criar outra estrutura organizada em capítulos (conjuntos de tópicos). Permitir capítulos de capítulos, etc. talvez usar grafos de grafos...
 - each topic only loads a sample of K questions (max) in random order.
+- session management. close after inactive time.
 - radio e checkboxes, aceitar numeros como seleccao das opcoes.
 - reload das perguntas enquanto online. ver signal em http://stackabuse.com/python-async-await-tutorial/
 - pertuntas tipo tristate: (sim, não, não sei
@@ -29,6 +27,7 @@
 # FIXED
+- generators e correct scripts que durem muito tempo bloqueiam o eventloop do tornado.
 - servir imagens/ficheiros.
 - radio: suporte para multiplas opcoes correctas e erradas, escolhendo-se uma selecção aleatoria destas (so com 1 certa).
 - checkbox: cada opção pode ser uma dupla (certo, errado) sendo escolhida uma aleatória.
@@ -6,7 +6,7 @@
     type: radio
     title: Sistema solar
     text: |
-        ![planetas](planetsa.png " Planetas do Sistema Solar")
+        ![planetas](planets.png " Planetas do Sistema Solar")
         Qual é o maior planeta do Sistema Solar?
     options:
@@ -152,7 +152,7 @@ class LearnApp(object):
         try:
             ok = self.online[uid]['state'].init_topic(topic)
         except KeyError as e:
-            logger.warning(f'User "{uid}" denied nonexistent "{topic}"')
+            logger.warning(f'User "{uid}" tried to open nonexistent topic: "{topic}"')
             raise e
         else:
             if ok:
@@ -7,6 +7,7 @@ import base64
 import uuid
 import logging.config
 import argparse
+from concurrent.futures import ThreadPoolExecutor
 # user installed libraries
 import tornado.ioloop
@@ -14,6 +15,9 @@ import tornado.web
 import tornado.httpserver
 from tornado import template    #, gen
+from tornado.concurrent import run_on_executor
+from tornado.platform.asyncio import to_tornado_future
+
 # this project
 from learnapp import LearnApp
 from tools import load_yaml, md_to_html
@@ -142,15 +146,18 @@ class TopicHandler(BaseHandler):
             else:
                 self.redirect('/')
+
 # ----------------------------------------------------------------------------
+# Serves files from the /public subdir of the topics.
 # Based on https://bhch.github.io/posts/2017/12/serving-large-files-with-tornado-safely-without-blocking/
+# ----------------------------------------------------------------------------
 class FileHandler(BaseHandler):
     @tornado.web.authenticated
     async def get(self, filename):
         uid = self.current_user
         public_dir = self.learn.get_current_public_dir(uid)
         filepath = path.expanduser(path.join(public_dir, filename))
-        chunk_size = 1024 * 1024 # serve 1MiB multiple times
+        chunk_size = 1024 * 1024 # serve up to 1MiB multiple times
         try:
             f = open(filepath, 'rb')
         except FileNotFoundError:
@@ -159,9 +166,8 @@ class FileHandler(BaseHandler):
             logging.error(f'No permission: {filepath}')
         else:
             with f:
-                while True:
-                    chunk = f.read(chunk_size)
-                    if not chunk: break
+                chunk = f.read(chunk_size)
+                while chunk:
                     try:
                         self.write(chunk)   # write the cunk to response
                         await self.flush()  # flush the current chunk to socket
@@ -172,12 +178,15 @@ class FileHandler(BaseHandler):
                         del chunk
                         await gen.sleep(0.000000001) # 1 nanosecond (hack)
                         # in tornnado 5.0 use `await asyncio.sleep(0)` instead
+                    chunk = f.read(chunk_size)
 # ----------------------------------------------------------------------------
 # respond to AJAX to get a JSON question
 # ----------------------------------------------------------------------------
 class QuestionHandler(BaseHandler):
+    executor = ThreadPoolExecutor(max_workers=2)
+
     templates = {
         'checkbox':         'question-checkbox.html',
         'radio':            'question-radio.html',
@@ -194,6 +203,13 @@ class QuestionHandler(BaseHandler):
         # 'alert':      '', FIXME
     }
+    # Blocking function to be run on the executor
+    @run_on_executor()
+    def check_answer(self, user, answer):
+        return self.learn.check_answer(user, answer)
+
+
+    # --- get question to render
     @tornado.web.authenticated
     def get(self):
         logging.debug('QuestionHandler.get()')
@@ -211,9 +227,9 @@ class QuestionHandler(BaseHandler):
                 }
             })
-    # handles answer posted
+    # --- post answer, returns what to do next: shake, new_question, finished
     @tornado.web.authenticated
-    def post(self):
+    async def post(self):
         logging.debug('QuestionHandler.post()')
         user = self.current_user
@@ -229,7 +245,8 @@ class QuestionHandler(BaseHandler):
             elif qtype != 'checkbox':   # radio, text, textarea, ...
                 answer = answer[0]
-        grade = self.learn.check_answer(user, answer)
+        # check answer in another thread (nonblocking)
+        grade = await to_tornado_future(self.check_answer(user, answer))
         question = self.learn.get_student_question(user)
         if grade <= 0.999:      # wrong answer
@@ -91,9 +91,7 @@
 <footer class="footer">
     <div class="container">
         <button class="btn btn-primary btn-lg btn-block my-3" id="submit" data-toggle="tooltip" data-placement="right" title="Shift-Enter">Continuar</button>
-<!--
-        <span class="text-muted"></span>
- -->    </div>
+    </div>
 </footer>
 </body>
	@@ -6,7 +6,7 @@		@@ -6,7 +6,7 @@
6	type: radio	6	type: radio
7	title: Sistema solar	7	title: Sistema solar
8	text: \|	8	text: \|
9	- ![planetas](planetsa.png " Planetas do Sistema Solar")	9	+ ![planetas](planets.png " Planetas do Sistema Solar")
10		10
11	Qual é o maior planeta do Sistema Solar?	11	Qual é o maior planeta do Sistema Solar?
12	options:	12	options:
	@@ -152,7 +152,7 @@ class LearnApp(object):		@@ -152,7 +152,7 @@ class LearnApp(object):
152	try:	152	try:
153	ok = self.online[uid]['state'].init_topic(topic)	153	ok = self.online[uid]['state'].init_topic(topic)
154	except KeyError as e:	154	except KeyError as e:
155	- logger.warning(f'User "{uid}" denied nonexistent "{topic}"')	155	+ logger.warning(f'User "{uid}" tried to open nonexistent topic: "{topic}"')
156	raise e	156	raise e
157	else:	157	else:
158	if ok:	158	if ok: