Merge pull request #1121 from minrk/async

async fixes

Author: minrk

nbviewer/app.py

@@ -4,6 +4,7 @@
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 # -----------------------------------------------------------------------------
+import asyncio
 import io
 import json
 import logging
@@ -21,7 +22,6 @@
 from nbconvert import get_exporter  # type: ignore
 from nbconvert.exporters.templateexporter import ExtensionTolerantLoader  # type: ignore
 from tornado import httpserver
-from tornado import ioloop
 from tornado import web
 from tornado.curl_httpclient import curl_log
 from tornado.log import access_log
@@ -802,6 +802,17 @@ def __init__(self, *args, **kwargs):
 
 def main(argv=None):
     # create and start the app
+    loop = asyncio.new_event_loop()
+    loop.run_until_complete(async_main(argv=argv))
+    try:
+        loop.run_forever()
+    except KeyboardInterrupt:
+        pass
+    finally:
+        loop.close()
+
+
+async def async_main(argv=None):
     nbviewer = NBViewer()
     app = nbviewer.tornado_application
 
@@ -819,10 +830,6 @@ def main(argv=None):
     )
 
     http_server.listen(nbviewer.port, nbviewer.host)
-    try:
-        ioloop.IOLoop.current().start()
-    except KeyboardInterrupt:
-        pass
 
 
 if __name__ == "__main__":

nbviewer/cache.py

@@ -124,8 +124,6 @@ def __init__(self, *args, **kwargs):
         self.mc = pylibmc.Client(*args, **kwargs)
         self.mc_pool = pylibmc.ThreadMappedPool(self.mc)
 
-        self.loop = asyncio.get_event_loop()
-
     async def _call_in_thread(self, method_name, *args, **kwargs):
         # https://stackoverflow.com/questions/34376814/await-future-from-executor-future-cant-be-used-in-await-expression
 
@@ -140,7 +138,8 @@ def f():
                 meth = getattr(mc, method_name)
                 return meth(*args, **kwargs)
 
-        return await self.loop.run_in_executor(self.pool, f)
+        loop = asyncio.get_running_loop()
+        return await loop.run_in_executor(self.pool, f)
 
     async def get(self, *args, **kwargs):
         return await self._call_in_thread("get", *args, **kwargs)

nbviewer/providers/base.py

@@ -675,7 +675,7 @@ async def finish_notebook(
                     "Rendering %d B notebook from %s", len(json_notebook), download_url
                 )
                 render_time = self.statsd.timer("rendering.nbrender.time").start()
-                loop = asyncio.get_event_loop()
+                loop = asyncio.get_running_loop()
                 nbhtml, config = await loop.run_in_executor(
                     self.pool,
                     render_notebook,