Fixes for profiler (#2664)

* Fixes for profiler

* Fall back to disabling async_mode in pyinstrument profiling

panel/command/serve.py

@@ -14,8 +14,10 @@
 from bokeh.command.util import build_single_handler_applications
 
 from bokeh.application import Application
+from bokeh.application.handlers.document_lifecycle import DocumentLifecycleHandler
 from bokeh.application.handlers.function import FunctionHandler
 from bokeh.server.contexts import ApplicationContext
+from tornado.ioloop import PeriodicCallback, IOLoop
 from tornado.web import StaticFileHandler
 
 from ..auth import OAuthProvider
@@ -63,6 +65,28 @@ def parse_vars(items):
     return dict((parse_var(item) for item in items))
 
 
+class AdminApplicationContext(ApplicationContext):
+
+    def __init__(self, application, unused_timeout=15000, **kwargs):
+        super().__init__(application, io_loop=IOLoop.current(), **kwargs)
+        self._unused_timeout = unused_timeout
+        self._cleanup_cb = None
+        self._loop.add_callback(self.run_load_hook)
+
+    async def cleanup_sessions(self):
+        await self._cleanup_sessions(self._unused_timeout)
+
+    def run_load_hook(self):
+        self._cleanup_cb = PeriodicCallback(self.cleanup_sessions, self._unused_timeout)
+        self._cleanup_cb.start()
+        super().run_load_hook()
+
+    def run_unload_hook(self):
+        if self._cleanup_cb:
+            self._cleanup_cb.stop()
+        super().run_unload_hook()
+
+
 class Serve(_BkServe):
 
     args = _BkServe.args + (
@@ -203,23 +227,30 @@ def customize_kwargs(self, args, server_kwargs):
                     doc = app.create_document()
                     _cleanup_doc(doc)
 
+        prefix = args.prefix
+        if prefix is None:
+            prefix = ""
+        prefix = prefix.strip("/")
+        if prefix:
+            prefix = "/" + prefix
+
         config.profiler = args.profiler
         if args.admin:
             from ..io.admin import admin_panel
             from ..io.server import per_app_patterns
             config._admin = True
             app = Application(FunctionHandler(admin_panel))
-            app_ctx = ApplicationContext(app, url='/admin')
+            unused_timeout = args.check_unused_sessions or 15000
+            app_ctx = AdminApplicationContext(app, unused_timeout=unused_timeout, url='/admin')
+            if all(not isinstance(handler, DocumentLifecycleHandler) for handler in app._handlers):
+                app.add(DocumentLifecycleHandler())
             app_patterns = []
             for p in per_app_patterns:
                 route = '/admin' + p[0]
                 context = {"application_context": app_ctx}
-                route = (args.prefix or '') + route
+                route = prefix + route
                 app_patterns.append((route, p[1], context))
 
-            from tornado.ioloop import IOLoop
-            app_ctx._loop = IOLoop.current()
-
             websocket_path = None
             for r in app_patterns:
                 if r[0].endswith("/ws"):
@@ -238,7 +269,6 @@ def customize_kwargs(self, args, server_kwargs):
                 pass
             patterns.extend(app_patterns)
 
-
         config.session_history = args.session_history
         if args.rest_session_info:
             pattern = REST_PROVIDERS['param'](files, 'rest')

panel/config.py

@@ -95,8 +95,9 @@ class _config(_base_config):
     loading_color = param.Color(default='#c3c3c3', doc="""
         Color of the loading indicator.""")
 
-    profiler = param.Selector(default=None, objects=['pyinstrument', 'snakeviz'], doc="""
-        The profiler to enable.""")
+    profiler = param.Selector(default=None, allow_None=True, objects=[
+        'pyinstrument', 'snakeviz'], doc="""
+        The profiler engine to enable.""")
 
     safe_embed = param.Boolean(default=False, doc="""
         Ensure all bokeh property changes trigger events which are

panel/io/profile.py

@@ -117,8 +117,12 @@ def profile_ctx(engine='pyinstrument'):
     """
     if engine == 'pyinstrument':
         from pyinstrument import Profiler
-        prof = Profiler()
-        prof.start()
+        try:
+            prof = Profiler()
+            prof.start()
+        except RuntimeError:
+            prof = Profiler(async_mode='disabled')
+            prof.start()
     elif engine == 'snakeviz':
         prof = Profile()
         prof.enable()