''' Provides the ``ApplicationContext`` class.
'''
from __future__ import absolute_import
import logging
log = logging.getLogger(__name__)
from tornado import gen
from .session import ServerSession
from .exceptions import ProtocolError
from bokeh.application.application import ServerContext, SessionContext
from bokeh.document import Document
from bokeh.util.tornado import _CallbackGroup, yield_for_all_futures
class BokehServerContext(ServerContext):
def __init__(self, application_context):
self.application_context = application_context
self._callbacks = _CallbackGroup(self.application_context.io_loop)
def _remove_all_callbacks(self):
self._callbacks.remove_all_callbacks()
@property
def sessions(self):
result = []
for session in self.application_context.sessions:
result.append(session.session_context)
return result
def add_next_tick_callback(self, callback):
self._callbacks.add_next_tick_callback(callback)
def remove_next_tick_callback(self, callback):
self._callbacks.remove_next_tick_callback(callback)
def add_timeout_callback(self, callback, timeout_milliseconds):
self._callbacks.add_timeout_callback(callback, timeout_milliseconds)
def remove_timeout_callback(self, callback):
self._callbacks.remove_timeout_callback(callback)
def add_periodic_callback(self, callback, period_milliseconds):
self._callbacks.add_periodic_callback(callback, period_milliseconds)
def remove_periodic_callback(self, callback):
self._callbacks.remove_periodic_callback(callback)
class BokehSessionContext(SessionContext):
def __init__(self, session_id, server_context, document):
self._document = document
self._session = None
super(BokehSessionContext, self).__init__(server_context,
session_id)
# request arguments used to instantiate this session
self._request = None
def _set_session(self, session):
self._session = session
@gen.coroutine
def with_locked_document(self, func):
if self._session is None:
# this means we are in on_session_created, so no locking yet,
# we have exclusive access
yield yield_for_all_futures(func(self._document))
else:
self._session.with_document_locked(func, self._document)
@property
def destroyed(self):
if self._session is None:
# this means we are in on_session_created
return False
else:
return self._session.destroyed
@property
def request(self):
return self._request
[docs]class ApplicationContext(object):
''' Server-side holder for bokeh.application.Application plus any associated data.
This holds data that's global to all sessions, while ServerSession holds
data specific to an "instance" of the application.
'''
def __init__(self, application, io_loop=None):
self._application = application
self._loop = io_loop
self._sessions = dict()
self._pending_sessions = dict()
self._session_contexts = dict()
self._server_context = None
@property
def io_loop(self):
return self._loop
@property
def application(self):
return self._application
@property
def server_context(self):
if self._server_context is None:
self._server_context = BokehServerContext(self)
return self._server_context
@property
def sessions(self):
return self._sessions.values()
def run_load_hook(self):
try:
result = self._application.on_server_loaded(self.server_context)
if isinstance(result, gen.Future):
log.error("on_server_loaded returned a Future; this doesn't make sense "
"because we run this hook before starting the IO loop.")
except Exception as e:
log.error("Error in server loaded hook %r", e, exc_info=True)
def run_unload_hook(self):
try:
result = self._application.on_server_unloaded(self.server_context)
if isinstance(result, gen.Future):
log.error("on_server_unloaded returned a Future; this doesn't make sense "
"because we stop the IO loop right away after calling on_server_unloaded.")
except Exception as e:
log.error("Error in server unloaded hook %r", e, exc_info=True)
self.server_context._remove_all_callbacks()
@gen.coroutine
def create_session_if_needed(self, session_id, request=None):
# this is because empty session_ids would be "falsey" and
# potentially open up a way for clients to confuse us
if len(session_id) == 0:
raise ProtocolError("Session ID must not be empty")
if session_id not in self._sessions and \
session_id not in self._pending_sessions:
future = self._pending_sessions[session_id] = gen.Future()
doc = Document()
session_context = BokehSessionContext(session_id,
self.server_context,
doc)
# using private attr so users only have access to a read-only property
session_context._request = request
# expose the session context to the document
# use the _attribute to set the public property .session_context
doc._session_context = session_context
try:
yield yield_for_all_futures(self._application.on_session_created(session_context))
except Exception as e:
log.error("Failed to run session creation hooks %r", e, exc_info=True)
self._application.initialize_document(doc)
session = ServerSession(session_id, doc, io_loop=self._loop)
del self._pending_sessions[session_id]
self._sessions[session_id] = session
session_context._set_session(session)
self._session_contexts[session_id] = session_context
# notify anyone waiting on the pending session
future.set_result(session)
if session_id in self._pending_sessions:
# another create_session_if_needed is working on
# creating this session
session = yield self._pending_sessions[session_id]
else:
session = self._sessions[session_id]
raise gen.Return(session)
def get_session(self, session_id):
if session_id in self._sessions:
session = self._sessions[session_id]
return session
else:
raise ProtocolError("No such session " + session_id)
@gen.coroutine
def _discard_session(self, session, should_discard):
if session.connection_count > 0:
raise RuntimeError("Should not be discarding a session with open connections")
log.debug("Discarding session %r last in use %r milliseconds ago", session.id, session.milliseconds_since_last_unsubscribe)
session_context = self._session_contexts[session.id]
# session.destroy() wants the document lock so it can shut down the document
# callbacks.
def do_discard():
# while we yielded for the document lock, the discard-worthiness of the
# session may have changed.
# However, since we have the document lock, our own lock will cause the
# block count to be 1. If there's any other block count besides our own,
# we want to skip session destruction though.
if should_discard(session) and session.expiration_blocked_count == 1:
session.destroy()
del self._sessions[session.id]
del self._session_contexts[session.id]
else:
log.debug("Session %r was scheduled to discard but came back to life", session.id)
yield session.with_document_locked(do_discard)
# session lifecycle hooks are supposed to be called outside the document lock,
# we only run these if we actually ended up destroying the session.
if session_context.destroyed:
try:
result = self._application.on_session_destroyed(session_context)
yield yield_for_all_futures(result)
except Exception as e:
log.error("Failed to run session destroy hooks %r", e, exc_info=True)
raise gen.Return(None)
@gen.coroutine
def cleanup_sessions(self, unused_session_linger_milliseconds):
def should_discard_ignoring_block(session):
return session.connection_count == 0 and \
(session.milliseconds_since_last_unsubscribe > unused_session_linger_milliseconds or \
session.expiration_requested)
# build a temp list to avoid trouble from self._sessions changes
to_discard = []
for session in self._sessions.values():
if should_discard_ignoring_block(session) and not session.expiration_blocked:
to_discard.append(session)
# asynchronously reconsider each session
for session in to_discard:
if should_discard_ignoring_block(session) and not session.expiration_blocked:
yield self._discard_session(session, should_discard_ignoring_block)
raise gen.Return(None)
