from __future__ import annotations
import asyncio
import dataclasses
import datetime as dt
import inspect
import json
import logging
import threading
from contextlib import contextmanager
from functools import partial, wraps
from typing import (
Callable, Iterator, List, Optional,
)
from bokeh.application.application import SessionContext
from bokeh.document.document import Document
from bokeh.document.events import DocumentChangedEvent, ModelChangedEvent
from bokeh.models import CustomJS
from ..config import config
from .loading import LOADING_INDICATOR_CSS_CLASS
from .model import monkeypatch_events
from .state import curdoc_locked, state
logger = logging.getLogger(__name__)
#---------------------------------------------------------------------
# Private API
#---------------------------------------------------------------------
[docs]@dataclasses.dataclass
class Request:
headers : dict
cookies : dict
arguments : dict
[docs]class MockSessionContext(SessionContext):
def __init__(self, *args, document=None, **kwargs):
self._document = document
super().__init__(*args, server_context=None, session_id=None, **kwargs)
[docs] def with_locked_document(self, *args):
return
@property
def destroyed(self) -> bool:
return False
@property
def request(self):
return Request(headers={}, cookies={}, arguments={})
def _dispatch_events(doc: Document, events: List[DocumentChangedEvent]) -> None:
"""
Handles dispatch of events which could not be processed in
unlocked decorator.
"""
for event in events:
doc.callbacks.trigger_on_change(event)
def _cleanup_doc(doc, destroy=True):
for callback in doc.session_destroyed_callbacks:
try:
callback(None)
except Exception:
pass
if hasattr(doc.callbacks, '_change_callbacks'):
doc.callbacks._change_callbacks[None] = {}
# Remove views
from ..viewable import Viewable
views = {}
for ref, (pane, root, vdoc, comm) in list(state._views.items()):
if vdoc is doc:
pane._cleanup(root)
if isinstance(pane, Viewable):
pane._hooks = []
for p in pane.select():
p._hooks = []
p._param_watchers = {}
p._documents = {}
p._internal_callbacks = {}
pane._param_watchers = {}
pane._documents = {}
pane._internal_callbacks = {}
else:
views[ref] = (pane, root, doc, comm)
state._views = views
# When reusing sessions we must clean up the Panel state but we
# must **not** destroy the template or the document
if not destroy:
return
# Clean up templates
if doc in state._templates:
tmpl = state._templates[doc]
tmpl._documents = {}
del state._templates[doc]
# Destroy document
doc.destroy(None)
#---------------------------------------------------------------------
# Public API
#---------------------------------------------------------------------
def create_doc_if_none_exists(doc: Optional[Document]) -> Document:
curdoc = doc or curdoc_locked()
if curdoc is None:
curdoc = Document()
elif not isinstance(curdoc, Document):
curdoc = curdoc._doc
return curdoc
def init_doc(doc: Optional[Document]) -> Document:
curdoc = create_doc_if_none_exists(doc)
if not curdoc.session_context:
return curdoc
thread = threading.current_thread()
if thread:
state._thread_id_[curdoc] = thread.ident
if config.global_loading_spinner:
curdoc.js_on_event(
'document_ready', CustomJS(code=f"""
const body = document.getElementsByTagName('body')[0]
body.classList.remove({LOADING_INDICATOR_CSS_CLASS!r}, {config.loading_spinner!r})
""")
)
session_id = curdoc.session_context.id
sessions = state.session_info['sessions']
if session_id not in sessions:
return curdoc
sessions[session_id].update({
'started': dt.datetime.now().timestamp()
})
curdoc.on_event('document_ready', state._init_session)
return curdoc
[docs]def with_lock(func: Callable) -> Callable:
"""
Wrap a callback function to execute with a lock allowing the
function to modify bokeh models directly.
Arguments
---------
func: callable
The callable to wrap
Returns
-------
wrapper: callable
Function wrapped to execute without a Document lock.
"""
if inspect.iscoroutinefunction(func):
@wraps(func)
async def wrapper(*args, **kw):
return await func(*args, **kw)
else:
@wraps(func)
def wrapper(*args, **kw):
return func(*args, **kw)
wrapper.lock = True # type: ignore
return wrapper
def dispatch_tornado(conn, events):
from tornado.websocket import WebSocketHandler
socket = conn._socket
ws_conn = getattr(socket, 'ws_connection', False)
if not ws_conn or ws_conn.is_closing(): # type: ignore
return []
msg = conn.protocol.create('PATCH-DOC', events)
futures = [
WebSocketHandler.write_message(socket, msg.header_json),
WebSocketHandler.write_message(socket, msg.metadata_json),
WebSocketHandler.write_message(socket, msg.content_json)
]
for buffer in msg._buffers:
header = json.dumps(buffer.ref)
payload = buffer.to_bytes()
futures.extend([
WebSocketHandler.write_message(socket, header),
WebSocketHandler.write_message(socket, payload, binary=True)
])
return futures
def dispatch_django(conn, events):
socket = conn._socket
msg = conn.protocol.create('PATCH-DOC', events)
futures = [
socket.send(text_data=msg.header_json),
socket.send(text_data=msg.metadata_json),
socket.send(text_data=msg.content_json)
]
for buffer in msg._buffers:
header = json.dumps(buffer.ref)
payload = buffer.to_bytes()
futures.extend([
socket.send(text_data=header),
socket.send(binary_data=payload)
])
return futures
[docs]@contextmanager
def unlocked() -> Iterator:
"""
Context manager which unlocks a Document and dispatches
ModelChangedEvents triggered in the context body to all sockets
on current sessions.
"""
curdoc = state.curdoc
session_context = getattr(curdoc, 'session_context', None)
session = getattr(session_context, 'session', None)
if curdoc is None or session_context is None or session is None or state._jupyter_kernel_context:
yield
return
elif curdoc.callbacks.hold_value:
yield
monkeypatch_events(curdoc.callbacks._held_events)
return
from tornado.websocket import WebSocketClosedError, WebSocketHandler
connections = session._subscribed_connections
curdoc.hold()
try:
yield
locked = False
for conn in connections:
socket = conn._socket
if hasattr(socket, 'write_lock') and socket.write_lock._block._value == 0:
locked = True
break
events = curdoc.callbacks._held_events
monkeypatch_events(events)
remaining_events, dispatch_events = [], []
for event in events:
if isinstance(event, ModelChangedEvent) and not locked:
dispatch_events.append(event)
else:
remaining_events.append(event)
futures = []
for conn in connections:
if not dispatch_events:
continue
elif isinstance(conn._socket, WebSocketHandler):
futures += dispatch_tornado(conn, dispatch_events)
else:
futures += dispatch_django(conn, dispatch_events)
# Ensure that all write_message calls are awaited and handled
async def handle_write_errors():
for future in futures:
try:
await future
except WebSocketClosedError:
logger.warning("Failed sending message as connection was closed")
except Exception as e:
logger.warning(f"Failed sending message due to following error: {e}")
if futures:
if state._unblocked(curdoc):
try:
asyncio.ensure_future(handle_write_errors())
except RuntimeError:
curdoc.add_next_tick_callback(handle_write_errors)
else:
curdoc.add_next_tick_callback(handle_write_errors)
curdoc.callbacks._held_events = remaining_events
finally:
try:
curdoc.unhold()
except RuntimeError:
if remaining_events:
curdoc.add_next_tick_callback(partial(_dispatch_events, curdoc, remaining_events))
