Source code for

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 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 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 = sessions = state.session_info['sessions'] if session_id not in sessions: return curdoc sessions[session_id].update({ 'started': }) 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))