''' Provides the Bokeh Server Tornado application.
'''
from __future__ import absolute_import, print_function
import logging
log = logging.getLogger(__name__)
import os
from pprint import pformat
from tornado import gen
from tornado.ioloop import PeriodicCallback
from tornado.web import Application as TornadoApplication
from tornado.web import StaticFileHandler
from ..application import Application
from ..resources import Resources
from ..settings import settings
from .application_context import ApplicationContext
from .connection import ServerConnection
from .urls import per_app_patterns, toplevel_patterns
from .views.root_handler import RootHandler
from .views.static_handler import StaticHandler
[docs]class BokehTornado(TornadoApplication):
''' A Tornado Application used to implement the Bokeh Server.
Args:
applications (dict[str,Application] or Application) :
A map from paths to ``Application`` instances.
If the value is a single Application, then the following mapping
is generated:
.. code-block:: python
applications = { '/' : applications }
When a connection comes in to a given path, the associate
Application is used to generate a new document for the session.
prefix (str, optional) :
A URL prefix to use for all Bokeh server paths. (default: None)
extra_websocket_origins (list[str], optional) :
A list of hosts that can connect to the websocket.
This is typically required when embedding a Bokeh server app in an
external web site using :func:`~bokeh.embed.server_document` or
similar.
If None, ``["localhost"]`` will be assumed (default: None)
extra_patterns (seq[tuple], optional) :
A list of tuples of (str, http or websocket handler)
Use this argument to add additional endpoints to custom deployments
of the Bokeh Server.
If None, then ``[]`` will be used. (default: None)
secret_key (str, optional) :
A secret key for signing session IDs.
Defaults to the current value of the environment variable
``BOKEH_SECRET_KEY``
sign_sessions (bool, optional) :
Whether to cryptographically sign session IDs
Defaults to the current value of the environment variable
``BOKEH_SIGN_SESSIONS``. If ``True``, then ``secret_key`` must
also be provided (either via environment setting or passed as
a parameter value)
generate_session_ids (bool, optional) :
Whether to generate a session ID if one is not provided
(default: True)
keep_alive_milliseconds (int, optional) :
Number of milliseconds between keep-alive pings (default: 37000)
Pings normally required to keep the websocket open. Set to 0 to
disable pings.
check_unused_sessions_milliseconds (int, optional) :
Number of milliseconds between checking for unused sessions
(default: 17000)
unused_session_lifetime_milliseconds (int, optional) :
Number of milliseconds for unused session lifetime (default: 15000)
stats_log_frequency_milliseconds (int, optional) :
Number of milliseconds between logging stats (default: 15000)
use_index (bool, optional) :
Whether to generate an index of running apps in the ``RootHandler``
(default: True)
redirect_root (bool, optional) :
When there is only a single running application, whether to
redirect requests to ``"/"`` to that application automatically
(default: True)
If there are multiple Bokeh applications configured, this option
has no effect.
'''
def __init__(self,
applications,
prefix=None,
extra_websocket_origins=None,
extra_patterns=None,
secret_key=settings.secret_key_bytes(),
sign_sessions=settings.sign_sessions(),
generate_session_ids=True,
keep_alive_milliseconds=37000, # heroku, nginx default to 60s timeout, so use less than that
check_unused_sessions_milliseconds=17000,
unused_session_lifetime_milliseconds=15000,
stats_log_frequency_milliseconds=15000,
use_index=True,
redirect_root=True):
# This will be set when initialize is called
self._loop = None
if isinstance(applications, Application):
applications = { '/' : applications }
if prefix is None:
prefix = ""
prefix = prefix.strip("/")
if prefix:
prefix = "/" + prefix
self._prefix = prefix
if keep_alive_milliseconds < 0:
# 0 means "disable"
raise ValueError("keep_alive_milliseconds must be >= 0")
if check_unused_sessions_milliseconds <= 0:
raise ValueError("check_unused_sessions_milliseconds must be > 0")
if unused_session_lifetime_milliseconds <= 0:
raise ValueError("check_unused_sessions_milliseconds must be > 0")
if stats_log_frequency_milliseconds <= 0:
raise ValueError("stats_log_frequency_milliseconds must be > 0")
self._keep_alive_milliseconds = keep_alive_milliseconds
self._check_unused_sessions_milliseconds = check_unused_sessions_milliseconds
self._unused_session_lifetime_milliseconds = unused_session_lifetime_milliseconds
self._stats_log_frequency_milliseconds = stats_log_frequency_milliseconds
if extra_websocket_origins is None:
self._websocket_origins = set()
else:
self._websocket_origins = set(extra_websocket_origins)
self._secret_key = secret_key
self._sign_sessions = sign_sessions
self._generate_session_ids = generate_session_ids
log.debug("These host origins can connect to the websocket: %r", list(self._websocket_origins))
# Wrap applications in ApplicationContext
self._applications = dict()
for k,v in applications.items():
self._applications[k] = ApplicationContext(v,url=k)
extra_patterns = extra_patterns or []
all_patterns = []
for key, app in applications.items():
app_patterns = []
for p in per_app_patterns:
if key == "/":
route = p[0]
else:
route = key + p[0]
route = self._prefix + route
app_patterns.append((route, p[1], { "application_context" : self._applications[key] }))
websocket_path = None
for r in app_patterns:
if r[0].endswith("/ws"):
websocket_path = r[0]
if not websocket_path:
raise RuntimeError("Couldn't find websocket path")
for r in app_patterns:
r[2]["bokeh_websocket_path"] = websocket_path
all_patterns.extend(app_patterns)
# add a per-app static path if requested by the application
if app.static_path is not None:
if key == "/":
route = "/static/(.*)"
else:
route = key + "/static/(.*)"
route = self._prefix + route
all_patterns.append((route, StaticFileHandler, { "path" : app.static_path }))
for p in extra_patterns + toplevel_patterns:
if p[1] == RootHandler:
if use_index:
data = {"applications": self._applications,
"prefix": self._prefix,
"use_redirect": redirect_root}
prefixed_pat = (self._prefix + p[0],) + p[1:] + (data,)
all_patterns.append(prefixed_pat)
else:
prefixed_pat = (self._prefix + p[0],) + p[1:]
all_patterns.append(prefixed_pat)
log.debug("Patterns are:")
for line in pformat(all_patterns, width=60).split("\n"):
log.debug(" " + line)
super(BokehTornado, self).__init__(all_patterns)
[docs] def initialize(self, io_loop):
''' Start a Bokeh Server Tornado Application on a given Tornado IOLoop.
'''
self._loop = io_loop
for app_context in self._applications.values():
app_context._loop = self._loop
self._clients = set()
self._stats_job = PeriodicCallback(self._log_stats,
self._stats_log_frequency_milliseconds,
io_loop=self._loop)
self._cleanup_job = PeriodicCallback(self._cleanup_sessions,
self._check_unused_sessions_milliseconds,
io_loop=self._loop)
if self._keep_alive_milliseconds > 0:
self._ping_job = PeriodicCallback(self._keep_alive, self._keep_alive_milliseconds, io_loop=self._loop)
else:
self._ping_job = None
@property
def app_paths(self):
''' A list of all application paths for all Bokeh applications
configured on this Bokeh server instance.
'''
return set(self._applications)
@property
def io_loop(self):
''' The Tornado IOLoop that this Bokeh Server Tornado Application
is running on.
'''
return self._loop
@property
def prefix(self):
''' A URL prefix for this Bokeh Server Tornado Application to use
for all paths
'''
return self._prefix
@property
def websocket_origins(self):
''' A list of websocket origins permitted to connect to this server.
'''
return self._websocket_origins
@property
def secret_key(self):
''' A secret key for this Bokeh Server Tornado Application to use when
signing session IDs, if configured.
'''
return self._secret_key
@property
def sign_sessions(self):
''' Whether this Bokeh Server Tornado Application has been configured
to cryptographically sign session IDs
If ``True``, then ``secret_key`` must also have been configured.
'''
return self._sign_sessions
@property
def generate_session_ids(self):
''' Whether this Bokeh Server Tornado Application has been configured
to automatically generate session IDs.
'''
return self._generate_session_ids
[docs] def resources(self, absolute_url=None):
''' Provide a :class:`~bokeh.resources.Resources` that specifies where
Bokeh application sessions should load BokehJS resources from.
Args:
absolute_url (bool):
An absolute URL prefix to use for locating resources. If None,
relative URLs are used (default: None)
'''
if absolute_url:
return Resources(mode="server", root_url=absolute_url + self._prefix, path_versioner=StaticHandler.append_version)
return Resources(mode="server", root_url=self._prefix, path_versioner=StaticHandler.append_version)
[docs] def start(self):
''' Start the Bokeh Server application.
Starting the Bokeh Server Tornado application will run periodic
callbacks for stats logging, cleanup, pinging, etc. Additionally, any
startup hooks defined by the configured Bokeh applications will be run.
'''
self._stats_job.start()
self._cleanup_job.start()
if self._ping_job is not None:
self._ping_job.start()
for context in self._applications.values():
context.run_load_hook()
[docs] def stop(self, wait=True):
''' Stop the Bokeh Server application.
Args:
wait (bool): whether to wait for orderly cleanup (default: True)
Returns:
None
'''
# TODO should probably close all connections and shut down all sessions here
for context in self._applications.values():
context.run_unload_hook()
self._stats_job.stop()
self._cleanup_job.stop()
if self._ping_job is not None:
self._ping_job.stop()
self._clients.clear()
def new_connection(self, protocol, socket, application_context, session):
connection = ServerConnection(protocol, socket, application_context, session)
self._clients.add(connection)
return connection
def client_lost(self, connection):
self._clients.discard(connection)
connection.detach_session()
[docs] def get_session(self, app_path, session_id):
''' Get an active a session by name application path and session ID.
Args:
app_path (str) :
The configured application path for the application to return
a session for.
session_id (str) :
The session ID of the session to retrieve.
Returns:
ServerSession
'''
if app_path not in self._applications:
raise ValueError("Application %s does not exist on this server" % app_path)
return self._applications[app_path].get_session(session_id)
[docs] def get_sessions(self, app_path):
''' Gets all currently active sessions for an application.
Args:
app_path (str) :
The configured application path for the application to return
sessions for.
Returns:
list[ServerSession]
'''
if app_path not in self._applications:
raise ValueError("Application %s does not exist on this server" % app_path)
return list(self._applications[app_path].sessions)
# Periodic Callbacks ------------------------------------------------------
@gen.coroutine
def _cleanup_sessions(self):
for app in self._applications.values():
yield app._cleanup_sessions(self._unused_session_lifetime_milliseconds)
raise gen.Return(None)
def _log_stats(self):
if log.getEffectiveLevel() > logging.DEBUG:
# avoid the work below if we aren't going to log anything
return
log.debug("[pid %d] %d clients connected", os.getpid(), len(self._clients))
for app_path, app in self._applications.items():
sessions = list(app.sessions)
unused_count = 0
for s in sessions:
if s.connection_count == 0:
unused_count += 1
log.debug("[pid %d] %s has %d sessions with %d unused",
os.getpid(), app_path, len(sessions), unused_count)
def _keep_alive(self):
for c in self._clients:
c.send_ping()
