"""Base class for a kernel that talks to frontends over 0MQ.""" # Copyright (c) IPython Development Team. # Distributed under the terms of the Modified BSD License. from __future__ import print_function import sys import time import logging import uuid from datetime import datetime try: # jupyter_client >= 5, use tz-aware now from jupyter_client.session import utcnow as now except ImportError: # jupyter_client < 5, use local now() now = datetime.now from signal import signal, default_int_handler, SIGINT import zmq from tornado import ioloop from zmq.eventloop.zmqstream import ZMQStream from traitlets.config.configurable import SingletonConfigurable from IPython.core.error import StdinNotImplementedError from ipython_genutils import py3compat from ipython_genutils.py3compat import unicode_type, string_types from ipykernel.jsonutil import json_clean from traitlets import ( Any, Instance, Float, Dict, List, Set, Integer, Unicode, Bool, observe, default ) from jupyter_client.session import Session from ._version import kernel_protocol_version class Kernel(SingletonConfigurable): #--------------------------------------------------------------------------- # Kernel interface #--------------------------------------------------------------------------- # attribute to override with a GUI eventloop = Any(None) @observe('eventloop') def _update_eventloop(self, change): """schedule call to eventloop from IOLoop""" loop = ioloop.IOLoop.current() if change.new is not None: loop.add_callback(self.enter_eventloop) session = Instance(Session, allow_none=True) profile_dir = Instance('IPython.core.profiledir.ProfileDir', allow_none=True) shell_streams = List() control_stream = Instance(ZMQStream, allow_none=True) iopub_socket = Any() iopub_thread = Any() stdin_socket = Any() log = Instance(logging.Logger, allow_none=True) # identities: int_id = Integer(-1) ident = Unicode() @default('ident') def _default_ident(self): return unicode_type(uuid.uuid4()) # This should be overridden by wrapper kernels that implement any real # language. language_info = {} # any links that should go in the help menu help_links = List() # Private interface _darwin_app_nap = Bool(True, help="""Whether to use appnope for compatiblity with OS X App Nap. Only affects OS X >= 10.9. """ ).tag(config=True) # track associations with current request _allow_stdin = Bool(False) _parent_header = Dict() _parent_ident = Any(b'') # Time to sleep after flushing the stdout/err buffers in each execute # cycle. While this introduces a hard limit on the minimal latency of the # execute cycle, it helps prevent output synchronization problems for # clients. # Units are in seconds. The minimum zmq latency on local host is probably # ~150 microseconds, set this to 500us for now. We may need to increase it # a little if it's not enough after more interactive testing. _execute_sleep = Float(0.0005).tag(config=True) # Frequency of the kernel's event loop. # Units are in seconds, kernel subclasses for GUI toolkits may need to # adapt to milliseconds. _poll_interval = Float(0.05).tag(config=True) # If the shutdown was requested over the network, we leave here the # necessary reply message so it can be sent by our registered atexit # handler. This ensures that the reply is only sent to clients truly at # the end of our shutdown process (which happens after the underlying # IPython shell's own shutdown). _shutdown_message = None # This is a dict of port number that the kernel is listening on. It is set # by record_ports and used by connect_request. _recorded_ports = Dict() # set of aborted msg_ids aborted = Set() # Track execution count here. For IPython, we override this to use the # execution count we store in the shell. execution_count = 0 msg_types = [ 'execute_request', 'complete_request', 'inspect_request', 'history_request', 'comm_info_request', 'kernel_info_request', 'connect_request', 'shutdown_request', 'is_complete_request', # deprecated: 'apply_request', ] # add deprecated ipyparallel control messages control_msg_types = msg_types + ['clear_request', 'abort_request'] def __init__(self, **kwargs): super(Kernel, self).__init__(**kwargs) # Build dict of handlers for message types self.shell_handlers = {} for msg_type in self.msg_types: self.shell_handlers[msg_type] = getattr(self, msg_type) self.control_handlers = {} for msg_type in self.control_msg_types: self.control_handlers[msg_type] = getattr(self, msg_type) def dispatch_control(self, msg): """dispatch control requests""" idents,msg = self.session.feed_identities(msg, copy=False) try: msg = self.session.deserialize(msg, content=True, copy=False) except: self.log.error("Invalid Control Message", exc_info=True) return self.log.debug("Control received: %s", msg) # Set the parent message for side effects. self.set_parent(idents, msg) self._publish_status(u'busy') header = msg['header'] msg_type = header['msg_type'] handler = self.control_handlers.get(msg_type, None) if handler is None: self.log.error("UNKNOWN CONTROL MESSAGE TYPE: %r", msg_type) else: try: handler(self.control_stream, idents, msg) except Exception: self.log.error("Exception in control handler:", exc_info=True) sys.stdout.flush() sys.stderr.flush() self._publish_status(u'idle') def should_handle(self, stream, msg, idents): """Check whether a shell-channel message should be handled Allows subclasses to prevent handling of certain messages (e.g. aborted requests). """ msg_id = msg['header']['msg_id'] if msg_id in self.aborted: msg_type = msg['header']['msg_type'] # is it safe to assume a msg_id will not be resubmitted? self.aborted.remove(msg_id) reply_type = msg_type.split('_')[0] + '_reply' status = {'status' : 'aborted'} md = {'engine' : self.ident} md.update(status) self.session.send(stream, reply_type, metadata=md, content=status, parent=msg, ident=idents) return False return True def dispatch_shell(self, stream, msg): """dispatch shell requests""" # flush control requests first if self.control_stream: self.control_stream.flush() idents,msg = self.session.feed_identities(msg, copy=False) try: msg = self.session.deserialize(msg, content=True, copy=False) except: self.log.error("Invalid Message", exc_info=True) return # Set the parent message for side effects. self.set_parent(idents, msg) self._publish_status(u'busy') msg_type = msg['header']['msg_type'] # Print some info about this message and leave a '--->' marker, so it's # easier to trace visually the message chain when debugging. Each # handler prints its message at the end. self.log.debug('\n*** MESSAGE TYPE:%s***', msg_type) self.log.debug(' Content: %s\n --->\n ', msg['content']) if not self.should_handle(stream, msg, idents): return handler = self.shell_handlers.get(msg_type, None) if handler is None: self.log.warning("Unknown message type: %r", msg_type) else: self.log.debug("%s: %s", msg_type, msg) self.pre_handler_hook() try: handler(stream, idents, msg) except Exception: self.log.error("Exception in message handler:", exc_info=True) finally: self.post_handler_hook() sys.stdout.flush() sys.stderr.flush() self._publish_status(u'idle') def pre_handler_hook(self): """Hook to execute before calling message handler""" # ensure default_int_handler during handler call self.saved_sigint_handler = signal(SIGINT, default_int_handler) def post_handler_hook(self): """Hook to execute after calling message handler""" signal(SIGINT, self.saved_sigint_handler) def enter_eventloop(self): """enter eventloop""" self.log.info("entering eventloop %s", self.eventloop) for stream in self.shell_streams: # flush any pending replies, # which may be skipped by entering the eventloop stream.flush(zmq.POLLOUT) # restore default_int_handler self.pre_handler_hook() while self.eventloop is not None: try: self.eventloop(self) except KeyboardInterrupt: # Ctrl-C shouldn't crash the kernel self.log.error("KeyboardInterrupt caught in kernel") continue else: # eventloop exited cleanly, this means we should stop (right?) self.eventloop = None break self.post_handler_hook() self.log.info("exiting eventloop") def start(self): """register dispatchers for streams""" self.io_loop = ioloop.IOLoop.current() if self.control_stream: self.control_stream.on_recv(self.dispatch_control, copy=False) def make_dispatcher(stream): def dispatcher(msg): return self.dispatch_shell(stream, msg) return dispatcher for s in self.shell_streams: s.on_recv(make_dispatcher(s), copy=False) # publish idle status self._publish_status('starting') def do_one_iteration(self): """step eventloop just once""" if self.control_stream: self.control_stream.flush() for stream in self.shell_streams: # handle at most one request per iteration stream.flush(zmq.POLLIN, 1) stream.flush(zmq.POLLOUT) def record_ports(self, ports): """Record the ports that this kernel is using. The creator of the Kernel instance must call this methods if they want the :meth:`connect_request` method to return the port numbers. """ self._recorded_ports = ports #--------------------------------------------------------------------------- # Kernel request handlers #--------------------------------------------------------------------------- def _publish_execute_input(self, code, parent, execution_count): """Publish the code request on the iopub stream.""" self.session.send(self.iopub_socket, u'execute_input', {u'code':code, u'execution_count': execution_count}, parent=parent, ident=self._topic('execute_input') ) def _publish_status(self, status, parent=None): """send status (busy/idle) on IOPub""" self.session.send(self.iopub_socket, u'status', {u'execution_state': status}, parent=parent or self._parent_header, ident=self._topic('status'), ) def set_parent(self, ident, parent): """Set the current parent_header Side effects (IOPub messages) and replies are associated with the request that caused them via the parent_header. The parent identity is used to route input_request messages on the stdin channel. """ self._parent_ident = ident self._parent_header = parent def send_response(self, stream, msg_or_type, content=None, ident=None, buffers=None, track=False, header=None, metadata=None): """Send a response to the message we're currently processing. This accepts all the parameters of :meth:`jupyter_client.session.Session.send` except ``parent``. This relies on :meth:`set_parent` having been called for the current message. """ return self.session.send(stream, msg_or_type, content, self._parent_header, ident, buffers, track, header, metadata) def init_metadata(self, parent): """Initialize metadata. Run at the beginning of execution requests. """ # FIXME: `started` is part of ipyparallel # Remove for ipykernel 5.0 return { 'started': now(), } def finish_metadata(self, parent, metadata, reply_content): """Finish populating metadata. Run after completing an execution request. """ return metadata def execute_request(self, stream, ident, parent): """handle an execute_request""" try: content = parent[u'content'] code = py3compat.cast_unicode_py2(content[u'code']) silent = content[u'silent'] store_history = content.get(u'store_history', not silent) user_expressions = content.get('user_expressions', {}) allow_stdin = content.get('allow_stdin', False) except: self.log.error("Got bad msg: ") self.log.error("%s", parent) return stop_on_error = content.get('stop_on_error', True) metadata = self.init_metadata(parent) # Re-broadcast our input for the benefit of listening clients, and # start computing output if not silent: self.execution_count += 1 self._publish_execute_input(code, parent, self.execution_count) reply_content = self.do_execute(code, silent, store_history, user_expressions, allow_stdin) # Flush output before sending the reply. sys.stdout.flush() sys.stderr.flush() # FIXME: on rare occasions, the flush doesn't seem to make it to the # clients... This seems to mitigate the problem, but we definitely need # to better understand what's going on. if self._execute_sleep: time.sleep(self._execute_sleep) # Send the reply. reply_content = json_clean(reply_content) metadata = self.finish_metadata(parent, metadata, reply_content) reply_msg = self.session.send(stream, u'execute_reply', reply_content, parent, metadata=metadata, ident=ident) self.log.debug("%s", reply_msg) if not silent and reply_msg['content']['status'] == u'error' and stop_on_error: self._abort_queues() def do_execute(self, code, silent, store_history=True, user_expressions=None, allow_stdin=False): """Execute user code. Must be overridden by subclasses. """ raise NotImplementedError def complete_request(self, stream, ident, parent): content = parent['content'] code = content['code'] cursor_pos = content['cursor_pos'] matches = self.do_complete(code, cursor_pos) matches = json_clean(matches) completion_msg = self.session.send(stream, 'complete_reply', matches, parent, ident) def do_complete(self, code, cursor_pos): """Override in subclasses to find completions. """ return {'matches' : [], 'cursor_end' : cursor_pos, 'cursor_start' : cursor_pos, 'metadata' : {}, 'status' : 'ok'} def inspect_request(self, stream, ident, parent): content = parent['content'] reply_content = self.do_inspect(content['code'], content['cursor_pos'], content.get('detail_level', 0)) # Before we send this object over, we scrub it for JSON usage reply_content = json_clean(reply_content) msg = self.session.send(stream, 'inspect_reply', reply_content, parent, ident) self.log.debug("%s", msg) def do_inspect(self, code, cursor_pos, detail_level=0): """Override in subclasses to allow introspection. """ return {'status': 'ok', 'data': {}, 'metadata': {}, 'found': False} def history_request(self, stream, ident, parent): content = parent['content'] reply_content = self.do_history(**content) reply_content = json_clean(reply_content) msg = self.session.send(stream, 'history_reply', reply_content, parent, ident) self.log.debug("%s", msg) def do_history(self, hist_access_type, output, raw, session=None, start=None, stop=None, n=None, pattern=None, unique=False): """Override in subclasses to access history. """ return {'status': 'ok', 'history': []} def connect_request(self, stream, ident, parent): if self._recorded_ports is not None: content = self._recorded_ports.copy() else: content = {} content['status'] = 'ok' msg = self.session.send(stream, 'connect_reply', content, parent, ident) self.log.debug("%s", msg) @property def kernel_info(self): return { 'protocol_version': kernel_protocol_version, 'implementation': self.implementation, 'implementation_version': self.implementation_version, 'language_info': self.language_info, 'banner': self.banner, 'help_links': self.help_links, } def kernel_info_request(self, stream, ident, parent): content = {'status': 'ok'} content.update(self.kernel_info) msg = self.session.send(stream, 'kernel_info_reply', content, parent, ident) self.log.debug("%s", msg) def comm_info_request(self, stream, ident, parent): content = parent['content'] target_name = content.get('target_name', None) # Should this be moved to ipkernel? if hasattr(self, 'comm_manager'): comms = { k: dict(target_name=v.target_name) for (k, v) in self.comm_manager.comms.items() if v.target_name == target_name or target_name is None } else: comms = {} reply_content = dict(comms=comms, status='ok') msg = self.session.send(stream, 'comm_info_reply', reply_content, parent, ident) self.log.debug("%s", msg) def shutdown_request(self, stream, ident, parent): content = self.do_shutdown(parent['content']['restart']) self.session.send(stream, u'shutdown_reply', content, parent, ident=ident) # same content, but different msg_id for broadcasting on IOPub self._shutdown_message = self.session.msg(u'shutdown_reply', content, parent ) self._at_shutdown() # call sys.exit after a short delay loop = ioloop.IOLoop.current() loop.add_timeout(time.time()+0.1, loop.stop) def do_shutdown(self, restart): """Override in subclasses to do things when the frontend shuts down the kernel. """ return {'status': 'ok', 'restart': restart} def is_complete_request(self, stream, ident, parent): content = parent['content'] code = content['code'] reply_content = self.do_is_complete(code) reply_content = json_clean(reply_content) reply_msg = self.session.send(stream, 'is_complete_reply', reply_content, parent, ident) self.log.debug("%s", reply_msg) def do_is_complete(self, code): """Override in subclasses to find completions. """ return {'status' : 'unknown', } #--------------------------------------------------------------------------- # Engine methods (DEPRECATED) #--------------------------------------------------------------------------- def apply_request(self, stream, ident, parent): self.log.warning("apply_request is deprecated in kernel_base, moving to ipyparallel.") try: content = parent[u'content'] bufs = parent[u'buffers'] msg_id = parent['header']['msg_id'] except: self.log.error("Got bad msg: %s", parent, exc_info=True) return md = self.init_metadata(parent) reply_content, result_buf = self.do_apply(content, bufs, msg_id, md) # flush i/o sys.stdout.flush() sys.stderr.flush() md = self.finish_metadata(parent, md, reply_content) self.session.send(stream, u'apply_reply', reply_content, parent=parent, ident=ident,buffers=result_buf, metadata=md) def do_apply(self, content, bufs, msg_id, reply_metadata): """DEPRECATED""" raise NotImplementedError #--------------------------------------------------------------------------- # Control messages (DEPRECATED) #--------------------------------------------------------------------------- def abort_request(self, stream, ident, parent): """abort a specific msg by id""" self.log.warning("abort_request is deprecated in kernel_base. It os only part of IPython parallel") msg_ids = parent['content'].get('msg_ids', None) if isinstance(msg_ids, string_types): msg_ids = [msg_ids] if not msg_ids: self._abort_queues() for mid in msg_ids: self.aborted.add(str(mid)) content = dict(status='ok') reply_msg = self.session.send(stream, 'abort_reply', content=content, parent=parent, ident=ident) self.log.debug("%s", reply_msg) def clear_request(self, stream, idents, parent): """Clear our namespace.""" self.log.warning("clear_request is deprecated in kernel_base. It os only part of IPython parallel") content = self.do_clear() self.session.send(stream, 'clear_reply', ident=idents, parent=parent, content = content) def do_clear(self): """DEPRECATED""" raise NotImplementedError #--------------------------------------------------------------------------- # Protected interface #--------------------------------------------------------------------------- def _topic(self, topic): """prefixed topic for IOPub messages""" base = "kernel.%s" % self.ident return py3compat.cast_bytes("%s.%s" % (base, topic)) def _abort_queues(self): for stream in self.shell_streams: if stream: self._abort_queue(stream) def _abort_queue(self, stream): poller = zmq.Poller() poller.register(stream.socket, zmq.POLLIN) while True: idents,msg = self.session.recv(stream, zmq.NOBLOCK, content=True) if msg is None: return self.log.info("Aborting:") self.log.info("%s", msg) msg_type = msg['header']['msg_type'] reply_type = msg_type.split('_')[0] + '_reply' status = {'status' : 'aborted'} md = {'engine' : self.ident} md.update(status) self._publish_status('busy', parent=msg) reply_msg = self.session.send(stream, reply_type, metadata=md, content=status, parent=msg, ident=idents) self._publish_status('idle', parent=msg) self.log.debug("%s", reply_msg) # We need to wait a bit for requests to come in. This can probably # be set shorter for true asynchronous clients. poller.poll(50) def _no_raw_input(self): """Raise StdinNotImplentedError if active frontend doesn't support stdin.""" raise StdinNotImplementedError("raw_input was called, but this " "frontend does not support stdin.") def getpass(self, prompt='', stream=None): """Forward getpass to frontends Raises ------ StdinNotImplentedError if active frontend doesn't support stdin. """ if not self._allow_stdin: raise StdinNotImplementedError( "getpass was called, but this frontend does not support input requests." ) if stream is not None: import warnings warnings.warn("The `stream` parameter of `getpass.getpass` will have no effect when using ipykernel", UserWarning, stacklevel=2) return self._input_request(prompt, self._parent_ident, self._parent_header, password=True, ) def raw_input(self, prompt=''): """Forward raw_input to frontends Raises ------ StdinNotImplentedError if active frontend doesn't support stdin. """ if not self._allow_stdin: raise StdinNotImplementedError( "raw_input was called, but this frontend does not support input requests." ) return self._input_request(str(prompt), self._parent_ident, self._parent_header, password=False, ) def _input_request(self, prompt, ident, parent, password=False): # Flush output before making the request. sys.stderr.flush() sys.stdout.flush() # flush the stdin socket, to purge stale replies while True: try: self.stdin_socket.recv_multipart(zmq.NOBLOCK) except zmq.ZMQError as e: if e.errno == zmq.EAGAIN: break else: raise # Send the input request. content = json_clean(dict(prompt=prompt, password=password)) self.session.send(self.stdin_socket, u'input_request', content, parent, ident=ident) # Await a response. while True: try: ident, reply = self.session.recv(self.stdin_socket, 0) except Exception: self.log.warning("Invalid Message:", exc_info=True) except KeyboardInterrupt: # re-raise KeyboardInterrupt, to truncate traceback raise KeyboardInterrupt else: break try: value = py3compat.unicode_to_str(reply['content']['value']) except: self.log.error("Bad input_reply: %s", parent) value = '' if value == '\x04': # EOF raise EOFError return value def _at_shutdown(self): """Actions taken at shutdown by the kernel, called by python's atexit. """ # io.raw_print("Kernel at_shutdown") # dbg if self._shutdown_message is not None: self.session.send(self.iopub_socket, self._shutdown_message, ident=self._topic('shutdown')) self.log.debug("%s", self._shutdown_message) [ s.flush(zmq.POLLOUT) for s in self.shell_streams ]