"""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 from signal import ( signal, default_int_handler, SIGINT ) import zmq from zmq.eventloop import ioloop from zmq.eventloop.zmqstream import ZMQStream from IPython.config.configurable import SingletonConfigurable from IPython.core.error import StdinNotImplementedError from IPython.core import release from IPython.utils import py3compat from IPython.utils.py3compat import unicode_type, string_types from IPython.utils.jsonutil import json_clean from IPython.utils.traitlets import ( Any, Instance, Float, Dict, List, Set, Integer, Unicode, Bool, ) from .session import Session class Kernel(SingletonConfigurable): #--------------------------------------------------------------------------- # Kernel interface #--------------------------------------------------------------------------- # attribute to override with a GUI eventloop = Any(None) def _eventloop_changed(self, name, old, new): """schedule call to eventloop from IOLoop""" loop = ioloop.IOLoop.instance() loop.add_callback(self.enter_eventloop) session = Instance(Session) profile_dir = Instance('IPython.core.profiledir.ProfileDir') shell_streams = List() control_stream = Instance(ZMQStream) iopub_socket = Instance(zmq.Socket) stdin_socket = Instance(zmq.Socket) log = Instance(logging.Logger) # identities: int_id = Integer(-1) ident = Unicode() def _ident_default(self): return unicode_type(uuid.uuid4()) # Private interface _darwin_app_nap = Bool(True, config=True, help="""Whether to use appnope for compatiblity with OS X App Nap. Only affects OS X >= 10.9. """ ) # 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, 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, 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 def __init__(self, **kwargs): super(Kernel, self).__init__(**kwargs) # Build dict of handlers for message types msg_types = [ 'execute_request', 'complete_request', 'inspect_request', 'history_request', 'kernel_info_request', 'connect_request', 'shutdown_request', 'apply_request', 'is_complete_request', ] self.shell_handlers = {} for msg_type in msg_types: self.shell_handlers[msg_type] = getattr(self, msg_type) control_msg_types = msg_types + [ 'clear_request', 'abort_request' ] self.control_handlers = {} for msg_type in 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.unserialize(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 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.unserialize(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') header = msg['header'] msg_id = header['msg_id'] 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 msg_id in self.aborted: self.aborted.remove(msg_id) # is it safe to assume a msg_id will not be resubmitted? 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 handler = self.shell_handlers.get(msg_type, None) if handler is None: self.log.error("UNKNOWN MESSAGE TYPE: %r", msg_type) else: # ensure default_int_handler during handler call sig = signal(SIGINT, default_int_handler) self.log.debug("%s: %s", msg_type, msg) try: handler(stream, idents, msg) except Exception: self.log.error("Exception in message handler:", exc_info=True) finally: signal(SIGINT, sig) sys.stdout.flush() sys.stderr.flush() self._publish_status(u'idle') 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 signal(SIGINT, default_int_handler) 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.log.info("exiting eventloop") def start(self): """register dispatchers for streams""" 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 _make_metadata(self, other=None): """init metadata dict, for execute/apply_reply""" new_md = { 'dependencies_met' : True, 'engine' : self.ident, 'started': datetime.now(), } if other: new_md.update(other) return new_md 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:`IPython.kernel.zmq.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 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 md = self._make_metadata(parent['metadata']) # 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) md['status'] = reply_content['status'] if reply_content['status'] == 'error' and \ reply_content['ename'] == 'UnmetDependency': md['dependencies_met'] = False reply_msg = self.session.send(stream, u'execute_reply', reply_content, parent, metadata=md, ident=ident) self.log.debug("%s", reply_msg) if not silent and reply_msg['content']['status'] == u'error': self._abort_queues() def do_execute(self, code, silent, store_history=True, user_experssions=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) self.log.debug("%s", completion_msg) 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 {'history': []} def connect_request(self, stream, ident, parent): if self._recorded_ports is not None: content = self._recorded_ports.copy() else: content = {} msg = self.session.send(stream, 'connect_reply', content, parent, ident) self.log.debug("%s", msg) @property def kernel_info(self): return { 'protocol_version': release.kernel_protocol_version, 'implementation': self.implementation, 'implementation_version': self.implementation_version, 'language': self.language, 'language_version': self.language_version, 'banner': self.banner, } def kernel_info_request(self, stream, ident, parent): msg = self.session.send(stream, 'kernel_info_reply', self.kernel_info, 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.instance() 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 #--------------------------------------------------------------------------- def apply_request(self, stream, ident, parent): 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._make_metadata(parent['metadata']) reply_content, result_buf = self.do_apply(content, bufs, msg_id, md) # put 'ok'/'error' status in header, for scheduler introspection: md['status'] = reply_content['status'] # flush i/o sys.stdout.flush() sys.stderr.flush() 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): """Override in subclasses to support the IPython parallel framework. """ raise NotImplementedError #--------------------------------------------------------------------------- # Control messages #--------------------------------------------------------------------------- def abort_request(self, stream, ident, parent): """abort a specific msg by id""" 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.""" content = self.do_clear() self.session.send(stream, 'clear_reply', ident=idents, parent=parent, content = content) def do_clear(self): """Override in subclasses to clear the namespace This is only required for IPython.parallel. """ raise NotImplementedError #--------------------------------------------------------------------------- # Protected interface #--------------------------------------------------------------------------- def _topic(self, topic): """prefixed topic for IOPub messages""" if self.int_id >= 0: base = "engine.%i" % self.int_id else: 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) reply_msg = self.session.send(stream, reply_type, metadata=md, content=status, parent=msg, ident=idents) 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=''): """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." ) 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(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.warn("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.rprint("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 ]