"""Implements an async kernel client""" # Copyright (c) Jupyter Development Team. # Distributed under the terms of the Modified BSD License. from functools import partial from getpass import getpass from queue import Empty import sys import time import zmq import zmq.asyncio import asyncio from traitlets import (Type, Instance) from jupyter_client.channels import HBChannel from jupyter_client.client import KernelClient from .channels import ZMQSocketChannel def reqrep(meth, channel='shell'): def wrapped(self, *args, **kwargs): reply = kwargs.pop('reply', False) timeout = kwargs.pop('timeout', None) msg_id = meth(self, *args, **kwargs) if not reply: return msg_id return self._recv_reply(msg_id, timeout=timeout, channel=channel) if not meth.__doc__: # python -OO removes docstrings, # so don't bother building the wrapped docstring return wrapped basedoc, _ = meth.__doc__.split('Returns\n', 1) parts = [basedoc.strip()] if 'Parameters' not in basedoc: parts.append(""" Parameters ---------- """) parts.append(""" reply: bool (default: False) Whether to wait for and return reply timeout: float or None (default: None) Timeout to use when waiting for a reply Returns ------- msg_id: str The msg_id of the request sent, if reply=False (default) reply: dict The reply message for this request, if reply=True """) wrapped.__doc__ = '\n'.join(parts) return wrapped class AsyncKernelClient(KernelClient): """A KernelClient with async APIs ``get_[channel]_msg()`` methods wait for and return messages on channels, raising :exc:`queue.Empty` if no message arrives within ``timeout`` seconds. """ # The PyZMQ Context to use for communication with the kernel. context = Instance(zmq.asyncio.Context) def _context_default(self): return zmq.asyncio.Context() #-------------------------------------------------------------------------- # Channel proxy methods #-------------------------------------------------------------------------- async def get_shell_msg(self, *args, **kwargs): """Get a message from the shell channel""" return await self.shell_channel.get_msg(*args, **kwargs) async def get_iopub_msg(self, *args, **kwargs): """Get a message from the iopub channel""" return await self.iopub_channel.get_msg(*args, **kwargs) async def get_stdin_msg(self, *args, **kwargs): """Get a message from the stdin channel""" return await self.stdin_channel.get_msg(*args, **kwargs) async def get_control_msg(self, *args, **kwargs): """Get a message from the control channel""" return await self.control_channel.get_msg(*args, **kwargs) @property def hb_channel(self): """Get the hb channel object for this kernel.""" if self._hb_channel is None: url = self._make_url('hb') self.log.debug("connecting heartbeat channel to %s", url) loop = asyncio.new_event_loop() self._hb_channel = self.hb_channel_class( self.context, self.session, url, loop ) return self._hb_channel async def wait_for_ready(self, timeout=None): """Waits for a response when a client is blocked - Sets future time for timeout - Blocks on shell channel until a message is received - Exit if the kernel has died - If client times out before receiving a message from the kernel, send RuntimeError - Flush the IOPub channel """ if timeout is None: abs_timeout = float('inf') else: abs_timeout = time.time() + timeout from ..manager import KernelManager if not isinstance(self.parent, KernelManager): # This Client was not created by a KernelManager, # so wait for kernel to become responsive to heartbeats # before checking for kernel_info reply while not self.is_alive(): if time.time() > abs_timeout: raise RuntimeError("Kernel didn't respond to heartbeats in %d seconds and timed out" % timeout) await asyncio.sleep(0.2) # Wait for kernel info reply on shell channel while True: try: msg = await self.shell_channel.get_msg(timeout=1) except Empty: pass else: if msg['msg_type'] == 'kernel_info_reply': self._handle_kernel_info_reply(msg) break if not await self.is_alive(): raise RuntimeError('Kernel died before replying to kernel_info') # Check if current time is ready check time plus timeout if time.time() > abs_timeout: raise RuntimeError("Kernel didn't respond in %d seconds" % timeout) # Flush IOPub channel while True: try: msg = await self.iopub_channel.get_msg(timeout=0.2) except Empty: break # The classes to use for the various channels shell_channel_class = Type(ZMQSocketChannel) iopub_channel_class = Type(ZMQSocketChannel) stdin_channel_class = Type(ZMQSocketChannel) hb_channel_class = Type(HBChannel) control_channel_class = Type(ZMQSocketChannel) async def _recv_reply(self, msg_id, timeout=None, channel='shell'): """Receive and return the reply for a given request""" if timeout is not None: deadline = time.monotonic() + timeout while True: if timeout is not None: timeout = max(0, deadline - time.monotonic()) try: if channel == 'control': reply = await self.get_control_msg(timeout=timeout) else: reply = await self.get_shell_msg(timeout=timeout) except Empty as e: raise TimeoutError("Timeout waiting for reply") from e if reply['parent_header'].get('msg_id') != msg_id: # not my reply, someone may have forgotten to retrieve theirs continue return reply # replies come on the shell channel execute = reqrep(KernelClient.execute) history = reqrep(KernelClient.history) complete = reqrep(KernelClient.complete) inspect = reqrep(KernelClient.inspect) kernel_info = reqrep(KernelClient.kernel_info) comm_info = reqrep(KernelClient.comm_info) # replies come on the control channel shutdown = reqrep(KernelClient.shutdown, channel='control') def _stdin_hook_default(self, msg): """Handle an input request""" content = msg['content'] if content.get('password', False): prompt = getpass else: prompt = input try: raw_data = prompt(content["prompt"]) except EOFError: # turn EOFError into EOF character raw_data = '\x04' except KeyboardInterrupt: sys.stdout.write('\n') return # only send stdin reply if there *was not* another request # or execution finished while we were reading. if not (self.stdin_channel.msg_ready() or self.shell_channel.msg_ready()): self.input(raw_data) def _output_hook_default(self, msg): """Default hook for redisplaying plain-text output""" msg_type = msg['header']['msg_type'] content = msg['content'] if msg_type == 'stream': stream = getattr(sys, content['name']) stream.write(content['text']) elif msg_type in ('display_data', 'execute_result'): sys.stdout.write(content['data'].get('text/plain', '')) elif msg_type == 'error': print('\n'.join(content['traceback']), file=sys.stderr) def _output_hook_kernel(self, session, socket, parent_header, msg): """Output hook when running inside an IPython kernel adds rich output support. """ msg_type = msg['header']['msg_type'] if msg_type in ('display_data', 'execute_result', 'error'): session.send(socket, msg_type, msg['content'], parent=parent_header) else: self._output_hook_default(msg) async def is_alive(self): """Is the kernel process still running?""" from ..manager import KernelManager, AsyncKernelManager if isinstance(self.parent, KernelManager): # This KernelClient was created by a KernelManager, # we can ask the parent KernelManager: if isinstance(self.parent, AsyncKernelManager): return await self.parent.is_alive() return self.parent.is_alive() if self._hb_channel is not None: # We don't have access to the KernelManager, # so we use the heartbeat. return self._hb_channel.is_beating() else: # no heartbeat and not local, we can't tell if it's running, # so naively return True return True async def execute_interactive(self, code, silent=False, store_history=True, user_expressions=None, allow_stdin=None, stop_on_error=True, timeout=None, output_hook=None, stdin_hook=None, ): """Execute code in the kernel interactively Output will be redisplayed, and stdin prompts will be relayed as well. If an IPython kernel is detected, rich output will be displayed. You can pass a custom output_hook callable that will be called with every IOPub message that is produced instead of the default redisplay. Parameters ---------- code : str A string of code in the kernel's language. silent : bool, optional (default False) If set, the kernel will execute the code as quietly possible, and will force store_history to be False. store_history : bool, optional (default True) If set, the kernel will store command history. This is forced to be False if silent is True. user_expressions : dict, optional A dict mapping names to expressions to be evaluated in the user's dict. The expression values are returned as strings formatted using :func:`repr`. allow_stdin : bool, optional (default self.allow_stdin) Flag for whether the kernel can send stdin requests to frontends. Some frontends (e.g. the Notebook) do not support stdin requests. If raw_input is called from code executed from such a frontend, a StdinNotImplementedError will be raised. stop_on_error: bool, optional (default True) Flag whether to abort the execution queue, if an exception is encountered. timeout: float or None (default: None) Timeout to use when waiting for a reply output_hook: callable(msg) Function to be called with output messages. If not specified, output will be redisplayed. stdin_hook: callable(msg) Function to be called with stdin_request messages. If not specified, input/getpass will be called. Returns ------- reply: dict The reply message for this request """ if not self.iopub_channel.is_alive(): raise RuntimeError("IOPub channel must be running to receive output") if allow_stdin is None: allow_stdin = self.allow_stdin if allow_stdin and not self.stdin_channel.is_alive(): raise RuntimeError("stdin channel must be running to allow input") msg_id = await self.execute(code, silent=silent, store_history=store_history, user_expressions=user_expressions, allow_stdin=allow_stdin, stop_on_error=stop_on_error, ) if stdin_hook is None: stdin_hook = self._stdin_hook_default if output_hook is None: # detect IPython kernel if 'IPython' in sys.modules: from IPython import get_ipython ip = get_ipython() in_kernel = getattr(ip, 'kernel', False) if in_kernel: output_hook = partial( self._output_hook_kernel, ip.display_pub.session, ip.display_pub.pub_socket, ip.display_pub.parent_header, ) if output_hook is None: # default: redisplay plain-text outputs output_hook = self._output_hook_default # set deadline based on timeout if timeout is not None: deadline = time.monotonic() + timeout else: timeout_ms = None poller = zmq.Poller() iopub_socket = self.iopub_channel.socket poller.register(iopub_socket, zmq.POLLIN) if allow_stdin: stdin_socket = self.stdin_channel.socket poller.register(stdin_socket, zmq.POLLIN) else: stdin_socket = None # wait for output and redisplay it while True: if timeout is not None: timeout = max(0, deadline - time.monotonic()) timeout_ms = 1e3 * timeout events = dict(poller.poll(timeout_ms)) if not events: raise TimeoutError("Timeout waiting for output") if stdin_socket in events: req = await self.stdin_channel.get_msg(timeout=0) stdin_hook(req) continue if iopub_socket not in events: continue msg = await self.iopub_channel.get_msg(timeout=0) if msg['parent_header'].get('msg_id') != msg_id: # not from my request continue output_hook(msg) # stop on idle if msg['header']['msg_type'] == 'status' and \ msg['content']['execution_state'] == 'idle': break # output is done, get the reply if timeout is not None: timeout = max(0, deadline - time.monotonic()) return await self._recv_reply(msg_id, timeout=timeout)