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185 lines
5.5 KiB
185 lines
5.5 KiB
"""Base class for a Comm"""
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# Copyright (c) IPython Development Team.
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# Distributed under the terms of the Modified BSD License.
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import uuid
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from traitlets import Any, Bool, Bytes, Dict, Instance, Unicode, default
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from traitlets.config import LoggingConfigurable
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from ipykernel.jsonutil import json_clean
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from ipykernel.kernelbase import Kernel
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class Comm(LoggingConfigurable):
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"""Class for communicating between a Frontend and a Kernel"""
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kernel = Instance("ipykernel.kernelbase.Kernel", allow_none=True)
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@default("kernel")
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def _default_kernel(self):
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if Kernel.initialized():
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return Kernel.instance()
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comm_id = Unicode()
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@default("comm_id")
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def _default_comm_id(self):
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return uuid.uuid4().hex
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primary = Bool(True, help="Am I the primary or secondary Comm?")
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target_name = Unicode("comm")
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target_module = Unicode(
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None,
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allow_none=True,
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help="""requirejs module from
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which to load comm target.""",
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)
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topic = Bytes()
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@default("topic")
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def _default_topic(self):
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return ("comm-%s" % self.comm_id).encode("ascii")
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_open_data = Dict(help="data dict, if any, to be included in comm_open")
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_close_data = Dict(help="data dict, if any, to be included in comm_close")
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_msg_callback = Any()
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_close_callback = Any()
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_closed = Bool(True)
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def __init__(self, target_name="", data=None, metadata=None, buffers=None, **kwargs):
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if target_name:
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kwargs["target_name"] = target_name
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super().__init__(**kwargs)
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if self.kernel:
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if self.primary:
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# I am primary, open my peer.
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self.open(data=data, metadata=metadata, buffers=buffers)
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else:
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self._closed = False
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def _publish_msg(self, msg_type, data=None, metadata=None, buffers=None, **keys):
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"""Helper for sending a comm message on IOPub"""
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data = {} if data is None else data
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metadata = {} if metadata is None else metadata
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content = json_clean(dict(data=data, comm_id=self.comm_id, **keys))
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self.kernel.session.send(
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self.kernel.iopub_socket,
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msg_type,
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content,
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metadata=json_clean(metadata),
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parent=self.kernel.get_parent("shell"),
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ident=self.topic,
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buffers=buffers,
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)
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def __del__(self):
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"""trigger close on gc"""
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self.close(deleting=True)
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# publishing messages
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def open(self, data=None, metadata=None, buffers=None):
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"""Open the frontend-side version of this comm"""
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if data is None:
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data = self._open_data
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comm_manager = getattr(self.kernel, "comm_manager", None)
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if comm_manager is None:
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raise RuntimeError(
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"Comms cannot be opened without a kernel "
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"and a comm_manager attached to that kernel."
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)
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comm_manager.register_comm(self)
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try:
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self._publish_msg(
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"comm_open",
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data=data,
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metadata=metadata,
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buffers=buffers,
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target_name=self.target_name,
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target_module=self.target_module,
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)
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self._closed = False
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except Exception:
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comm_manager.unregister_comm(self)
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raise
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def close(self, data=None, metadata=None, buffers=None, deleting=False):
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"""Close the frontend-side version of this comm"""
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if self._closed:
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# only close once
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return
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self._closed = True
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# nothing to send if we have no kernel
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# can be None during interpreter cleanup
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if not self.kernel:
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return
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if data is None:
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data = self._close_data
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self._publish_msg(
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"comm_close",
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data=data,
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metadata=metadata,
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buffers=buffers,
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)
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if not deleting:
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# If deleting, the comm can't be registered
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self.kernel.comm_manager.unregister_comm(self)
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def send(self, data=None, metadata=None, buffers=None):
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"""Send a message to the frontend-side version of this comm"""
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self._publish_msg(
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"comm_msg",
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data=data,
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metadata=metadata,
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buffers=buffers,
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)
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# registering callbacks
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def on_close(self, callback):
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"""Register a callback for comm_close
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Will be called with the `data` of the close message.
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Call `on_close(None)` to disable an existing callback.
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"""
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self._close_callback = callback
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def on_msg(self, callback):
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"""Register a callback for comm_msg
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Will be called with the `data` of any comm_msg messages.
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Call `on_msg(None)` to disable an existing callback.
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"""
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self._msg_callback = callback
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# handling of incoming messages
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def handle_close(self, msg):
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"""Handle a comm_close message"""
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self.log.debug("handle_close[%s](%s)", self.comm_id, msg)
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if self._close_callback:
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self._close_callback(msg)
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def handle_msg(self, msg):
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"""Handle a comm_msg message"""
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self.log.debug("handle_msg[%s](%s)", self.comm_id, msg)
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if self._msg_callback:
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shell = self.kernel.shell
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if shell:
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shell.events.trigger("pre_execute")
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self._msg_callback(msg)
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if shell:
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shell.events.trigger("post_execute")
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__all__ = ["Comm"]
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