IPython/kernel/zmq/ipkernel.py

"""The IPython kernel implementation"""

import getpass
import sys
import traceback

from IPython.core import release
from IPython.utils.py3compat import builtin_mod, PY3
from IPython.utils.tokenutil import token_at_cursor, line_at_cursor
from IPython.utils.traitlets import Instance, Type, Any
from IPython.utils.decorators import undoc

from ..comm import CommManager
from .kernelbase import Kernel as KernelBase
from .serialize import serialize_object, unpack_apply_message
from .zmqshell import ZMQInteractiveShell


def lazy_import_handle_comm_opened(*args, **kwargs):
    from IPython.html.widgets import Widget
    Widget.handle_comm_opened(*args, **kwargs)


class IPythonKernel(KernelBase):
    shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
    shell_class = Type(ZMQInteractiveShell)

    user_module = Any()
    def _user_module_changed(self, name, old, new):
        if self.shell is not None:
            self.shell.user_module = new

    user_ns = Instance(dict, args=None, allow_none=True)
    def _user_ns_changed(self, name, old, new):
        if self.shell is not None:
            self.shell.user_ns = new
            self.shell.init_user_ns()

    # A reference to the Python builtin 'raw_input' function.
    # (i.e., __builtin__.raw_input for Python 2.7, builtins.input for Python 3)
    _sys_raw_input = Any()
    _sys_eval_input = Any()

    def __init__(self, **kwargs):
        super(IPythonKernel, self).__init__(**kwargs)

        # Initialize the InteractiveShell subclass
        self.shell = self.shell_class.instance(parent=self,
            profile_dir = self.profile_dir,
            user_module = self.user_module,
            user_ns     = self.user_ns,
            kernel      = self,
        )
        self.shell.displayhook.session = self.session
        self.shell.displayhook.pub_socket = self.iopub_socket
        self.shell.displayhook.topic = self._topic('execute_result')
        self.shell.display_pub.session = self.session
        self.shell.display_pub.pub_socket = self.iopub_socket
        self.shell.data_pub.session = self.session
        self.shell.data_pub.pub_socket = self.iopub_socket

        # TMP - hack while developing
        self.shell._reply_content = None

        self.comm_manager = CommManager(shell=self.shell, parent=self, 
                                        kernel=self)
        self.comm_manager.register_target('ipython.widget', lazy_import_handle_comm_opened)

        self.shell.configurables.append(self.comm_manager)
        comm_msg_types = [ 'comm_open', 'comm_msg', 'comm_close' ]
        for msg_type in comm_msg_types:
            self.shell_handlers[msg_type] = getattr(self.comm_manager, msg_type)

    # Kernel info fields
    implementation = 'ipython'
    implementation_version = release.version
    language_info = {
                     'name': 'python',
                     'version': sys.version.split()[0],
                     'mimetype': 'text/x-python',
                     'codemirror_mode': {'name': 'ipython',
                                         'version': sys.version_info[0]},
                     'pygments_lexer': 'ipython%d' % (3 if PY3 else 2),
                     'nbconvert_exporter': 'python',
                     'file_extension': '.py'
                    }
    @property
    def banner(self):
        return self.shell.banner

    def start(self):
        self.shell.exit_now = False
        super(IPythonKernel, self).start()

    def set_parent(self, ident, parent):
        """Overridden from parent to tell the display hook and output streams
        about the parent message.
        """
        super(IPythonKernel, self).set_parent(ident, parent)
        self.shell.set_parent(parent)

    def _forward_input(self, allow_stdin=False):
        """Forward raw_input and getpass to the current frontend.

        via input_request
        """
        self._allow_stdin = allow_stdin

        if PY3:
            self._sys_raw_input = builtin_mod.input
            builtin_mod.input = self.raw_input
        else:
            self._sys_raw_input = builtin_mod.raw_input
            self._sys_eval_input = builtin_mod.input
            builtin_mod.raw_input = self.raw_input
            builtin_mod.input = lambda prompt='': eval(self.raw_input(prompt))
        self._save_getpass = getpass.getpass
        getpass.getpass = self.getpass

    def _restore_input(self):
        """Restore raw_input, getpass"""
        if PY3:
            builtin_mod.input = self._sys_raw_input
        else:
            builtin_mod.raw_input = self._sys_raw_input
            builtin_mod.input = self._sys_eval_input

        getpass.getpass = self._save_getpass

    @property
    def execution_count(self):
        return self.shell.execution_count

    @execution_count.setter
    def execution_count(self, value):
        # Ignore the incrememnting done by KernelBase, in favour of our shell's
        # execution counter.
        pass

    def do_execute(self, code, silent, store_history=True,
                   user_expressions=None, allow_stdin=False):
        shell = self.shell # we'll need this a lot here

        self._forward_input(allow_stdin)

        reply_content = {}
        # FIXME: the shell calls the exception handler itself.
        shell._reply_content = None
        try:
            shell.run_cell(code, store_history=store_history, silent=silent)
        except:
            status = u'error'
            # FIXME: this code right now isn't being used yet by default,
            # because the run_cell() call above directly fires off exception
            # reporting.  This code, therefore, is only active in the scenario
            # where runlines itself has an unhandled exception.  We need to
            # uniformize this, for all exception construction to come from a
            # single location in the codbase.
            etype, evalue, tb = sys.exc_info()
            tb_list = traceback.format_exception(etype, evalue, tb)
            reply_content.update(shell._showtraceback(etype, evalue, tb_list))
        else:
            status = u'ok'
        finally:
            self._restore_input()

        reply_content[u'status'] = status

        # Return the execution counter so clients can display prompts
        reply_content['execution_count'] = shell.execution_count - 1

        # FIXME - fish exception info out of shell, possibly left there by
        # runlines.  We'll need to clean up this logic later.
        if shell._reply_content is not None:
            reply_content.update(shell._reply_content)
            e_info = dict(engine_uuid=self.ident, engine_id=self.int_id, method='execute')
            reply_content['engine_info'] = e_info
            # reset after use
            shell._reply_content = None

        if 'traceback' in reply_content:
            self.log.info("Exception in execute request:\n%s", '\n'.join(reply_content['traceback']))


        # At this point, we can tell whether the main code execution succeeded
        # or not.  If it did, we proceed to evaluate user_expressions
        if reply_content['status'] == 'ok':
            reply_content[u'user_expressions'] = \
                         shell.user_expressions(user_expressions or {})
        else:
            # If there was an error, don't even try to compute expressions
            reply_content[u'user_expressions'] = {}

        # Payloads should be retrieved regardless of outcome, so we can both
        # recover partial output (that could have been generated early in a
        # block, before an error) and clear the payload system always.
        reply_content[u'payload'] = shell.payload_manager.read_payload()
        # Be agressive about clearing the payload because we don't want
        # it to sit in memory until the next execute_request comes in.
        shell.payload_manager.clear_payload()

        return reply_content

    def do_complete(self, code, cursor_pos):
        # FIXME: IPython completers currently assume single line,
        # but completion messages give multi-line context
        # For now, extract line from cell, based on cursor_pos:
        if cursor_pos is None:
            cursor_pos = len(code)
        line, offset = line_at_cursor(code, cursor_pos)
        line_cursor = cursor_pos - offset

        txt, matches = self.shell.complete('', line, line_cursor)
        return {'matches' : matches,
                'cursor_end' : cursor_pos,
                'cursor_start' : cursor_pos - len(txt),
                'metadata' : {},
                'status' : 'ok'}

    def do_inspect(self, code, cursor_pos, detail_level=0):
        name = token_at_cursor(code, cursor_pos)
        info = self.shell.object_inspect(name)

        reply_content = {'status' : 'ok'}
        reply_content['data'] = data = {}
        reply_content['metadata'] = {}
        reply_content['found'] = info['found']
        if info['found']:
            info_text = self.shell.object_inspect_text(
                name,
                detail_level=detail_level,
            )
            data['text/plain'] = info_text

        return reply_content

    def do_history(self, hist_access_type, output, raw, session=None, start=None,
                   stop=None, n=None, pattern=None, unique=False):
        if hist_access_type == 'tail':
            hist = self.shell.history_manager.get_tail(n, raw=raw, output=output,
                                                            include_latest=True)

        elif hist_access_type == 'range':
            hist = self.shell.history_manager.get_range(session, start, stop,
                                                        raw=raw, output=output)

        elif hist_access_type == 'search':
            hist = self.shell.history_manager.search(
                pattern, raw=raw, output=output, n=n, unique=unique)
        else:
            hist = []

        return {'history' : list(hist)}

    def do_shutdown(self, restart):
        self.shell.exit_now = True
        return dict(status='ok', restart=restart)

    def do_is_complete(self, code):
        status, indent_spaces = self.shell.input_transformer_manager.check_complete(code)
        r = {'status': status}
        if status == 'incomplete':
            r['indent'] = ' ' * indent_spaces
        return r

    def do_apply(self, content, bufs, msg_id, reply_metadata):
        shell = self.shell
        try:
            working = shell.user_ns

            prefix = "_"+str(msg_id).replace("-","")+"_"

            f,args,kwargs = unpack_apply_message(bufs, working, copy=False)

            fname = getattr(f, '__name__', 'f')

            fname = prefix+"f"
            argname = prefix+"args"
            kwargname = prefix+"kwargs"
            resultname = prefix+"result"

            ns = { fname : f, argname : args, kwargname : kwargs , resultname : None }
            # print ns
            working.update(ns)
            code = "%s = %s(*%s,**%s)" % (resultname, fname, argname, kwargname)
            try:
                exec(code, shell.user_global_ns, shell.user_ns)
                result = working.get(resultname)
            finally:
                for key in ns:
                    working.pop(key)

            result_buf = serialize_object(result,
                buffer_threshold=self.session.buffer_threshold,
                item_threshold=self.session.item_threshold,
            )

        except:
            # invoke IPython traceback formatting
            shell.showtraceback()
            # FIXME - fish exception info out of shell, possibly left there by
            # run_code.  We'll need to clean up this logic later.
            reply_content = {}
            if shell._reply_content is not None:
                reply_content.update(shell._reply_content)
                e_info = dict(engine_uuid=self.ident, engine_id=self.int_id, method='apply')
                reply_content['engine_info'] = e_info
                # reset after use
                shell._reply_content = None

            self.send_response(self.iopub_socket, u'error', reply_content,
                                ident=self._topic('error'))
            self.log.info("Exception in apply request:\n%s", '\n'.join(reply_content['traceback']))
            result_buf = []

            if reply_content['ename'] == 'UnmetDependency':
                reply_metadata['dependencies_met'] = False
        else:
            reply_content = {'status' : 'ok'}

        return reply_content, result_buf

    def do_clear(self):
        self.shell.reset(False)
        return dict(status='ok')


# This exists only for backwards compatibility - use IPythonKernel instead

@undoc
class Kernel(IPythonKernel):
    def __init__(self, *args, **kwargs):
        import warnings
        warnings.warn('Kernel is a deprecated alias of IPython.kernel.zmq.ipkernel.IPythonKernel',
                      DeprecationWarning)
        super(Kernel, self).__init__(*args, **kwargs)