Merge pull request #2649 from tkf/kernel-version

Add version_request/reply to message spec

and protocol_version added to core.release

IPython/core/release.py

@@ -38,6 +38,9 b" __version__ = '.'.join(map(str, _ver))"
 version = __version__  # backwards compatibility name
 version_info = (_version_major, _version_minor, _version_micro, _version_extra)
 
+# Change this when incrementing the kernel protocol version
+kernel_protocol_version_info = (4, 0)
+
 description = "IPython: Productive Interactive Computing"
 
 long_description = \

IPython/zmq/ipkernel.py

@@ -39,6 +39,7 b' from IPython.config.configurable import Configurable'
 from IPython.config.application import boolean_flag, catch_config_error
 from IPython.core.application import ProfileDir
 from IPython.core.error import StdinNotImplementedError
+from IPython.core import release
 from IPython.core.shellapp import (
     InteractiveShellApp, shell_flags, shell_aliases
 )
@@ -61,6 +62,11 b' from zmqshell import ZMQInteractiveShell'
 # Main kernel class
 #-----------------------------------------------------------------------------
 
+protocol_version = list(release.kernel_protocol_version_info)
+ipython_version = list(release.version_info)
+language_version = list(sys.version_info[:3])
+
+
 class Kernel(Configurable):
 
     #---------------------------------------------------------------------------
@@ -156,6 +162,7 b' class Kernel(Configurable):'
         # Build dict of handlers for message types
         msg_types = [ 'execute_request', 'complete_request',
                       'object_info_request', 'history_request',
+                      'kernel_info_request',
                       'connect_request', 'shutdown_request',
                       'apply_request',
                     ]
@@ -509,6 +516,17 b' class Kernel(Configurable):'
                                 content, parent, ident)
         self.log.debug("%s", msg)
 
+    def kernel_info_request(self, stream, ident, parent):
+        vinfo = {
+            'protocol_version': protocol_version,
+            'ipython_version': ipython_version,
+            'language_version': language_version,
+            'language': 'python',
+        }
+        msg = self.session.send(stream, 'kernel_info_reply',
+                                vinfo, parent, ident)
+        self.log.debug("%s", msg)
+
     def shutdown_request(self, stream, ident, parent):
         self.shell.exit_now = True
         content = dict(status='ok')

IPython/zmq/kernelmanager.py

@@ -363,6 +363,12 b' class ShellSocketChannel(ZMQSocketChannel):'
         self._queue_send(msg)
         return msg['header']['msg_id']
 
+    def kernel_info(self):
+        """Request kernel info."""
+        msg = self.session.msg('kernel_info_request')
+        self._queue_send(msg)
+        return msg['header']['msg_id']
+
     def shutdown(self, restart=False):
         """Request an immediate kernel shutdown.
 

IPython/zmq/session.py

@@ -43,7 +43,6 b' from zmq.utils import jsonapi'
 from zmq.eventloop.ioloop import IOLoop
 from zmq.eventloop.zmqstream import ZMQStream
 
-import IPython
 from IPython.config.application import Application, boolean_flag
 from IPython.config.configurable import Configurable, LoggingConfigurable
 from IPython.utils.importstring import import_item
@@ -75,7 +74,6 b' def squash_unicode(obj):'
 # globals and defaults
 #-----------------------------------------------------------------------------
 
-_version_info_list = list(IPython.version_info)
 # ISO8601-ify datetime objects
 json_packer = lambda obj: jsonapi.dumps(obj, default=date_default)
 json_unpacker = lambda s: extract_dates(jsonapi.loads(s))
@@ -188,7 +186,6 b' class Message(object):'
 
 def msg_header(msg_id, msg_type, username, session):
     date = datetime.now()
-    version = _version_info_list
     return locals()
 
 def extract_header(msg_or_header):

IPython/zmq/tests/test_message_spec.py

@@ -21,7 +21,7 b' from ..blockingkernelmanager import BlockingKernelManager'
 from IPython.testing import decorators as dec
 from IPython.utils import io
 from IPython.utils.traitlets import (
-    HasTraits, TraitError, Bool, Unicode, Dict, Integer, List, Enum,
+    HasTraits, TraitError, Bool, Unicode, Dict, Integer, List, Enum, Any,
 )
 
 #-----------------------------------------------------------------------------
@@ -83,7 +83,17 b" def execute(code='', **kwargs):"
 
 
 class Reference(HasTraits):
-    
+
+    """
+    Base class for message spec specification testing.
+
+    This class is the core of the message specification test.  The
+    idea is that child classes implement trait attributes for each
+    message keys, so that message keys can be tested against these
+    traits using :meth:`check` method.
+
+    """
+
     def check(self, d):
         """validate a dict against our traits"""
         for key in self.trait_names():
@@ -185,6 +195,25 b' class CompleteReply(Reference):'
     matches = List(Unicode)
 
 
+def Version(num, trait=Integer):
+    return List(trait, default_value=[0] * num, minlen=num, maxlen=num)
+
+
+class KernelInfoReply(Reference):
+
+    protocol_version = Version(2)
+    ipython_version = Version(4, Any)
+    language_version = Version(3)
+    language = Unicode()
+
+    def _ipython_version_changed(self, name, old, new):
+        for v in new:
+            nt.assert_true(
+                isinstance(v, int) or isinstance(v, basestring),
+                'expected int or string as version component, got {0!r}'
+                .format(v))
+
+
 # IOPub messages
 
 class PyIn(Reference):
@@ -226,12 +255,16 b' references = {'
     'object_info_reply' : OInfoReply(),
     'status' : Status(),
     'complete_reply' : CompleteReply(),
+    'kernel_info_reply': KernelInfoReply(),
     'pyin' : PyIn(),
     'pyout' : PyOut(),
     'pyerr' : PyErr(),
     'stream' : Stream(),
     'display_data' : DisplayData(),
 }
+"""
+Specifications of `content` part of the reply messages.
+"""
 
 
 def validate_message(msg, msg_type=None, parent=None):
@@ -421,6 +454,18 b' def test_complete():'
         yield nt.assert_true(name in matches, "Missing match: %r" % name)
 
 
[e-mail]
+def test_kernel_info_request():
+    flush_channels()
+
+    shell = KM.shell_channel
+
+    msg_id = shell.kernel_info()
+    reply = shell.get_msg(timeout=2)
+    for tst in validate_message(reply, 'kernel_info_reply', msg_id):
+        yield tst
+
+
 # IOPub channel
 
 

docs/source/development/messaging.txt

@@ -670,6 +670,47 b' Message type: ``connect_reply``::'
     }
 
 
+Kernel info
+-----------
+
+If a client needs to know what protocol the kernel supports, it can
+ask version number of the messaging protocol supported by the kernel.
+This message can be used to fetch other core information of the
+kernel, including language (e.g., Python), language version number and
+IPython version number.
+
+Message type: ``kernel_info_request``::
+
+    content = {
+    }
+
+Message type: ``kernel_info_reply``::
+
+    content = {
+        # Version of messaging protocol (mandatory).
+        # The first integer indicates major version.  It is incremented when
+        # there is any backward incompatible change.
+        # The second integer indicates minor version.  It is incremented when
+        # there is any backward compatible change.
+        'protocol_version': [int, int],
+
+        # IPython version number (optional).
+        # Non-python kernel backend may not have this version number.
+        # The last component is an extra field, which may be 'dev' or
+        # 'rc1' in development version.  It is an empty string for
+        # released version.
+        'ipython_version': [int, int, int, str],
+
+        # Language version number (mandatory).
+        # It is Python version number (e.g., [2, 7, 3]) for the kernel
+        # included in IPython.
+        'language_version': [int, ...],
+
+        # Programming language in which kernel is implemented (mandatory).
+        # Kernel included in IPython returns 'python'.
+        'language': str,
+    }
+
 
 Kernel shutdown
 ---------------