Backport PR #3978: fix `--existing` with non-localhost IP

there's still some cleanup to do with duplicate code in ConsoleApp that should be invoked from ConnectionFileMixin, but this fixes the bug.

closes  #3977

IPython/consoleapp.py

@@ -24,7 +24,6 b' Authors:'
 import atexit
 import json
 import os
-import shutil
 import signal
 import sys
 import uuid
@@ -32,7 +31,6 b' import uuid'
 
 # Local imports
 from IPython.config.application import boolean_flag
-from IPython.config.configurable import Configurable
 from IPython.core.profiledir import ProfileDir
 from IPython.kernel.blocking import BlockingKernelClient
 from IPython.kernel import KernelManager
@@ -40,7 +38,7 b' from IPython.kernel import tunnel_to_kernel, find_connection_file, swallow_argv'
 from IPython.utils.path import filefind
 from IPython.utils.py3compat import str_to_bytes
 from IPython.utils.traitlets import (
-    Dict, List, Unicode, CUnicode, Int, CBool, Any, CaselessStrEnum
+    Dict, List, Unicode, CUnicode, Int, CBool, Any
 )
 from IPython.kernel.zmq.kernelapp import (
     kernel_flags,
@@ -49,12 +47,13 b' from IPython.kernel.zmq.kernelapp import ('
 )
 from IPython.kernel.zmq.session import Session, default_secure
 from IPython.kernel.zmq.zmqshell import ZMQInteractiveShell
+from IPython.kernel.connect import ConnectionFileMixin
 
 #-----------------------------------------------------------------------------
 # Network Constants
 #-----------------------------------------------------------------------------
 
-from IPython.utils.localinterfaces import LOCALHOST, LOCAL_IPS
+from IPython.utils.localinterfaces import LOCALHOST
 
 #-----------------------------------------------------------------------------
 # Globals
@@ -89,8 +88,8 b' aliases = dict(kernel_aliases)'
 
 # also scrub aliases from the frontend
 app_aliases = dict(
-    ip = 'KernelManager.ip',
-    transport = 'KernelManager.transport',
+    ip = 'IPythonConsoleApp.ip',
+    transport = 'IPythonConsoleApp.transport',
     hb = 'IPythonConsoleApp.hb_port',
     shell = 'IPythonConsoleApp.shell_port',
     iopub = 'IPythonConsoleApp.iopub_port',
@@ -120,7 +119,7 b' except ImportError:'
 else:
     classes.append(InlineBackend)
 
-class IPythonConsoleApp(Configurable):
+class IPythonConsoleApp(ConnectionFileMixin):
     name = 'ipython-console-mixin'
 
     description = """
@@ -254,11 +253,10 b' class IPythonConsoleApp(Configurable):'
         self.log.debug(u"Loading connection file %s", fname)
         with open(fname) as f:
             cfg = json.load(f)
+        self.transport = cfg.get('transport', 'tcp')
+        self.ip = cfg.get('ip', LOCALHOST)
         
-        self.config.KernelManager.transport = cfg.get('transport', 'tcp')
-        self.config.KernelManager.ip = cfg.get('ip', LOCALHOST)
-        
-        for channel in ('hb', 'shell', 'iopub', 'stdin'):
+        for channel in ('hb', 'shell', 'iopub', 'stdin', 'control'):
             name = channel + '_port'
             if getattr(self, name) == 0 and name in cfg:
                 # not overridden by config or cl_args
@@ -272,11 +270,10 b' class IPythonConsoleApp(Configurable):'
         """set up ssh tunnels, if needed."""
         if not self.existing or (not self.sshserver and not self.sshkey):
             return
-        
         self.load_connection_file()
         
-        transport = self.config.KernelManager.transport
-        ip = self.config.KernelManager.ip
+        transport = self.transport
+        ip = self.ip
         
         if transport != 'tcp':
             self.log.error("Can only use ssh tunnels with TCP sockets, not %s", transport)
@@ -298,7 +295,7 b' class IPythonConsoleApp(Configurable):'
         self.log.info("Forwarding connections to %s via %s"%(ip, self.sshserver))
         
         # tunnels return a new set of ports, which will be on localhost:
-        self.config.KernelManager.ip = LOCALHOST
+        self.ip = LOCALHOST
         try:
             newports = tunnel_to_kernel(info, self.sshserver, self.sshkey)
         except:
@@ -337,6 +334,8 b' class IPythonConsoleApp(Configurable):'
 
         # Create a KernelManager and start a kernel.
         self.kernel_manager = self.kernel_manager_class(
+                                ip=self.ip,
+                                transport=self.transport,
                                 shell_port=self.shell_port,
                                 iopub_port=self.iopub_port,
                                 stdin_port=self.stdin_port,
@@ -367,6 +366,8 b' class IPythonConsoleApp(Configurable):'
             self.kernel_client = self.kernel_manager.client()
         else:
             self.kernel_client = self.kernel_client_class(
+                                ip=self.ip,
+                                transport=self.transport,
                                 shell_port=self.shell_port,
                                 iopub_port=self.iopub_port,
                                 stdin_port=self.stdin_port,

IPython/kernel/client.py

@@ -147,8 +147,10 b' class KernelClient(LoggingConfigurable, ConnectionFileMixin):'
     def shell_channel(self):
         """Get the shell channel object for this kernel."""
         if self._shell_channel is None:
+            url = self._make_url('shell')
+            self.log.debug("connecting shell channel to %s", url)
             self._shell_channel = self.shell_channel_class(
-                self.context, self.session, self._make_url('shell')
+                self.context, self.session, url
             )
         return self._shell_channel
 
@@ -156,8 +158,10 b' class KernelClient(LoggingConfigurable, ConnectionFileMixin):'
     def iopub_channel(self):
         """Get the iopub channel object for this kernel."""
         if self._iopub_channel is None:
+            url = self._make_url('iopub')
+            self.log.debug("connecting iopub channel to %s", url)
             self._iopub_channel = self.iopub_channel_class(
-                self.context, self.session, self._make_url('iopub')
+                self.context, self.session, url
             )
         return self._iopub_channel
 
@@ -165,8 +169,10 b' class KernelClient(LoggingConfigurable, ConnectionFileMixin):'
     def stdin_channel(self):
         """Get the stdin channel object for this kernel."""
         if self._stdin_channel is None:
+            url = self._make_url('stdin')
+            self.log.debug("connecting stdin channel to %s", url)
             self._stdin_channel = self.stdin_channel_class(
-                self.context, self.session, self._make_url('stdin')
+                self.context, self.session, url
             )
         return self._stdin_channel
 
@@ -174,8 +180,10 b' class KernelClient(LoggingConfigurable, ConnectionFileMixin):'
     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)
             self._hb_channel = self.hb_channel_class(
-                self.context, self.session, self._make_url('hb')
+                self.context, self.session, url
             )
         return self._hb_channel
 

IPython/qt/console/qtconsoleapp.py

@@ -249,10 +249,7 b' class IPythonQtConsoleApp(BaseIPythonApplication, IPythonConsoleApp):'
         self.app.icon = QtGui.QIcon(icon_path)
         QtGui.QApplication.setWindowIcon(self.app.icon)
 
-        try:
-            ip = self.config.KernelManager.ip
-        except AttributeError:
-            ip = LOCALHOST
+        ip = self.ip
         local_kernel = (not self.existing) or ip in LOCAL_IPS
         self.widget = self.widget_factory(config=self.config,
                                         local_kernel=local_kernel)