split QtConsole.init_ssh into generic tunnel_to_kernel

added to new IPython.lib.kernel with other kernel connection utilities.

IPython/frontend/qt/console/qtconsoleapp.py

@@ -1,604 +1,606 b''
 """ A minimal application using the Qt console-style IPython frontend.
 
 This is not a complete console app, as subprocess will not be able to receive
 input, there is no real readline support, among other limitations.
 
 Authors:
 
 * Evan Patterson
 * Min RK
 * Erik Tollerud
 * Fernando Perez
 
 """
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # stdlib imports
 import glob
 import os
 import signal
 import sys
-from getpass import getpass
 
 # System library imports
 from IPython.external.qt import QtGui
 from pygments.styles import get_all_styles
 from zmq.utils import jsonapi as json
 
-# external imports
-from IPython.external.ssh import tunnel
-
 # Local imports
 from IPython.config.application import boolean_flag
 from IPython.core.application import BaseIPythonApplication
 from IPython.core.profiledir import ProfileDir
+from IPython.lib.kernel import tunnel_to_kernel
 from IPython.frontend.qt.console.frontend_widget import FrontendWidget
 from IPython.frontend.qt.console.ipython_widget import IPythonWidget
 from IPython.frontend.qt.console.rich_ipython_widget import RichIPythonWidget
 from IPython.frontend.qt.console import styles
 from IPython.frontend.qt.kernelmanager import QtKernelManager
-from IPython.parallel.util import select_random_ports
 from IPython.utils.path import filefind
 from IPython.utils.py3compat import str_to_bytes
 from IPython.utils.traitlets import (
     Dict, List, Unicode, Int, CaselessStrEnum, CBool, Any
 )
 from IPython.zmq.ipkernel import (
     flags as ipkernel_flags,
     aliases as ipkernel_aliases,
     IPKernelApp
 )
 from IPython.zmq.session import Session, default_secure
 from IPython.zmq.zmqshell import ZMQInteractiveShell
 
 
 #-----------------------------------------------------------------------------
 # Network Constants
 #-----------------------------------------------------------------------------
 
 from IPython.utils.localinterfaces import LOCALHOST, LOCAL_IPS
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 _examples = """
 ipython qtconsole                 # start the qtconsole
 ipython qtconsole --pylab=inline  # start with pylab in inline plotting mode
 """
 
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 
 class MainWindow(QtGui.QMainWindow):
 
     #---------------------------------------------------------------------------
     # 'object' interface
     #---------------------------------------------------------------------------
     
     def __init__(self, app, frontend, existing=False, may_close=True,
                     confirm_exit=True):
         """ Create a MainWindow for the specified FrontendWidget.
         
         The app is passed as an argument to allow for different
         closing behavior depending on whether we are the Kernel's parent.
         
         If existing is True, then this Console does not own the Kernel.
         
         If may_close is True, then this Console is permitted to close the kernel
         """
         super(MainWindow, self).__init__()
         self._app = app
         self._frontend = frontend
         self._existing = existing
         if existing:
             self._may_close = may_close
         else:
             self._may_close = True
         self._frontend.exit_requested.connect(self.close)
         self._confirm_exit = confirm_exit
         self.setCentralWidget(frontend)
 
     #---------------------------------------------------------------------------
     # QWidget interface
     #---------------------------------------------------------------------------
     
     def closeEvent(self, event):
         """ Close the window and the kernel (if necessary).
         
         This will prompt the user if they are finished with the kernel, and if
         so, closes the kernel cleanly. Alternatively, if the exit magic is used,
         it closes without prompt.
         """
         keepkernel = None #Use the prompt by default
         if hasattr(self._frontend,'_keep_kernel_on_exit'): #set by exit magic
             keepkernel = self._frontend._keep_kernel_on_exit
         
         kernel_manager = self._frontend.kernel_manager
         
         if keepkernel is None and not self._confirm_exit:
             # don't prompt, just terminate the kernel if we own it
             # or leave it alone if we don't
             keepkernel = not self._existing
         
         if keepkernel is None: #show prompt
             if kernel_manager and kernel_manager.channels_running:
                 title = self.window().windowTitle()
                 cancel = QtGui.QMessageBox.Cancel
                 okay = QtGui.QMessageBox.Ok
                 if self._may_close:
                     msg = "You are closing this Console window."
                     info = "Would you like to quit the Kernel and all attached Consoles as well?"
                     justthis = QtGui.QPushButton("&No, just this Console", self)
                     justthis.setShortcut('N')
                     closeall = QtGui.QPushButton("&Yes, quit everything", self)
                     closeall.setShortcut('Y')
                     box = QtGui.QMessageBox(QtGui.QMessageBox.Question,
                                             title, msg)
                     box.setInformativeText(info)
                     box.addButton(cancel)
                     box.addButton(justthis, QtGui.QMessageBox.NoRole)
                     box.addButton(closeall, QtGui.QMessageBox.YesRole)
                     box.setDefaultButton(closeall)
                     box.setEscapeButton(cancel)
                     reply = box.exec_()
                     if reply == 1: # close All
                         kernel_manager.shutdown_kernel()
                         #kernel_manager.stop_channels()
                         event.accept()
                     elif reply == 0: # close Console
                         if not self._existing:
                             # Have kernel: don't quit, just close the window
                             self._app.setQuitOnLastWindowClosed(False)
                             self.deleteLater()
                         event.accept()
                     else:
                         event.ignore()
                 else:
                     reply = QtGui.QMessageBox.question(self, title,
                         "Are you sure you want to close this Console?"+
                         "\nThe Kernel and other Consoles will remain active.",
                         okay|cancel,
                         defaultButton=okay
                         )
                     if reply == okay:
                         event.accept()
                     else:
                         event.ignore()
         elif keepkernel: #close console but leave kernel running (no prompt)
             if kernel_manager and kernel_manager.channels_running:
                 if not self._existing:
                     # I have the kernel: don't quit, just close the window
                     self._app.setQuitOnLastWindowClosed(False)
                 event.accept()
         else: #close console and kernel (no prompt)
             if kernel_manager and kernel_manager.channels_running:
                 kernel_manager.shutdown_kernel()
                 event.accept()
 
 #-----------------------------------------------------------------------------
 # Aliases and Flags
 #-----------------------------------------------------------------------------
 
 flags = dict(ipkernel_flags)
 qt_flags = {
     'existing' : ({'IPythonQtConsoleApp' : {'existing' : 'kernel*.json'}},
             "Connect to an existing kernel. If no argument specified, guess most recent"),
     'pure' : ({'IPythonQtConsoleApp' : {'pure' : True}},
             "Use a pure Python kernel instead of an IPython kernel."),
     'plain' : ({'ConsoleWidget' : {'kind' : 'plain'}},
             "Disable rich text support."),
 }
 qt_flags.update(boolean_flag(
     'gui-completion', 'ConsoleWidget.gui_completion',
     "use a GUI widget for tab completion",
     "use plaintext output for completion"
 ))
 qt_flags.update(boolean_flag(
     'confirm-exit', 'IPythonQtConsoleApp.confirm_exit',
     """Set to display confirmation dialog on exit. You can always use 'exit' or 'quit',
        to force a direct exit without any confirmation.
     """,
     """Don't prompt the user when exiting. This will terminate the kernel
        if it is owned by the frontend, and leave it alive if it is external.
     """
 ))
 flags.update(qt_flags)
 
 aliases = dict(ipkernel_aliases)
 
 qt_aliases = dict(
     hb = 'IPythonQtConsoleApp.hb_port',
     shell = 'IPythonQtConsoleApp.shell_port',
     iopub = 'IPythonQtConsoleApp.iopub_port',
     stdin = 'IPythonQtConsoleApp.stdin_port',
     ip = 'IPythonQtConsoleApp.ip',
     existing = 'IPythonQtConsoleApp.existing',
     f = 'IPythonQtConsoleApp.connection_file',
 
     style = 'IPythonWidget.syntax_style',
     stylesheet = 'IPythonQtConsoleApp.stylesheet',
     colors = 'ZMQInteractiveShell.colors',
 
     editor = 'IPythonWidget.editor',
     paging = 'ConsoleWidget.paging',
     ssh = 'IPythonQtConsoleApp.sshserver',
 )
 aliases.update(qt_aliases)
 
 
 #-----------------------------------------------------------------------------
 # IPythonQtConsole
 #-----------------------------------------------------------------------------
 
 
 class IPythonQtConsoleApp(BaseIPythonApplication):
     name = 'ipython-qtconsole'
     default_config_file_name='ipython_config.py'
     
     description = """
         The IPython QtConsole.
         
         This launches a Console-style application using Qt.  It is not a full
         console, in that launched terminal subprocesses will not be able to accept
         input.
         
         The QtConsole supports various extra features beyond the Terminal IPython
         shell, such as inline plotting with matplotlib, via:
         
             ipython qtconsole --pylab=inline
         
         as well as saving your session as HTML, and printing the output.
         
     """
     examples = _examples
 
     classes = [IPKernelApp, IPythonWidget, ZMQInteractiveShell, ProfileDir, Session]
     flags = Dict(flags)
     aliases = Dict(aliases)
 
     kernel_argv = List(Unicode)
 
     # create requested profiles by default, if they don't exist:
     auto_create = CBool(True)
     # connection info:
     ip = Unicode(LOCALHOST, config=True,
         help="""Set the kernel\'s IP address [default localhost].
         If the IP address is something other than localhost, then
         Consoles on other machines will be able to connect
         to the Kernel, so be careful!"""
     )
     
     sshserver = Unicode('', config=True,
         help="""The SSH server to use to connect to the kernel.""")
     sshkey = Unicode('', config=True,
         help="""Path to the ssh key to use for logging in to the ssh server.""")
     
     hb_port = Int(0, config=True,
         help="set the heartbeat port [default: random]")
     shell_port = Int(0, config=True,
         help="set the shell (XREP) port [default: random]")
     iopub_port = Int(0, config=True,
         help="set the iopub (PUB) port [default: random]")
     stdin_port = Int(0, config=True,
         help="set the stdin (XREQ) port [default: random]")
     connection_file = Unicode('', config=True,
         help="""JSON file in which to store connection info [default: kernel-<pid>.json]
 
         This file will contain the IP, ports, and authentication key needed to connect
         clients to this kernel. By default, this file will be created in the security-dir
         of the current profile, but can be specified by absolute path.
         """)
     def _connection_file_default(self):
         return 'kernel-%i.json' % os.getpid()
 
     existing = Unicode('', config=True,
         help="""Connect to an already running kernel""")
 
     stylesheet = Unicode('', config=True,
         help="path to a custom CSS stylesheet")
 
     pure = CBool(False, config=True,
         help="Use a pure Python kernel instead of an IPython kernel.")
     plain = CBool(False, config=True,
         help="Use a plaintext widget instead of rich text (plain can't print/save).")
 
     def _pure_changed(self, name, old, new):
         kind = 'plain' if self.plain else 'rich'
         self.config.ConsoleWidget.kind = kind
         if self.pure:
             self.widget_factory = FrontendWidget
         elif self.plain:
             self.widget_factory = IPythonWidget
         else:
             self.widget_factory = RichIPythonWidget
 
     _plain_changed = _pure_changed
 
     confirm_exit = CBool(True, config=True,
         help="""
         Set to display confirmation dialog on exit. You can always use 'exit' or 'quit',
         to force a direct exit without any confirmation.""",
     )
     
     # the factory for creating a widget
     widget_factory = Any(RichIPythonWidget)
 
     def parse_command_line(self, argv=None):
         super(IPythonQtConsoleApp, self).parse_command_line(argv)
         if argv is None:
             argv = sys.argv[1:]
 
         self.kernel_argv = list(argv) # copy
         # kernel should inherit default config file from frontend
         self.kernel_argv.append("--KernelApp.parent_appname='%s'"%self.name)
         # Scrub frontend-specific flags
         for a in argv:
             if a.startswith('-') and a.lstrip('-') in qt_flags:
                 self.kernel_argv.remove(a)
         swallow_next = False
         for a in argv:
             if swallow_next:
                 self.kernel_argv.remove(a)
                 swallow_next = False
                 continue
             if a.startswith('-'):
                 split = a.lstrip('-').split('=')[0]
                 alias = split[0]
                 if alias in qt_aliases:
                     self.kernel_argv.remove(a)
                     if len(split) == 1:
                         # alias passed with arg via space
                         swallow_next = True
     
     def init_connection_file(self):
         """find the connection file, and load the info if found.
         
         The current working directory and the current profile's security
         directory will be searched for the file if it is not given by
         absolute path.
         
         When attempting to connect to an existing kernel and the `--existing`
         argument does not match an existing file, it will be interpreted as a
         fileglob, and the matching file in the current profile's security dir
         with the latest access time will be used.
         """
         sec = self.profile_dir.security_dir
         if self.existing:
             try:
                 # first, try explicit name
                 cf = filefind(self.existing, ['.', sec])
             except IOError:
                 # not found by full name
                 if '*' in self.existing:
                     # given as a glob already
                     pat = self.existing
                 else:
                     # accept any substring match
                     pat = '*%s*' % self.existing
                 matches = glob.glob( os.path.join(sec, pat) )
                 if not matches:
                     self.log.critical("Could not find existing kernel connection file %s", self.existing)
                     self.exit(1)
                 else:
                     # get most recent match:
                     cf = sorted(matches, key=lambda f: os.stat(f).st_atime)[-1]
             self.log.info("Connecting to existing kernel: %s" % cf)
             self.connection_file = cf
         # should load_connection_file only be used for existing?
         # as it is now, this allows reusing ports if an existing
         # file is requested
         self.load_connection_file()
     
     def load_connection_file(self):
         """load ip/port/hmac config from JSON connection file"""
         # this is identical to KernelApp.load_connection_file
         # perhaps it can be centralized somewhere?
         try:
             fname = filefind(self.connection_file, ['.', self.profile_dir.security_dir])
         except IOError:
             self.log.debug("Connection File not found: %s", self.connection_file)
             return
         self.log.debug(u"Loading connection file %s", fname)
         with open(fname) as f:
             s = f.read()
         cfg = json.loads(s)
         if self.ip == LOCALHOST and 'ip' in cfg:
             # not overridden by config or cl_args
             self.ip = cfg['ip']
         for channel in ('hb', 'shell', 'iopub', 'stdin'):
             name = channel + '_port'
             if getattr(self, name) == 0 and name in cfg:
                 # not overridden by config or cl_args
                 setattr(self, name, cfg[name])
         if 'key' in cfg:
             self.config.Session.key = str_to_bytes(cfg['key'])
     
     def init_ssh(self):
         """set up ssh tunnels, if needed."""
         if not self.sshserver and not self.sshkey:
             return
         
         if self.sshkey and not self.sshserver:
+            # specifying just the key implies that we are connecting directly
             self.sshserver = self.ip
-            self.ip=LOCALHOST
+            self.ip = LOCALHOST
         
-        lports = select_random_ports(4)
-        rports = self.shell_port, self.iopub_port, self.stdin_port, self.hb_port
-        self.shell_port, self.iopub_port, self.stdin_port, self.hb_port = lports
+        # build connection dict for tunnels:
+        info = dict(ip=self.ip,
+                    shell_port=self.shell_port,
+                    iopub_port=self.iopub_port,
+                    stdin_port=self.stdin_port,
+                    hb_port=self.hb_port
+        )
         
-        remote_ip = self.ip
-        self.ip = LOCALHOST
-        self.log.info("Forwarding connections to %s via %s"%(remote_ip, self.sshserver))
+        self.log.info("Forwarding connections to %s via %s"%(self.ip, self.sshserver))
         
-        if tunnel.try_passwordless_ssh(self.sshserver, self.sshkey):
-            password=False
-        else:
-            password = getpass("SSH Password for %s: "%self.sshserver)
+        # tunnels return a new set of ports, which will be on localhost:
+        self.ip = LOCALHOST
+        try:
+            newports = tunnel_to_kernel(info, self.sshserver, self.sshkey)
+        except:
+            # even catch KeyboardInterrupt
+            self.log.error("Could not setup tunnels", exc_info=True)
+            self.exit(1)
         
-        for lp,rp in zip(lports, rports):
-            tunnel.ssh_tunnel(lp, rp, self.sshserver, remote_ip, self.sshkey, password)
+        self.shell_port, self.iopub_port, self.stdin_port, self.hb_port = newports
         
         cf = self.connection_file
         base,ext = os.path.splitext(cf)
         base = os.path.basename(base)
         self.connection_file = os.path.basename(base)+'-ssh'+ext
         self.log.critical("To connect another client via this tunnel, use:")
         self.log.critical("--existing %s" % self.connection_file)
 
     def init_kernel_manager(self):
         # Don't let Qt or ZMQ swallow KeyboardInterupts.
         signal.signal(signal.SIGINT, signal.SIG_DFL)
         sec = self.profile_dir.security_dir
         try:
             cf = filefind(self.connection_file, ['.', sec])
         except IOError:
             # file might not exist
             if self.connection_file == os.path.basename(self.connection_file):
                 # just shortname, put it in security dir
                 cf = os.path.join(sec, self.connection_file)
             else:
                 cf = self.connection_file
 
         # Create a KernelManager and start a kernel.
         self.kernel_manager = QtKernelManager(
                                 ip=self.ip,
                                 shell_port=self.shell_port,
                                 iopub_port=self.iopub_port,
                                 stdin_port=self.stdin_port,
                                 hb_port=self.hb_port,
                                 connection_file=cf,
                                 config=self.config,
         )
         # start the kernel
         if not self.existing:
             kwargs = dict(ipython=not self.pure)
             kwargs['extra_arguments'] = self.kernel_argv
             self.kernel_manager.start_kernel(**kwargs)
         elif self.sshserver:
             # ssh, write new connection file
             self.kernel_manager.write_connection_file()
         self.kernel_manager.start_channels()
 
 
     def init_qt_elements(self):
         # Create the widget.
         self.app = QtGui.QApplication([])
         local_kernel = (not self.existing) or self.ip in LOCAL_IPS
         self.widget = self.widget_factory(config=self.config,
                                         local_kernel=local_kernel)
         self.widget.kernel_manager = self.kernel_manager
         self.window = MainWindow(self.app, self.widget, self.existing,
                                 may_close=local_kernel,
                                 confirm_exit=self.confirm_exit)
         self.window.setWindowTitle('Python' if self.pure else 'IPython')
 
     def init_colors(self):
         """Configure the coloring of the widget"""
         # Note: This will be dramatically simplified when colors
         # are removed from the backend.
 
         if self.pure:
             # only IPythonWidget supports styling
             return
 
         # parse the colors arg down to current known labels
         try:
             colors = self.config.ZMQInteractiveShell.colors
         except AttributeError:
             colors = None
         try:
             style = self.config.IPythonWidget.colors
         except AttributeError:
             style = None
 
         # find the value for colors:
         if colors:
             colors=colors.lower()
             if colors in ('lightbg', 'light'):
                 colors='lightbg'
             elif colors in ('dark', 'linux'):
                 colors='linux'
             else:
                 colors='nocolor'
         elif style:
             if style=='bw':
                 colors='nocolor'
             elif styles.dark_style(style):
                 colors='linux'
             else:
                 colors='lightbg'
         else:
             colors=None
 
         # Configure the style.
         widget = self.widget
         if style:
             widget.style_sheet = styles.sheet_from_template(style, colors)
             widget.syntax_style = style
             widget._syntax_style_changed()
             widget._style_sheet_changed()
         elif colors:
             # use a default style
             widget.set_default_style(colors=colors)
         else:
             # this is redundant for now, but allows the widget's
             # defaults to change
             widget.set_default_style()
 
         if self.stylesheet:
             # we got an expicit stylesheet
             if os.path.isfile(self.stylesheet):
                 with open(self.stylesheet) as f:
                     sheet = f.read()
                 widget.style_sheet = sheet
                 widget._style_sheet_changed()
             else:
                 raise IOError("Stylesheet %r not found."%self.stylesheet)
 
     def initialize(self, argv=None):
         super(IPythonQtConsoleApp, self).initialize(argv)
         self.init_connection_file()
         default_secure(self.config)
         self.init_ssh()
         self.init_kernel_manager()
         self.init_qt_elements()
         self.init_colors()
         self.init_window_shortcut()
 
     def init_window_shortcut(self):
         fullScreenAction = QtGui.QAction('Toggle Full Screen', self.window)
         fullScreenAction.setShortcut('Ctrl+Meta+Space')
         fullScreenAction.triggered.connect(self.toggleFullScreen)
         self.window.addAction(fullScreenAction)
 
     def toggleFullScreen(self):
         if not self.window.isFullScreen():
             self.window.showFullScreen()
         else:
             self.window.showNormal()
 
     def start(self):
 
         # draw the window
         self.window.show()
 
         # Start the application main loop.
         self.app.exec_()
 
 #-----------------------------------------------------------------------------
 # Main entry point
 #-----------------------------------------------------------------------------
 
 def main():
     app = IPythonQtConsoleApp()
     app.initialize()
     app.start()
 
 
 if __name__ == '__main__':
     main()

IPython/lib/kernel.py

@@ -1,99 +1,152 b''
 """Utilities for connecting to kernels
 
 Authors:
 
 * Min Ragan-Kelley
 
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import json
 import sys
+from getpass import getpass
 from subprocess import Popen, PIPE
 
+# external imports
+from IPython.external.ssh import tunnel
+
+# IPython imports
 from IPython.utils.path import filefind
 from IPython.utils.py3compat import str_to_bytes
 
 
 #-----------------------------------------------------------------------------
 # Functions
 #-----------------------------------------------------------------------------
 
 def get_connection_file(app=None):
     """Return the path to the connection file of an app
     
     Parameters
     ----------
     app : KernelApp instance [optional]
         If unspecified, the currently running app will be used
     """
     if app is None:
         from IPython.zmq.kernelapp import KernelApp
         if not KernelApp.initialized():
             raise RuntimeError("app not specified, and not in a running Kernel")
 
         app = KernelApp.instance()
     return filefind(app.connection_file, ['.', app.profile_dir.security_dir])
         
 def get_connection_info(unpack=False):
     """Return the connection information for the current Kernel.
     
     Parameters
     ----------
     unpack : bool [default: False]
         if True, return the unpacked dict, otherwise just the string contents
         of the file.
     
     Returns
     -------
     The connection dictionary of the current kernel, as string or dict,
     depending on `unpack`.
     """
     cf = get_connection_file()
     with open(cf) as f:
         info = f.read()
     
     if unpack:
         info = json.loads(info)
         # ensure key is bytes:
         info['key'] = str_to_bytes(info.get('key', ''))
     return info
 
 def connect_qtconsole(argv=None):
     """Connect a qtconsole to the current kernel.
     
     This is useful for connecting a second qtconsole to a kernel, or to a
     local notebook.
     
     Parameters
     ----------
     argv : list [optional]
         Any extra args to be passed to the console.
     
     Returns
     -------
     subprocess.Popen instance running the qtconsole frontend
     """
     argv = [] if argv is None else argv
     
     # get connection file from current kernel
     cf = get_connection_file()
     
     cmd = ';'.join([
         "from IPython.frontend.qt.console import qtconsoleapp",
         "qtconsoleapp.main()"
     ])
     
     return Popen([sys.executable, '-c', cmd, '--existing', cf] + argv, stdout=PIPE, stderr=PIPE)
 
+def tunnel_to_kernel(connection_info, sshserver, sshkey=None):
+    """tunnel connections to a kernel via ssh
+    
+    This will open four SSH tunnels from localhost on this machine to the
+    ports associated with the kernel.  They can be either direct
+    localhost-localhost tunnels, or if an intermediate server is necessary,
+    the kernel must be listening on a public IP.
+    
+    Parameters
+    ----------
+    connection_info : dict or str (path)
+        Either a connection dict, or the path to a JSON connection file
+    sshserver : str
+        The ssh sever to use to tunnel to the kernel. Can be a full
+        `user@server:port` string. ssh config aliases are respected.
+    sshkey : str [optional]
+        Path to file containing ssh key to use for authentication.
+        Only necessary if your ssh config does not already associate
+        a keyfile with the host.
+    
+    Returns
+    -------
+    
+    (shell, iopub, stdin, hb) : ints
+        The four ports on localhost that have been forwarded to the kernel.
+    """
+    if isinstance(connection_info, basestring):
+        # it's a path, unpack it
+        with open(connection_info) as f:
+            connection_info = json.loads(f.read())
+    
+    cf = connection_info
+    
+    lports = tunnel.select_random_ports(4)
+    rports = cf['shell_port'], cf['iopub_port'], cf['stdin_port'], cf['hb_port']
+    
+    remote_ip = cf['ip']
+    
+    if tunnel.try_passwordless_ssh(sshserver, sshkey):
+        password=False
+    else:
+        password = getpass("SSH Password for %s: "%sshserver)
+    
+    for lp,rp in zip(lports, rports):
+        tunnel.ssh_tunnel(lp, rp, sshserver, remote_ip, sshkey, password)
+    
+    return tuple(lports)
+