[IPython-dev] ipython embedded in twisted, no threads
Jörgen Stenarson
jorgen.stenarson at bostream.nu
Mon Apr 16 14:16:07 EDT 2007
Hi Stefan,
I'm not sure exactly what you are after (I don't use twisted myself).
But in pyreadline it is now fairly straightforward to add a new console
class (there are currently two: the standard win32 and one for
.NET/IronPython) which should implement the lowlevel keyboard and screen
output routines. If this is what is needed I would be happy to accept
patches and answer questions to help make it happen. We would probably
also have to work out a more sofisticated method of choosing low-level
console backend than what is used now.
/Jörgen
Stefan Rank skrev:
> Hi,
> [apologies if this arrives twice, posting via gmane didn't work - yet.]
>
> attached is an ugly first attempt at embedding IPython in a twisted
> application without using threads.
>
> twisted.internet.stdio and a LineReceiver implementation are responsible
> for getting input events.
> I had to subclass the IPython shell and rearrange code to
> create a non-blocking callback interface (splitting on the main,
> blocking, raw_input call).
>
> It's far from perfect: readline functionality is missing (no commandline
> navigation, history navigation, completion), and sometimes continuation
> lines eat the input counter (In[2] ... In[4]).
>
> Would IPython developers be interested in patches that allow a less ugly
> version of such a callback-friendly subclass? ;-)
> The basic idea: refactor the main loop (InteractiveShell.interact) to::
>
> setup()
> while ...:
> promptforline()
> raw_input
> handleline()
> teardown()
>
> (I think it might also be interesting for the frontend to the IPython
> parallel computing effort, which uses twisted.)
>
> cheers,
> stefan
>
>
> ------------------------------------------------------------------------
>
> '''Testing a way to embed IPython in a twisted app without using threads.
> (seems to work on Py25/WinXP, twisted2.5 patched with #2157, IPython0.8.0)
>
> twisted.internet.stdio is responsible for getting user input.
> An implementation of the LineReceiver protocol passes received lines
> to a custom subclass of the IPython shell (main raw_input call removed).
>
> No readline behaviour is available.
> (But IPython still sets up readline and uses it for colour printing.)
>
> TODO:
> integrate readline functionality: two possibilities
>
> 1) Change pyreadline so that it can be called back by t.i.stdio for
> all things except waiting for input (i.e. completion, key bindings, ...)
> This would mean no further changes to IPython, which would still
> be using pyreadline directly.
> (or use a GNU readline callback interface: a t.i.stdio-alike would be
> polling/selecting for input, but then call readline to actually consume it.)
> 2) Build a readline compatible interface for t.i.stdio
> (only the parts for setting up completeres, key bindings, ...)
> and make the IPython subclass use that instead of pyreadline
>
> As there is a lot of pasted IPython code including comments, I added
> ##### multi-hash comments and
> docstrings explaining the rearrangements.
>
> :author: strank
> '''
>
> __docformat__ = "restructuredtext en"
>
> import sys
> import __builtin__
>
> from twisted.internet import reactor, stdio
> from twisted.protocols import basic
> from IPython.Shell import IPShellEmbed
> from IPython.iplib import InteractiveShell, ultraTB
> from IPython.ipmaker import make_IPython
>
>
> def main():
> ###### this is what we want:
> reactor.callWhenRunning(startTwistedStdioShell)
> ###### because this blocks the reactor while IPython is active:
> #reactor.callWhenRunning(startIPShell)
> reactor.run()
>
>
> def startIPShell(args=None):
> '''The non-twisted-friendly way of embedding IPython.'''
> if args is None:
> args = []
> some_recognisable_local = 'WAGAWAGA' # gets exposed in Shell
> ipshell = IPShellEmbed(args,
> banner='Standard IPython called from twisted (blocking)',
> exit_msg='Leaving Interpreter, back to program.')
> ipshell('***Called from top level. '
> 'Hit Ctrl-D to exit interpreter and continue program.')
> reactor.stop()
>
>
> def startTwistedStdioShell(args=None, local_ns=None):
> '''On Windows, this only works with a patched twisted,
> because twisted.internet.stdio in twisted2.5 is unix only,
> see ticket #2157.
> '''
> if args is None:
> args = []
> ipshell = TwistedIPShellEmbed([],
> banner='IPython embedded in a Twisted application',
> exit_msg='Leaving Interpreter, back to program.')
> sp = ShellProtocol(ipshell, '***Called from top level. ', local_ns=local_ns)
> #sp.setRawMode()
> stdio.StandardIO(sp)
>
>
> class TwistedIPShellEmbed(IPShellEmbed):
> '''Same as superclass, BUT:
> __init__ is duplicated, with a single difference:
> The actual IP shell_class is set to our own subclass.
> __call__ is split into two methods for setup / teardown.
> '''
>
> def __init__(self,argv=None,banner='',exit_msg=None,rc_override=None,
> user_ns=None):
> """Note that argv here is a string, NOT a list."""
> self.set_banner(banner)
> self.set_exit_msg(exit_msg)
> self.set_dummy_mode(0)
> # sys.displayhook is a global, we need to save the user's original
> # Don't rely on __displayhook__, as the user may have changed that.
> self.sys_displayhook_ori = sys.displayhook
> # save readline completer status
> try:
> #print 'Save completer',sys.ipcompleter # dbg
> self.sys_ipcompleter_ori = sys.ipcompleter
> except:
> pass # not nested with IPython
> self.IP = make_IPython(argv,rc_override=rc_override,
> embedded=True,
> user_ns=user_ns,
> ###### HERE IS THE DIFFERENCE -- StefanRank
> shell_class=TwistedInteractiveShell)
> # copy our own displayhook also
> self.sys_displayhook_embed = sys.displayhook
> # and leave the system's display hook clean
> sys.displayhook = self.sys_displayhook_ori
> # don't use the ipython crash handler so that user exceptions aren't
> # trapped
> sys.excepthook = ultraTB.FormattedTB(color_scheme = self.IP.rc.colors,
> mode = self.IP.rc.xmode,
> call_pdb = self.IP.rc.pdb)
> self.restore_system_completer()
>
> def __call__(self,header='',local_ns=None,global_ns=None,dummy=None):
> # Set global subsystems (display,completions) to our values
> sys.displayhook = self.sys_displayhook_embed
> if self.IP.has_readline:
> self.IP.set_completer()
> if self.banner and header:
> format = '%s\n%s\n'
> else:
> format = '%s%s\n'
> banner = format % (self.banner,header)
> # Call the embedding code with a stack depth of 1 so it can skip over
> # our call and get the original caller's namespaces.
> ###### STOP HERE, THIS embed_mainloop DOESN'T BLOCK, RETURN THE SHELL --StefanRank
> return self.IP.embed_mainloop(banner,local_ns,global_ns,stack_depth=1)
>
> def teardown(self):
> ###### call the code that would have been called at the end of IP.embed_mainloop:
> self.IP.teardown()
> ###### This is the code formerly known as: the end of __call__:
> if self.exit_msg:
> print self.exit_msg
> # Restore global systems (display, completion)
> sys.displayhook = self.sys_displayhook_ori
> self.restore_system_completer()
>
>
> class TwistedInteractiveShell(InteractiveShell):
> '''Subclassing to remove raw_input call and provide a callback interface.
> Copy-pasted and split up code of embed_mainloop, interact, raw_input.
> '''
>
> def embed_mainloop(self,header='',local_ns=None,global_ns=None,stack_depth=0):
> # Get locals and globals from caller
> if local_ns is None or global_ns is None:
> call_frame = sys._getframe(stack_depth).f_back
> if local_ns is None:
> local_ns = call_frame.f_locals
> if global_ns is None:
> global_ns = call_frame.f_globals
> self.user_global_ns = global_ns
> local_varnames = local_ns.keys()
> self.user_ns.update(local_ns)
> if local_ns is None and global_ns is None:
> self.user_global_ns.update(__main__.__dict__)
> self.set_completer_frame()
> self.add_builtins()
> self.interact(header)
> return self ###### needed for later calls, interact is now non-blocking
>
> def teardown(self):
> '''This is the code formerly known as: the end of interact and embed_mainloop.'''
> ##### from interact:
> # We are off again...
> __builtin__.__dict__['__IPYTHON__active'] -= 1
> ##### from embed_mainloop:
> # now, purge out the user namespace from anything we might have added
> # from the caller's local namespace
> ###### local_varnames not accessible any more,
> ###### should probably be saved... (TODO)
> ###delvar = self.user_ns.pop
> ###for var in local_varnames:
> ### delvar(var,None)
> # and clean builtins we may have overridden
> self.clean_builtins()
>
> def interact(self, banner=None):
> ###### HERE IT GETS HAIRY: code copied from self.interact(header)
> if self.exit_now:
> # batch run -> do not interact
> return ###### This does not make any sense now, since we are non-blocking
> cprt = 'Type "copyright", "credits" or "license" for more information.'
> if banner is None:
> self.write("Python %s on %s\n%s\n(%s)\n" %
> (sys.version, sys.platform, cprt,
> self.__class__.__name__))
> else:
> self.write(banner)
> more = 0
> # Mark activity in the builtins
> __builtin__.__dict__['__IPYTHON__active'] += 1
> self.promptForLine(more)
> return self
>
> def promptForLine(self, more):
> '''New method. To be called before waiting for the next line.'''
> prompt = ''
> ###### THIS NEEDED TO BE UNTANGLED: originally a while loop in self.interact
> # exit_now is set by a call to %Exit or %Quit
> if not self.exit_now:
> if more:
> prompt = self.hooks.generate_prompt(True)
> if self.autoindent:
> self.readline_startup_hook(self.pre_readline)
> else:
> prompt = self.hooks.generate_prompt(False)
> ####### code from self.raw_input:
> self.set_completer()
> ####### write the prompt here, writing it in the LineReceiver
> ####### with sendLine messes up the colouring
> self.write(prompt)
> ####### raw_input BEGONE!!!
> ####### unfortunately all the exception handling in self.interact is also gone.
> ####### return and wait for a call to useLine
>
> def useLine(self, line, continue_prompt=False):
> '''New method. To be called with a new received line.'''
> ####### code from self.raw_input:
> if line.strip():
> if continue_prompt:
> self.input_hist_raw[-1] += '%s\n' % line
> if self.has_readline: # and some config option is set?
> try:
> histlen = self.readline.get_current_history_length()
> newhist = self.input_hist_raw[-1].rstrip()
> self.readline.remove_history_item(histlen-1)
> self.readline.replace_history_item(histlen-2,newhist)
> except AttributeError:
> pass # re{move,place}_history_item are new in 2.4.
> else:
> self.input_hist_raw.append('%s\n' % line)
> try:
> lineout = self.prefilter(line,continue_prompt)
> except:
> # blanket except, in case a user-defined prefilter crashes, so it
> # can't take all of ipython with it.
> self.showtraceback()
> lineout = ''
> ###### CODE FROM INTERACT AGAIN:
> more = self.push(lineout)
> if (self.SyntaxTB.last_syntax_error and
> self.rc.autoedit_syntax):
> self.edit_syntax_error()
> self.promptForLine(more)
> ###### indicate if we want to quit
> return not self.exit_now
>
>
> class ShellProtocol(basic.LineReceiver):
> delimiter = '\n' # does not work with '\r\n' on Windows...
> # this might be an issue with the #2157 patches?
>
> def __init__(self, ipshell, banner, **kwargs):
> self.ipshell = ipshell
> self.banner = banner
> self.kwargs = kwargs
>
> def connectionMade(self):
> #self.sendLine("Yay, type something!")
> # locals here are available in the shell:
> # (but in practice the locals of the ShellProtocol() call site
> # would be more interesting.)
> another_strange_local = 'hubabuba'
> from twisted.internet import reactor
> self.sheller = self.ipshell(self.banner
> + '\n quit.....quits via LineReceiver,'
> + '\n exit()...quits via IPython,'
> + '\n pause....test pausing the LineReceiver',
> **self.kwargs)
>
> def lineReceived(self, line):
> if line == 'quit':
> self.sendLine('OK quitting')
> self.transport.loseConnection()
> return
> if line == 'pause':
> self.sendLine('OK pausing for 2 seconds')
> self.pauseProducing()
> self.clearLineBuffer()
> # still receives keys typed during the pause,
> # no matter how many clearLineBuffer()s, I use.
> # might be a feature of Windows cmd... ?
> def restart():
> self.clearLineBuffer()
> self.resumeProducing()
> self.clearLineBuffer()
> reactor.callLater(2, restart)
> return
> #self.sendLine("Echo: " + line)
> if not self.sheller.useLine(line): # processes line, prints output and next prompt
> self.sendLine("IPython wants to quit")
> self.transport.loseConnection()
> #self.transport.write("Yay, type more!")
>
> #def rawDataReceived(self, data):
> # self.sendLine('RawEcho: ' + str(data))
> # self.transport.write("Yay, type more!")
>
> def connectionLost(self, reason):
> try:
> self.ipshell.teardown()
> except IOError:
> pass # is raised by IPython code when you type quit
> # stop the reactor, only because this is meant to be run in Stdio.
> reactor.stop()
>
>
> if __name__ == '__main__':
> main()
>
>
> ------------------------------------------------------------------------
>
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