aesthetics pass on AsyncResult.display_outputs

adds a few delimiters when there are rich outputs, and cleans up a few cases of extra trailing whitespace on stdout/err

IPython/parallel/client/asyncresult.py

@@ -1,652 +1,670 b''
 """AsyncResult objects for the client
 
 Authors:
 
 * MinRK
 """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010-2011  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
 #-----------------------------------------------------------------------------
 
+from __future__ import print_function
+
 import sys
 import time
 from datetime import datetime
 
 from zmq import MessageTracker
 
-from IPython.core.display import clear_output, display
+from IPython.core.display import clear_output, display, display_pretty
 from IPython.external.decorator import decorator
 from IPython.parallel import error
 
 #-----------------------------------------------------------------------------
 # Functions
 #-----------------------------------------------------------------------------
 
 def _total_seconds(td):
     """timedelta.total_seconds was added in 2.7"""
     try:
         # Python >= 2.7
         return td.total_seconds()
     except AttributeError:
         # Python 2.6
         return 1e-6 * (td.microseconds + (td.seconds + td.days * 24 * 3600) * 10**6)
 
+def _raw_text(s):
+    display_pretty(s, raw=True)
+
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 
 # global empty tracker that's always done:
 finished_tracker = MessageTracker()
 
 @decorator
 def check_ready(f, self, *args, **kwargs):
     """Call spin() to sync state prior to calling the method."""
     self.wait(0)
     if not self._ready:
         raise error.TimeoutError("result not ready")
     return f(self, *args, **kwargs)
 
 class AsyncResult(object):
     """Class for representing results of non-blocking calls.
 
     Provides the same interface as :py:class:`multiprocessing.pool.AsyncResult`.
     """
 
     msg_ids = None
     _targets = None
     _tracker = None
     _single_result = False
 
     def __init__(self, client, msg_ids, fname='unknown', targets=None, tracker=None):
         if isinstance(msg_ids, basestring):
             # always a list
             msg_ids = [msg_ids]
         if tracker is None:
             # default to always done
             tracker = finished_tracker
         self._client = client
         self.msg_ids = msg_ids
         self._fname=fname
         self._targets = targets
         self._tracker = tracker
         self._ready = False
         self._success = None
         self._metadata = None
         if len(msg_ids) == 1:
             self._single_result = not isinstance(targets, (list, tuple))
         else:
             self._single_result = False
 
     def __repr__(self):
         if self._ready:
             return "<%s: finished>"%(self.__class__.__name__)
         else:
             return "<%s: %s>"%(self.__class__.__name__,self._fname)
 
 
     def _reconstruct_result(self, res):
         """Reconstruct our result from actual result list (always a list)
 
         Override me in subclasses for turning a list of results
         into the expected form.
         """
         if self._single_result:
             return res[0]
         else:
             return res
 
     def get(self, timeout=-1):
         """Return the result when it arrives.
 
         If `timeout` is not ``None`` and the result does not arrive within
         `timeout` seconds then ``TimeoutError`` is raised. If the
         remote call raised an exception then that exception will be reraised
         by get() inside a `RemoteError`.
         """
         if not self.ready():
             self.wait(timeout)
 
         if self._ready:
             if self._success:
                 return self._result
             else:
                 raise self._exception
         else:
             raise error.TimeoutError("Result not ready.")
 
     def ready(self):
         """Return whether the call has completed."""
         if not self._ready:
             self.wait(0)
         return self._ready
 
     def wait(self, timeout=-1):
         """Wait until the result is available or until `timeout` seconds pass.
 
         This method always returns None.
         """
         if self._ready:
             return
         self._ready = self._client.wait(self.msg_ids, timeout)
         if self._ready:
             try:
                 results = map(self._client.results.get, self.msg_ids)
                 self._result = results
                 if self._single_result:
                     r = results[0]
                     if isinstance(r, Exception):
                         raise r
                 else:
                     results = error.collect_exceptions(results, self._fname)
                 self._result = self._reconstruct_result(results)
             except Exception, e:
                 self._exception = e
                 self._success = False
             else:
                 self._success = True
             finally:
                 self._metadata = map(self._client.metadata.get, self.msg_ids)
 
 
     def successful(self):
         """Return whether the call completed without raising an exception.
 
         Will raise ``AssertionError`` if the result is not ready.
         """
         assert self.ready()
         return self._success
 
     #----------------------------------------------------------------
     # Extra methods not in mp.pool.AsyncResult
     #----------------------------------------------------------------
 
     def get_dict(self, timeout=-1):
         """Get the results as a dict, keyed by engine_id.
 
         timeout behavior is described in `get()`.
         """
 
         results = self.get(timeout)
         engine_ids = [ md['engine_id'] for md in self._metadata ]
         bycount = sorted(engine_ids, key=lambda k: engine_ids.count(k))
         maxcount = bycount.count(bycount[-1])
         if maxcount > 1:
             raise ValueError("Cannot build dict, %i jobs ran on engine #%i"%(
                     maxcount, bycount[-1]))
 
         return dict(zip(engine_ids,results))
 
     @property
     def result(self):
         """result property wrapper for `get(timeout=0)`."""
         return self.get()
 
     # abbreviated alias:
     r = result
 
     @property
     @check_ready
     def metadata(self):
         """property for accessing execution metadata."""
         if self._single_result:
             return self._metadata[0]
         else:
             return self._metadata
 
     @property
     def result_dict(self):
         """result property as a dict."""
         return self.get_dict()
 
     def __dict__(self):
         return self.get_dict(0)
 
     def abort(self):
         """abort my tasks."""
         assert not self.ready(), "Can't abort, I am already done!"
         return self._client.abort(self.msg_ids, targets=self._targets, block=True)
 
     @property
     def sent(self):
         """check whether my messages have been sent."""
         return self._tracker.done
 
     def wait_for_send(self, timeout=-1):
         """wait for pyzmq send to complete.
 
         This is necessary when sending arrays that you intend to edit in-place.
         `timeout` is in seconds, and will raise TimeoutError if it is reached
         before the send completes.
         """
         return self._tracker.wait(timeout)
 
     #-------------------------------------
     # dict-access
     #-------------------------------------
 
     @check_ready
     def __getitem__(self, key):
         """getitem returns result value(s) if keyed by int/slice, or metadata if key is str.
         """
         if isinstance(key, int):
             return error.collect_exceptions([self._result[key]], self._fname)[0]
         elif isinstance(key, slice):
             return error.collect_exceptions(self._result[key], self._fname)
         elif isinstance(key, basestring):
             values = [ md[key] for md in self._metadata ]
             if self._single_result:
                 return values[0]
             else:
                 return values
         else:
             raise TypeError("Invalid key type %r, must be 'int','slice', or 'str'"%type(key))
 
     def __getattr__(self, key):
         """getattr maps to getitem for convenient attr access to metadata."""
         try:
             return self.__getitem__(key)
         except (error.TimeoutError, KeyError):
             raise AttributeError("%r object has no attribute %r"%(
                     self.__class__.__name__, key))
 
     # asynchronous iterator:
     def __iter__(self):
         if self._single_result:
             raise TypeError("AsyncResults with a single result are not iterable.")
         try:
             rlist = self.get(0)
         except error.TimeoutError:
             # wait for each result individually
             for msg_id in self.msg_ids:
                 ar = AsyncResult(self._client, msg_id, self._fname)
                 yield ar.get()
         else:
             # already done
             for r in rlist:
                 yield r
     
     def __len__(self):
         return len(self.msg_ids)
     
     #-------------------------------------
     # Sugar methods and attributes
     #-------------------------------------
     
     def timedelta(self, start, end, start_key=min, end_key=max):
         """compute the difference between two sets of timestamps
         
         The default behavior is to use the earliest of the first
         and the latest of the second list, but this can be changed
         by passing a different
         
         Parameters
         ----------
         
         start : one or more datetime objects (e.g. ar.submitted)
         end : one or more datetime objects (e.g. ar.received)
         start_key : callable
             Function to call on `start` to extract the relevant
             entry [defalt: min]
         end_key : callable
             Function to call on `end` to extract the relevant
             entry [default: max]
         
         Returns
         -------
         
         dt : float
             The time elapsed (in seconds) between the two selected timestamps.
         """
         if not isinstance(start, datetime):
             # handle single_result AsyncResults, where ar.stamp is single object,
             # not a list
             start = start_key(start)
         if not isinstance(end, datetime):
             # handle single_result AsyncResults, where ar.stamp is single object,
             # not a list
             end = end_key(end)
         return _total_seconds(end - start)
         
     @property
     def progress(self):
         """the number of tasks which have been completed at this point.
         
         Fractional progress would be given by 1.0 * ar.progress / len(ar)
         """
         self.wait(0)
         return len(self) - len(set(self.msg_ids).intersection(self._client.outstanding))
     
     @property
     def elapsed(self):
         """elapsed time since initial submission"""
         if self.ready():
             return self.wall_time
         
         now = submitted = datetime.now()
         for msg_id in self.msg_ids:
             if msg_id in self._client.metadata:
                 stamp = self._client.metadata[msg_id]['submitted']
                 if stamp and stamp < submitted:
                     submitted = stamp
         return _total_seconds(now-submitted)
     
     @property
     @check_ready
     def serial_time(self):
         """serial computation time of a parallel calculation
         
         Computed as the sum of (completed-started) of each task
         """
         t = 0
         for md in self._metadata:
             t += _total_seconds(md['completed'] - md['started'])
         return t
     
     @property
     @check_ready
     def wall_time(self):
         """actual computation time of a parallel calculation
         
         Computed as the time between the latest `received` stamp
         and the earliest `submitted`.
         
         Only reliable if Client was spinning/waiting when the task finished, because
         the `received` timestamp is created when a result is pulled off of the zmq queue,
         which happens as a result of `client.spin()`.
         
         For similar comparison of other timestamp pairs, check out AsyncResult.timedelta.
         
         """
         return self.timedelta(self.submitted, self.received)
     
     def wait_interactive(self, interval=1., timeout=None):
         """interactive wait, printing progress at regular intervals"""
         N = len(self)
         tic = time.time()
         while not self.ready() and (timeout is None or time.time() - tic <= timeout):
             self.wait(interval)
             clear_output()
-            print "%4i/%i tasks finished after %4i s" % (self.progress, N, self.elapsed),
+            print("%4i/%i tasks finished after %4i s" % (self.progress, N, self.elapsed), end="")
             sys.stdout.flush()
-        print
-        print "done"
+        print()
+        print("done")
     
     def _republish_displaypub(self, content, eid):
         """republish individual displaypub content dicts"""
         try:
             ip = get_ipython()
         except NameError:
             # displaypub is meaningless outside IPython
             return
         md = content['metadata'] or {}
         md['engine'] = eid
         ip.display_pub.publish(content['source'], content['data'], md)
+    
+    def _display_stream(self, text, prefix='', file=None):
+        if not text:
+            # nothing to display
+            return
+        if file is None:
+            file = sys.stdout
+        end = '' if text.endswith('\n') else '\n'
         
+        multiline = text.count('\n') > int(text.endswith('\n'))
+        if prefix and multiline and not text.startswith('\n'):
+            prefix = prefix + '\n'
+        print("%s%s" % (prefix, text), file=file, end=end)
         
+    
     def _display_single_result(self):
-        if self.stdout:
-            print self.stdout
-        if self.stderr:
-            print >> sys.stderr, self.stderr
+        self._display_stream(self.stdout)
+        self._display_stream(self.stderr, file=sys.stderr)
         
         try:
             get_ipython()
         except NameError:
             # displaypub is meaningless outside IPython
             return
-            
+        
         for output in self.outputs:
             self._republish_displaypub(output, self.engine_id)
         
         if self.pyout is not None:
             display(self.get())
     
     @check_ready
     def display_outputs(self, groupby="type"):
         """republish the outputs of the computation
         
         Parameters
         ----------
         
         groupby : str [default: type]
             if 'type':
                 Group outputs by type (show all stdout, then all stderr, etc.):
                 
                 [stdout:1] foo
                 [stdout:2] foo
                 [stderr:1] bar
                 [stderr:2] bar
             if 'engine':
                 Display outputs for each engine before moving on to the next:
                 
                 [stdout:1] foo
                 [stderr:1] bar
                 [stdout:2] foo
                 [stderr:2] bar
                 
             if 'order':
                 Like 'type', but further collate individual displaypub
                 outputs.  This is meant for cases of each command producing
                 several plots, and you would like to see all of the first
                 plots together, then all of the second plots, and so on.
         """
         # flush iopub, just in case
         self._client._flush_iopub(self._client._iopub_socket)
         if self._single_result:
             self._display_single_result()
             return
         
-        stdouts = [s.rstrip() for s in self.stdout]
-        stderrs = [s.rstrip() for s in self.stderr]
-        pyouts  = [p for p in self.pyout]
+        stdouts = self.stdout
+        stderrs = self.stderr
+        pyouts  = self.pyout
         output_lists = self.outputs
         results = self.get()
         
         targets = self.engine_id
         
         if groupby == "engine":
             for eid,stdout,stderr,outputs,r,pyout in zip(
                     targets, stdouts, stderrs, output_lists, results, pyouts
                 ):
-                if stdout:
-                    print '[stdout:%i]' % eid, stdout
-                if stderr:
-                    print >> sys.stderr, '[stderr:%i]' % eid, stderr
+                self._display_stream(stdout, '[stdout:%i] ' % eid)
+                self._display_stream(stderr, '[stderr:%i] ' % eid, file=sys.stderr)
                 
                 try:
                     get_ipython()
                 except NameError:
                     # displaypub is meaningless outside IPython
                     return 
                 
+                if outputs or pyout is not None:
+                    _raw_text('[output:%i]' % eid)
+                
                 for output in outputs:
                     self._republish_displaypub(output, eid)
                 
                 if pyout is not None:
                     display(r)
         
         elif groupby in ('type', 'order'):
             # republish stdout:
-            if any(stdouts):
-                for eid,stdout in zip(targets, stdouts):
-                    print '[stdout:%i]' % eid, stdout
+            for eid,stdout in zip(targets, stdouts):
+                self._display_stream(stdout, '[stdout:%i] ' % eid)
         
             # republish stderr:
-            if any(stderrs):
-                for eid,stderr in zip(targets, stderrs):
-                    print >> sys.stderr, '[stderr:%i]' % eid, stderr
+            for eid,stderr in zip(targets, stderrs):
+                self._display_stream(stderr, '[stderr:%i] ' % eid, file=sys.stderr)
         
             try:
                 get_ipython()
             except NameError:
                 # displaypub is meaningless outside IPython
                 return
             
             if groupby == 'order':
                 output_dict = dict((eid, outputs) for eid,outputs in zip(targets, output_lists))
                 N = max(len(outputs) for outputs in output_lists)
                 for i in range(N):
                     for eid in targets:
                         outputs = output_dict[eid]
                         if len(outputs) >= N:
+                            _raw_text('[output:%i]' % eid)
                             self._republish_displaypub(outputs[i], eid)
             else:
                 # republish displaypub output
                 for eid,outputs in zip(targets, output_lists):
+                    if outputs:
+                        _raw_text('[output:%i]' % eid)
                     for output in outputs:
                         self._republish_displaypub(output, eid)
         
             # finally, add pyout:
             for eid,r,pyout in zip(targets, results, pyouts):
                 if pyout is not None:
                     display(r)
         
         else:
             raise ValueError("groupby must be one of 'type', 'engine', 'collate', not %r" % groupby)
         
         
 
 
 class AsyncMapResult(AsyncResult):
     """Class for representing results of non-blocking gathers.
 
     This will properly reconstruct the gather.
     
     This class is iterable at any time, and will wait on results as they come.
     
     If ordered=False, then the first results to arrive will come first, otherwise
     results will be yielded in the order they were submitted.
     
     """
 
     def __init__(self, client, msg_ids, mapObject, fname='', ordered=True):
         AsyncResult.__init__(self, client, msg_ids, fname=fname)
         self._mapObject = mapObject
         self._single_result = False
         self.ordered = ordered
 
     def _reconstruct_result(self, res):
         """Perform the gather on the actual results."""
         return self._mapObject.joinPartitions(res)
 
     # asynchronous iterator:
     def __iter__(self):
         it = self._ordered_iter if self.ordered else self._unordered_iter
         for r in it():
             yield r
 
     # asynchronous ordered iterator:
     def _ordered_iter(self):
         """iterator for results *as they arrive*, preserving submission order."""
         try:
             rlist = self.get(0)
         except error.TimeoutError:
             # wait for each result individually
             for msg_id in self.msg_ids:
                 ar = AsyncResult(self._client, msg_id, self._fname)
                 rlist = ar.get()
                 try:
                     for r in rlist:
                         yield r
                 except TypeError:
                     # flattened, not a list
                     # this could get broken by flattened data that returns iterables
                     # but most calls to map do not expose the `flatten` argument
                     yield rlist
         else:
             # already done
             for r in rlist:
                 yield r
 
     # asynchronous unordered iterator:
     def _unordered_iter(self):
         """iterator for results *as they arrive*, on FCFS basis, ignoring submission order."""
         try:
             rlist = self.get(0)
         except error.TimeoutError:
             pending = set(self.msg_ids)
             while pending:
                 try:
                     self._client.wait(pending, 1e-3)
                 except error.TimeoutError:
                     # ignore timeout error, because that only means
                     # *some* jobs are outstanding
                     pass
                 # update ready set with those no longer outstanding:
                 ready = pending.difference(self._client.outstanding)
                 # update pending to exclude those that are finished
                 pending = pending.difference(ready)
                 while ready:
                     msg_id = ready.pop()
                     ar = AsyncResult(self._client, msg_id, self._fname)
                     rlist = ar.get()
                     try:
                         for r in rlist:
                             yield r
                     except TypeError:
                         # flattened, not a list
                         # this could get broken by flattened data that returns iterables
                         # but most calls to map do not expose the `flatten` argument
                         yield rlist
         else:
             # already done
             for r in rlist:
                 yield r
 
 
 
 class AsyncHubResult(AsyncResult):
     """Class to wrap pending results that must be requested from the Hub.
 
     Note that waiting/polling on these objects requires polling the Hubover the network,
     so use `AsyncHubResult.wait()` sparingly.
     """
 
     def wait(self, timeout=-1):
         """wait for result to complete."""
         start = time.time()
         if self._ready:
             return
         local_ids = filter(lambda msg_id: msg_id in self._client.outstanding, self.msg_ids)
         local_ready = self._client.wait(local_ids, timeout)
         if local_ready:
             remote_ids = filter(lambda msg_id: msg_id not in self._client.results, self.msg_ids)
             if not remote_ids:
                 self._ready = True
             else:
                 rdict = self._client.result_status(remote_ids, status_only=False)
                 pending = rdict['pending']
                 while pending and (timeout < 0 or time.time() < start+timeout):
                     rdict = self._client.result_status(remote_ids, status_only=False)
                     pending = rdict['pending']
                     if pending:
                         time.sleep(0.1)
                 if not pending:
                     self._ready = True
         if self._ready:
             try:
                 results = map(self._client.results.get, self.msg_ids)
                 self._result = results
                 if self._single_result:
                     r = results[0]
                     if isinstance(r, Exception):
                         raise r
                 else:
                     results = error.collect_exceptions(results, self._fname)
                 self._result = self._reconstruct_result(results)
             except Exception, e:
                 self._exception = e
                 self._success = False
             else:
                 self._success = True
             finally:
                 self._metadata = map(self._client.metadata.get, self.msg_ids)
 
 __all__ = ['AsyncResult', 'AsyncMapResult', 'AsyncHubResult']
  No newline at end of file

IPython/parallel/client/client.py

@@ -1,1655 +1,1659 b''
 """A semi-synchronous Client for the ZMQ cluster
 
 Authors:
 
 * MinRK
 """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010-2011  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 os
 import json
 import sys
 from threading import Thread, Event
 import time
 import warnings
 from datetime import datetime
 from getpass import getpass
 from pprint import pprint
 
 pjoin = os.path.join
 
 import zmq
 # from zmq.eventloop import ioloop, zmqstream
 
 from IPython.config.configurable import MultipleInstanceError
 from IPython.core.application import BaseIPythonApplication
 
 from IPython.utils.coloransi import TermColors
 from IPython.utils.jsonutil import rekey
 from IPython.utils.localinterfaces import LOCAL_IPS
 from IPython.utils.path import get_ipython_dir
 from IPython.utils.py3compat import cast_bytes
 from IPython.utils.traitlets import (HasTraits, Integer, Instance, Unicode,
                                     Dict, List, Bool, Set, Any)
 from IPython.external.decorator import decorator
 from IPython.external.ssh import tunnel
 
 from IPython.parallel import Reference
 from IPython.parallel import error
 from IPython.parallel import util
 
 from IPython.zmq.session import Session, Message
 
 from .asyncresult import AsyncResult, AsyncHubResult
 from IPython.core.profiledir import ProfileDir, ProfileDirError
 from .view import DirectView, LoadBalancedView
 
 if sys.version_info[0] >= 3:
     # xrange is used in a couple 'isinstance' tests in py2
     # should be just 'range' in 3k
     xrange = range
 
 #--------------------------------------------------------------------------
 # Decorators for Client methods
 #--------------------------------------------------------------------------
 
 @decorator
 def spin_first(f, self, *args, **kwargs):
     """Call spin() to sync state prior to calling the method."""
     self.spin()
     return f(self, *args, **kwargs)
 
 
 #--------------------------------------------------------------------------
 # Classes
 #--------------------------------------------------------------------------
 
 
 class ExecuteReply(object):
     """wrapper for finished Execute results"""
     def __init__(self, msg_id, content, metadata):
         self.msg_id = msg_id
         self._content = content
         self.execution_count = content['execution_count']
         self.metadata = metadata
     
     def __getitem__(self, key):
         return self.metadata[key]
     
     def __getattr__(self, key):
         if key not in self.metadata:
             raise AttributeError(key)
         return self.metadata[key]
     
     def __repr__(self):
         pyout = self.metadata['pyout'] or {'data':{}}
         text_out = pyout['data'].get('text/plain', '')
         if len(text_out) > 32:
             text_out = text_out[:29] + '...'
         
         return "<ExecuteReply[%i]: %s>" % (self.execution_count, text_out)
     
     def _repr_pretty_(self, p, cycle):
         pyout = self.metadata['pyout'] or {'data':{}}
         text_out = pyout['data'].get('text/plain', '')
         
         if not text_out:
             return
         
         try:
             ip = get_ipython()
         except NameError:
             colors = "NoColor"
         else:
             colors = ip.colors
         
         if colors == "NoColor":
             out = normal = ""
         else:
             out = TermColors.Red
             normal = TermColors.Normal
         
+        if '\n' in text_out and not text_out.startswith('\n'):
+            # add newline for multiline reprs
+            text_out = '\n' + text_out
+        
         p.text(
-            u'[%i] ' % self.metadata['engine_id'] +
-            out + u'Out[%i]: ' % self.execution_count +
-            normal + text_out
+            out + u'Out[%i:%i]: ' % (
+                self.metadata['engine_id'], self.execution_count
+            ) + normal + text_out
         )
     
     def _repr_html_(self):
         pyout = self.metadata['pyout'] or {'data':{}}
         return pyout['data'].get("text/html")
     
     def _repr_latex_(self):
         pyout = self.metadata['pyout'] or {'data':{}}
         return pyout['data'].get("text/latex")
     
     def _repr_json_(self):
         pyout = self.metadata['pyout'] or {'data':{}}
         return pyout['data'].get("application/json")
     
     def _repr_javascript_(self):
         pyout = self.metadata['pyout'] or {'data':{}}
         return pyout['data'].get("application/javascript")
     
     def _repr_png_(self):
         pyout = self.metadata['pyout'] or {'data':{}}
         return pyout['data'].get("image/png")
     
     def _repr_jpeg_(self):
         pyout = self.metadata['pyout'] or {'data':{}}
         return pyout['data'].get("image/jpeg")
     
     def _repr_svg_(self):
         pyout = self.metadata['pyout'] or {'data':{}}
         return pyout['data'].get("image/svg+xml")
 
 
 class Metadata(dict):
     """Subclass of dict for initializing metadata values.
 
     Attribute access works on keys.
 
     These objects have a strict set of keys - errors will raise if you try
     to add new keys.
     """
     def __init__(self, *args, **kwargs):
         dict.__init__(self)
         md = {'msg_id' : None,
               'submitted' : None,
               'started' : None,
               'completed' : None,
               'received' : None,
               'engine_uuid' : None,
               'engine_id' : None,
               'follow' : None,
               'after' : None,
               'status' : None,
 
               'pyin' : None,
               'pyout' : None,
               'pyerr' : None,
               'stdout' : '',
               'stderr' : '',
               'outputs' : [],
             }
         self.update(md)
         self.update(dict(*args, **kwargs))
 
     def __getattr__(self, key):
         """getattr aliased to getitem"""
         if key in self.iterkeys():
             return self[key]
         else:
             raise AttributeError(key)
 
     def __setattr__(self, key, value):
         """setattr aliased to setitem, with strict"""
         if key in self.iterkeys():
             self[key] = value
         else:
             raise AttributeError(key)
 
     def __setitem__(self, key, value):
         """strict static key enforcement"""
         if key in self.iterkeys():
             dict.__setitem__(self, key, value)
         else:
             raise KeyError(key)
 
 
 class Client(HasTraits):
     """A semi-synchronous client to the IPython ZMQ cluster
 
     Parameters
     ----------
 
     url_or_file : bytes or unicode; zmq url or path to ipcontroller-client.json
         Connection information for the Hub's registration.  If a json connector
         file is given, then likely no further configuration is necessary.
         [Default: use profile]
     profile : bytes
         The name of the Cluster profile to be used to find connector information.
         If run from an IPython application, the default profile will be the same
         as the running application, otherwise it will be 'default'.
     context : zmq.Context
         Pass an existing zmq.Context instance, otherwise the client will create its own.
     debug : bool
         flag for lots of message printing for debug purposes
     timeout : int/float
         time (in seconds) to wait for connection replies from the Hub
         [Default: 10]
 
     #-------------- session related args ----------------
 
     config : Config object
         If specified, this will be relayed to the Session for configuration
     username : str
         set username for the session object
     packer : str (import_string) or callable
         Can be either the simple keyword 'json' or 'pickle', or an import_string to a
         function to serialize messages. Must support same input as
         JSON, and output must be bytes.
         You can pass a callable directly as `pack`
     unpacker : str (import_string) or callable
         The inverse of packer.  Only necessary if packer is specified as *not* one
         of 'json' or 'pickle'.
 
     #-------------- ssh related args ----------------
     # These are args for configuring the ssh tunnel to be used
     # credentials are used to forward connections over ssh to the Controller
     # Note that the ip given in `addr` needs to be relative to sshserver
     # The most basic case is to leave addr as pointing to localhost (127.0.0.1),
     # and set sshserver as the same machine the Controller is on. However,
     # the only requirement is that sshserver is able to see the Controller
     # (i.e. is within the same trusted network).
 
     sshserver : str
         A string of the form passed to ssh, i.e. 'server.tld' or '[e-mail]:port'
         If keyfile or password is specified, and this is not, it will default to
         the ip given in addr.
     sshkey : str; path to ssh private key file
         This specifies a key to be used in ssh login, default None.
         Regular default ssh keys will be used without specifying this argument.
     password : str
         Your ssh password to sshserver. Note that if this is left None,
         you will be prompted for it if passwordless key based login is unavailable.
     paramiko : bool
         flag for whether to use paramiko instead of shell ssh for tunneling.
         [default: True on win32, False else]
 
     ------- exec authentication args -------
     If even localhost is untrusted, you can have some protection against
     unauthorized execution by signing messages with HMAC digests.
     Messages are still sent as cleartext, so if someone can snoop your
     loopback traffic this will not protect your privacy, but will prevent
     unauthorized execution.
 
     exec_key : str
         an authentication key or file containing a key
         default: None
 
 
     Attributes
     ----------
 
     ids : list of int engine IDs
         requesting the ids attribute always synchronizes
         the registration state. To request ids without synchronization,
         use semi-private _ids attributes.
 
     history : list of msg_ids
         a list of msg_ids, keeping track of all the execution
         messages you have submitted in order.
 
     outstanding : set of msg_ids
         a set of msg_ids that have been submitted, but whose
         results have not yet been received.
 
     results : dict
         a dict of all our results, keyed by msg_id
 
     block : bool
         determines default behavior when block not specified
         in execution methods
 
     Methods
     -------
 
     spin
         flushes incoming results and registration state changes
         control methods spin, and requesting `ids` also ensures up to date
 
     wait
         wait on one or more msg_ids
 
     execution methods
         apply
         legacy: execute, run
 
     data movement
         push, pull, scatter, gather
 
     query methods
         queue_status, get_result, purge, result_status
 
     control methods
         abort, shutdown
 
     """
 
 
     block = Bool(False)
     outstanding = Set()
     results = Instance('collections.defaultdict', (dict,))
     metadata = Instance('collections.defaultdict', (Metadata,))
     history = List()
     debug = Bool(False)
     _spin_thread = Any()
     _stop_spinning = Any()
 
     profile=Unicode()
     def _profile_default(self):
         if BaseIPythonApplication.initialized():
             # an IPython app *might* be running, try to get its profile
             try:
                 return BaseIPythonApplication.instance().profile
             except (AttributeError, MultipleInstanceError):
                 # could be a *different* subclass of config.Application,
                 # which would raise one of these two errors.
                 return u'default'
         else:
             return u'default'
 
 
     _outstanding_dict = Instance('collections.defaultdict', (set,))
     _ids = List()
     _connected=Bool(False)
     _ssh=Bool(False)
     _context = Instance('zmq.Context')
     _config = Dict()
     _engines=Instance(util.ReverseDict, (), {})
     # _hub_socket=Instance('zmq.Socket')
     _query_socket=Instance('zmq.Socket')
     _control_socket=Instance('zmq.Socket')
     _iopub_socket=Instance('zmq.Socket')
     _notification_socket=Instance('zmq.Socket')
     _mux_socket=Instance('zmq.Socket')
     _task_socket=Instance('zmq.Socket')
     _task_scheme=Unicode()
     _closed = False
     _ignored_control_replies=Integer(0)
     _ignored_hub_replies=Integer(0)
 
     def __new__(self, *args, **kw):
         # don't raise on positional args
         return HasTraits.__new__(self, **kw)
 
     def __init__(self, url_or_file=None, profile=None, profile_dir=None, ipython_dir=None,
             context=None, debug=False, exec_key=None,
             sshserver=None, sshkey=None, password=None, paramiko=None,
             timeout=10, **extra_args
             ):
         if profile:
             super(Client, self).__init__(debug=debug, profile=profile)
         else:
             super(Client, self).__init__(debug=debug)
         if context is None:
             context = zmq.Context.instance()
         self._context = context
         self._stop_spinning = Event()
 
         self._setup_profile_dir(self.profile, profile_dir, ipython_dir)
         if self._cd is not None:
             if url_or_file is None:
                 url_or_file = pjoin(self._cd.security_dir, 'ipcontroller-client.json')
         if url_or_file is None:
             raise ValueError(
                 "I can't find enough information to connect to a hub!"
                 " Please specify at least one of url_or_file or profile."
             )
 
         if not util.is_url(url_or_file):
             # it's not a url, try for a file
             if not os.path.exists(url_or_file):
                 if self._cd:
                     url_or_file = os.path.join(self._cd.security_dir, url_or_file)
                 if not os.path.exists(url_or_file):
                     raise IOError("Connection file not found: %r" % url_or_file)
             with open(url_or_file) as f:
                 cfg = json.loads(f.read())
         else:
             cfg = {'url':url_or_file}
 
         # sync defaults from args, json:
         if sshserver:
             cfg['ssh'] = sshserver
         if exec_key:
             cfg['exec_key'] = exec_key
         exec_key = cfg['exec_key']
         location = cfg.setdefault('location', None)
         cfg['url'] = util.disambiguate_url(cfg['url'], location)
         url = cfg['url']
         proto,addr,port = util.split_url(url)
         if location is not None and addr == '127.0.0.1':
             # location specified, and connection is expected to be local
             if location not in LOCAL_IPS and not sshserver:
                 # load ssh from JSON *only* if the controller is not on
                 # this machine
                 sshserver=cfg['ssh']
             if location not in LOCAL_IPS and not sshserver:
                 # warn if no ssh specified, but SSH is probably needed
                 # This is only a warning, because the most likely cause
                 # is a local Controller on a laptop whose IP is dynamic
                 warnings.warn("""
             Controller appears to be listening on localhost, but not on this machine.
             If this is true, you should specify Client(...,sshserver='you@%s')
             or instruct your controller to listen on an external IP."""%location,
                 RuntimeWarning)
         elif not sshserver:
             # otherwise sync with cfg
             sshserver = cfg['ssh']
 
         self._config = cfg
 
         self._ssh = bool(sshserver or sshkey or password)
         if self._ssh and sshserver is None:
             # default to ssh via localhost
             sshserver = url.split('://')[1].split(':')[0]
         if self._ssh and password is None:
             if tunnel.try_passwordless_ssh(sshserver, sshkey, paramiko):
                 password=False
             else:
                 password = getpass("SSH Password for %s: "%sshserver)
         ssh_kwargs = dict(keyfile=sshkey, password=password, paramiko=paramiko)
 
         # configure and construct the session
         if exec_key is not None:
             if os.path.isfile(exec_key):
                 extra_args['keyfile'] = exec_key
             else:
                 exec_key = cast_bytes(exec_key)
                 extra_args['key'] = exec_key
         self.session = Session(**extra_args)
 
         self._query_socket = self._context.socket(zmq.DEALER)
         self._query_socket.setsockopt(zmq.IDENTITY, self.session.bsession)
         if self._ssh:
             tunnel.tunnel_connection(self._query_socket, url, sshserver, **ssh_kwargs)
         else:
             self._query_socket.connect(url)
 
         self.session.debug = self.debug
 
         self._notification_handlers = {'registration_notification' : self._register_engine,
                                     'unregistration_notification' : self._unregister_engine,
                                     'shutdown_notification' : lambda msg: self.close(),
                                     }
         self._queue_handlers = {'execute_reply' : self._handle_execute_reply,
                                 'apply_reply' : self._handle_apply_reply}
         self._connect(sshserver, ssh_kwargs, timeout)
 
     def __del__(self):
         """cleanup sockets, but _not_ context."""
         self.close()
 
     def _setup_profile_dir(self, profile, profile_dir, ipython_dir):
         if ipython_dir is None:
             ipython_dir = get_ipython_dir()
         if profile_dir is not None:
             try:
                 self._cd = ProfileDir.find_profile_dir(profile_dir)
                 return
             except ProfileDirError:
                 pass
         elif profile is not None:
             try:
                 self._cd = ProfileDir.find_profile_dir_by_name(
                     ipython_dir, profile)
                 return
             except ProfileDirError:
                 pass
         self._cd = None
 
     def _update_engines(self, engines):
         """Update our engines dict and _ids from a dict of the form: {id:uuid}."""
         for k,v in engines.iteritems():
             eid = int(k)
             self._engines[eid] = v
             self._ids.append(eid)
         self._ids = sorted(self._ids)
         if sorted(self._engines.keys()) != range(len(self._engines)) and \
                         self._task_scheme == 'pure' and self._task_socket:
             self._stop_scheduling_tasks()
 
     def _stop_scheduling_tasks(self):
         """Stop scheduling tasks because an engine has been unregistered
         from a pure ZMQ scheduler.
         """
         self._task_socket.close()
         self._task_socket = None
         msg = "An engine has been unregistered, and we are using pure " +\
               "ZMQ task scheduling.  Task farming will be disabled."
         if self.outstanding:
             msg += " If you were running tasks when this happened, " +\
                    "some `outstanding` msg_ids may never resolve."
         warnings.warn(msg, RuntimeWarning)
 
     def _build_targets(self, targets):
         """Turn valid target IDs or 'all' into two lists:
         (int_ids, uuids).
         """
         if not self._ids:
             # flush notification socket if no engines yet, just in case
             if not self.ids:
                 raise error.NoEnginesRegistered("Can't build targets without any engines")
 
         if targets is None:
             targets = self._ids
         elif isinstance(targets, basestring):
             if targets.lower() == 'all':
                 targets = self._ids
             else:
                 raise TypeError("%r not valid str target, must be 'all'"%(targets))
         elif isinstance(targets, int):
             if targets < 0:
                 targets = self.ids[targets]
             if targets not in self._ids:
                 raise IndexError("No such engine: %i"%targets)
             targets = [targets]
 
         if isinstance(targets, slice):
             indices = range(len(self._ids))[targets]
             ids = self.ids
             targets = [ ids[i] for i in indices ]
 
         if not isinstance(targets, (tuple, list, xrange)):
             raise TypeError("targets by int/slice/collection of ints only, not %s"%(type(targets)))
 
         return [cast_bytes(self._engines[t]) for t in targets], list(targets)
 
     def _connect(self, sshserver, ssh_kwargs, timeout):
         """setup all our socket connections to the cluster. This is called from
         __init__."""
 
         # Maybe allow reconnecting?
         if self._connected:
             return
         self._connected=True
 
         def connect_socket(s, url):
             url = util.disambiguate_url(url, self._config['location'])
             if self._ssh:
                 return tunnel.tunnel_connection(s, url, sshserver, **ssh_kwargs)
             else:
                 return s.connect(url)
 
         self.session.send(self._query_socket, 'connection_request')
         # use Poller because zmq.select has wrong units in pyzmq 2.1.7
         poller = zmq.Poller()
         poller.register(self._query_socket, zmq.POLLIN)
         # poll expects milliseconds, timeout is seconds
         evts = poller.poll(timeout*1000)
         if not evts:
             raise error.TimeoutError("Hub connection request timed out")
         idents,msg = self.session.recv(self._query_socket,mode=0)
         if self.debug:
             pprint(msg)
         msg = Message(msg)
         content = msg.content
         self._config['registration'] = dict(content)
         if content.status == 'ok':
             ident = self.session.bsession
             if content.mux:
                 self._mux_socket = self._context.socket(zmq.DEALER)
                 self._mux_socket.setsockopt(zmq.IDENTITY, ident)
                 connect_socket(self._mux_socket, content.mux)
             if content.task:
                 self._task_scheme, task_addr = content.task
                 self._task_socket = self._context.socket(zmq.DEALER)
                 self._task_socket.setsockopt(zmq.IDENTITY, ident)
                 connect_socket(self._task_socket, task_addr)
             if content.notification:
                 self._notification_socket = self._context.socket(zmq.SUB)
                 connect_socket(self._notification_socket, content.notification)
                 self._notification_socket.setsockopt(zmq.SUBSCRIBE, b'')
             # if content.query:
             #     self._query_socket = self._context.socket(zmq.DEALER)
             #     self._query_socket.setsockopt(zmq.IDENTITY, self.session.bsession)
             #     connect_socket(self._query_socket, content.query)
             if content.control:
                 self._control_socket = self._context.socket(zmq.DEALER)
                 self._control_socket.setsockopt(zmq.IDENTITY, ident)
                 connect_socket(self._control_socket, content.control)
             if content.iopub:
                 self._iopub_socket = self._context.socket(zmq.SUB)
                 self._iopub_socket.setsockopt(zmq.SUBSCRIBE, b'')
                 self._iopub_socket.setsockopt(zmq.IDENTITY, ident)
                 connect_socket(self._iopub_socket, content.iopub)
             self._update_engines(dict(content.engines))
         else:
             self._connected = False
             raise Exception("Failed to connect!")
 
     #--------------------------------------------------------------------------
     # handlers and callbacks for incoming messages
     #--------------------------------------------------------------------------
 
     def _unwrap_exception(self, content):
         """unwrap exception, and remap engine_id to int."""
         e = error.unwrap_exception(content)
         # print e.traceback
         if e.engine_info:
             e_uuid = e.engine_info['engine_uuid']
             eid = self._engines[e_uuid]
             e.engine_info['engine_id'] = eid
         return e
 
     def _extract_metadata(self, header, parent, content):
         md = {'msg_id' : parent['msg_id'],
               'received' : datetime.now(),
               'engine_uuid' : header.get('engine', None),
               'follow' : parent.get('follow', []),
               'after' : parent.get('after', []),
               'status' : content['status'],
             }
 
         if md['engine_uuid'] is not None:
             md['engine_id'] = self._engines.get(md['engine_uuid'], None)
 
         if 'date' in parent:
             md['submitted'] = parent['date']
         if 'started' in header:
             md['started'] = header['started']
         if 'date' in header:
             md['completed'] = header['date']
         return md
 
     def _register_engine(self, msg):
         """Register a new engine, and update our connection info."""
         content = msg['content']
         eid = content['id']
         d = {eid : content['queue']}
         self._update_engines(d)
 
     def _unregister_engine(self, msg):
         """Unregister an engine that has died."""
         content = msg['content']
         eid = int(content['id'])
         if eid in self._ids:
             self._ids.remove(eid)
             uuid = self._engines.pop(eid)
 
             self._handle_stranded_msgs(eid, uuid)
 
         if self._task_socket and self._task_scheme == 'pure':
             self._stop_scheduling_tasks()
 
     def _handle_stranded_msgs(self, eid, uuid):
         """Handle messages known to be on an engine when the engine unregisters.
 
         It is possible that this will fire prematurely - that is, an engine will
         go down after completing a result, and the client will be notified
         of the unregistration and later receive the successful result.
         """
 
         outstanding = self._outstanding_dict[uuid]
 
         for msg_id in list(outstanding):
             if msg_id in self.results:
                 # we already
                 continue
             try:
                 raise error.EngineError("Engine %r died while running task %r"%(eid, msg_id))
             except:
                 content = error.wrap_exception()
             # build a fake message:
             parent = {}
             header = {}
             parent['msg_id'] = msg_id
             header['engine'] = uuid
             header['date'] = datetime.now()
             msg = dict(parent_header=parent, header=header, content=content)
             self._handle_apply_reply(msg)
 
     def _handle_execute_reply(self, msg):
         """Save the reply to an execute_request into our results.
 
         execute messages are never actually used. apply is used instead.
         """
 
         parent = msg['parent_header']
         msg_id = parent['msg_id']
         if msg_id not in self.outstanding:
             if msg_id in self.history:
                 print ("got stale result: %s"%msg_id)
             else:
                 print ("got unknown result: %s"%msg_id)
         else:
             self.outstanding.remove(msg_id)
 
         content = msg['content']
         header = msg['header']
 
         # construct metadata:
         md = self.metadata[msg_id]
         md.update(self._extract_metadata(header, parent, content))
         # is this redundant?
         self.metadata[msg_id] = md
         
         e_outstanding = self._outstanding_dict[md['engine_uuid']]
         if msg_id in e_outstanding:
             e_outstanding.remove(msg_id)
 
         # construct result:
         if content['status'] == 'ok':
             self.results[msg_id] = ExecuteReply(msg_id, content, md)
         elif content['status'] == 'aborted':
             self.results[msg_id] = error.TaskAborted(msg_id)
         elif content['status'] == 'resubmitted':
             # TODO: handle resubmission
             pass
         else:
             self.results[msg_id] = self._unwrap_exception(content)
 
     def _handle_apply_reply(self, msg):
         """Save the reply to an apply_request into our results."""
         parent = msg['parent_header']
         msg_id = parent['msg_id']
         if msg_id not in self.outstanding:
             if msg_id in self.history:
                 print ("got stale result: %s"%msg_id)
                 print self.results[msg_id]
                 print msg
             else:
                 print ("got unknown result: %s"%msg_id)
         else:
             self.outstanding.remove(msg_id)
         content = msg['content']
         header = msg['header']
 
         # construct metadata:
         md = self.metadata[msg_id]
         md.update(self._extract_metadata(header, parent, content))
         # is this redundant?
         self.metadata[msg_id] = md
 
         e_outstanding = self._outstanding_dict[md['engine_uuid']]
         if msg_id in e_outstanding:
             e_outstanding.remove(msg_id)
 
         # construct result:
         if content['status'] == 'ok':
             self.results[msg_id] = util.unserialize_object(msg['buffers'])[0]
         elif content['status'] == 'aborted':
             self.results[msg_id] = error.TaskAborted(msg_id)
         elif content['status'] == 'resubmitted':
             # TODO: handle resubmission
             pass
         else:
             self.results[msg_id] = self._unwrap_exception(content)
 
     def _flush_notifications(self):
         """Flush notifications of engine registrations waiting
         in ZMQ queue."""
         idents,msg = self.session.recv(self._notification_socket, mode=zmq.NOBLOCK)
         while msg is not None:
             if self.debug:
                 pprint(msg)
             msg_type = msg['header']['msg_type']
             handler = self._notification_handlers.get(msg_type, None)
             if handler is None:
                 raise Exception("Unhandled message type: %s"%msg.msg_type)
             else:
                 handler(msg)
             idents,msg = self.session.recv(self._notification_socket, mode=zmq.NOBLOCK)
 
     def _flush_results(self, sock):
         """Flush task or queue results waiting in ZMQ queue."""
         idents,msg = self.session.recv(sock, mode=zmq.NOBLOCK)
         while msg is not None:
             if self.debug:
                 pprint(msg)
             msg_type = msg['header']['msg_type']
             handler = self._queue_handlers.get(msg_type, None)
             if handler is None:
                 raise Exception("Unhandled message type: %s"%msg.msg_type)
             else:
                 handler(msg)
             idents,msg = self.session.recv(sock, mode=zmq.NOBLOCK)
 
     def _flush_control(self, sock):
         """Flush replies from the control channel waiting
         in the ZMQ queue.
 
         Currently: ignore them."""
         if self._ignored_control_replies <= 0:
             return
         idents,msg = self.session.recv(sock, mode=zmq.NOBLOCK)
         while msg is not None:
             self._ignored_control_replies -= 1
             if self.debug:
                 pprint(msg)
             idents,msg = self.session.recv(sock, mode=zmq.NOBLOCK)
 
     def _flush_ignored_control(self):
         """flush ignored control replies"""
         while self._ignored_control_replies > 0:
             self.session.recv(self._control_socket)
             self._ignored_control_replies -= 1
 
     def _flush_ignored_hub_replies(self):
         ident,msg = self.session.recv(self._query_socket, mode=zmq.NOBLOCK)
         while msg is not None:
             ident,msg = self.session.recv(self._query_socket, mode=zmq.NOBLOCK)
 
     def _flush_iopub(self, sock):
         """Flush replies from the iopub channel waiting
         in the ZMQ queue.
         """
         idents,msg = self.session.recv(sock, mode=zmq.NOBLOCK)
         while msg is not None:
             if self.debug:
                 pprint(msg)
             parent = msg['parent_header']
             # ignore IOPub messages with no parent.
             # Caused by print statements or warnings from before the first execution.
             if not parent:
                 continue
             msg_id = parent['msg_id']
             content = msg['content']
             header = msg['header']
             msg_type = msg['header']['msg_type']
 
             # init metadata:
             md = self.metadata[msg_id]
 
             if msg_type == 'stream':
                 name = content['name']
                 s = md[name] or ''
                 md[name] = s + content['data']
             elif msg_type == 'pyerr':
                 md.update({'pyerr' : self._unwrap_exception(content)})
             elif msg_type == 'pyin':
                 md.update({'pyin' : content['code']})
             elif msg_type == 'display_data':
                 md['outputs'].append(content)
             elif msg_type == 'pyout':
                 md['pyout'] = content
             else:
                 # unhandled msg_type (status, etc.)
                 pass
 
             # reduntant?
             self.metadata[msg_id] = md
 
             idents,msg = self.session.recv(sock, mode=zmq.NOBLOCK)
 
     #--------------------------------------------------------------------------
     # len, getitem
     #--------------------------------------------------------------------------
 
     def __len__(self):
         """len(client) returns # of engines."""
         return len(self.ids)
 
     def __getitem__(self, key):
         """index access returns DirectView multiplexer objects
 
         Must be int, slice, or list/tuple/xrange of ints"""
         if not isinstance(key, (int, slice, tuple, list, xrange)):
             raise TypeError("key by int/slice/iterable of ints only, not %s"%(type(key)))
         else:
             return self.direct_view(key)
 
     #--------------------------------------------------------------------------
     # Begin public methods
     #--------------------------------------------------------------------------
 
     @property
     def ids(self):
         """Always up-to-date ids property."""
         self._flush_notifications()
         # always copy:
         return list(self._ids)
 
     def close(self):
         if self._closed:
             return
         self.stop_spin_thread()
         snames = filter(lambda n: n.endswith('socket'), dir(self))
         for socket in map(lambda name: getattr(self, name), snames):
             if isinstance(socket, zmq.Socket) and not socket.closed:
                 socket.close()
         self._closed = True
 
     def _spin_every(self, interval=1):
         """target func for use in spin_thread"""
         while True:
             if self._stop_spinning.is_set():
                 return
             time.sleep(interval)
             self.spin()
 
     def spin_thread(self, interval=1):
         """call Client.spin() in a background thread on some regular interval
         
         This helps ensure that messages don't pile up too much in the zmq queue
         while you are working on other things, or just leaving an idle terminal.
         
         It also helps limit potential padding of the `received` timestamp
         on AsyncResult objects, used for timings.
         
         Parameters
         ----------
         
         interval : float, optional
             The interval on which to spin the client in the background thread
             (simply passed to time.sleep).
         
         Notes
         -----
         
         For precision timing, you may want to use this method to put a bound
         on the jitter (in seconds) in `received` timestamps used
         in AsyncResult.wall_time.
         
         """
         if self._spin_thread is not None:
             self.stop_spin_thread()
         self._stop_spinning.clear()
         self._spin_thread = Thread(target=self._spin_every, args=(interval,))
         self._spin_thread.daemon = True
         self._spin_thread.start()
     
     def stop_spin_thread(self):
         """stop background spin_thread, if any"""
         if self._spin_thread is not None:
             self._stop_spinning.set()
             self._spin_thread.join()
             self._spin_thread = None
 
     def spin(self):
         """Flush any registration notifications and execution results
         waiting in the ZMQ queue.
         """
         if self._notification_socket:
             self._flush_notifications()
         if self._iopub_socket:
             self._flush_iopub(self._iopub_socket)
         if self._mux_socket:
             self._flush_results(self._mux_socket)
         if self._task_socket:
             self._flush_results(self._task_socket)
         if self._control_socket:
             self._flush_control(self._control_socket)
         if self._query_socket:
             self._flush_ignored_hub_replies()
 
     def wait(self, jobs=None, timeout=-1):
         """waits on one or more `jobs`, for up to `timeout` seconds.
 
         Parameters
         ----------
 
         jobs : int, str, or list of ints and/or strs, or one or more AsyncResult objects
                 ints are indices to self.history
                 strs are msg_ids
                 default: wait on all outstanding messages
         timeout : float
                 a time in seconds, after which to give up.
                 default is -1, which means no timeout
 
         Returns
         -------
 
         True : when all msg_ids are done
         False : timeout reached, some msg_ids still outstanding
         """
         tic = time.time()
         if jobs is None:
             theids = self.outstanding
         else:
             if isinstance(jobs, (int, basestring, AsyncResult)):
                 jobs = [jobs]
             theids = set()
             for job in jobs:
                 if isinstance(job, int):
                     # index access
                     job = self.history[job]
                 elif isinstance(job, AsyncResult):
                     map(theids.add, job.msg_ids)
                     continue
                 theids.add(job)
         if not theids.intersection(self.outstanding):
             return True
         self.spin()
         while theids.intersection(self.outstanding):
             if timeout >= 0 and ( time.time()-tic ) > timeout:
                 break
             time.sleep(1e-3)
             self.spin()
         return len(theids.intersection(self.outstanding)) == 0
 
     #--------------------------------------------------------------------------
     # Control methods
     #--------------------------------------------------------------------------
 
     @spin_first
     def clear(self, targets=None, block=None):
         """Clear the namespace in target(s)."""
         block = self.block if block is None else block
         targets = self._build_targets(targets)[0]
         for t in targets:
             self.session.send(self._control_socket, 'clear_request', content={}, ident=t)
         error = False
         if block:
             self._flush_ignored_control()
             for i in range(len(targets)):
                 idents,msg = self.session.recv(self._control_socket,0)
                 if self.debug:
                     pprint(msg)
                 if msg['content']['status'] != 'ok':
                     error = self._unwrap_exception(msg['content'])
         else:
             self._ignored_control_replies += len(targets)
         if error:
             raise error
 
 
     @spin_first
     def abort(self, jobs=None, targets=None, block=None):
         """Abort specific jobs from the execution queues of target(s).
 
         This is a mechanism to prevent jobs that have already been submitted
         from executing.
 
         Parameters
         ----------
 
         jobs : msg_id, list of msg_ids, or AsyncResult
             The jobs to be aborted
             
             If unspecified/None: abort all outstanding jobs.
 
         """
         block = self.block if block is None else block
         jobs = jobs if jobs is not None else list(self.outstanding)
         targets = self._build_targets(targets)[0]
         
         msg_ids = []
         if isinstance(jobs, (basestring,AsyncResult)):
             jobs = [jobs]
         bad_ids = filter(lambda obj: not isinstance(obj, (basestring, AsyncResult)), jobs)
         if bad_ids:
             raise TypeError("Invalid msg_id type %r, expected str or AsyncResult"%bad_ids[0])
         for j in jobs:
             if isinstance(j, AsyncResult):
                 msg_ids.extend(j.msg_ids)
             else:
                 msg_ids.append(j)
         content = dict(msg_ids=msg_ids)
         for t in targets:
             self.session.send(self._control_socket, 'abort_request',
                     content=content, ident=t)
         error = False
         if block:
             self._flush_ignored_control()
             for i in range(len(targets)):
                 idents,msg = self.session.recv(self._control_socket,0)
                 if self.debug:
                     pprint(msg)
                 if msg['content']['status'] != 'ok':
                     error = self._unwrap_exception(msg['content'])
         else:
             self._ignored_control_replies += len(targets)
         if error:
             raise error
 
     @spin_first
     def shutdown(self, targets=None, restart=False, hub=False, block=None):
         """Terminates one or more engine processes, optionally including the hub."""
         block = self.block if block is None else block
         if hub:
             targets = 'all'
         targets = self._build_targets(targets)[0]
         for t in targets:
             self.session.send(self._control_socket, 'shutdown_request',
                         content={'restart':restart},ident=t)
         error = False
         if block or hub:
             self._flush_ignored_control()
             for i in range(len(targets)):
                 idents,msg = self.session.recv(self._control_socket, 0)
                 if self.debug:
                     pprint(msg)
                 if msg['content']['status'] != 'ok':
                     error = self._unwrap_exception(msg['content'])
         else:
             self._ignored_control_replies += len(targets)
 
         if hub:
             time.sleep(0.25)
             self.session.send(self._query_socket, 'shutdown_request')
             idents,msg = self.session.recv(self._query_socket, 0)
             if self.debug:
                 pprint(msg)
             if msg['content']['status'] != 'ok':
                 error = self._unwrap_exception(msg['content'])
 
         if error:
             raise error
 
     #--------------------------------------------------------------------------
     # Execution related methods
     #--------------------------------------------------------------------------
 
     def _maybe_raise(self, result):
         """wrapper for maybe raising an exception if apply failed."""
         if isinstance(result, error.RemoteError):
             raise result
 
         return result
 
     def send_apply_request(self, socket, f, args=None, kwargs=None, subheader=None, track=False,
                             ident=None):
         """construct and send an apply message via a socket.
 
         This is the principal method with which all engine execution is performed by views.
         """
 
         if self._closed:
             raise RuntimeError("Client cannot be used after its sockets have been closed")
         
         # defaults:
         args = args if args is not None else []
         kwargs = kwargs if kwargs is not None else {}
         subheader = subheader if subheader is not None else {}
 
         # validate arguments
         if not callable(f) and not isinstance(f, Reference):
             raise TypeError("f must be callable, not %s"%type(f))
         if not isinstance(args, (tuple, list)):
             raise TypeError("args must be tuple or list, not %s"%type(args))
         if not isinstance(kwargs, dict):
             raise TypeError("kwargs must be dict, not %s"%type(kwargs))
         if not isinstance(subheader, dict):
             raise TypeError("subheader must be dict, not %s"%type(subheader))
 
         bufs = util.pack_apply_message(f,args,kwargs)
 
         msg = self.session.send(socket, "apply_request", buffers=bufs, ident=ident,
                             subheader=subheader, track=track)
 
         msg_id = msg['header']['msg_id']
         self.outstanding.add(msg_id)
         if ident:
             # possibly routed to a specific engine
             if isinstance(ident, list):
                 ident = ident[-1]
             if ident in self._engines.values():
                 # save for later, in case of engine death
                 self._outstanding_dict[ident].add(msg_id)
         self.history.append(msg_id)
         self.metadata[msg_id]['submitted'] = datetime.now()
 
         return msg
 
     def send_execute_request(self, socket, code, silent=True, subheader=None, ident=None):
         """construct and send an execute request via a socket.
 
         """
 
         if self._closed:
             raise RuntimeError("Client cannot be used after its sockets have been closed")
         
         # defaults:
         subheader = subheader if subheader is not None else {}
 
         # validate arguments
         if not isinstance(code, basestring):
             raise TypeError("code must be text, not %s" % type(code))
         if not isinstance(subheader, dict):
             raise TypeError("subheader must be dict, not %s" % type(subheader))
         
         content = dict(code=code, silent=bool(silent), user_variables=[], user_expressions={})
 
 
         msg = self.session.send(socket, "execute_request", content=content, ident=ident,
                             subheader=subheader)
 
         msg_id = msg['header']['msg_id']
         self.outstanding.add(msg_id)
         if ident:
             # possibly routed to a specific engine
             if isinstance(ident, list):
                 ident = ident[-1]
             if ident in self._engines.values():
                 # save for later, in case of engine death
                 self._outstanding_dict[ident].add(msg_id)
         self.history.append(msg_id)
         self.metadata[msg_id]['submitted'] = datetime.now()
 
         return msg
 
     #--------------------------------------------------------------------------
     # construct a View object
     #--------------------------------------------------------------------------
 
     def load_balanced_view(self, targets=None):
         """construct a DirectView object.
 
         If no arguments are specified, create a LoadBalancedView
         using all engines.
 
         Parameters
         ----------
 
         targets: list,slice,int,etc. [default: use all engines]
             The subset of engines across which to load-balance
         """
         if targets == 'all':
             targets = None
         if targets is not None:
             targets = self._build_targets(targets)[1]
         return LoadBalancedView(client=self, socket=self._task_socket, targets=targets)
 
     def direct_view(self, targets='all'):
         """construct a DirectView object.
 
         If no targets are specified, create a DirectView using all engines.
         
         rc.direct_view('all') is distinguished from rc[:] in that 'all' will
         evaluate the target engines at each execution, whereas rc[:] will connect to
         all *current* engines, and that list will not change.
         
         That is, 'all' will always use all engines, whereas rc[:] will not use
         engines added after the DirectView is constructed.
 
         Parameters
         ----------
 
         targets: list,slice,int,etc. [default: use all engines]
             The engines to use for the View
         """
         single = isinstance(targets, int)
         # allow 'all' to be lazily evaluated at each execution
         if targets != 'all':
             targets = self._build_targets(targets)[1]
         if single:
             targets = targets[0]
         return DirectView(client=self, socket=self._mux_socket, targets=targets)
 
     #--------------------------------------------------------------------------
     # Query methods
     #--------------------------------------------------------------------------
 
     @spin_first
     def get_result(self, indices_or_msg_ids=None, block=None):
         """Retrieve a result by msg_id or history index, wrapped in an AsyncResult object.
 
         If the client already has the results, no request to the Hub will be made.
 
         This is a convenient way to construct AsyncResult objects, which are wrappers
         that include metadata about execution, and allow for awaiting results that
         were not submitted by this Client.
 
         It can also be a convenient way to retrieve the metadata associated with
         blocking execution, since it always retrieves
 
         Examples
         --------
         ::
 
             In [10]: r = client.apply()
 
         Parameters
         ----------
 
         indices_or_msg_ids : integer history index, str msg_id, or list of either
             The indices or msg_ids of indices to be retrieved
 
         block : bool
             Whether to wait for the result to be done
 
         Returns
         -------
 
         AsyncResult
             A single AsyncResult object will always be returned.
 
         AsyncHubResult
             A subclass of AsyncResult that retrieves results from the Hub
 
         """
         block = self.block if block is None else block
         if indices_or_msg_ids is None:
             indices_or_msg_ids = -1
 
         if not isinstance(indices_or_msg_ids, (list,tuple)):
             indices_or_msg_ids = [indices_or_msg_ids]
 
         theids = []
         for id in indices_or_msg_ids:
             if isinstance(id, int):
                 id = self.history[id]
             if not isinstance(id, basestring):
                 raise TypeError("indices must be str or int, not %r"%id)
             theids.append(id)
 
         local_ids = filter(lambda msg_id: msg_id in self.history or msg_id in self.results, theids)
         remote_ids = filter(lambda msg_id: msg_id not in local_ids, theids)
 
         if remote_ids:
             ar = AsyncHubResult(self, msg_ids=theids)
         else:
             ar = AsyncResult(self, msg_ids=theids)
 
         if block:
             ar.wait()
 
         return ar
 
     @spin_first
     def resubmit(self, indices_or_msg_ids=None, subheader=None, block=None):
         """Resubmit one or more tasks.
 
         in-flight tasks may not be resubmitted.
 
         Parameters
         ----------
 
         indices_or_msg_ids : integer history index, str msg_id, or list of either
             The indices or msg_ids of indices to be retrieved
 
         block : bool
             Whether to wait for the result to be done
 
         Returns
         -------
 
         AsyncHubResult
             A subclass of AsyncResult that retrieves results from the Hub
 
         """
         block = self.block if block is None else block
         if indices_or_msg_ids is None:
             indices_or_msg_ids = -1
 
         if not isinstance(indices_or_msg_ids, (list,tuple)):
             indices_or_msg_ids = [indices_or_msg_ids]
 
         theids = []
         for id in indices_or_msg_ids:
             if isinstance(id, int):
                 id = self.history[id]
             if not isinstance(id, basestring):
                 raise TypeError("indices must be str or int, not %r"%id)
             theids.append(id)
 
         content = dict(msg_ids = theids)
 
         self.session.send(self._query_socket, 'resubmit_request', content)
 
         zmq.select([self._query_socket], [], [])
         idents,msg = self.session.recv(self._query_socket, zmq.NOBLOCK)
         if self.debug:
             pprint(msg)
         content = msg['content']
         if content['status'] != 'ok':
             raise self._unwrap_exception(content)
         mapping = content['resubmitted']
         new_ids = [ mapping[msg_id] for msg_id in theids ]
 
         ar = AsyncHubResult(self, msg_ids=new_ids)
 
         if block:
             ar.wait()
 
         return ar
 
     @spin_first
     def result_status(self, msg_ids, status_only=True):
         """Check on the status of the result(s) of the apply request with `msg_ids`.
 
         If status_only is False, then the actual results will be retrieved, else
         only the status of the results will be checked.
 
         Parameters
         ----------
 
         msg_ids : list of msg_ids
             if int:
                 Passed as index to self.history for convenience.
         status_only : bool (default: True)
             if False:
                 Retrieve the actual results of completed tasks.
 
         Returns
         -------
 
         results : dict
             There will always be the keys 'pending' and 'completed', which will
             be lists of msg_ids that are incomplete or complete. If `status_only`
             is False, then completed results will be keyed by their `msg_id`.
         """
         if not isinstance(msg_ids, (list,tuple)):
             msg_ids = [msg_ids]
 
         theids = []
         for msg_id in msg_ids:
             if isinstance(msg_id, int):
                 msg_id = self.history[msg_id]
             if not isinstance(msg_id, basestring):
                 raise TypeError("msg_ids must be str, not %r"%msg_id)
             theids.append(msg_id)
 
         completed = []
         local_results = {}
 
         # comment this block out to temporarily disable local shortcut:
         for msg_id in theids:
             if msg_id in self.results:
                 completed.append(msg_id)
                 local_results[msg_id] = self.results[msg_id]
                 theids.remove(msg_id)
 
         if theids: # some not locally cached
             content = dict(msg_ids=theids, status_only=status_only)
             msg = self.session.send(self._query_socket, "result_request", content=content)
             zmq.select([self._query_socket], [], [])
             idents,msg = self.session.recv(self._query_socket, zmq.NOBLOCK)
             if self.debug:
                 pprint(msg)
             content = msg['content']
             if content['status'] != 'ok':
                 raise self._unwrap_exception(content)
             buffers = msg['buffers']
         else:
             content = dict(completed=[],pending=[])
 
         content['completed'].extend(completed)
 
         if status_only:
             return content
 
         failures = []
         # load cached results into result:
         content.update(local_results)
 
         # update cache with results:
         for msg_id in sorted(theids):
             if msg_id in content['completed']:
                 rec = content[msg_id]
                 parent = rec['header']
                 header = rec['result_header']
                 rcontent = rec['result_content']
                 iodict = rec['io']
                 if isinstance(rcontent, str):
                     rcontent = self.session.unpack(rcontent)
 
                 md = self.metadata[msg_id]
                 md.update(self._extract_metadata(header, parent, rcontent))
                 if rec.get('received'):
                     md['received'] = rec['received']
                 md.update(iodict)
 
                 if rcontent['status'] == 'ok':
                     res,buffers = util.unserialize_object(buffers)
                 else:
                     print rcontent
                     res = self._unwrap_exception(rcontent)
                     failures.append(res)
 
                 self.results[msg_id] = res
                 content[msg_id] = res
 
         if len(theids) == 1 and failures:
                 raise failures[0]
 
         error.collect_exceptions(failures, "result_status")
         return content
 
     @spin_first
     def queue_status(self, targets='all', verbose=False):
         """Fetch the status of engine queues.
 
         Parameters
         ----------
 
         targets : int/str/list of ints/strs
                 the engines whose states are to be queried.
                 default : all
         verbose : bool
                 Whether to return lengths only, or lists of ids for each element
         """
         if targets == 'all':
             # allow 'all' to be evaluated on the engine
             engine_ids = None
         else:
             engine_ids = self._build_targets(targets)[1]
         content = dict(targets=engine_ids, verbose=verbose)
         self.session.send(self._query_socket, "queue_request", content=content)
         idents,msg = self.session.recv(self._query_socket, 0)
         if self.debug:
             pprint(msg)
         content = msg['content']
         status = content.pop('status')
         if status != 'ok':
             raise self._unwrap_exception(content)
         content = rekey(content)
         if isinstance(targets, int):
             return content[targets]
         else:
             return content
 
     @spin_first
     def purge_results(self, jobs=[], targets=[]):
         """Tell the Hub to forget results.
 
         Individual results can be purged by msg_id, or the entire
         history of specific targets can be purged.
 
         Use `purge_results('all')` to scrub everything from the Hub's db.
 
         Parameters
         ----------
 
         jobs : str or list of str or AsyncResult objects
                 the msg_ids whose results should be forgotten.
         targets : int/str/list of ints/strs
                 The targets, by int_id, whose entire history is to be purged.
 
                 default : None
         """
         if not targets and not jobs:
             raise ValueError("Must specify at least one of `targets` and `jobs`")
         if targets:
             targets = self._build_targets(targets)[1]
 
         # construct msg_ids from jobs
         if jobs == 'all':
             msg_ids = jobs
         else:
             msg_ids = []
             if isinstance(jobs, (basestring,AsyncResult)):
                 jobs = [jobs]
             bad_ids = filter(lambda obj: not isinstance(obj, (basestring, AsyncResult)), jobs)
             if bad_ids:
                 raise TypeError("Invalid msg_id type %r, expected str or AsyncResult"%bad_ids[0])
             for j in jobs:
                 if isinstance(j, AsyncResult):
                     msg_ids.extend(j.msg_ids)
                 else:
                     msg_ids.append(j)
 
         content = dict(engine_ids=targets, msg_ids=msg_ids)
         self.session.send(self._query_socket, "purge_request", content=content)
         idents, msg = self.session.recv(self._query_socket, 0)
         if self.debug:
             pprint(msg)
         content = msg['content']
         if content['status'] != 'ok':
             raise self._unwrap_exception(content)
 
     @spin_first
     def hub_history(self):
         """Get the Hub's history
 
         Just like the Client, the Hub has a history, which is a list of msg_ids.
         This will contain the history of all clients, and, depending on configuration,
         may contain history across multiple cluster sessions.
 
         Any msg_id returned here is a valid argument to `get_result`.
 
         Returns
         -------
 
         msg_ids : list of strs
                 list of all msg_ids, ordered by task submission time.
         """
 
         self.session.send(self._query_socket, "history_request", content={})
         idents, msg = self.session.recv(self._query_socket, 0)
 
         if self.debug:
             pprint(msg)
         content = msg['content']
         if content['status'] != 'ok':
             raise self._unwrap_exception(content)
         else:
             return content['history']
 
     @spin_first
     def db_query(self, query, keys=None):
         """Query the Hub's TaskRecord database
 
         This will return a list of task record dicts that match `query`
 
         Parameters
         ----------
 
         query : mongodb query dict
             The search dict. See mongodb query docs for details.
         keys : list of strs [optional]
             The subset of keys to be returned.  The default is to fetch everything but buffers.
             'msg_id' will *always* be included.
         """
         if isinstance(keys, basestring):
             keys = [keys]
         content = dict(query=query, keys=keys)
         self.session.send(self._query_socket, "db_request", content=content)
         idents, msg = self.session.recv(self._query_socket, 0)
         if self.debug:
             pprint(msg)
         content = msg['content']
         if content['status'] != 'ok':
             raise self._unwrap_exception(content)
 
         records = content['records']
 
         buffer_lens = content['buffer_lens']
         result_buffer_lens = content['result_buffer_lens']
         buffers = msg['buffers']
         has_bufs = buffer_lens is not None
         has_rbufs = result_buffer_lens is not None
         for i,rec in enumerate(records):
             # relink buffers
             if has_bufs:
                 blen = buffer_lens[i]
                 rec['buffers'], buffers = buffers[:blen],buffers[blen:]
             if has_rbufs:
                 blen = result_buffer_lens[i]
                 rec['result_buffers'], buffers = buffers[:blen],buffers[blen:]
 
         return records
 
 __all__ = [ 'Client' ]

IPython/parallel/tests/test_asyncresult.py

@@ -1,264 +1,266 b''
 """Tests for asyncresult.py
 
 Authors:
 
 * Min RK
 """
 
 #-------------------------------------------------------------------------------
 #  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 time
 
 from IPython.parallel.error import TimeoutError
 
 from IPython.parallel import error, Client
 from IPython.parallel.tests import add_engines
 from .clienttest import ClusterTestCase, capture_output
 
 def setup():
     add_engines(2, total=True)
 
 def wait(n):
     import time
     time.sleep(n)
     return n
 
 class AsyncResultTest(ClusterTestCase):
 
     def test_single_result_view(self):
         """various one-target views get the right value for single_result"""
         eid = self.client.ids[-1]
         ar = self.client[eid].apply_async(lambda : 42)
         self.assertEquals(ar.get(), 42)
         ar = self.client[[eid]].apply_async(lambda : 42)
         self.assertEquals(ar.get(), [42])
         ar = self.client[-1:].apply_async(lambda : 42)
         self.assertEquals(ar.get(), [42])
 
     def test_get_after_done(self):
         ar = self.client[-1].apply_async(lambda : 42)
         ar.wait()
         self.assertTrue(ar.ready())
         self.assertEquals(ar.get(), 42)
         self.assertEquals(ar.get(), 42)
 
     def test_get_before_done(self):
         ar = self.client[-1].apply_async(wait, 0.1)
         self.assertRaises(TimeoutError, ar.get, 0)
         ar.wait(0)
         self.assertFalse(ar.ready())
         self.assertEquals(ar.get(), 0.1)
 
     def test_get_after_error(self):
         ar = self.client[-1].apply_async(lambda : 1/0)
         ar.wait(10)
         self.assertRaisesRemote(ZeroDivisionError, ar.get)
         self.assertRaisesRemote(ZeroDivisionError, ar.get)
         self.assertRaisesRemote(ZeroDivisionError, ar.get_dict)
     
     def test_get_dict(self):
         n = len(self.client)
         ar = self.client[:].apply_async(lambda : 5)
         self.assertEquals(ar.get(), [5]*n)
         d = ar.get_dict()
         self.assertEquals(sorted(d.keys()), sorted(self.client.ids))
         for eid,r in d.iteritems():
             self.assertEquals(r, 5)
     
     def test_list_amr(self):
         ar = self.client.load_balanced_view().map_async(wait, [0.1]*5)
         rlist = list(ar)
     
     def test_getattr(self):
         ar = self.client[:].apply_async(wait, 0.5)
         self.assertRaises(AttributeError, lambda : ar._foo)
         self.assertRaises(AttributeError, lambda : ar.__length_hint__())
         self.assertRaises(AttributeError, lambda : ar.foo)
         self.assertRaises(AttributeError, lambda : ar.engine_id)
         self.assertFalse(hasattr(ar, '__length_hint__'))
         self.assertFalse(hasattr(ar, 'foo'))
         self.assertFalse(hasattr(ar, 'engine_id'))
         ar.get(5)
         self.assertRaises(AttributeError, lambda : ar._foo)
         self.assertRaises(AttributeError, lambda : ar.__length_hint__())
         self.assertRaises(AttributeError, lambda : ar.foo)
         self.assertTrue(isinstance(ar.engine_id, list))
         self.assertEquals(ar.engine_id, ar['engine_id'])
         self.assertFalse(hasattr(ar, '__length_hint__'))
         self.assertFalse(hasattr(ar, 'foo'))
         self.assertTrue(hasattr(ar, 'engine_id'))
 
     def test_getitem(self):
         ar = self.client[:].apply_async(wait, 0.5)
         self.assertRaises(TimeoutError, lambda : ar['foo'])
         self.assertRaises(TimeoutError, lambda : ar['engine_id'])
         ar.get(5)
         self.assertRaises(KeyError, lambda : ar['foo'])
         self.assertTrue(isinstance(ar['engine_id'], list))
         self.assertEquals(ar.engine_id, ar['engine_id'])
     
     def test_single_result(self):
         ar = self.client[-1].apply_async(wait, 0.5)
         self.assertRaises(TimeoutError, lambda : ar['foo'])
         self.assertRaises(TimeoutError, lambda : ar['engine_id'])
         self.assertTrue(ar.get(5) == 0.5)
         self.assertTrue(isinstance(ar['engine_id'], int))
         self.assertTrue(isinstance(ar.engine_id, int))
         self.assertEquals(ar.engine_id, ar['engine_id'])
     
     def test_abort(self):
         e = self.client[-1]
         ar = e.execute('import time; time.sleep(1)', block=False)
         ar2 = e.apply_async(lambda : 2)
         ar2.abort()
         self.assertRaises(error.TaskAborted, ar2.get)
         ar.get()
     
     def test_len(self):
         v = self.client.load_balanced_view()
         ar = v.map_async(lambda x: x, range(10))
         self.assertEquals(len(ar), 10)
         ar = v.apply_async(lambda x: x, range(10))
         self.assertEquals(len(ar), 1)
         ar = self.client[:].apply_async(lambda x: x, range(10))
         self.assertEquals(len(ar), len(self.client.ids))
     
     def test_wall_time_single(self):
         v = self.client.load_balanced_view()
         ar = v.apply_async(time.sleep, 0.25)
         self.assertRaises(TimeoutError, getattr, ar, 'wall_time')
         ar.get(2)
         self.assertTrue(ar.wall_time < 1.)
         self.assertTrue(ar.wall_time > 0.2)
 
     def test_wall_time_multi(self):
         self.minimum_engines(4)
         v = self.client[:]
         ar = v.apply_async(time.sleep, 0.25)
         self.assertRaises(TimeoutError, getattr, ar, 'wall_time')
         ar.get(2)
         self.assertTrue(ar.wall_time < 1.)
         self.assertTrue(ar.wall_time > 0.2)
 
     def test_serial_time_single(self):
         v = self.client.load_balanced_view()
         ar = v.apply_async(time.sleep, 0.25)
         self.assertRaises(TimeoutError, getattr, ar, 'serial_time')
         ar.get(2)
         self.assertTrue(ar.serial_time < 1.)
         self.assertTrue(ar.serial_time > 0.2)
 
     def test_serial_time_multi(self):
         self.minimum_engines(4)
         v = self.client[:]
         ar = v.apply_async(time.sleep, 0.25)
         self.assertRaises(TimeoutError, getattr, ar, 'serial_time')
         ar.get(2)
         self.assertTrue(ar.serial_time < 2.)
         self.assertTrue(ar.serial_time > 0.8)
 
     def test_elapsed_single(self):
         v = self.client.load_balanced_view()
         ar = v.apply_async(time.sleep, 0.25)
         while not ar.ready():
             time.sleep(0.01)
             self.assertTrue(ar.elapsed < 1)
         self.assertTrue(ar.elapsed < 1)
         ar.get(2)
 
     def test_elapsed_multi(self):
         v = self.client[:]
         ar = v.apply_async(time.sleep, 0.25)
         while not ar.ready():
             time.sleep(0.01)
             self.assertTrue(ar.elapsed < 1)
         self.assertTrue(ar.elapsed < 1)
         ar.get(2)
 
     def test_hubresult_timestamps(self):
         self.minimum_engines(4)
         v = self.client[:]
         ar = v.apply_async(time.sleep, 0.25)
         ar.get(2)
         rc2 = Client(profile='iptest')
         # must have try/finally to close second Client, otherwise
         # will have dangling sockets causing problems
         try:
             time.sleep(0.25)
             hr = rc2.get_result(ar.msg_ids)
             self.assertTrue(hr.elapsed > 0., "got bad elapsed: %s" % hr.elapsed)
             hr.get(1)
             self.assertTrue(hr.wall_time < ar.wall_time + 0.2, "got bad wall_time: %s > %s" % (hr.wall_time, ar.wall_time))
             self.assertEquals(hr.serial_time, ar.serial_time)
         finally:
             rc2.close()
 
     def test_display_empty_streams_single(self):
         """empty stdout/err are not displayed (single result)"""
         self.minimum_engines(1)
         
         v = self.client[-1]
         ar = v.execute("print (5555)")
         ar.get(5)
         with capture_output() as io:
             ar.display_outputs()
         self.assertEquals(io.stderr, '')
-        self.assertTrue('5555' in io.stdout)
+        self.assertEquals('5555\n', io.stdout)
 
         ar = v.execute("a=5")
         ar.get(5)
         with capture_output() as io:
             ar.display_outputs()
         self.assertEquals(io.stderr, '')
         self.assertEquals(io.stdout, '')
         
     def test_display_empty_streams_type(self):
         """empty stdout/err are not displayed (groupby type)"""
         self.minimum_engines(1)
         
         v = self.client[:]
         ar = v.execute("print (5555)")
         ar.get(5)
         with capture_output() as io:
             ar.display_outputs()
         self.assertEquals(io.stderr, '')
         self.assertEquals(io.stdout.count('5555'), len(v), io.stdout)
+        self.assertFalse('\n\n' in io.stdout, io.stdout)
         self.assertEquals(io.stdout.count('[stdout:'), len(v), io.stdout)
 
         ar = v.execute("a=5")
         ar.get(5)
         with capture_output() as io:
             ar.display_outputs()
         self.assertEquals(io.stderr, '')
         self.assertEquals(io.stdout, '')
 
     def test_display_empty_streams_engine(self):
         """empty stdout/err are not displayed (groupby engine)"""
         self.minimum_engines(1)
         
         v = self.client[:]
         ar = v.execute("print (5555)")
         ar.get(5)
         with capture_output() as io:
             ar.display_outputs('engine')
         self.assertEquals(io.stderr, '')
         self.assertEquals(io.stdout.count('5555'), len(v), io.stdout)
+        self.assertFalse('\n\n' in io.stdout, io.stdout)
         self.assertEquals(io.stdout.count('[stdout:'), len(v), io.stdout)
 
         ar = v.execute("a=5")
         ar.get(5)
         with capture_output() as io:
             ar.display_outputs('engine')
         self.assertEquals(io.stderr, '')
         self.assertEquals(io.stdout, '')
         
 

IPython/parallel/tests/test_magics.py

@@ -1,342 +1,339 b''
 # -*- coding: utf-8 -*-
 """Test Parallel magics
 
 Authors:
 
 * Min RK
 """
 #-------------------------------------------------------------------------------
 #  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 re
 import sys
 import time
 
 import zmq
 from nose import SkipTest
 
 from IPython.testing import decorators as dec
 from IPython.testing.ipunittest import ParametricTestCase
 
 from IPython import parallel  as pmod
 from IPython.parallel import error
 from IPython.parallel import AsyncResult
 from IPython.parallel.util import interactive
 
 from IPython.parallel.tests import add_engines
 
 from .clienttest import ClusterTestCase, capture_output, generate_output
 
 def setup():
     add_engines(3, total=True)
 
 class TestParallelMagics(ClusterTestCase, ParametricTestCase):
     
     def test_px_blocking(self):
         ip = get_ipython()
         v = self.client[-1:]
         v.activate()
         v.block=True
 
         ip.magic('px a=5')
         self.assertEquals(v['a'], [5])
         ip.magic('px a=10')
         self.assertEquals(v['a'], [10])
         # just 'print a' works ~99% of the time, but this ensures that
         # the stdout message has arrived when the result is finished:
         with capture_output() as io:
             ip.magic(
                 'px import sys,time;print(a);sys.stdout.flush();time.sleep(0.2)'
             )
         out = io.stdout
         self.assertTrue('[stdout:' in out, out)
+        self.assertFalse('\n\n' in out)
         self.assertTrue(out.rstrip().endswith('10'))
         self.assertRaisesRemote(ZeroDivisionError, ip.magic, 'px 1/0')
     
+    def _check_generated_stderr(self, stderr, n):
+        expected = [
+            r'\[stderr:\d+\]',
+            '^stderr$',
+            '^stderr2$',
+        ] * n
+        
+        self.assertFalse('\n\n' in stderr, stderr)
+        lines = stderr.splitlines()
+        self.assertEquals(len(lines), len(expected), stderr)
+        for line,expect in zip(lines, expected):
+            if isinstance(expect, str):
+                expect = [expect]
+            for ex in expect:
+                self.assertTrue(re.search(ex, line) is not None, "Expected %r in %r" % (ex, line))
+        
     def test_cellpx_block_args(self):
         """%%px --[no]block flags work"""
         ip = get_ipython()
         v = self.client[-1:]
         v.activate()
         v.block=False
         
         for block in (True, False):
             v.block = block
             
             with capture_output() as io:
                 ip.run_cell_magic("px", "", "1")
             if block:
                 self.assertTrue(io.stdout.startswith("Parallel"), io.stdout)
             else:
                 self.assertTrue(io.stdout.startswith("Async"), io.stdout)
             
             with capture_output() as io:
                 ip.run_cell_magic("px", "--block", "1")
             self.assertTrue(io.stdout.startswith("Parallel"), io.stdout)
 
             with capture_output() as io:
                 ip.run_cell_magic("px", "--noblock", "1")
             self.assertTrue(io.stdout.startswith("Async"), io.stdout)
     
     def test_cellpx_groupby_engine(self):
         """%%px --group-outputs=engine"""
         ip = get_ipython()
         v = self.client[:]
         v.block = True
         v.activate()
         
         v['generate_output'] = generate_output
         
         with capture_output() as io:
             ip.run_cell_magic('px', '--group-outputs=engine', 'generate_output()')
         
-        lines = io.stdout.strip().splitlines()[1:]
+        self.assertFalse('\n\n' in io.stdout)
+        lines = io.stdout.splitlines()[1:]
         expected = [
-            ('[stdout:', '] stdout'),
+            r'\[stdout:\d+\]',
+            'stdout',
             'stdout2',
-            'IPython.core.display.HTML',
-            'IPython.core.display.Math',
-            ('] Out[', 'IPython.core.display.Math')
+            r'\[output:\d+\]',
+            r'IPython\.core\.display\.HTML',
+            r'IPython\.core\.display\.Math',
+            r'Out\[\d+:\d+\]:.*IPython\.core\.display\.Math',
             ] * len(v)
         
         self.assertEquals(len(lines), len(expected), io.stdout)
         for line,expect in zip(lines, expected):
             if isinstance(expect, str):
                 expect = [expect]
             for ex in expect:
-                self.assertTrue(ex in line, "Expected %r in %r" % (ex, line))
-        
-        expected = [
-            ('[stderr:', '] stderr'),
-            'stderr2',
-        ] * len(v)
+                self.assertTrue(re.search(ex, line) is not None, "Expected %r in %r" % (ex, line))
         
-        lines = io.stderr.strip().splitlines()
-        self.assertEquals(len(lines), len(expected), io.stderr)
-        for line,expect in zip(lines, expected):
-            if isinstance(expect, str):
-                expect = [expect]
-            for ex in expect:
-                self.assertTrue(ex in line, "Expected %r in %r" % (ex, line))
+        self._check_generated_stderr(io.stderr, len(v))
 
 
     def test_cellpx_groupby_order(self):
         """%%px --group-outputs=order"""
         ip = get_ipython()
         v = self.client[:]
         v.block = True
         v.activate()
         
         v['generate_output'] = generate_output
         
         with capture_output() as io:
             ip.run_cell_magic('px', '--group-outputs=order', 'generate_output()')
         
-        lines = io.stdout.strip().splitlines()[1:]
+        self.assertFalse('\n\n' in io.stdout)
+        lines = io.stdout.splitlines()[1:]
         expected = []
         expected.extend([
-            ('[stdout:', '] stdout'),
+            r'\[stdout:\d+\]',
+            'stdout',
             'stdout2',
         ] * len(v))
         expected.extend([
+            r'\[output:\d+\]',
             'IPython.core.display.HTML',
         ] * len(v))
         expected.extend([
+            r'\[output:\d+\]',
             'IPython.core.display.Math',
         ] * len(v))
         expected.extend([
-            ('] Out[', 'IPython.core.display.Math')
+            r'Out\[\d+:\d+\]:.*IPython\.core\.display\.Math'
         ] * len(v))
         
         self.assertEquals(len(lines), len(expected), io.stdout)
         for line,expect in zip(lines, expected):
             if isinstance(expect, str):
                 expect = [expect]
             for ex in expect:
-                self.assertTrue(ex in line, "Expected %r in %r" % (ex, line))
+                self.assertTrue(re.search(ex, line) is not None, "Expected %r in %r" % (ex, line))
         
-        expected = [
-            ('[stderr:', '] stderr'),
-            'stderr2',
-        ] * len(v)
-        
-        lines = io.stderr.strip().splitlines()
-        self.assertEquals(len(lines), len(expected), io.stderr)
-        for line,expect in zip(lines, expected):
-            if isinstance(expect, str):
-                expect = [expect]
-            for ex in expect:
-                self.assertTrue(ex in line, "Expected %r in %r" % (ex, line))
+        self._check_generated_stderr(io.stderr, len(v))
 
-    def test_cellpx_groupby_atype(self):
+    def test_cellpx_groupby_type(self):
         """%%px --group-outputs=type"""
         ip = get_ipython()
         v = self.client[:]
         v.block = True
         v.activate()
         
         v['generate_output'] = generate_output
         
         with capture_output() as io:
             ip.run_cell_magic('px', '--group-outputs=type', 'generate_output()')
         
-        lines = io.stdout.strip().splitlines()[1:]
+        self.assertFalse('\n\n' in io.stdout)
+        lines = io.stdout.splitlines()[1:]
         
         expected = []
         expected.extend([
-            ('[stdout:', '] stdout'),
+            r'\[stdout:\d+\]',
+            'stdout',
             'stdout2',
         ] * len(v))
         expected.extend([
-            'IPython.core.display.HTML',
-            'IPython.core.display.Math',
+            r'\[output:\d+\]',
+            r'IPython\.core\.display\.HTML',
+            r'IPython\.core\.display\.Math',
         ] * len(v))
         expected.extend([
-            ('] Out[', 'IPython.core.display.Math')
+            (r'Out\[\d+:\d+\]', r'IPython\.core\.display\.Math')
         ] * len(v))
         
         self.assertEquals(len(lines), len(expected), io.stdout)
         for line,expect in zip(lines, expected):
             if isinstance(expect, str):
                 expect = [expect]
             for ex in expect:
-                self.assertTrue(ex in line, "Expected %r in %r" % (ex, line))
+                self.assertTrue(re.search(ex, line) is not None, "Expected %r in %r" % (ex, line))
         
-        expected = [
-            ('[stderr:', '] stderr'),
-            'stderr2',
-        ] * len(v)
-        
-        lines = io.stderr.strip().splitlines()
-        self.assertEquals(len(lines), len(expected), io.stderr)
-        for line,expect in zip(lines, expected):
-            if isinstance(expect, str):
-                expect = [expect]
-            for ex in expect:
-                self.assertTrue(ex in line, "Expected %r in %r" % (ex, line))
+        self._check_generated_stderr(io.stderr, len(v))
 
 
     def test_px_nonblocking(self):
         ip = get_ipython()
         v = self.client[-1:]
         v.activate()
         v.block=False
 
         ip.magic('px a=5')
         self.assertEquals(v['a'], [5])
         ip.magic('px a=10')
         self.assertEquals(v['a'], [10])
         with capture_output() as io:
             ar = ip.magic('px print (a)')
         self.assertTrue(isinstance(ar, AsyncResult))
         self.assertTrue('Async' in io.stdout)
         self.assertFalse('[stdout:' in io.stdout)
+        self.assertFalse('\n\n' in io.stdout)
+        
         ar = ip.magic('px 1/0')
         self.assertRaisesRemote(ZeroDivisionError, ar.get)
     
     def test_autopx_blocking(self):
         ip = get_ipython()
         v = self.client[-1]
         v.activate()
         v.block=True
 
         with capture_output() as io:
             ip.magic('autopx')
             ip.run_cell('\n'.join(('a=5','b=12345','c=0')))
             ip.run_cell('b*=2')
             ip.run_cell('print (b)')
             ip.run_cell('b')
             ip.run_cell("b/c")
             ip.magic('autopx')
         
-        output = io.stdout.strip()
+        output = io.stdout
         
         self.assertTrue(output.startswith('%autopx enabled'), output)
-        self.assertTrue(output.endswith('%autopx disabled'), output)
+        self.assertTrue(output.rstrip().endswith('%autopx disabled'), output)
         self.assertTrue('RemoteError: ZeroDivisionError' in output, output)
-        self.assertTrue('] Out[' in output, output)
+        self.assertTrue('\nOut[' in output, output)
         self.assertTrue(': 24690' in output, output)
         ar = v.get_result(-1)
         self.assertEquals(v['a'], 5)
         self.assertEquals(v['b'], 24690)
         self.assertRaisesRemote(ZeroDivisionError, ar.get)
 
     def test_autopx_nonblocking(self):
         ip = get_ipython()
         v = self.client[-1]
         v.activate()
         v.block=False
 
         with capture_output() as io:
             ip.magic('autopx')
             ip.run_cell('\n'.join(('a=5','b=10','c=0')))
             ip.run_cell('print (b)')
             ip.run_cell('import time; time.sleep(0.1)')
             ip.run_cell("b/c")
             ip.run_cell('b*=2')
             ip.magic('autopx')
         
-        output = io.stdout.strip()
+        output = io.stdout.rstrip()
         
         self.assertTrue(output.startswith('%autopx enabled'))
         self.assertTrue(output.endswith('%autopx disabled'))
         self.assertFalse('ZeroDivisionError' in output)
         ar = v.get_result(-2)
         self.assertRaisesRemote(ZeroDivisionError, ar.get)
         # prevent TaskAborted on pulls, due to ZeroDivisionError
         time.sleep(0.5)
         self.assertEquals(v['a'], 5)
         # b*=2 will not fire, due to abort
         self.assertEquals(v['b'], 10)
     
     def test_result(self):
         ip = get_ipython()
         v = self.client[-1]
         v.activate()
         data = dict(a=111,b=222)
         v.push(data, block=True)
 
         ip.magic('px a')
         ip.magic('px b')
         for idx, name in [
                     ('', 'b'),
                     ('-1', 'b'),
                     ('2', 'b'),
                     ('1', 'a'),
                     ('-2', 'a'),
                 ]:
             with capture_output() as io:
                 ip.magic('result ' + idx)
-            output = io.stdout.strip()
+            output = io.stdout
             msg = "expected %s output to include %s, but got: %s" % \
                 ('%result '+idx, str(data[name]), output)
             self.assertTrue(str(data[name]) in output, msg)
         
     @dec.skipif_not_matplotlib
     def test_px_pylab(self):
         """%pylab works on engines"""
         ip = get_ipython()
         v = self.client[-1]
         v.block = True
         v.activate()
         
         with capture_output() as io:
             ip.magic("px %pylab inline")
         
         self.assertTrue("Welcome to pylab" in io.stdout, io.stdout)
         self.assertTrue("backend_inline" in io.stdout, io.stdout)
         
         with capture_output() as io:
             ip.magic("px plot(rand(100))")
         
-        self.assertTrue('] Out[' in io.stdout, io.stdout)
+        self.assertTrue('Out[' in io.stdout, io.stdout)
         self.assertTrue('matplotlib.lines' in io.stdout, io.stdout)
         
 

docs/examples/parallel/Parallel Magics.ipynb

@@ -1,228 +1,313 b''
 {
  "metadata": {
   "name": "Parallel Magics"
  },
  "nbformat": 3,
  "worksheets": [
   {
    "cells": [
     {
      "cell_type": "heading",
      "level": 1,
      "source": [
       "Using Parallel Magics"
      ]
     },
     {
      "cell_type": "markdown",
      "source": [
       "IPython has a few magics for working with your engines.",
       "",
       "This assumes you have started an IPython cluster, either with the notebook interface,",
       "or the `ipcluster/controller/engine` commands."
      ]
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
       "from IPython import parallel",
       "rc = parallel.Client()",
       "dv = rc[:]",
       "dv.block = True",
       "dv"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "markdown",
      "source": [
       "The parallel magics come from the `parallelmagics` IPython extension.",
       "The magics are set to work with a particular View object,",
       "so to activate them, you call the `activate()` method on a particular view:"
      ]
     },
     {
      "cell_type": "code",
      "collapsed": true,
      "input": [
       "dv.activate()"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "markdown",
      "source": [
       "Now we can execute code remotely with `%px`:"
      ]
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
       "%px a=5"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
       "%px print a"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
       "%px a"
      ],
      "language": "python",
      "outputs": []
     },
     {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "%px print >> sys.stderr, \"ERROR\""
+     ],
+     "language": "python",
+     "outputs": []
+    },
+    {
      "cell_type": "markdown",
      "source": [
       "You don't have to wait for results:"
      ]
     },
     {
      "cell_type": "code",
      "collapsed": true,
      "input": [
       "dv.block = False"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
       "%px import time",
       "%px time.sleep(5)",
       "%px time.time()"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "markdown",
      "source": [
       "But you will notice that this didn't output the result of the last command.",
       "For this, we have `%result`, which displays the output of the latest request:"
      ]
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
       "%result"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "markdown",
      "source": [
       "Remember, an IPython engine is IPython, so you can do magics remotely as well!"
      ]
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
       "dv.block = True",
       "%px %pylab inline"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "markdown",
      "source": [
       "`%%px` can also be used as a cell magic, for submitting whole blocks.",
       "This one acceps `--block` and `--noblock` flags to specify",
       "the blocking behavior, though the default is unchanged.",
       ""
      ]
     },
     {
      "cell_type": "code",
      "collapsed": true,
      "input": [
       "dv.scatter('id', dv.targets, flatten=True)",
       "dv['stride'] = len(dv)"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
       "%%px --noblock",
       "x = linspace(0,pi,1000)",
       "for n in range(id,12, stride):",
       "    print n",
       "    plt.plot(x,sin(n*x))",
       "plt.title(\"Plot %i\" % id)"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
       "%result"
      ],
      "language": "python",
      "outputs": []
     },
     {
      "cell_type": "markdown",
      "source": [
       "It also lets you choose some amount of the grouping of the outputs with `--group-outputs`:",
       "",
       "The choices are:",
       "",
       "* `engine` - all of an engine's output is collected together",
       "* `type` - where stdout of each engine is grouped, etc. (the default)",
       "* `order` - same as `type`, but individual displaypub outputs are interleaved.",
       "  That is, it will output the first plot from each engine, then the second from each,",
       "  etc."
      ]
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
       "%%px --group-outputs=engine",
       "x = linspace(0,pi,1000)",
       "for n in range(id,12, stride):",
       "    print n",
+      "    plt.figure()",
       "    plt.plot(x,sin(n*x))",
       "plt.title(\"Plot %i\" % id)"
      ],
      "language": "python",
      "outputs": []
     },
     {
+     "cell_type": "markdown",
+     "source": [
+      "When you specify 'order', then individual display outputs (e.g. plots) will be interleaved:"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "%%px --group-outputs=order",
+      "x = linspace(0,pi,1000)",
+      "for n in range(id,12, stride):",
+      "    print n",
+      "    plt.figure()",
+      "    plt.plot(x,sin(n*x))",
+      "plt.title(\"Plot %i\" % id)"
+     ],
+     "language": "python",
+     "outputs": []
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "source": [
+      "Single-engine views"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "source": [
+      "When a DirectView has a single target, the output is a bit simpler (no prefixes on stdout/err, etc.):"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": true,
+     "input": [
+      "def generate_output():",
+      "    \"\"\"function for testing output",
+      "    ",
+      "    publishes two outputs of each type, and returns something",
+      "    \"\"\"",
+      "    ",
+      "    import sys,os",
+      "    from IPython.core.display import display, HTML, Math",
+      "    ",
+      "    print \"stdout\"",
+      "    print >> sys.stderr, \"stderr\"",
+      "    ",
+      "    display(HTML(\"<b>HTML</b>\"))",
+      "    ",
+      "    print \"stdout2\"",
+      "    print >> sys.stderr, \"stderr2\"",
+      "    ",
+      "    display(Math(r\"\\alpha=\\beta\"))",
+      "    ",
+      "    return os.getpid()",
+      "",
+      "dv['generate_output'] = generate_output"
+     ],
+     "language": "python",
+     "outputs": []
+    },
+    {
      "cell_type": "code",
      "collapsed": true,
      "input": [
-      ""
+      "e0 = rc[-1]",
+      "e0.block = True",
+      "e0.activate()"
+     ],
+     "language": "python",
+     "outputs": []
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "%px generate_output()"
      ],
      "language": "python",
      "outputs": []
     }
    ]
   }
  ]
 }
  No newline at end of file