parallel.apps cleanup per review

STY: added spaces in string formatting calls
STY: expanded helpstring for cluster-id

ENH: allow BatchClusterAppMixin to be the second inherited class

IPython/parallel/apps/baseapp.py

@@ -119,9 +119,13 b' class BaseParallelApplication(BaseIPythonApplication):'
 
     cluster_id = Unicode('', config=True,
         help="""String id to add to runtime files, to prevent name collisions when
-        using multiple clusters with a single profile.
+        using multiple clusters with a single profile simultaneously.
         
         When set, files will be named like: 'ipcontroller-<cluster_id>-engine.json'
+        
+        Since this is text inserted into filenames, typical recommendations apply:
+        Simple character strings are ideal, and spaces are not recommended (but should
+        generally work).
         """
     )
     def _cluster_id_changed(self, name, old, new):

IPython/parallel/apps/ipcontrollerapp.py

@@ -183,8 +183,8 b' class IPControllerApp(BaseParallelApplication):'
     
     def _cluster_id_changed(self, name, old, new):
         super(IPControllerApp, self)._cluster_id_changed(name, old, new)
-        self.engine_json_file = "%s-engine.json"%self.name
-        self.client_json_file = "%s-client.json"%self.name
+        self.engine_json_file = "%s-engine.json" % self.name
+        self.client_json_file = "%s-client.json" % self.name
 
 
     # internal

IPython/parallel/apps/ipengineapp.py

@@ -93,7 +93,7 b' class MPI(Configurable):'
         help='How to enable MPI (mpi4py, pytrilinos, or empty string to disable).'
         )
 
-    def _on_use_changed(self, old, new):
+    def _use_changed(self, name, old, new):
         # load default init script if it's not set
         if not self.init_script:
             self.init_script = self.default_inits.get(new, '')
@@ -162,10 +162,10 b' class IPEngineApp(BaseParallelApplication):'
 
     def _cluster_id_changed(self, name, old, new):
         if new:
-            base = 'ipcontroller-%s'%new
+            base = 'ipcontroller-%s' % new
         else:
             base = 'ipcontroller'
-        self.url_file_name = "%s-engine.json"%base
+        self.url_file_name = "%s-engine.json" % base
 
     log_url = Unicode('', config=True,
         help="""The URL for the iploggerapp instance, for forwarding

IPython/parallel/apps/launcher.py

@@ -232,14 +232,14 b' class ControllerMixin(ClusterAppMixin):'
     controller_cmd = List(ipcontroller_cmd_argv, config=True,
         help="""Popen command to launch ipcontroller.""")
     # Command line arguments to ipcontroller.
-    controller_args = List(['--log-to-file','--log-level=%i'%logging.INFO], config=True,
+    controller_args = List(['--log-to-file','--log-level=%i' % logging.INFO], config=True,
         help="""command-line args to pass to ipcontroller""")
 
 class EngineMixin(ClusterAppMixin):
     engine_cmd = List(ipengine_cmd_argv, config=True,
         help="""command to launch the Engine.""")
     # Command line arguments for ipengine.
-    engine_args = List(['--log-to-file','--log-level=%i'%logging.INFO], config=True,
+    engine_args = List(['--log-to-file','--log-level=%i' % logging.INFO], config=True,
         help="command-line arguments to pass to ipengine"
     )
 
@@ -807,12 +807,19 b' class WindowsHPCEngineSetLauncher(WindowsHPCLauncher, ClusterAppMixin):'
 #-----------------------------------------------------------------------------
 
 class BatchClusterAppMixin(ClusterAppMixin):
-    """ClusterApp mixin that updates context dict, rather than args"""
-    context = Dict({'profile_dir':'', 'cluster_id':''})
+    """ClusterApp mixin that updates the self.context dict, rather than cl-args."""
     def _profile_dir_changed(self, name, old, new):
         self.context[name] = new
     _cluster_id_changed = _profile_dir_changed
 
+    def _profile_dir_default(self):
+        self.context['profile_dir'] = ''
+        return ''
+    def _cluster_id_default(self):
+        self.context['cluster_id'] = ''
+        return ''
+
+
 class BatchSystemLauncher(BaseLauncher):
     """Launch an external process using a batch system.
 
@@ -956,7 +963,7 b' class PBSLauncher(BatchSystemLauncher):'
     queue_template = Unicode('#PBS -q {queue}')
 
 
-class PBSControllerLauncher(BatchClusterAppMixin, PBSLauncher):
+class PBSControllerLauncher(PBSLauncher, BatchClusterAppMixin):
     """Launch a controller using PBS."""
 
     batch_file_name = Unicode(u'pbs_controller', config=True,
@@ -974,7 +981,7 b' class PBSControllerLauncher(BatchClusterAppMixin, PBSLauncher):'
         return super(PBSControllerLauncher, self).start(1)
 
 
-class PBSEngineSetLauncher(BatchClusterAppMixin, PBSLauncher):
+class PBSEngineSetLauncher(PBSLauncher, BatchClusterAppMixin):
     """Launch Engines using PBS"""
     batch_file_name = Unicode(u'pbs_engines', config=True,
         help="batch file name for the engine(s) job.")
@@ -998,7 +1005,7 b' class SGELauncher(PBSLauncher):'
     queue_regexp = Unicode('#\$\W+-q\W+\$?\w+')
     queue_template = Unicode('#$ -q {queue}')
 
-class SGEControllerLauncher(BatchClusterAppMixin, SGELauncher):
+class SGEControllerLauncher(SGELauncher, BatchClusterAppMixin):
     """Launch a controller using SGE."""
 
     batch_file_name = Unicode(u'sge_controller', config=True,
@@ -1014,7 +1021,7 b' class SGEControllerLauncher(BatchClusterAppMixin, SGELauncher):'
         self.log.info("Starting PBSControllerLauncher: %r" % self.args)
         return super(SGEControllerLauncher, self).start(1)
 
-class SGEEngineSetLauncher(BatchClusterAppMixin, SGELauncher):
+class SGEEngineSetLauncher(SGELauncher, BatchClusterAppMixin):
     """Launch Engines with SGE"""
     batch_file_name = Unicode(u'sge_engines', config=True,
         help="batch file name for the engine(s) job.")
@@ -1066,7 +1073,7 b' class LSFLauncher(BatchSystemLauncher):'
         return job_id
 
 
-class LSFControllerLauncher(BatchClusterAppMixin, LSFLauncher):
+class LSFControllerLauncher(LSFLauncher, BatchClusterAppMixin):
     """Launch a controller using LSF."""
     
     batch_file_name = Unicode(u'lsf_controller', config=True,
@@ -1084,7 +1091,7 b' class LSFControllerLauncher(BatchClusterAppMixin, LSFLauncher):'
         return super(LSFControllerLauncher, self).start(1)
 
 
-class LSFEngineSetLauncher(BatchClusterAppMixin, LSFLauncher):
+class LSFEngineSetLauncher(LSFLauncher, BatchClusterAppMixin):
     """Launch Engines using LSF"""
     batch_file_name = Unicode(u'lsf_engines', config=True,
                               help="batch file name for the engine(s) job.")