ipcontroller cleans up connection files unless reuse=True

Connection files are not valid across sessions if reuse is False, but were previously preserved, which could cause engines to try to connect to the wrong ports if the Controller took too long to start and/or write new connection files.

Also shuffles signal-handling around a bit, so that a clean exit occurs, rather than calling sys.exit directly in the signal handler.

IPython/parallel/apps/ipcontrollerapp.py

@@ -30,6 +30,7 b' import stat'
 import sys
 
 from multiprocessing import Process
+from signal import signal, SIGINT, SIGABRT, SIGTERM
 
 import zmq
 from zmq.devices import ProcessMonitoredQueue
@@ -55,7 +56,7 b' from IPython.parallel.controller.hub import HubFactory'
 from IPython.parallel.controller.scheduler import TaskScheduler,launch_scheduler
 from IPython.parallel.controller.sqlitedb import SQLiteDB
 
-from IPython.parallel.util import signal_children, split_url, disambiguate_url
+from IPython.parallel.util import split_url, disambiguate_url
 
 # conditional import of MongoDB backend class
 
@@ -151,7 +152,9 b' class IPControllerApp(BaseParallelApplication):'
         help="""Whether to create profile dir if it doesn't exist.""")
     
     reuse_files = Bool(False, config=True,
-        help='Whether to reuse existing json connection files.'
+        help="""Whether to reuse existing json connection files.
+        If False, connection files will be removed on a clean exit.
+        """
     )
     ssh_server = Unicode(u'', config=True,
         help="""ssh url for clients to use when connecting to the Controller
@@ -192,6 +195,12 b' class IPControllerApp(BaseParallelApplication):'
 
     def _use_threads_changed(self, name, old, new):
         self.mq_class = 'zmq.devices.%sMonitoredQueue'%('Thread' if new else 'Process')
+    
+    write_connection_files = Bool(True,
+        help="""Whether to write connection files to disk.
+        True in all cases other than runs with `reuse_files=True` *after the first*
+        """
+    )
 
     aliases = Dict(aliases)
     flags = Dict(flags)
@@ -256,6 +265,20 b' class IPControllerApp(BaseParallelApplication):'
             self.ssh_server = cfg['ssh']
         assert int(ports) == c.HubFactory.regport, "regport mismatch"
     
+    def cleanup_connection_files(self):
+        if self.reuse_files:
+            self.log.debug("leaving JSON connection files for reuse")
+            return
+        self.log.debug("cleaning up JSON connection files")
+        for f in (self.client_json_file, self.engine_json_file):
+            f = os.path.join(self.profile_dir.security_dir, f)
+            try:
+                os.remove(f)
+            except Exception as e:
+                self.log.error("Failed to cleanup connection file: %s", e)
+            else:
+                self.log.debug(u"removed %s", f)
+    
     def load_secondary_config(self):
         """secondary config, loading from JSON and setting defaults"""
         if self.reuse_files:
@@ -263,7 +286,11 b' class IPControllerApp(BaseParallelApplication):'
                 self.load_config_from_json()
             except (AssertionError,IOError) as e:
                 self.log.error("Could not load config from JSON: %s" % e)
-                self.reuse_files=False
+            else:
+                # successfully loaded config from JSON, and reuse=True
+                # no need to wite back the same file
+                self.write_connection_files = False
+                
         # switch Session.key default to secure
         default_secure(self.config)
         self.log.debug("Config changed")
@@ -284,7 +311,7 b' class IPControllerApp(BaseParallelApplication):'
             self.log.error("Couldn't construct the Controller", exc_info=True)
             self.exit(1)
         
-        if not self.reuse_files:
+        if self.write_connection_files:
             # save to new json config files
             f = self.factory
             cdict = {'exec_key' : f.session.key.decode('ascii'),
@@ -298,7 +325,6 b' class IPControllerApp(BaseParallelApplication):'
             edict['ssh'] = self.engine_ssh_server
             self.save_connection_dict(self.engine_json_file, edict)
 
-    #
     def init_schedulers(self):
         children = self.children
         mq = import_item(str(self.mq_class))
@@ -367,21 +393,31 b' class IPControllerApp(BaseParallelApplication):'
                 kwargs['in_thread'] = True
                 launch_scheduler(*sargs, **kwargs)
 
+    def terminate_children(self):
+        child_procs = []
+        for child in self.children:
+            if isinstance(child, ProcessMonitoredQueue):
+                child_procs.append(child.launcher)
+            elif isinstance(child, Process):
+                child_procs.append(child)
+        if child_procs:
+            self.log.critical("terminating children...")
+            for child in child_procs:
+                try:
+                    child.terminate()
+                except OSError:
+                    # already dead
+                    pass
     
-    def save_urls(self):
-        """save the registration urls to files."""
-        c = self.config
-        
-        sec_dir = self.profile_dir.security_dir
-        cf = self.factory
-        
-        with open(os.path.join(sec_dir, 'ipcontroller-engine.url'), 'w') as f:
-            f.write("%s://%s:%s"%(cf.engine_transport, cf.engine_ip, cf.regport))
-        
-        with open(os.path.join(sec_dir, 'ipcontroller-client.url'), 'w') as f:
-            f.write("%s://%s:%s"%(cf.client_transport, cf.client_ip, cf.regport))
-        
+    def handle_signal(self, sig, frame):
+        self.log.critical("Received signal %i, shutting down", sig)
+        self.terminate_children()
+        self.loop.stop()
     
+    def init_signal(self):
+        for sig in (SIGINT, SIGABRT, SIGTERM):
+            signal(sig, self.handle_signal)
+
     def do_import_statements(self):
         statements = self.import_statements
         for s in statements:
@@ -415,15 +451,11 b' class IPControllerApp(BaseParallelApplication):'
     def start(self):
         # Start the subprocesses:
         self.factory.start()
-        child_procs = []
+        # children must be started before signals are setup,
+        # otherwise signal-handling will fire multiple times
         for child in self.children:
             child.start()
-            if isinstance(child, ProcessMonitoredQueue):
-                child_procs.append(child.launcher)
-            elif isinstance(child, Process):
-                child_procs.append(child)
-        if child_procs:
-            signal_children(child_procs)
+        self.init_signal()
 
         self.write_pid_file(overwrite=True)
 
@@ -431,6 +463,8 b' class IPControllerApp(BaseParallelApplication):'
             self.factory.loop.start()
         except KeyboardInterrupt:
             self.log.critical("Interrupted, Exiting...\n")
+        finally:
+            self.cleanup_connection_files()
             
 
 

IPython/parallel/controller/scheduler.py

@@ -722,5 +722,5 b' def launch_scheduler(in_addr, out_addr, mon_addr, not_addr, config=None,'
         try:
             loop.start()
         except KeyboardInterrupt:
-            print ("interrupted, exiting...", file=sys.__stderr__)
+            scheduler.log.critical("Interrupted, exiting...")