log exceptions in Comm handlers

IPython/html/static/services/kernels/js/comm.js

@@ -1,169 +1,183
 //----------------------------------------------------------------------------
 //  Copyright (C) 2013  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.
 //----------------------------------------------------------------------------
 
 //============================================================================
 // Comm and CommManager bases
 //============================================================================
 /**
  * Base Comm classes
  * @module IPython
  * @namespace IPython
  * @submodule comm
  */
 
 var IPython = (function (IPython) {
     "use strict";
 
     //-----------------------------------------------------------------------
     // CommManager class
     //-----------------------------------------------------------------------
     
     var CommManager = function (kernel) {
         this.comms = {};
         this.targets = {};
         if (kernel !== undefined) {
             this.init_kernel(kernel);
         }
     };
     
     CommManager.prototype.init_kernel = function (kernel) {
         // connect the kernel, and register message handlers
         this.kernel = kernel;
         var msg_types = ['comm_open', 'comm_msg', 'comm_close'];
         for (var i = 0; i < msg_types.length; i++) {
             var msg_type = msg_types[i];
             kernel.register_iopub_handler(msg_type, $.proxy(this[msg_type], this));
         }
     };
     
     CommManager.prototype.register_target = function (target_name, f) {
         // Register a target function for a given target name
         this.targets[target_name] = f;
     };
     
     CommManager.prototype.unregister_target = function (target_name, f) {
         // Unregister a target function for a given target name
         delete this.targets[target_name];
     };
 
     CommManager.prototype.register_comm = function (comm) {
         // Register a comm in the mapping
         this.comms[comm.comm_id] = comm;
         comm.kernel = this.kernel;
         return comm.comm_id;
     };
     
     CommManager.prototype.unregister_comm = function (comm_id) {
         // Remove a comm from the mapping
         delete this.comms[comm_id];
     };
     
     // comm message handlers
     
     CommManager.prototype.comm_open = function (msg) {
         var content = msg.content;
         var f = this.targets[content.target_name];
         if (f === undefined) {
             console.log("No such target registered: ", content.target_name);
             console.log("Available targets are: ", this.targets);
             return;
         }
         var comm = new Comm(content.comm_id);
         this.register_comm(comm);
+        try {
         f(comm, msg);
+        } catch (e) {
+            console.log("Exception opening new comm:", e, msg);
+            comm.close();
+            this.unregister_comm(comm);
+        }
     };
     
     CommManager.prototype.comm_close = function (msg) {
         var content = msg.content;
         var comm = this.comms[content.comm_id];
         if (comm === undefined) {
             return;
         }
         delete this.comms[content.comm_id];
+        try {
         comm.handle_close(msg);
+        } catch (e) {
+            console.log("Exception closing comm: ", e, msg);
+        }
     };
     
     CommManager.prototype.comm_msg = function (msg) {
         var content = msg.content;
         var comm = this.comms[content.comm_id];
         if (comm === undefined) {
             return;
         }
+        try {
         comm.handle_msg(msg);
+        } catch (e) {
+            console.log("Exception handling comm msg: ", e, msg);
+        }
     };
     
     //-----------------------------------------------------------------------
     // Comm base class
     //-----------------------------------------------------------------------
     
     var Comm = function (comm_id, target_name) {
         this.comm_id = comm_id || new IPython.utils.uuid();
         this.target_name = target_name;
         this._msg_callback = this._close_callback = null;
     };
     
     // methods for sending messages
     Comm.prototype.open = function (data, callbacks, metadata) {
         var content = {
             comm_id : this.comm_id,
             target_name : this.target_name,
             data : data || {},
         };
         return this.kernel.send_shell_message("comm_open", content, callbacks, metadata);
     };
     
     Comm.prototype.send = function (data, callbacks, metadata) {
         var content = {
             comm_id : this.comm_id,
             data : data || {},
         };
         return this.kernel.send_shell_message("comm_msg", content, callbacks, metadata);
     };
     
     Comm.prototype.close = function (data, callbacks, metadata) {
         var content = {
             comm_id : this.comm_id,
             data : data || {},
         };
         return this.kernel.send_shell_message("comm_close", content, callbacks, metadata);
     };
     
     // methods for registering callbacks for incoming messages
     Comm.prototype._register_callback = function (key, callback) {
         this['_' + key + '_callback'] = callback;
     };
     
     Comm.prototype.on_msg = function (callback) {
         this._register_callback('msg', callback);
     };
     
     Comm.prototype.on_close = function (callback) {
         this._register_callback('close', callback);
     };
     
     // methods for handling incoming messages
     
     Comm.prototype._maybe_callback = function (key, msg) {
         var callback = this['_' + key + '_callback'];
         if (callback) callback(msg);
     };
     
     Comm.prototype.handle_msg = function (msg) {
         this._maybe_callback('msg', msg);
     };
     
     Comm.prototype.handle_close = function (msg) {
         this._maybe_callback('close', msg);
     };
     
     IPython.CommManager = CommManager;
     IPython.Comm = Comm;
     
     return IPython;
 
 }(IPython));
 

IPython/kernel/comm/manager.py

@@ -1,170 +1,185
 """Base class to manage comms"""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2013  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 sys
 
 from IPython.config import LoggingConfigurable
 from IPython.core.prompts import LazyEvaluate
 from IPython.core.getipython import get_ipython
 
 from IPython.utils.importstring import import_item
 from IPython.utils.traitlets import Instance, Unicode, Dict, Any
 
 from .comm import Comm
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 def lazy_keys(dikt):
     """Return lazy-evaluated string representation of a dictionary's keys
     
     Key list is only constructed if it will actually be used.
     Used for debug-logging.
     """
     return LazyEvaluate(lambda d: list(d.keys()))
 
 
 def with_output(method):
     """method decorator for ensuring output is handled properly in a message handler
     
     - sets parent header before entering the method
     - publishes busy/idle
     - flushes stdout/stderr after
     """
     def method_with_output(self, stream, ident, msg):
         parent = msg['header']
         self.shell.set_parent(parent)
         self.shell.kernel._publish_status('busy')
         try:
             return method(self, stream, ident, msg)
         finally:
             sys.stdout.flush()
             sys.stderr.flush()
             self.shell.kernel._publish_status('idle')
     
     return method_with_output
 
 
 class CommManager(LoggingConfigurable):
     """Manager for Comms in the Kernel"""
     
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
     def _shell_default(self):
         return get_ipython()
     iopub_socket = Any()
     def _iopub_socket_default(self):
         return self.shell.kernel.iopub_socket
     session = Instance('IPython.kernel.zmq.session.Session')
     def _session_default(self):
         if self.shell is None:
             return
         return self.shell.kernel.session
     
     comms = Dict()
     targets = Dict()
     
     # Public APIs
     
     def register_target(self, target_name, f):
         """Register a callable f for a given target name
         
-        f will be called with a Comm object as its only argument
-        when a comm_open message is received with `target`.
+        f will be called with two arguments when a comm_open message is received with `target`:
+        
+        - the Comm instance
+        - the `comm_open` message itself.
         
         f can be a Python callable or an import string for one.
         """
         if isinstance(f, basestring):
             f = import_item(f)
         
         self.targets[target_name] = f
     
     def unregister_target(self, target_name, f):
         """Unregister a callable registered with register_target"""
         return self.targets.pop(target_name);
 
     def register_comm(self, comm):
         """Register a new comm"""
         comm_id = comm.comm_id
         comm.shell = self.shell
         comm.iopub_socket = self.iopub_socket
         self.comms[comm_id] = comm
         return comm_id
     
     def unregister_comm(self, comm_id):
         """Unregister a comm, and close its counterpart"""
         # unlike get_comm, this should raise a KeyError
         comm = self.comms.pop(comm_id)
         comm.close()
     
     def get_comm(self, comm_id):
         """Get a comm with a particular id
         
         Returns the comm if found, otherwise None.
         
         This will not raise an error,
         it will log messages if the comm cannot be found.
         """
         if comm_id not in self.comms:
             self.log.error("No such comm: %s", comm_id)
             self.log.debug("Current comms: %s", lazy_keys(self.comms))
             return
         # call, because we store weakrefs
         comm = self.comms[comm_id]
         return comm
     
     # Message handlers
     @with_output
     def comm_open(self, stream, ident, msg):
         """Handler for comm_open messages"""
         content = msg['content']
         comm_id = content['comm_id']
         target_name = content['target_name']
         f = self.targets.get(target_name, None)
         comm = Comm(comm_id=comm_id,
                     shell=self.shell,
                     iopub_socket=self.iopub_socket,
                     primary=False,
         )
         if f is None:
             self.log.error("No such comm target registered: %s", target_name)
             comm.close()
             return
         self.register_comm(comm)
+        try:
         f(comm, msg)
+        except Exception:
+            self.log.error("Exception opening comm with target: %s", target_name, exc_info=True)
+            comm.close()
+            self.unregister_comm(comm_id)
     
     @with_output
     def comm_msg(self, stream, ident, msg):
         """Handler for comm_msg messages"""
         content = msg['content']
         comm_id = content['comm_id']
         comm = self.get_comm(comm_id)
         if comm is None:
             # no such comm
             return
+        try:
         comm.handle_msg(msg)
+        except Exception:
+            self.log.error("Exception in comm_msg for %s", comm_id, exc_info=True)
     
     @with_output
     def comm_close(self, stream, ident, msg):
         """Handler for comm_close messages"""
         content = msg['content']
         comm_id = content['comm_id']
         comm = self.get_comm(comm_id)
         if comm is None:
             # no such comm
+            self.log.debug("No such comm to close: %s", comm_id)
             return
         del self.comms[comm_id]
+        
+        try:
         comm.handle_close(msg)
+        except Exception:
+            self.log.error("Exception handling comm_close for %s", comm_id, exc_info=True)
 
 
 __all__ = ['CommManager']