Only set channels to null when they are fully closed

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

@@ -1,746 +1,762
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
 define([
     'base/js/namespace',
     'jquery',
     'base/js/utils',
     'services/kernels/js/comm',
     'widgets/js/init',
 ], function(IPython, $, utils, comm, widgetmanager) {
     "use strict";
 
     // Initialization and connection.
     /**
      * A Kernel Class to communicate with the Python kernel
      * @Class Kernel
      */
     var Kernel = function (kernel_service_url, ws_url, notebook, id, name) {
         this.events = notebook.events;
 
         this.id = id;
         this.name = name;
 
         this.channels = {
             'shell': null,
             'iopub': null,
             'stdin': null
         };
 
         this.kernel_service_url = kernel_service_url;
         this.kernel_url = utils.url_join_encode(this.kernel_service_url, this.id);
         this.ws_url = ws_url || IPython.utils.get_body_data("wsUrl");
         if (!this.ws_url) {
             // trailing 's' in https will become wss for secure web sockets
             this.ws_url = location.protocol.replace('http', 'ws') + "//" + location.host;
         }
 
         this.username = "username";
         this.session_id = utils.uuid();
         this._msg_callbacks = {};
 
         if (typeof(WebSocket) !== 'undefined') {
             this.WebSocket = WebSocket;
         } else if (typeof(MozWebSocket) !== 'undefined') {
             this.WebSocket = MozWebSocket;
         } else {
             alert('Your browser does not have WebSocket support, please try Chrome, Safari or Firefox ≥ 6. Firefox 4 and 5 are also supported by you have to enable WebSockets in about:config.');
         }
         
         this.bind_events();
         this.init_iopub_handlers();
         this.comm_manager = new comm.CommManager(this);
         this.widget_manager = new widgetmanager.WidgetManager(this.comm_manager, notebook);
         
         this.last_msg_id = null;
         this.last_msg_callbacks = {};
     };
 
 
     Kernel.prototype._get_msg = function (msg_type, content, metadata) {
         var msg = {
             header : {
                 msg_id : utils.uuid(),
                 username : this.username,
                 session : this.session_id,
                 msg_type : msg_type,
                 version : "5.0"
             },
             metadata : metadata || {},
             content : content,
             parent_header : {}
         };
         return msg;
     };
     
     Kernel.prototype.bind_events = function () {
         var that = this;
         this.events.on('send_input_reply.Kernel', function(evt, data) { 
             that.send_input_reply(data);
         });
     };
     
     // Initialize the iopub handlers
     
     Kernel.prototype.init_iopub_handlers = function () {
         var output_msg_types = ['stream', 'display_data', 'execute_result', 'error'];
         this._iopub_handlers = {};
         this.register_iopub_handler('status', $.proxy(this._handle_status_message, this));
         this.register_iopub_handler('clear_output', $.proxy(this._handle_clear_output, this));
         
         for (var i=0; i < output_msg_types.length; i++) {
             this.register_iopub_handler(output_msg_types[i], $.proxy(this._handle_output_message, this));
         }
     };
 
     /**
      * GET /api/kernels
      */
     Kernel.prototype.list = function (success, error) {
         $.ajax(this.kernel_service_url, {
             processData: false,
             cache: false,
             type: "GET",
             dataType: "json",
             success: success,
             error: this._on_error(error)
         });
     };
 
     /**
      * POST /api/kernels
      */
     Kernel.prototype.start = function (success, error) {
         var that = this;
         var on_success = function (data, status, xhr) {
             that._kernel_started(data);
             if (success) {
                 success(data, status, xhr);
             }
         };
 
         $.ajax(this.kernel_service_url, {
             processData: false,
             cache: false,
             type: "POST",
             dataType: "json",
             success: this._on_success(on_success),
             error: this._on_error(error)
         });
     };
 
     /**
      * GET /api/kernels/[:kernel_id]
      */
     Kernel.prototype.get_info = function (success, error) {
         $.ajax(this.kernel_url, {
             processData: false,
             cache: false,
             type: "GET",
             dataType: "json",
             success: this._on_success(success),
             error: this._on_error(error)
         });
     };
 
     /**
      * DELETE /api/kernels/[:kernel_id]
      */
     Kernel.prototype.kill = function (success, error) {
         this._kernel_dead();
         $.ajax(this.kernel_url, {
             processData: false,
             cache: false,
             type: "DELETE",
             dataType: "json",
             success: this._on_success(success),
             error: this._on_error(error)
         });
     };
 
     /**
      * POST /api/kernels/[:kernel_id]/interrupt
      */
     Kernel.prototype.interrupt = function (success, error) {
         this.events.trigger('status_interrupting.Kernel', {kernel: this});
         var url = utils.url_join_encode(this.kernel_url, 'interrupt');
         $.ajax(url, {
             processData: false,
             cache: false,
             type: "POST",
             dataType: "json",
             success: this._on_success(success),
             error: this._on_error(error)
         });
     };
 
     /**
      * POST /api/kernels/[:kernel_id]/restart
      */
     Kernel.prototype.restart = function (success, error) {
         this.events.trigger('status_restarting.Kernel', {kernel: this});
         this.stop_channels();
 
         var that = this;
         var on_success = function (data, status, xhr) {
             that._kernel_started(data, status, xhr);
             if (success) {
                 success(data, status, xhr);
             }
         };
 
         var url = utils.url_join_encode(this.kernel_url, 'restart');
         $.ajax(url, {
             processData: false,
             cache: false,
             type: "POST",
             dataType: "json",
             success: this._on_success(on_success),
             error: this._on_error(error)
         });
     };
 
     /**
      * Not actually a HTTP request, but useful function nonetheless
      * for reconnecting to the kernel if the connection is somehow lost
      */
     Kernel.prototype.reconnect = function () {
         this.events.trigger('status_reconnecting.Kernel');
         var that = this;
         setTimeout(function () {
             that.start_channels();
         }, 5000);
     };
 
     Kernel.prototype._on_success = function (success) {
         var that = this;
         return function (data, status, xhr) {
             if (data) {
                 that.id = data.id;
                 that.name = data.name;
             }
             that.kernel_url = utils.url_join_encode(that.kernel_service_url, that.id);
             if (success) {
                 success(data, status, xhr);
             }
         };
     };
 
     Kernel.prototype._on_error = function (error) {
         return function (xhr, status, err) {
             utils.log_ajax_error(xhr, status, err);
             if (error) {
                 error(xhr, status, err);
             }
         };
     };
 
     Kernel.prototype._kernel_started = function (json) {
         console.log("Kernel started: ", json.id);
         this.events.trigger('status_started.Kernel', {kernel: this});
         this.start_channels();
     };
 
     Kernel.prototype._kernel_connected = function () {
         var that = this;
         console.log('Connected to kernel: ', this.id);
         this.events.trigger('status_connected.Kernel');
         this.kernel_info(function () {
             that.events.trigger('status_idle.Kernel');
         });
     };
 
     Kernel.prototype._kernel_dead = function () {
         this.events.trigger('status_dead.Kernel');
         this.stop_channels();
     };
 
 
     /**
      * Start the `shell`and `iopub` channels.
      * Will stop and restart them if they already exist.
      *
      * @method start_channels
      */
     Kernel.prototype.start_channels = function () {
         var that = this;
         this.stop_channels();
         var ws_host_url = this.ws_url + this.kernel_url;
         console.log("Starting WebSockets:", ws_host_url);
         this.channels.shell = new this.WebSocket(
             this.ws_url + utils.url_join_encode(this.kernel_url, "shell")
         );
         this.channels.stdin = new this.WebSocket(
             this.ws_url + utils.url_join_encode(this.kernel_url, "stdin")
         );
         this.channels.iopub = new this.WebSocket(
             this.ws_url + utils.url_join_encode(this.kernel_url, "iopub")
         );
         
         var already_called_onclose = false; // only alert once
         var ws_closed_early = function(evt){
             if (already_called_onclose){
                 return;
             }
             already_called_onclose = true;
             if ( ! evt.wasClean ){
                 that._ws_closed(ws_host_url, true);
             }
         };
         var ws_closed_late = function(evt){
             if (already_called_onclose){
                 return;
             }
             already_called_onclose = true;
             if ( ! evt.wasClean ){
                 that._ws_closed(ws_host_url, false);
             }
         };
         var ws_error = function(evt){
             if (already_called_onclose){
                 return;
             }
             already_called_onclose = true;
             that._ws_closed(ws_host_url, false);
         };
 
         for (var c in this.channels) {
             this.channels[c].onopen = $.proxy(this._ws_opened, this);
             this.channels[c].onclose = ws_closed_early;
             this.channels[c].onerror = ws_error;
         }
         // switch from early-close to late-close message after 1s
         setTimeout(function() {
             for (var c in that.channels) {
                 if (that.channels[c] !== null) {
                     that.channels[c].onclose = ws_closed_late;
                 }
             }
         }, 1000);
         this.channels.shell.onmessage = $.proxy(this._handle_shell_reply, this);
         this.channels.iopub.onmessage = $.proxy(this._handle_iopub_message, this);
         this.channels.stdin.onmessage = $.proxy(this._handle_input_request, this);
     };
 
     /**
      * Handle a websocket entering the open state
      * sends session and cookie authentication info as first message.
      * Once all sockets are open, signal the Kernel.status_started event.
      * @method _ws_opened
      */
     Kernel.prototype._ws_opened = function (evt) {
         // send the session id so the Session object Python-side
         // has the same identity
         evt.target.send(this.session_id + ':' + document.cookie);
 
         if (this.is_connected()) {
             // all events ready, trigger started event.
             this._kernel_connected();
         }
     };
     
     Kernel.prototype._ws_closed = function(ws_url, early) {
         this.stop_channels();
         this.events.trigger('status_disconnected.Kernel');
         if (!early) {
             this.reconnect();
         } else {
             console.log('WebSocket connection failed: ', ws_url);
             this.events.trigger('early_disconnect.Kernel', ws_url);
         }
     };
 
     /**
      * Stop the websocket channels.
      * @method stop_channels
      */
     Kernel.prototype.stop_channels = function () {
+        var that = this;
+        var close = function (c) {
+            return function () {
+                if (that.channels[c].readyState === WebSocket.CLOSED) {
+                    that.channels[c] = null;
+                }
+            };
+        };
         for (var c in this.channels) {
             if ( this.channels[c] !== null ) {
-                this.channels[c].onclose = null;
+                this.channels[c].onclose = close(c);
                 this.channels[c].close();
-                this.channels[c] = null;
             }
         }
     };
 
     // Main public methods.
 
     Kernel.prototype.is_connected = function () {
         for (var c in this.channels) {
             // if any channel is not ready, then we're not connected
             if (this.channels[c] === null) {
                 return false;
             }
             if (this.channels[c].readyState !== WebSocket.OPEN) {
                 return false;
             }
         }
         return true;
     };
     
+    Kernel.prototype.is_fully_disconnected = function () {
+        for (var c in this.channels) {
+            if (this.channels[c] === null) {
+                return true;
+            }
+        }
+        return false;
+    };
+    
     // send a message on the Kernel's shell channel
     Kernel.prototype.send_shell_message = function (msg_type, content, callbacks, metadata) {
         if (!this.is_connected()) {
             throw new Error("kernel is not connected");
         }
         var msg = this._get_msg(msg_type, content, metadata);
         this.channels.shell.send(JSON.stringify(msg));
         this.set_callbacks_for_msg(msg.header.msg_id, callbacks);
         return msg.header.msg_id;
     };
 
     /**
      * Get kernel info
      *
      * @param callback {function}
      * @method kernel_info
      *
      * When calling this method, pass a callback function that expects one argument.
      * The callback will be passed the complete `kernel_info_reply` message documented
      * [here](http://ipython.org/ipython-doc/dev/development/messaging.html#kernel-info)
      */
     Kernel.prototype.kernel_info = function (callback) {
         var callbacks;
         if (callback) {
             callbacks = { shell : { reply : callback } };
         }
         return this.send_shell_message("kernel_info_request", {}, callbacks);
     };
 
     /**
      * Get info on an object
      *
      * @param code {string}
      * @param cursor_pos {integer}
      * @param callback {function}
      * @method inspect
      *
      * When calling this method, pass a callback function that expects one argument.
      * The callback will be passed the complete `inspect_reply` message documented
      * [here](http://ipython.org/ipython-doc/dev/development/messaging.html#object-information)
      */
     Kernel.prototype.inspect = function (code, cursor_pos, callback) {
         var callbacks;
         if (callback) {
             callbacks = { shell : { reply : callback } };
         }
         
         var content = {
             code : code,
             cursor_pos : cursor_pos,
             detail_level : 0
         };
         return this.send_shell_message("inspect_request", content, callbacks);
     };
 
     /**
      * Execute given code into kernel, and pass result to callback.
      *
      * @async
      * @method execute
      * @param {string} code
      * @param [callbacks] {Object} With the following keys (all optional)
      *      @param callbacks.shell.reply {function}
      *      @param callbacks.shell.payload.[payload_name] {function}
      *      @param callbacks.iopub.output {function}
      *      @param callbacks.iopub.clear_output {function}
      *      @param callbacks.input {function}
      * @param {object} [options]
      *      @param [options.silent=false] {Boolean}
      *      @param [options.user_expressions=empty_dict] {Dict}
      *      @param [options.allow_stdin=false] {Boolean} true|false
      *
      * @example
      *
      * The options object should contain the options for the execute call. Its default
      * values are:
      *
      *      options = {
      *        silent : true,
      *        user_expressions : {},
      *        allow_stdin : false
      *      }
      *
      * When calling this method pass a callbacks structure of the form:
      *
      *      callbacks = {
      *       shell : {
      *         reply : execute_reply_callback,
      *         payload : {
      *           set_next_input : set_next_input_callback,
      *         }
      *       },
      *       iopub : {
      *         output : output_callback,
      *         clear_output : clear_output_callback,
      *       },
      *       input : raw_input_callback
      *      }
      *
      * Each callback will be passed the entire message as a single arugment.
      * Payload handlers will be passed the corresponding payload and the execute_reply message.
      */
     Kernel.prototype.execute = function (code, callbacks, options) {
         var content = {
             code : code,
             silent : true,
             store_history : false,
             user_expressions : {},
             allow_stdin : false
         };
         callbacks = callbacks || {};
         if (callbacks.input !== undefined) {
             content.allow_stdin = true;
         }
         $.extend(true, content, options);
         this.events.trigger('execution_request.Kernel', {kernel: this, content:content});
         return this.send_shell_message("execute_request", content, callbacks);
     };
 
     /**
      * When calling this method, pass a function to be called with the `complete_reply` message
      * as its only argument when it arrives.
      *
      * `complete_reply` is documented
      * [here](http://ipython.org/ipython-doc/dev/development/messaging.html#complete)
      *
      * @method complete
      * @param code {string}
      * @param cursor_pos {integer}
      * @param callback {function}
      *
      */
     Kernel.prototype.complete = function (code, cursor_pos, callback) {
         var callbacks;
         if (callback) {
             callbacks = { shell : { reply : callback } };
         }
         var content = {
             code : code,
             cursor_pos : cursor_pos
         };
         return this.send_shell_message("complete_request", content, callbacks);
     };
 
     Kernel.prototype.send_input_reply = function (input) {
         if (!this.is_connected()) {
             throw new Error("kernel is not connected");
         }
         var content = {
             value : input
         };
         this.events.trigger('input_reply.Kernel', {kernel: this, content:content});
         var msg = this._get_msg("input_reply", content);
         this.channels.stdin.send(JSON.stringify(msg));
         return msg.header.msg_id;
     };
 
 
     // Reply handlers
 
     Kernel.prototype.register_iopub_handler = function (msg_type, callback) {
         this._iopub_handlers[msg_type] = callback;
     };
 
     Kernel.prototype.get_iopub_handler = function (msg_type) {
         // get iopub handler for a specific message type
         return this._iopub_handlers[msg_type];
     };
 
 
     Kernel.prototype.get_callbacks_for_msg = function (msg_id) {
         // get callbacks for a specific message
         if (msg_id == this.last_msg_id) {
             return this.last_msg_callbacks;
         } else {
             return this._msg_callbacks[msg_id];
         }
     };
 
 
     Kernel.prototype.clear_callbacks_for_msg = function (msg_id) {
         if (this._msg_callbacks[msg_id] !== undefined ) {
             delete this._msg_callbacks[msg_id];
         }
     };
     
     Kernel.prototype._finish_shell = function (msg_id) {
         var callbacks = this._msg_callbacks[msg_id];
         if (callbacks !== undefined) {
             callbacks.shell_done = true;
             if (callbacks.iopub_done) {
                 this.clear_callbacks_for_msg(msg_id);
             }
         }
     };
 
     Kernel.prototype._finish_iopub = function (msg_id) {
         var callbacks = this._msg_callbacks[msg_id];
         if (callbacks !== undefined) {
             callbacks.iopub_done = true;
             if (callbacks.shell_done) {
                 this.clear_callbacks_for_msg(msg_id);
             }
         }
     };
     
     /* Set callbacks for a particular message.
      * Callbacks should be a struct of the following form:
      * shell : {
      * 
      * }
     
      */
     Kernel.prototype.set_callbacks_for_msg = function (msg_id, callbacks) {
         this.last_msg_id = msg_id;
         if (callbacks) {
             // shallow-copy mapping, because we will modify it at the top level
             var cbcopy = this._msg_callbacks[msg_id] = this.last_msg_callbacks = {};
             cbcopy.shell = callbacks.shell;
             cbcopy.iopub = callbacks.iopub;
             cbcopy.input = callbacks.input;
             cbcopy.shell_done = (!callbacks.shell);
             cbcopy.iopub_done = (!callbacks.iopub);
         } else {
             this.last_msg_callbacks = {};
         }
     };
 
 
     Kernel.prototype._handle_shell_reply = function (e) {
         var reply = $.parseJSON(e.data);
         this.events.trigger('shell_reply.Kernel', {kernel: this, reply:reply});
         var content = reply.content;
         var metadata = reply.metadata;
         var parent_id = reply.parent_header.msg_id;
         var callbacks = this.get_callbacks_for_msg(parent_id);
         if (!callbacks || !callbacks.shell) {
             return;
         }
         var shell_callbacks = callbacks.shell;
         
         // signal that shell callbacks are done
         this._finish_shell(parent_id);
         
         if (shell_callbacks.reply !== undefined) {
             shell_callbacks.reply(reply);
         }
         if (content.payload && shell_callbacks.payload) {
             this._handle_payloads(content.payload, shell_callbacks.payload, reply);
         }
     };
 
 
     Kernel.prototype._handle_payloads = function (payloads, payload_callbacks, msg) {
         var l = payloads.length;
         // Payloads are handled by triggering events because we don't want the Kernel
         // to depend on the Notebook or Pager classes.
         for (var i=0; i<l; i++) {
             var payload = payloads[i];
             var callback = payload_callbacks[payload.source];
             if (callback) {
                 callback(payload, msg);
             }
         }
     };
 
     Kernel.prototype._handle_status_message = function (msg) {
         var execution_state = msg.content.execution_state;
         var parent_id = msg.parent_header.msg_id;
         
         // dispatch status msg callbacks, if any
         var callbacks = this.get_callbacks_for_msg(parent_id);
         if (callbacks && callbacks.iopub && callbacks.iopub.status) {
             try {
                 callbacks.iopub.status(msg);
             } catch (e) {
                 console.log("Exception in status msg handler", e, e.stack);
             }
         }
         
         if (execution_state === 'busy') {
             this.events.trigger('status_busy.Kernel', {kernel: this});
         } else if (execution_state === 'idle') {
             // signal that iopub callbacks are (probably) done
             // async output may still arrive,
             // but only for the most recent request
             this._finish_iopub(parent_id);
             
             // trigger status_idle event
             this.events.trigger('status_idle.Kernel', {kernel: this});
         } else if (execution_state === 'restarting') {
             // autorestarting is distinct from restarting,
             // in that it means the kernel died and the server is restarting it.
             // status_restarting sets the notification widget,
             // autorestart shows the more prominent dialog.
             this.events.trigger('status_autorestarting.Kernel', {kernel: this});
             this.events.trigger('status_restarting.Kernel', {kernel: this});
         } else if (execution_state === 'dead') {
             this.stop_channels();
             this.events.trigger('status_dead.Kernel', {kernel: this});
             this.events.trigger('status_restart_failed.Kernel', {kernel: this});
         }
     };
     
     
     // handle clear_output message
     Kernel.prototype._handle_clear_output = function (msg) {
         var callbacks = this.get_callbacks_for_msg(msg.parent_header.msg_id);
         if (!callbacks || !callbacks.iopub) {
             return;
         }
         var callback = callbacks.iopub.clear_output;
         if (callback) {
             callback(msg);
         }
     };
 
 
     // handle an output message (execute_result, display_data, etc.)
     Kernel.prototype._handle_output_message = function (msg) {
         var callbacks = this.get_callbacks_for_msg(msg.parent_header.msg_id);
         if (!callbacks || !callbacks.iopub) {
             return;
         }
         var callback = callbacks.iopub.output;
         if (callback) {
             callback(msg);
         }
     };
 
     // dispatch IOPub messages to respective handlers.
     // each message type should have a handler.
     Kernel.prototype._handle_iopub_message = function (e) {
         var msg = $.parseJSON(e.data);
 
         var handler = this.get_iopub_handler(msg.header.msg_type);
         if (handler !== undefined) {
             handler(msg);
         }
     };
 
 
     Kernel.prototype._handle_input_request = function (e) {
         var request = $.parseJSON(e.data);
         var header = request.header;
         var content = request.content;
         var metadata = request.metadata;
         var msg_type = header.msg_type;
         if (msg_type !== 'input_request') {
             console.log("Invalid input request!", request);
             return;
         }
         var callbacks = this.get_callbacks_for_msg(request.parent_header.msg_id);
         if (callbacks) {
             if (callbacks.input) {
                 callbacks.input(request);
             }
         }
     };
 
     // Backwards compatability.
     IPython.Kernel = Kernel;
 
     return {'Kernel': Kernel};
 });