[Issue: 169] Frontend hardcodes python3

Dockerfile.kernel

@@ -1,7 +1,7 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 
-FROM jupyter/pyspark-notebook:0017b56d93c9
+FROM jupyter/all-spark-notebook:0017b56d93c9
 
 RUN pip install jupyter_kernel_gateway==0.5.0
 # install ipywidgets 5.x

client/js/dashboard.js

@@ -58,7 +58,7 @@ if (Element && !Element.prototype.matches) {
         _registerKernelErrorHandler(kernel);
 
         // initialize an ipywidgets manager
-        var widgetManager = new WidgetManager(kernel, _consumeMessage);
+        var widgetManager = new WidgetManager(kernel, Config.kernelname, _consumeMessage);
 
         // initialize Declarative Widgets library
         var widgetsReady = _initDeclWidgets();

client/js/kernel.js

@@ -25,7 +25,7 @@ var Services = require('jupyter-js-services');
         var kernelOptions = {
             baseUrl: kernelUrl,
             wsUrl: kernelUrl.replace(/^http/, 'ws'),
-            name: 'python3',
+            name: '', // Set by API when making POST request to kernel gateway
             clientId: clientId,
             ajaxSettings: {
                 requestHeaders: {

client/js/widget-manager.js

@@ -10,7 +10,7 @@
 var $ = require('jquery');
 var Widgets = require('jupyter-js-widgets');
 
-    var WidgetManager = function(kernel, msgHandler) {
+    var WidgetManager = function(kernel, kernelname, msgHandler) {
         //  Call the base class.
         Widgets.ManagerBase.call(this);
 
@@ -24,17 +24,21 @@ var Widgets = require('jupyter-js-widgets');
         // Register the comm target
         this.commManager.register_target(this.comm_target_name, this.handle_comm_open.bind(this));
 
-        // Validate the version requested by the backend.
-        var validate = (function validate() {
-            this.validateVersion().then(function(valid) {
-                if (!valid) {
-                    console.warn('Widget frontend version does not match the backend.');
-                }
-            }).catch(function(err) {
-                console.error('Could not cross validate the widget frontend and backend versions.', err);
-            });
-        }).bind(this);
-        validate();
+        // Validate the version requested by the backend -- required for ipywidgets
+        // If kernel name is not defined, default to python3
+        kernelname = kernelname.toLowerCase();
+        if (!kernelname || kernelname === 'python3' || kernelname === 'python2') {
+            var validate = (function validate() {
+                this.validateVersion().then(function(valid) {
+                    if (!valid) {
+                        console.warn('Widget frontend version does not match the backend.');
+                    }
+                }).catch(function(err) {
+                    console.error('Could not cross validate the widget frontend and backend versions.', err);
+                });
+            }).bind(this);
+            validate();
+        }
 
         this._shimWidgetsLibs();
     };

etc/notebooks/test/test_scala_hello_world.ipynb

@@ -0,0 +1,67 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false,
+    "urth": {
+     "dashboard": {
+      "layout": {
+       "col": 0,
+       "height": 4,
+       "row": 0,
+       "width": 4
+      }
+     }
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Hello World!\n"
+     ]
+    }
+   ],
+   "source": [
+    "println(\"Hello World!\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": true,
+    "urth": {
+     "dashboard": {
+      "hidden": true
+     }
+    }
+   },
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Apache_Toree",
+   "language": "",
+   "name": "apache_toree"
+  },
+  "language_info": {
+   "name": "scala"
+  },
+  "urth": {
+   "dashboard": {
+    "cellMargin": 10,
+    "defaultCellHeight": 20,
+    "layout": "grid",
+    "maxColumns": 12
+   }
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}

routes/api.js

@@ -14,6 +14,8 @@ var urljoin = require('url-join');
 var urlToDashboard = require('../app/url-to-dashboard');
 var WsRewriter = require('../app/ws-rewriter');
 
+var nbstore = require('../app/notebook-store');
+
 var kgUrl = config.get('KERNEL_GATEWAY_URL');
 var kgAuthToken = config.get('KG_AUTH_TOKEN');
 var kgBaseUrl = config.get('KG_BASE_URL');
@@ -40,12 +42,12 @@ function initWsProxy(server) {
     if (wsProxy) {
         return;
     }
-    
+
     var headers = null;
     if(kgAuthToken) {
-        // include the kg auth token if we have one
-        headers = {};
-        headers.Authorization = 'token ' + kgAuthToken;
+       // include the kg auth token if we have one
+       headers = {};
+       headers.Authorization = 'token ' + kgAuthToken;
     }
 
     wsProxy = new WsRewriter({
@@ -130,7 +132,7 @@ var removeSession = function(sessionId) {
 // configurations.
 router.post('/kernels', bodyParser.json({ type: 'text/plain' }), function(req, res) {
     var headers = {};
-    if(kgAuthToken) {
+    if (kgAuthToken) {
         headers['Authorization'] = 'token ' + kgAuthToken;
     }
 
@@ -139,42 +141,67 @@ router.post('/kernels', bodyParser.json({ type: 'text/plain' }), function(req, r
     initWsProxy(req.connection.server);
 
     // Forward the user object in the session to the kernel gateway.
-    if(config.get('KG_FORWARD_USER_AUTH') && req.user) {
+    if (config.get('KG_FORWARD_USER_AUTH') && req.user) {
         req.body.env = {
              KERNEL_USER_AUTH: JSON.stringify(req.user)
         };
     }
 
-    // Pass the (modified) request to the kernel gateway.
-    request({
-        url: urljoin(kgUrl, kgBaseUrl, '/api/kernels'),
-        method: 'POST',
-        headers: headers,
-        json: req.body
-    }, function(err, response, body) {
-        if(err) {
-            error('Error proxying kernel creation request:' + err.toString());
-            return res.status(500).end();
-        }
-        // Store the notebook path for use within the WS proxy.
-        var notebookPathHeader = req.headers['x-jupyter-notebook-path'];
-        var sessionId = req.headers['x-jupyter-session-id'];
-        if (!notebookPathHeader || !sessionId) {
-            error('Missing notebook path or session ID headers');
-            return res.status(500).end();
-        }
-        var matches = notebookPathHeader.match(/^\/(?:dashboards(-plain)?)?(.*)$/);
-        if (!matches) {
-            error('Invalid notebook path header');
-            return res.status(500).end();
-        }
+    // Get notebook path from request headers
+    var notebookPathHeader = req.headers['x-jupyter-notebook-path'];
+    var sessionId = req.headers['x-jupyter-session-id'];
+    if (!notebookPathHeader || !sessionId) {
+        error('Missing notebook path or session ID headers');
+        return res.status(500).end();
+    }
+
+    var matches = notebookPathHeader.match(/^\/(?:dashboards(-plain)?)?(.*)$/);
+    if (!matches) {
+        error('Invalid notebook path header');
+        return res.status(500).end();
+    } else {
+        var notebookPath = matches[2];
         // Store notebook path for later use
-        sessions[sessionId] = matches[2];
+        sessions[sessionId] = notebookPath;
 
-        // Pass the kernel gateway response back to the client.
-        res.set(response.headers);
-        res.status(response.statusCode).json(body);
-    });
+        // Retrieve notebook from store to pull out kernel name
+        nbstore.get(notebookPath)
+        .then(function success(notebook){
+
+            if (notebook.metadata.kernelspec.name) {
+                var kernelName = notebook.metadata.kernelspec.name;
+                debug('Notebook kernel name found: ' + kernelName);
+                if (kernelName === 'apache_toree') {
+                    kernelName = 'scala';
+                }
+                req.body.name = kernelName;
+            } else {
+                // Default to Python 3
+                debug('Notebook kernel name not found, defaulting to Python 3');
+                req.body.name = 'python3';
+            }
+            debug('Issuing request for kernel: ' + req.body);
+            // Pass the (modified) request to the kernel gateway.
+            request({
+                url: urljoin(kgUrl, kgBaseUrl, '/api/kernels'),
+                method: 'POST',
+                headers: headers,
+                json: req.body
+            }, function(err, response, body) {
+                if (err) {
+                    error('Error proxying kernel creation request:' + err.toString());
+                    return res.status(500).end();
+                }
+                // Pass the kernel gateway response back to the client.
+                res.set(response.headers);
+                res.status(response.statusCode).json(body);
+            });
+        })
+        .catch(function(err) {
+            error('Unknown notebook path: ' + notebookPath);
+            return res.status(500).end();
+        });
+    }
 });
 
 // Proxy all unhandled requests to the kernel gateway.

views/dashboard.handlebars

@@ -39,6 +39,7 @@
     (function() {
         var db = window.jupyter_dashboard = window.jupyter_dashboard || {};
         var Config = db.Config = db.Config || {};
+        Config.kernelname = "{{notebook.metadata.kernelspec.name}}";
         // values from notebook metadata
         {{#each notebook.metadata.urth.dashboard}}
             Config.{{@key}} = "{{this}}";