Async kernels update

lib/config.coffee

@@ -0,0 +1,59 @@
+module.exports =
+    languageMappings:
+        title: "Language Mappings"
+        description: 'Some packages may change the name of the grammar for
+                      a language (e.g. "Python" -> "Python Django"). That
+                      leaves Hydrogen unable to figure out what kernel to
+                      use for your code.
+
+                      This field should be valid JSON mapping a nonstandard
+                      language name to a standard one, e.g.
+
+                      ```{"Python Django": "python", "Ruby (Rails)": "ruby"}```'
+        type: 'string'
+        default: '{}'
+    grammarToKernel:
+        description: 'JSON mappings between specific kernel and a
+                      language/grammar. This value is updated automatically
+                      by the "switch kernel" command. If you switch from
+                      python2 to python3, python3 will be used the next time
+                      you open a Python file. You probably shouldn\'t
+                      change this by hand.'
+        type: 'string'
+        default: '{}'
+    kernelspec:
+        title: "Kernel Spec"
+        description: 'This field is autogenerated on every launch in up-to-date environments,
+        also you can regenerate this with hydrogen:update-kernels command.
+        
+        
+        ```
+        Kernel specs as reported by:
+          $ jupyter kernelspecs list --json
+            or
+          $ ipython kernelspecs list --json
+        ```
+
+        If this commands fails in your environment you can use this field to specify your kernels, like:
+        ```
+        {
+          "kernelspecs": {
+            "ijavascript": {
+              "spec": {
+                "display_name": "IJavascript",
+                "env": {},
+                "argv": [
+                  "node",
+                  "/home/user/node_modules/ijavascript/lib/kernel.js",
+                  "--protocol=5.0",
+                  "{connection_file}"
+                ],
+                "language": "javascript"
+              },
+              "resources_dir": "/home/user/node_modules/ijavascript/images"
+            }
+          }
+        }
+        ```'
+        type: 'string'
+        default: '{}'

lib/kernel-manager.coffee

@@ -4,29 +4,35 @@ child_process = require 'child_process'
 Kernel = require './kernel'
 
 module.exports = KernelManager =
-    availableKernels:  []
     runningKernels: {}
-
+    kernelsUpdatedOnce: false
+
     getAvailableKernels: ->
-        @availableKernels = @getConfigJson 'kernelspecs', @availableKernels
-        @updateKernels() unless @availableKernels.length
-        @availableKernels
+        kernels = _.pluck @getConfigJson('kernelspec', []).kernelspecs, 'spec'
+        @updateKernels() unless @kernelsUpdatedOnce
+        kernels
 
     updateKernels: ->
+        @kernelsUpdatedOnce = true
         save = (out) =>
             try
-                kernelspec = JSON.parse(out).kernelspecs
+                kernelspec = JSON.parse(out)
             catch e
-                atom.notifications.addError "Can't parse neither 'ipython kernelspecs nor 'jupyter kernelspecs'"
+                unless @getAvailableKernels().length
+                    return atom.notifications.addError """
+Can't parse neither 'ipython kernelspecs nor 'jupyter kernelspecs'
+""", detail: """Use kernelspec option in Hydrogen options OR update
+your ipython/jupyter to version that supports kernelspec option:
+$ jupyter kernelspec list --json || ipython kernelspec list --json
+"""
 
-            @availableKernels = _.pluck kernelspec, 'spec'
-            @setConfigJson 'kernelspecs', @availableKernels
+            @setConfigJson 'kernelspec', kernelspec
             atom.notifications.addInfo 'Hydrogen Kernels updated:',
-              detail: (_.pluck @availableKernels, 'display_name').join('\n')
+              detail: (_.pluck @getAvailableKernels(), 'display_name').join('\n')
 
-        child_process.exec 'jupyter kernelspec list --json', (e, stdout, stderr) ->
+        child_process.exec 'jupter kernelspec list --json', (e, stdout, stderr) ->
             return save stdout unless e
-            child_process.exec 'ipython kernelspec list --json', (e, stdout, stderr) ->
+            child_process.exec 'iython kernelspec list --json', (e, stdout, stderr) ->
                 save stdout
 
     getRunningKernels: ->

lib/main.coffee

@@ -13,55 +13,7 @@ WatchLanguagePicker = require './watch-language-picker'
 AutocompleteProvider = require './autocomplete-provider'
 
 module.exports = Hydrogen =
-    config:
-        languageMappings:
-            title: "Language Mappings"
-            description: 'Some packages may change the name of the grammar for
-                          a language (e.g. "Python" -> "Python Django"). That
-                          leaves Hydrogen unable to figure out what kernel to
-                          use for your code.
-
-                          This field should be valid JSON mapping a nonstandard
-                          language name to a standard one, e.g.
-
-                          {"Python Django": "python", "Ruby (Rails)": "ruby"}'
-            type: 'string'
-            default: '{}'
-        grammarToKernel:
-            description: 'JSON mappings between specific kernel and a
-                          language/grammar. This value is updated automatically
-                          by the "switch kernel" command. If you switch from
-                          python2 to python3, python3 will be used the next time
-                          you open a Python file. You probably shouldn\'t
-                          change this by hand.'
-            type: 'string'
-            default: '{}'
-        kernelspecs:
-            title: "Kernel Specs"
-            description: 'Kernel specs as reported by:
-
-                            $ jupyter kernelspecs list --json
-
-                          E.g.:
-
-                            {
-                              "ijavascript": {
-                                "spec": {
-                                  "display_name": "IJavascript",
-                                  "env": {},
-                                  "argv": [
-                                    "node",
-                                    "/home/user/node_modules/ijavascript/lib/kernel.js",
-                                    "--protocol=5.0",
-                                    "{connection_file}"
-                                  ],
-                                  "language": "javascript"
-                                },
-                                "resources_dir": "/home/user/node_modules/ijavascript/images"
-                              }
-                            }'
-            type: 'string'
-            default: '{}'
+    config: require './config'
 
 
     subscriptions: null
@@ -83,7 +35,7 @@ module.exports = Hydrogen =
             'hydrogen:select-watch-kernel': => @showWatchLanguagePicker()
             'hydrogen:add-watch': => @watchSidebar.addWatchFromEditor()
             'hydrogen:remove-watch': => @watchSidebar.removeWatch()
-            'hydrogen:update-kernels': -> KernelManager.updateKernels true
+            'hydrogen:update-kernels': -> KernelManager.updateKernels()
 
         @subscriptions.add atom.commands.add 'atom-workspace',
             'hydrogen:clear-results': => @clearResultBubbles()