Add kube profile spawner

Reference jupyterhub#135

kubespawner/__init__.py

@@ -14,5 +14,6 @@
 instead of the more verbose import kubespawner.spawner.KubeSpawner.
 """
 from kubespawner.spawner import KubeSpawner
+from kubespawner.profile_spawner import KubeProfileSpawner
 
-__all__ = [KubeSpawner]
+__all__ = [KubeSpawner, KubeProfileSpawner]

kubespawner/profile_spawner.py

@@ -0,0 +1,74 @@
+from traitlets import (
+    Instance, Type, Tuple, List, Dict, Integer, Unicode, Float, Any
+)
+from jupyterhub.spawner import Spawner
+from kubespawner.spawner import KubeSpawner
+
+class KubeProfileSpawner(KubeSpawner):
+
+    UNDEFINED_DISPLAY_NAME = "?? undefined 'display_name' ??"
+
+    form_template = Unicode(
+        """<label for="profile">Please select a profile for your Jupyter instance:</label>
+        <select class="form-control" name="profile" required autofocus>
+        {input_template}
+        </select>
+        """,
+        config = True,
+        help = """Template to use to construct options_form text. {input_template} is replaced with
+            the result of formatting input_template against each item in the profiles list."""
+        )
+
+    input_template = Unicode("""
+        <option value="{key}" {first}>{display}</option>""",
+        config = True,
+        help = """Template to construct {input_template} in form_template. This text will be formatted
+            against each item in the profiles list, in order, using the following key names:
+            ( display, key, type ) for the first three items in the tuple, and additionally
+            first = "checked" (taken from first_template) for the first item in the list, so that
+            the first item starts selected."""
+        )
+
+    first_template = Unicode('selected',
+        config=True,
+        help="Text to substitute as {first} in input_template"
+        )
+
+    options_form = Unicode()
+
+    single_user_profile_list = List(
+        trait = Dict(),
+        default_value = [],
+        minlen = 1,
+        config = True,
+        help = """List of profiles to offer for selection. Signature is:
+            List(Dict()), where each item is a dictionary that has two keys:
+            - 'display_name': the human readable display name
+            - 'kubespawner_overrride': a dictionary with overrides to apply to the KubeSpawner 
+              settings."""
+        )
+
+    def __init__(self, *args, **kwargs):
+        Spawner.__init__(self, *args, **kwargs)
+
+    def _options_form_default(self):
+        temp_keys = [
+            {
+                'display': p.get('display_name', self.UNDEFINED_DISPLAY_NAME), 
+                'key': i, 
+                'first': '',
+        } for i, p in enumerate(self.single_user_profile_list)]
+        temp_keys[0]['first'] = self.first_template
+        text = ''.join([ self.input_template.format(**tk) for tk in temp_keys ])
+        return self.form_template.format(input_template=text)
+
+    def options_from_form(self, formdata):
+        # Default to first profile if somehow none is provided
+        selected_profile = int(formdata.get('profile',[0])[0])
+        options = self.single_user_profile_list[selected_profile]
+        self.log.debug("Applying KubeSpawner override for profile '%s'", 
+                  options.get('display_name', self.UNDEFINED_DISPLAY_NAME))
+        kubespawner_overrride = options.get('kubespawner_overrride', {})
+        for k, v in kubespawner_overrride.items():
+            setattr(self, k, v)
+        return options