Merge pull request #111 from yuvipanda/more-parameters

Allow easily augmenting the pod config before launching

kubespawner/spawner.py

@@ -27,7 +27,7 @@
 import escapism
 
 from kubespawner.traitlets import Callable
-from kubespawner.utils import request_maker, k8s_url
+from kubespawner.utils import request_maker, k8s_url, Callable
 from kubespawner.objects import make_pod, make_pvc
 from kubespawner.reflector import PodReflector
 
@@ -438,6 +438,28 @@ def _hub_connect_port_default(self):
         """
     )
 
+    modify_pod_hook = Callable(
+        None,
+        allow_none=True,
+        config=True,
+        help="""
+        Callable to augment the Pod object before launching.
+
+        Expects a callable that takes two parameters:
+
+           1. The spawner object that is doing the spawning
+           2. The Pod object that is to be launched
+
+        You should modify the Pod object and return it.
+
+        This can be a coroutine if necessary. When set to none, no augmenting is done.
+
+        This is very useful if you want to modify the pod being launched dynamically.
+        Note that the spawner object can change between versions of KubeSpawner and JupyterHub,
+        so be careful relying on this!
+        """
+    )
+
     volumes = List(
         [],
         config=True,
@@ -909,6 +931,8 @@ def start(self):
         # FIXME: Have better / cleaner retry logic!
         retry_times = 4
         pod = yield self.get_pod_manifest()
+        if self.modify_pod_hook:
+            pod = yield gen.maybe_future(self.modify_pod_hook(self, pod))
         for i in range(retry_times):
             try:
                 yield self.asynchronize(

kubespawner/utils.py

@@ -5,6 +5,7 @@
 import yaml
 
 from tornado.httpclient import HTTPRequest
+from traitlets import TraitType
 
 
 def request_maker():
@@ -130,3 +131,19 @@ def k8s_url(namespace, kind, name=None):
     if name is not None:
         url_parts.append(name)
     return '/' + '/'.join(url_parts)
+
+
+class Callable(TraitType):
+    """A trait which is callable.
+    Notes
+    -----
+    Classes are callable, as are instances
+    with a __call__() method."""
+
+    info_text = 'a callable'
+
+    def validate(self, obj, value):
+        if callable(value):
+            return value
+        else:
+            self.error(obj, value)