Add hook for custom jupyterhub_config.py content

This lets extensions directly control how JupyterHub
is configured

integration-tests/plugins/simplest/tljh_simplest.py

@@ -35,4 +35,8 @@ def tljh_config_post_install(config):
     # Put an arbitrary marker we can test for
     config['simplest_plugin'] = {
         'present': True
-    }
+    }
+
+@hookimpl
+def tljh_custom_jupyterhub_config(c):
+    c.JupyterHub.authenticator_class = 'tmpauthenticator.TmpAuthenticator'

integration-tests/test_simplest_plugin.py

@@ -2,6 +2,7 @@
 Test simplest plugin
 """
 from ruamel.yaml import YAML
+import requests
 import os
 import subprocess
 from tljh.config import CONFIG_FILE, USER_ENV_PREFIX, HUB_ENV_PREFIX
@@ -52,3 +53,11 @@ def test_config_hook():
         data = yaml.load(f)
 
     assert data['simplest_plugin']['present']
+
+def test_jupyterhub_config_hook():
+    """
+    Test that tmpauthenticator is enabled by our custom config plugin
+    """
+    resp = requests.get('http://localhost/hub/tmplogin', allow_redirects=False)
+    assert resp.status_code == 302
+    assert resp.headers['Location'] == '/hub/spawn'

tljh/hooks.py

@@ -38,6 +38,15 @@ def tljh_extra_apt_packages():
     """
     pass
 
+@hookspec
+def tljh_custom_jupyterhub_config(c):
+    """
+    Provide custom traitlet based config to JupyterHub.
+
+    Anything you can put in `jupyterhub_config.py` can
+    be here.
+    """
+    pass
 
 @hookspec
 def tljh_config_post_install(config):

tljh/jupyterhub_config.py

@@ -6,7 +6,7 @@ from glob import glob
 import os
 
 from systemdspawner import SystemdSpawner
-from tljh import configurer, user
+from tljh import configurer, user, hooks
 from tljh.config import INSTALL_PREFIX, USER_ENV_PREFIX, CONFIG_DIR
 from tljh.normalize import generate_system_username
 from tljh.yaml import yaml
@@ -57,6 +57,9 @@ c.SystemdSpawner.unit_name_template = 'jupyter-{USERNAME}'
 tljh_config = configurer.load_config()
 configurer.apply_config(tljh_config, c)
 
+# Let TLJH hooks modify `c` if they want
+hooks.tljh_custom_jupyterhub_config(c)
+
 # Load arbitrary .py config files if they exist.
 # This is our escape hatch
 extra_configs = sorted(glob(os.path.join(CONFIG_DIR, 'jupyterhub_config.d', '*.py')))