Merge pull request #87 from yuvipanda/escape-hatch

Load arbitrary .py config files from a conf.d dir

docs/index.rst

@@ -83,6 +83,7 @@ Topic guides provide in-depth explanations of specific topics.
    topic/installer-actions
    topic/tljh-config
    topic/authenticator-configuration
+   topic/escape-hatch
 
 
 Troubleshooting

docs/topic/escape-hatch.rst

@@ -0,0 +1,17 @@
+.. _topic/escape-hatch:
+
+========================================
+Custom ``jupyterhub_config.py`` snippets
+========================================
+
+Sometimes you need to customize TLJH in ways that are not officially supported.
+We provide an easy escape hatch for those cases with a ``jupyterhub_conf.d``
+directory that lets you load multiple ``jupyterhub_config.py`` snippets for
+your configuration. You need to create the directory when you use it for
+the first time.
+
+Any files in ``/opt/tljh/jupyterhub_config.d`` that end in ``.py`` will be
+loaded in alphabetical order as python files to provide configuration for
+JupyterHub. Any config that can go in a regular ``jupyterhub_config.py``
+file is valid in these files. They will be loaded *after* any of the config
+options specified with ``tljh-config`` are loaded.

tljh/jupyterhub_config.py

@@ -3,8 +3,8 @@ JupyterHub config for the littlest jupyterhub.
 """
 import copy
 import os
-
 import yaml
+from glob import glob
 
 from systemdspawner import SystemdSpawner
 from tljh import user, configurer
@@ -47,3 +47,9 @@ if os.path.exists(config_overrides_path):
 else:
     config_overrides = {}
 configurer.apply_config(config_overrides, c)
+
+# Load arbitrary .py config files if they exist.
+# This is our escape hatch
+extra_configs = sorted(glob(os.path.join(INSTALL_PREFIX, 'jupyterhub_config.d', '*.py')))
+for ec in extra_configs:
+    load_subconfig(ec)