Get app subcommands from pkg_resources entrypoints.

Author: jcb91

README.md

@@ -19,6 +19,7 @@ Changes
 0.3.0
 -----
 
+* Get `jupyter contrib` app subcommands from `pkg_resources` entrypoints
 * Add `_maybe_copy` and `_should_copy` to nbextensions private API, since the
   `logger` keyword arg was only added after notebook 4.1
 

src/jupyter_contrib_core/application.py

@@ -9,6 +9,7 @@
 
 import sys
 
+import pkg_resources
 from jupyter_core.application import JupyterApp
 
 from jupyter_contrib_core import __version__
@@ -22,6 +23,28 @@ class JupyterContribApp(JupyterApp):
     description = (
         'community-contributed spice for Jupyter Interactive Computing')
 
+    def __init__(self, *args, **kwargs):
+        self._refresh_subcommands()
+        super(JupyterContribApp, self).__init__(*args, **kwargs)
+
+    def _refresh_subcommands(self):
+        """
+        Finds subcommands which have registered entry points.
+
+        Each entry point is a function which returns a subcommands-style dict,
+        where the keys are the name of the subcommand, and the values are
+        2-tuples containing the sub-application class, and a description of the
+        subcommand's action.
+        """
+        group = 'jupyter_contrib_core.app.subcommands'
+        new_subcommands = {}
+        # import ipdb; ipdb.set_trace()
+        for entrypoint in pkg_resources.iter_entry_points(group=group):
+            get_subcommands_dict = entrypoint.load()
+            new_subcommands.update(get_subcommands_dict())
+        self.subcommands.clear()
+        self.subcommands.update(new_subcommands)
+
     def start(self):
         """Perform the App's actions as configured"""
         super(JupyterContribApp, self).start()