feat: add init task to pip-install mounted edx-platform

TODO details

Closes openedx-unsupported/wg-developer-experience#152

changelog.d/20230111_143421_kdmc_egg_info_init_task.md

@@ -0,0 +1,10 @@
+<!--
+Create a changelog entry for every new user-facing change. Please respect the following instructions:
+- Indicate breaking changes by prepending an explosion 💥 character.
+- Prefix your changes with either [Bugfix], [Improvement], [Feature], [Security], [Deprecation].
+- You may optionally append "(by @<author>)" at the end of the line, where "<author>" is either one (just one)
+  of your GitHub username, real name or affiliated organization. These affiliations will be displayed in
+  the release notes for every release.
+-->
+
+- [Improvement] Before, Open edX developers needed to pip-install requirements when bind-mounting a local copy of edx-platform the first time. Now, they can just launch the bind-mounted platform instead: ``tutor ... launch --mount=edx-platform`` (by @kdmccormick).

docs/dev.rst

@@ -200,7 +200,7 @@ Setting up a development environment for edx-platform
 
 Following the instructions :ref:`above <bind_mounts>` on how to bind-mount directories from the host above, you may mount your own `edx-platform <https://github.com/openedx/edx-platform/>`__ fork in your containers by running::
 
-    tutor dev start -d --mount=/path/to/edx-platform lms
+    tutor dev launch -d --mount=/path/to/edx-platform
 
 But to achieve that, you will have to make sure that your fork works with Tutor.
 
@@ -211,16 +211,17 @@ Then, you should run the following commands::
     # Run bash in the lms container
     tutor dev run --mount=/path/to/edx-platform lms bash
 
-    # Compile local python requirements
-    pip install --requirement requirements/edx/development.txt
-
     # Install nodejs packages in node_modules/
     npm clean-install
 
     # Rebuild static assets
     openedx-assets build --env=dev
 
-After running all these commands, your edx-platform repository will be ready for local development. To debug a local edx-platform repository, you can then add a `python breakpoint <https://docs.python.org/3/library/functions.html#breakpoint>`__ with ``breakpoint()`` anywhere in your code and run::
+After running all these commands, your edx-platform repository will be ready for local development. Going forward, for the same copy of edx-platform, you can use ``start`` instead of ``launch`` to start the platform more quickly::
+
+   tutor dev start -d --mount=/path/to/edx/platform
+
+To debug a local edx-platform repository, you can then add a `python breakpoint <https://docs.python.org/3/library/functions.html#breakpoint>`__ with ``breakpoint()`` anywhere in your code and run::
 
     tutor dev start --mount=/path/to/edx-platform lms
 

tutor/templates/jobs/init/lms.sh

@@ -1,5 +1,15 @@
+# When a local copy of edx-platform is bind-mounted, its
+# egg-info directory may be missing or out of date. (The
+# egg-info contains compiled Python entrypoint metadata, which
+# is used by XBlock, Django App Plugins, and console scripts.)
+# So, we regenerate egg-info by pip-installing this directory.
+ENTRY_POINTS_INFO=Open_edX.egg-info/entry_points.txt
+if [ ! -f "$ENTRY_POINTS_INFO" ] || [ "$ENTRY_POINTS_INFO" -ot setup.py ]; then
+  pip install -e .
+fi
 dockerize -wait tcp://{{ MYSQL_HOST }}:{{ MYSQL_PORT }} -timeout 20s
 
+# Wait for MongoDB.
 {%- if MONGODB_HOST.startswith("mongodb+srv://") %}
 echo "MongoDB is using SRV records, so we cannot wait for it to be ready"
 {%- else %}
@@ -8,6 +18,7 @@ dockerize -wait tcp://{{ MONGODB_HOST }}:{{ MONGODB_PORT }} -timeout 20s
 
 echo "Loading settings $DJANGO_SETTINGS_MODULE"
 
+# Run migrations.
 ./manage.py lms migrate
 
 # Create oauth2 apps for CMS SSO