use Docker Compose for the development environment

docker-compose.yml

@@ -0,0 +1,11 @@
+version: "3.9"
+services:
+  hub:
+    build: ./integration-tests
+    privileged: true
+    volumes:
+      - type: bind
+        source: .
+        target: /srv/src
+    ports:
+      - "12000:80"

docs/contributing/dev-setup.rst

@@ -10,46 +10,27 @@ The easiest & safest way to develop & test TLJH is with `Docker <https://www.doc
    `their website <https://www.docker.com/community-edition>`_.
 
 #. Clone the `git repo <https://github.com/jupyterhub/the-littlest-jupyterhub>`_ (or your fork of it).
-#. Build a docker image that has a functional systemd in it.
+#. Build the Docker image and start the container.
 
    .. code-block:: bash
 
-      docker build -t tljh-systemd . -f integration-tests/Dockerfile
+      docker-compose up --build
 
-#. Run a docker container with the image in the background, while bind mounting
-   your TLJH repository under ``/srv/src``.
-
-   .. code-block:: bash
-
-      docker run \
-        --privileged \
-        --detach \
-        --name=tljh-dev \
-        --publish 12000:80 \
-        --mount type=bind,source=$(pwd),target=/srv/src \
-        tljh-systemd
-
-#. Get a shell inside the running docker container.
-
-   .. code-block:: bash
-
-      docker exec -it tljh-dev /bin/bash
-
-#. Run the bootstrapper from inside the container (see step above):
+#. From another terminal, run the bootstrapper:
    The container image is already set up to default to a ``dev`` install, so
    it'll install from your local repo rather than from github.
 
-   .. code-block:: console
+   .. code-block:: bash
 
-      python3 /srv/src/bootstrap/bootstrap.py --admin admin
+      docker-compose exec hub python3 /srv/src/bootstrap/bootstrap.py --admin admin
 
   Or, if you would like to setup the admin's password during install,
   you can use this command (replace "admin" with the desired admin username
   and "password" with the desired admin password):
 
-   .. code-block:: console
+   .. code-block:: bash
 
-      python3 /srv/src/bootstrap/bootstrap.py --admin admin:password
+      docker-compose exec hub python3 /srv/src/bootstrap/bootstrap.py --admin admin:password
 
    The primary hub environment will also be in your PATH already for convenience.
 
@@ -61,15 +42,26 @@ The easiest & safest way to develop & test TLJH is with `Docker <https://www.doc
    you changed.
 
    * If you changed the ``bootstrap/bootstrap.py`` script or any of its dependencies,
-     you can test it by running ``python3 /srv/src/bootstrap/bootstrap.py``.
+     you can test it by running:
+
+      .. code-block:: bash
+
+         docker-compose exec hub python3 /srv/src/bootstrap/bootstrap.py
 
    * If you changed the ``tljh/installer.py`` code (or any of its dependencies),
-     you can test it by running ``python3 -m tljh.installer``.
+     you can test it by running:
+
+      .. code-block:: bash
+
+         docker-compose exec hub python3 -m tljh.installer
 
    * If you changed ``tljh/jupyterhub_config.py``, ``tljh/configurer.py``,
      ``/opt/tljh/config/`` or any of their dependencies, you only need to
-     restart jupyterhub for them to take effect. ``tljh-config reload hub``
-     should do that.
+     restart jupyterhub for them to take effect:
+
+      .. code-block:: bash
+
+         docker-compose exec hub tljh-config reload hub
 
 :ref:`troubleshooting/logs` has information on looking at various logs in the container
 to debug issues you might have.