Make it possible to run plugin subcommands

CHANGELOG.md

@@ -4,7 +4,8 @@ Note: Breaking changes between versions are indicated by "💥".
 
 ## Unreleased
 
-- [Improvement] Move ``-r/--root`` option to parent command level
+- [Feature] Add plugin subcommands
+- 💥[Improvement] Move ``-r/--root`` option to parent command level
 - [Bugfix] Fix course about page visibility
 - [Improvement] Print gunicorn access logs in the console
 - 💥[Improvement] Get rid of the `indexcourses` and `portainer` command (#269)

docs/plugins.rst

@@ -175,6 +175,43 @@ Example::
 
 With the above declaration, you can store plugin-specific templates in the ``templates/myplugin`` folder next to the ``plugin.py`` file.
 
+``command``
+~~~~~~~~~~~
+
+A plugin can provide custom command line commands. Commands are assumed to be `click.Command <https://click.palletsprojects.com/en/7.x/api/#commands>`__ objects.
+
+Example::
+    
+    import click
+    
+    @click.command(help="I'm a plugin command")
+    def command():
+        click.echo("Hello from myplugin!")
+
+Any user who installs the ``myplugin`` plugin can then run::
+    
+    $ tutor myplugin
+    Hello from myplugin!
+
+You can even define subcommands by creating `command groups <https://click.palletsprojects.com/en/7.x/api/#click.Group>`__::
+    
+    import click
+    
+    @click.group(help="I'm a plugin command group")
+    def command():
+        pass
+    
+    @click.command(help="I'm a plugin subcommand")
+    def dosomething():
+        click.echo("This subcommand is awesome")
+
+This would allow any user to run::
+
+    $ tutor myplugin dosomething
+    This subcommand is awesome
+    
+See the official `click documentation <https://click.palletsprojects.com/en/7.x/>`__ for more information.
+
 Creating a new plugin
 ---------------------
 

tutor/commands/cli.py

@@ -11,7 +11,7 @@ from .dev import dev
 from .images import images_command
 from .k8s import k8s
 from .local import local
-from .plugins import plugins_command
+from .plugins import plugins_command, add_plugin_commands
 from .ui import ui
 from .webui import webui
 from ..__about__ import __version__
@@ -66,6 +66,7 @@ cli.add_command(ui)
 cli.add_command(webui)
 cli.add_command(print_help)
 cli.add_command(plugins_command)
+add_plugin_commands(cli)
 
 if __name__ == "__main__":
     main()

tutor/commands/plugins.py

@@ -62,14 +62,15 @@ def disable(context, plugin_names):
     )
 
 
-def iter_extra_plugin_commands():
+def add_plugin_commands(command_group):
     """
-    TODO document this. Merge with plugins.iter_commands? It's good to keepo
-    click-related stuff outside of the plugins module.
+    Add commands provided by all plugins to the given command group. Each command is
+    added with a name that is equal to the plugin name.
     """
     for plugin_name, command in plugins.iter_commands():
-        command.name = plugin_name
-        yield command
+        if isinstance(command, click.Command):
+            command.name = plugin_name
+            command_group.add_command(command)
 
 
 plugins_command.add_command(list_command)

tutor/plugins.py

@@ -160,9 +160,7 @@ def iter_templates(config):
 
 def iter_commands():
     """
-    TODO doesn't this slow down the cli? (we need to import all plugins)
-    Also, do we really need the `config` argument? Do we want to make it possible for disabled plugins to be loaded?
-    TODO document this
+    Iterate over all plugins that provide a `command` attribute.
     """
     for plugin_name, plugin in iter_installed():
         command = getattr(plugin, "command", None)