fix: add mechanism to discover external wutta subcommands

for sake of wuttasync, e.g. `wutta import-csv`

src/wuttjamaican/cli/__init__.py

@@ -33,5 +33,9 @@ This (``wuttjamaican.cli``) namespace exposes the following:
 
 from .base import wutta_typer, make_typer
 
-# TODO: is this the best we can do, to register available commands?
+# nb. must bring in all modules for discovery to work
 from . import make_uuid
+
+# discover more commands, installed via other packages
+from .base import typer_eager_imports
+typer_eager_imports(wutta_typer)

src/wuttjamaican/cli/base.py

@@ -41,6 +41,7 @@ import typer
 from typing_extensions import Annotated
 
 from wuttjamaican.conf import make_config
+from wuttjamaican.util import load_entry_points
 
 
 def make_cli_config(ctx: typer.Context):
@@ -84,6 +85,43 @@ def typer_callback(
     ctx.wutta_config = make_cli_config(ctx)
 
 
+def typer_eager_imports(
+        group: [typer.Typer, str]):
+    """
+    Eagerly import all modules which are registered as having
+    :term:`subcommands <subcommand>` belonging to the given group
+    (i.e. top-level :term:`command`).
+
+    This is used to locate subcommands which may be defined by
+    multiple different packages.  It is mostly needed for the main
+    ``wutta`` command, since e.g. various extension packages may
+    define additional subcommands for it.
+
+    Most custom apps will define their own top-level command and some
+    subcommands, but will have no need to "discover" additional
+    subcommands defined elsewhere.  Hence you normally would not need
+    to call this function.
+
+    However if you wish to define a ``wutta`` subcommand(s), you
+    *would* need to register the entry point for your module(s)
+    containing the subcommand(s) like so (in ``pyproject.toml``):
+
+    .. code-block:: ini
+
+       [project.entry-points."wutta.typer_imports"]
+       poser = "poser.commands"
+
+    Note that the ``wutta.typer_imports`` above indicates you are
+    registering a module which defines ``wutta`` subcommands.  The
+    ``poser`` name is arbitrary but should match your package name.
+
+    :param group: Typer group command, or the name of one.
+    """
+    if isinstance(group, typer.Typer):
+        group = group.info.name
+    load_entry_points(f'{group}.typer_imports')
+
+
 def make_typer(**kwargs):
     """
     Create a Typer command instance, per Wutta conventions.

tests/cli/test_base.py

@@ -2,7 +2,7 @@
 
 import os
 from unittest import TestCase
-from unittest.mock import MagicMock
+from unittest.mock import MagicMock, patch
 
 import typer
 
@@ -32,6 +32,15 @@ class TestTyperCallback(TestCase):
         self.assertEqual(ctx.wutta_config.files_read, [example_conf])
 
 
+class TestTyperEagerImports(TestCase):
+
+    def test_basic(self):
+        typr = mod.make_typer(name='foobreezy')
+        with patch.object(mod, 'load_entry_points') as load_entry_points:
+            mod.typer_eager_imports(typr)
+            load_entry_points.assert_called_once_with('foobreezy.typer_imports')
+
+
 class TestMakeTyper(TestCase):
 
     def test_basic(self):