Project api hooks

cassini/core.py

@@ -18,6 +18,7 @@
     Dict,
     ClassVar,
     Optional,
+    Callable,
     cast,
 )
 from warnings import warn
@@ -831,6 +832,14 @@ def __init__(
         self._rank_map: Dict[Type[TierABC], int] = {}
         self._hierarchy: List[Type[TierABC]] = []
 
+        self.__before_setup_files__: List[Callable[[Project], None]] = []
+        self.__after_setup_files__: List[Callable[[Project], None]] = []
+
+        self.__before_launch__: List[
+            Callable[[Project, Union[LabApp, None]], None]
+        ] = []
+        self.__after_launch__: List[Callable[[Project, Union[LabApp, None]], None]] = []
+
         self.hierarchy: List[Type[TierABC]] = hierarchy
 
         project_folder_path = Path(project_folder).resolve()
@@ -950,6 +959,9 @@ def setup_files(self) -> TierABC:
 
         Will put everything you need in `project_folder` to get going.
         """
+        for func in self.__before_setup_files__:
+            func(self)
+
         home = self.home
 
         if home.exists():
@@ -978,6 +990,9 @@ def setup_files(self) -> TierABC:
         home.setup_files()
         print("Success")
 
+        for func in self.__after_setup_files__:
+            func(self)
+
         return home
 
     def launch(
@@ -998,6 +1013,9 @@ def launch(
         patch_pythonpath : bool
             Add `self.project_folder` to the `PYTHONPATH`? (defaults to `True`)
         """
+        for func in self.__before_launch__:
+            func(self, app)
+
         self.setup_files()
 
         if patch_pythonpath:
@@ -1012,6 +1030,9 @@ def launch(
 
         app.launch_instance()
 
+        for func in self.__after_launch__:
+            func(self, app)
+
         return app
 
     def parse_name(self, name: str) -> Tuple[str, ...]:

tests/test_extensibility.py

@@ -0,0 +1,60 @@
+from unittest.mock import Mock
+from typing import Any
+
+from utils import patch_project
+
+
+def test_setup_files_hook(patch_project):
+    Tier, project = patch_project
+
+    home = project.home
+    home.exists = lambda: False
+
+    call_order = []
+
+    def stamp_call(label):
+        def wrapped(*args, **kwargs):
+            call_order.append(label)
+        return wrapped
+
+    home.setup_files = Mock(side_effect=stamp_call('home'))
+
+    before_mock = Mock(side_effect=stamp_call('before'))
+    after_mock = Mock(side_effect=stamp_call('after'))
+
+    project.__before_setup_files__.append(before_mock)
+    project.__after_setup_files__.append(after_mock)
+
+    project.setup_files()
+
+    assert before_mock.call_args.args == (project,)
+    assert after_mock.call_args.args == (project,)
+    assert call_order == ['before', 'home', 'after']
+
+
+def test_launch_hook(patch_project):
+    Tier, project = patch_project
+    project.exists = lambda self: False
+
+    call_order = []
+
+    def stamp_call(label):
+        def wrapped(*args, **kwargs):
+            call_order.append(label)
+        return wrapped
+
+    project.setup_files = Mock(side_effect=stamp_call('project'))
+
+    before_mock = Mock(side_effect=stamp_call('before'))
+    after_mock = Mock(side_effect=stamp_call('after'))
+
+    project.__before_launch__.append(before_mock)
+    project.__after_launch__.append(after_mock)
+
+    app = Mock()
+
+    project.launch(app)
+
+    assert before_mock.call_args.args == (project, app)
+    assert after_mock.call_args.args == (project, app)
+    assert call_order == ['before', 'project', 'after']