Add plugin registration init method

setup.cfg

@@ -31,5 +31,5 @@ where=src
 
 [options.entry_points]
 console_scripts =
-    deephaven-plugin-list-registrations = deephaven.plugin:list_registrations
-    deephaven-plugin-list-plugins = deephaven.plugin:list_plugins
+    deephaven-plugin-list-registrations = deephaven.plugin:list_registrations_console
+    deephaven-plugin-list-plugins = deephaven.plugin:list_plugins_console

src/deephaven/plugin/__init__.py

@@ -17,6 +17,11 @@ class Callback(abc.ABC):
         def register(self, plugin: Union[Plugin, Type[Plugin]]) -> None:
             pass
 
+    @classmethod
+    @abc.abstractmethod
+    def init(cls) -> None:
+        pass
+
     @classmethod
     @abc.abstractmethod
     def register_into(cls, callback: Callback) -> None:
@@ -50,6 +55,11 @@ def collect_registration_classes():
     return [e.load() for e in collect_registration_entrypoints()]
 
 
+def initialize_all():
+    for registration_cls in collect_registration_classes():
+        registration_cls.init()
+
+
 def register_all_into(callback: Registration.Callback):
     for registration_cls in collect_registration_classes():
         registration_cls.register_into(callback)
@@ -69,3 +79,19 @@ def list_plugins():
         plugins = registration_cls.collect_plugins()
         output += ''.join([f'\n    {plugin}' for plugin in plugins])
     print(output)
+
+
+def list_registrations_console():
+    """
+    Entrypoint for the console script deephaven-plugin-list-registrations
+    """
+    # note: don't need to initialize the registrations unless registering into
+    list_registrations()
+
+
+def list_plugins_console():
+    """
+    Entrypoint for the console script deephaven-plugin-list-plugins
+    """
+    initialize_all()
+    list_plugins()