1 files changed, 71 insertions, 0 deletions
diff --git a/src/pybind/mgr/dashboard/plugins/__init__.py b/src/pybind/mgr/dashboard/plugins/__init__.py
new file mode 100644
index 000000000..edc0b6594
--- /dev/null
+++ b/src/pybind/mgr/dashboard/plugins/__init__.py
@@ -0,0 +1,71 @@
+# -*- coding: utf-8 -*-
+
+import abc
+
+from .pluggy import HookimplMarker, HookspecMarker, PluginManager
+
+
+class Interface(object, metaclass=abc.ABCMeta):
+    pass
+
+
+class Mixin(object):
+    pass
+
+
+class DashboardPluginManager(object):
+    def __init__(self, project_name):
+        self.__pm = PluginManager(project_name)
+        self.__add_spec = HookspecMarker(project_name)
+        self.__add_abcspec = lambda *args, **kwargs: abc.abstractmethod(
+            self.__add_spec(*args, **kwargs))
+        self.__add_hook = HookimplMarker(project_name)
+
+    pm = property(lambda self: self.__pm)
+    hook = property(lambda self: self.pm.hook)
+
+    add_spec = property(lambda self: self.__add_spec)
+    add_abcspec = property(lambda self: self.__add_abcspec)
+    add_hook = property(lambda self: self.__add_hook)
+
+    def add_interface(self, cls):
+        assert issubclass(cls, Interface)
+        self.pm.add_hookspecs(cls)
+        return cls
+
+    @staticmethod
+    def final(func):
+        setattr(func, '__final__', True)
+        return func
+
+    def add_plugin(self, plugin):
+        """ Provides decorator interface for PluginManager.register():
+            @PLUGIN_MANAGER.add_plugin
+            class Plugin(...):
+                ...
+        Additionally it checks whether the Plugin instance has all Interface
+        methods implemented and marked with add_hook decorator.
+        As a con of this approach, plugins cannot call super() from __init__()
+        """
+        assert issubclass(plugin, Interface)
+        from inspect import getmembers, ismethod
+        for interface in plugin.__bases__:
+            for method_name, _ in getmembers(interface, predicate=ismethod):
+                if hasattr(getattr(interface, method_name), '__final__'):
+                    continue
+
+                if self.pm.parse_hookimpl_opts(plugin, method_name) is None:
+                    raise NotImplementedError(
+                        "Plugin '{}' implements interface '{}' but existing"
+                        " method '{}' is not declared added as hook".format(
+                            plugin.__name__,
+                            interface.__name__,
+                            method_name))
+        self.pm.register(plugin())
+        return plugin
+
+
+PLUGIN_MANAGER = DashboardPluginManager("ceph-mgr.dashboard")
+
+# Load all interfaces and their hooks
+from . import interfaces  # noqa pylint: disable=C0413,W0406