Allow sorting of Startup and ShutdownPlugins

src/octoprint/plugin/__init__.py

@@ -152,7 +152,7 @@ def plugin_settings(plugin_key, defaults=None, get_preprocessors=None, set_prepr
 	return PluginSettings(settings(), plugin_key, defaults=defaults, get_preprocessors=get_preprocessors, set_preprocessors=set_preprocessors)
 
 
-def call_plugin(types, method, args=None, kwargs=None, callback=None, error_callback=None):
+def call_plugin(types, method, args=None, kwargs=None, callback=None, error_callback=None, sorting_context=None):
 	"""
 	Helper method to invoke the indicated ``method`` on all registered plugin implementations implementing the
 	indicated ``types``. Allows providing method arguments and registering callbacks to call in case of success
@@ -198,7 +198,7 @@ def call_plugin(types, method, args=None, kwargs=None, callback=None, error_call
 	if kwargs is None:
 		kwargs = dict()
 
-	plugins = plugin_manager().get_implementations(*types)
+	plugins = plugin_manager().get_implementations(*types, sorting_context=sorting_context)
 	for plugin in plugins:
 		if hasattr(plugin, method):
 			try:

src/octoprint/plugin/core.py

@@ -1046,7 +1046,7 @@ class PluginManager(object):
 			result[h[0]] = h[1]
 		return result
 
-	def get_implementations(self, *types):
+	def get_implementations(self, *types, **kwargs):
 		"""
 		Get all mixin implementations that implement *all* of the provided ``types``.
 
@@ -1057,6 +1057,8 @@ class PluginManager(object):
 		    list: A list of all found implementations
 		"""
 
+		sorting_context = kwargs.get("sorting_context", None)
+
 		result = None
 
 		for t in types:
@@ -1067,10 +1069,26 @@ class PluginManager(object):
 				result = result.intersection(implementations)
 
 		if result is None:
-			return dict()
-		return [impl[1] for impl in result]
+			return []
 
-	def get_filtered_implementations(self, f, *types):
+		found_implementations = [impl[1] for impl in result]
+
+		if sorting_context is not None:
+			def sort_func(impl):
+				sorting_value = None
+				if isinstance(impl, SorteablePlugin):
+					try:
+						sorting_value = impl.get_sorting_key(sorting_context)
+					except:
+						self.logger.exception("Error while trying to retrieve sorting order for plugin {}".format(impl._identifier))
+
+				return sorting_value is None, sorting_value
+
+			found_implementations = sorted(found_implementations, key=sort_func)
+
+		return found_implementations
+
+	def get_filtered_implementations(self, f, sorting_context=None, *types):
 		"""
 		Get all mixin implementation that implementat *all* of the provided ``types`` and match the provided filter `f`.
 
@@ -1083,7 +1101,7 @@ class PluginManager(object):
 		"""
 
 		assert callable(f)
-		implementations = self.get_implementations(*types)
+		implementations = self.get_implementations(*types, sorting_context=sorting_context)
 		return filter(f, implementations)
 
 	def get_helpers(self, name, *helpers):
@@ -1242,6 +1260,10 @@ class Plugin(object):
 class RestartNeedingPlugin(Plugin):
 	pass
 
+class SorteablePlugin(Plugin):
+	def get_sorting_key(self, context=None):
+		return None
+
 class PluginNeedsRestart(Exception):
 	def __init__(self, name):
 		Exception.__init__(self)

src/octoprint/plugin/types.py

@@ -18,7 +18,7 @@ __license__ = 'GNU Affero General Public License http://www.gnu.org/licenses/agp
 __copyright__ = "Copyright (C) 2014 The OctoPrint Project - Released under terms of the AGPLv3 License"
 
 
-from .core import (Plugin, RestartNeedingPlugin)
+from .core import (Plugin, RestartNeedingPlugin, SorteablePlugin)
 
 
 class OctoPrintPlugin(Plugin):
@@ -99,7 +99,7 @@ class OctoPrintPlugin(Plugin):
 class ReloadNeedingPlugin(Plugin):
 	pass
 
-class StartupPlugin(OctoPrintPlugin):
+class StartupPlugin(OctoPrintPlugin, SorteablePlugin):
 	"""
 	The ``StartupPlugin`` allows hooking into the startup of OctoPrint. It can be used to start up additional services
 	on or just after the startup of the server.
@@ -127,7 +127,7 @@ class StartupPlugin(OctoPrintPlugin):
 		pass
 
 
-class ShutdownPlugin(OctoPrintPlugin):
+class ShutdownPlugin(OctoPrintPlugin, SorteablePlugin):
 	"""
 	The ``ShutdownPlugin`` allows hooking into the shutdown of OctoPrint. It's usually used in conjunction with the
 	:class:`StartupPlugin` mixin, to cleanly shut down additional services again that where started by the :class:`StartupPlugin`

src/octoprint/server/__init__.py

@@ -417,7 +417,8 @@ class Server(object):
 		# run our startup plugins
 		octoprint.plugin.call_plugin(octoprint.plugin.StartupPlugin,
 		                             "on_startup",
-		                             args=(self._host, self._port))
+		                             args=(self._host, self._port),
+		                             sorting_context="StartupPlugin.on_startup")
 
 		def call_on_startup(name, plugin):
 			implementation = plugin.get_implementation(octoprint.plugin.StartupPlugin)
@@ -437,7 +438,8 @@ class Server(object):
 			# control to the ioloop
 			def work():
 				octoprint.plugin.call_plugin(octoprint.plugin.StartupPlugin,
-				                             "on_after_startup")
+				                             "on_after_startup",
+				                             sorting_context="StartupPlugin.on_after_startup")
 
 				def call_on_after_startup(name, plugin):
 					implementation = plugin.get_implementation(octoprint.plugin.StartupPlugin)
@@ -458,7 +460,8 @@ class Server(object):
 			observer.stop()
 			observer.join()
 			octoprint.plugin.call_plugin(octoprint.plugin.ShutdownPlugin,
-			                             "on_shutdown")
+			                             "on_shutdown",
+			                             sorting_context="ShutdownPlugin.on_shutdown")
 			self._logger.info("Goodbye!")
 		atexit.register(on_shutdown)