Introduce ZooKeeper containers.

asab/application.py

@@ -336,15 +336,15 @@ def _hup(self):
 
 	# Modules
 
-	def add_module(self, module_class, *args, **kwargs):
+	def add_module(self, module_class):
 		""" Load a new module. """
 
 		for module in self.Modules:
 			if isinstance(module, module_class):
 				# Already loaded and registered
 				return
 
-		module = module_class(self, *args, **kwargs)
+		module = module_class(self)
 		self.Modules.append(module)
 
 		asyncio.ensure_future(module.initialize(self), loop=self.Loop)

asab/zookeeper/__init__.py

@@ -1,6 +1,7 @@
 import logging
 
 from .service import ZooKeeperService
+from .container import ZooKeeperContainer
 
 from ..abc.module import Module
 
@@ -13,6 +14,6 @@
 
 class Module(Module):
 
-	def __init__(self, app, config_section="zookeeper"):
+	def __init__(self, app):
 		super().__init__(app)
-		self.Service = ZooKeeperService(app, "asab.ZooKeeperService", config_section)
+		self.Service = ZooKeeperService(app, "asab.ZooKeeperService")

asab/zookeeper/container.py

@@ -0,0 +1,61 @@
+import aiozk
+import asyncio
+import json
+
+from ..config import ConfigObject
+
+
+class ZooKeeperContainer(ConfigObject):
+	"""
+	ZooKeeperContainer connects to Zookeeper via aiozk client:
+	https://zookeeper.apache.org/
+	https://pypi.org/project/aiozk/
+	"""
+
+	ConfigDefaults = {
+		"urls": "zookeeper:12181",
+		"path": "/asab",
+	}
+
+	def __init__(self, app, config_section_name, config=None):
+		super().__init__(config_section_name=config_section_name, config=config)
+		self.App = app
+		self.ConfigSectionName = config_section_name
+		self.ZooKeeper = aiozk.ZKClient(self.Config["urls"])
+		self.ZooKeeperPath = self.Config["path"]
+
+	async def initialize(self, app):
+		await self.ZooKeeper.start()
+		await self.ZooKeeper.ensure_path(self.ZooKeeperPath)
+
+	async def finalize(self, app):
+		await self.ZooKeeper.close()
+
+	async def advertise(self, data, encoding="utf-8"):
+		if isinstance(data, dict):
+			data = json.dumps(data).encode(encoding)
+		elif isinstance(data, str):
+			data = data.encode(encoding)
+		elif asyncio.iscoroutinefunction(data):
+			data = await data
+		elif callable(data):
+			data = data()
+
+		return await self.ZooKeeper.create(
+			"{}/i".format(self.ZooKeeperPath),
+			data=data,
+			sequential=True,
+			ephemeral=True
+		)
+
+	async def get_children(self):
+		return await self.ZooKeeper.get_children(self.ZooKeeperPath)
+
+	async def get_data(self, child, encoding="utf-8"):
+		raw_data = await self.get_raw_data(child)
+		if raw_data is None:
+			return {}
+		return json.loads(raw_data.decode(encoding))
+
+	async def get_raw_data(self, child):
+		return await self.ZooKeeper.get_data("{}/{}".format(self.ZooKeeperPath, child))

asab/zookeeper/service.py

@@ -1,10 +1,10 @@
-import aiozk
 import asyncio
-import json
 
 from ..abc.service import Service
 from ..config import Config
 
+from .container import ZooKeeperContainer
+
 
 class ZooKeeperService(Service):
 	"""
@@ -14,49 +14,63 @@ class ZooKeeperService(Service):
 	"""
 
 	Config.add_defaults({
-		"zookeeper": {
-			"urls": "zookeeper:12181",
-			"path": "/asab",
+		"zookeeper": {  # create a default container, also ensures backward compatibility
+			"urls": "",  # zookeeper:12181
+			"path": "",  # /asab
 		}
 	})
 
 	def __init__(self, app, service_name, config_section="zookeeper"):
 		super().__init__(app, service_name)
-		self.ZooKeeper = aiozk.ZKClient(Config[config_section]["urls"])
-		self.ZooKeeperPath = Config[config_section]["path"]
+		self.App = app
+		self.DefaultContainer = None
+		self.Containers = {}
+		self.Futures = []
 
 	async def initialize(self, app):
-		await self.ZooKeeper.start()
-		await self.ZooKeeper.ensure_path(self.ZooKeeperPath)
+		# Create a default container
+		# Default container ensures backward compatibility
+		urls = Config["zookeeper"]["urls"]
+		if len(urls) > 0:
+			self.DefaultContainer = ZooKeeperContainer(app, "zookeeper")
+			await self.DefaultContainer.initialize(app)
 
 	async def finalize(self, app):
-		await self.ZooKeeper.close()
-
-	async def advertise(self, data, encoding="utf-8"):
-		if isinstance(data, dict):
-			data = json.dumps(data).encode(encoding)
-		elif isinstance(data, str):
-			data = data.encode(encoding)
-		elif asyncio.iscoroutinefunction(data):
-			data = await data
-		elif callable(data):
-			data = data()
-
-		return await self.ZooKeeper.create(
-			"{}/i".format(self.ZooKeeperPath),
-			data=data,
-			sequential=True,
-			ephemeral=True
-		)
-
-	async def get_children(self):
-		return await self.ZooKeeper.get_children(self.ZooKeeperPath)
-
-	async def get_data(self, child, encoding="utf-8"):
-		raw_data = await self.get_raw_data(child)
-		if raw_data is None:
-			return {}
-		return json.loads(raw_data.decode(encoding))
-
-	async def get_raw_data(self, child):
-		return await self.ZooKeeper.get_data("{}/{}".format(self.ZooKeeperPath, child))
+		if len(self.Futures) > 0:
+			await asyncio.wait(self.Futures)
+		if self.DefaultContainer is not None:
+			await self.DefaultContainer.finalize(app)
+		for containers in self.Containers.values():
+			await containers.finalize(app)
+
+	def register_container(self, container):
+		self.Containers[container.ConfigSectionName] = container
+		self.Futures.append(asyncio.ensure_future(container.initialize(self.App)))
+
+	async def advertise(self, data, encoding="utf-8", container=None):
+		if container is None:
+			container = self.DefaultContainer
+		if container is None:
+			raise RuntimeError("The container must be specified.")
+		return await container.advertise(data, encoding)
+
+	async def get_children(self, container=None):
+		if container is None:
+			container = self.DefaultContainer
+		if container is None:
+			raise RuntimeError("The container must be specified.")
+		return await container.get_children()
+
+	async def get_data(self, child, encoding="utf-8", container=None):
+		if container is None:
+			container = self.DefaultContainer
+		if container is None:
+			raise RuntimeError("The container must be specified.")
+		return await container.get_data(child, encoding)
+
+	async def get_raw_data(self, child, container=None):
+		if container is None:
+			container = self.DefaultContainer
+		if container is None:
+			raise RuntimeError("The container must be specified.")
+		return await container.get_raw_data(child)