This uses a cache and lets us update metadata about components and act on changes quickly (as compared to the current launcher registry which doesn't have provision for live updates). This removes the launcher registry, so operators should take care to update all launchers within a short period of time since the functionality to yield to a specific provider depends on it. Change-Id: I6409db0edf022d711f4e825e2b3eb487e7a79922changes/51/841651/6
James E. Blair
9 months ago
parent
10df93540f
commit
a612aa603c
@ -0,0 +1,16 @@
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# Copyright 2022 Acme Gating, LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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# Currently unused. Included here for future use similar to Zuul.
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MODEL_API = 0
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@ -0,0 +1,413 @@
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# Copyright 2020 BMW Group
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# Copyright 2022 Acme Gating, LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import sys
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import json
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import logging
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import threading
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import time
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from collections import defaultdict
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from kazoo.exceptions import NoNodeError
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from kazoo.protocol.states import EventType
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from nodepool.zk import ZooKeeperBase
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from nodepool.model_api import MODEL_API
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COMPONENTS_ROOT = "/nodepool/components"
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class GlobalRegistry:
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def __init__(self):
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self.registry = None
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def create(self, zk_client):
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if not self.registry:
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self.registry = ComponentRegistry(zk_client)
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return self.registry
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def clearRegistry(self):
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self.registry = None
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@property
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def model_api(self):
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return self.registry.model_api
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COMPONENT_REGISTRY = GlobalRegistry()
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class BaseComponent(ZooKeeperBase):
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"""
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Read/write component object.
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This object holds an offline cache of all the component's attributes. In
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case of an failed update to ZooKeeper the local cache will still hold the
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fresh values. Updating any attribute uploads all attributes to ZooKeeper.
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This enables this object to be used as local key/value store even if the
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ZooKeeper connection got lost.
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:arg client ZooKeeperClient: The ZooKeeperClient object to use, or
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None if this should be a read-only component.
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:arg hostname str: The component's hostname (multiple components with
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the same hostname may be registered; the registry will create unique
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nodes for each).
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"""
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# Component states
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INITIALIZING = "initializing"
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RUNNING = "running"
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PAUSED = "paused"
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STOPPED = "stopped"
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log = logging.getLogger("nodepool.Component")
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kind = "base"
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def __init__(self, client, hostname, version=None):
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# Ensure that the content is available before setting any other
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# attribute, because our __setattr__ implementation is relying on it.
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self.__dict__["content"] = {
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"hostname": hostname,
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"state": self.STOPPED,
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"kind": self.kind,
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"version": version,
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"model_api": 0,
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}
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super().__init__(client)
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self.path = None
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self._zstat = None
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self.register_lock = threading.Lock()
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def __getattr__(self, name):
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try:
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return self.content[name]
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except KeyError:
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raise AttributeError
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def __setattr__(self, name, value):
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# If the specified attribute is not part of our content dictionary,
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# fall back to the default __settattr__ behaviour.
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if name not in self.content.keys():
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return super().__setattr__(name, value)
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# Set the value in the local content dict
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self.content[name] = value
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with self.register_lock:
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if not self.path:
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self.log.error(
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"Path is not set on this component, did you forget "
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"to call register()?"
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)
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return
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# Update the ZooKeeper node
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content = json.dumps(self.content, sort_keys=True).encode("utf-8")
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try:
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zstat = self.kazoo_client.set(
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self.path, content, version=self._zstat.version
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)
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self._zstat = zstat
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except NoNodeError:
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self.log.error("Could not update %s in ZooKeeper", self)
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def register(self, model_api=MODEL_API):
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self.content['model_api'] = model_api
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with self.register_lock:
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path = "/".join([COMPONENTS_ROOT, self.kind, self.hostname])
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self.log.info("Registering component in ZooKeeper %s", path)
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self.path, self._zstat = self.kazoo_client.create(
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path,
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json.dumps(self.content, sort_keys=True).encode("utf-8"),
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makepath=True,
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ephemeral=True,
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sequence=True,
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# Also return the zstat, which is necessary to successfully
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# update the component.
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include_data=True,
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)
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if not COMPONENT_REGISTRY.registry:
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return
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# Wait 5 seconds for the component to appear in our local
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# cache so that operations which rely on lists of available
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# labels, etc, behave more synchronously.
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for x in range(50):
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registered = set()
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for kind, components in COMPONENT_REGISTRY.registry.all():
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for component in components:
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registered.add(component.path)
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if self.path in registered:
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return
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time.sleep(0.1)
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self.log.info("Did not see component registration for %s", path)
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def unregister(self):
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with self.register_lock:
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self.log.info("Unregistering component in ZooKeeper %s", self.path)
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self.client.on_connect_listeners.remove(self._onConnect)
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self.client.on_disconnect_listeners.remove(self._onDisconnect)
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self.client.on_reconnect_listeners.remove(self._onReconnect)
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self.kazoo_client.delete(self.path)
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# Break the object so we can't register again
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del self.register_lock
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# Wait 5 seconds for the component to appear in our local
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# cache so that operations which rely on lists of available
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# labels, etc, behave more synchronously.
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for x in range(50):
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registered = set()
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for kind, components in COMPONENT_REGISTRY.registry.all():
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for component in components:
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registered.add(component.path)
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if self.path not in registered:
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return
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time.sleep(0.1)
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self.log.info("Did not see component unregistration for %s", self.path)
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def _onReconnect(self):
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self.register()
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def updateFromDict(self, data):
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self.content.update(data)
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@classmethod
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def fromDict(cls, client, hostname, data):
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component = cls(client, hostname)
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component.updateFromDict(data)
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return component
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def __repr__(self):
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return f"<{self.__class__.__name__} {self.content}>"
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class LauncherComponent(BaseComponent):
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kind = "launcher"
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class BuilderComponent(BaseComponent):
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kind = "builder"
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# Not a process, but rather a provider-pool within a launcher.
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class PoolComponent(BaseComponent):
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kind = "pool"
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def __init__(self, *args, **kwargs):
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super().__init__(*args, **kwargs)
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self.initial_state = {
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"id": None,
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"provider_name": None,
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"supported_labels": [],
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}
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self.content.update(self.initial_state)
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class ComponentRegistry(ZooKeeperBase):
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"""A component registry is organized like:
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/nodepool/components/{kind}/{sequence}
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Where kind corresponds to one of the classes in this module, and
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sequence is a ZK sequence node with a prefix of the hostname in
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order to produce a unique id for multiple identical components
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running on the same host. An example path:
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/nodepool/components/scheduler/hostname0000000000
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Components are ephemeral nodes, and so if the actual service
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disconnects from ZK, the node will disappear.
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Component objects returned by this class are read-only; updating
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their attributes will not be reflected in ZooKeeper.
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"""
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log = logging.getLogger("nodepool.ComponentRegistry")
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COMPONENT_CLASSES = {
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"pool": PoolComponent,
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"launcher": LauncherComponent,
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"builder": BuilderComponent,
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}
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def __init__(self, client):
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super().__init__(client)
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self.client = client
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self._component_tree = None
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# kind -> hostname -> component
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self._cached_components = defaultdict(dict)
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self.model_api = None
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# Have we initialized enough to trust the model_api
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self._init = False
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# If we are already connected when the class is instantiated, directly
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# call the onConnect callback.
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if self.client.connected:
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self._onConnect()
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def _getComponentRoot(self, kind):
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return '/'.join([COMPONENTS_ROOT, kind])
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def _getComponentPath(self, kind, hostname):
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return '/'.join([COMPONENTS_ROOT, kind, hostname])
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def _onConnect(self):
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for kind in self.COMPONENT_CLASSES.keys():
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root = self._getComponentRoot(kind)
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self.kazoo_client.ensure_path(root)
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self.kazoo_client.ChildrenWatch(
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root, self._makeComponentRootWatcher(kind))
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self._init = True
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self._updateMinimumModelApi()
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def _makeComponentRootWatcher(self, kind):
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def watch(children, event=None):
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return self._onComponentRootUpdate(kind, children, event)
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return watch
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def _onComponentRootUpdate(self, kind, children, event):
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for hostname in children:
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component = self._cached_components[kind].get(hostname)
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if not component:
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self.log.info("Noticed new %s component %s", kind, hostname)
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root = self._getComponentPath(kind, hostname)
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self.kazoo_client.DataWatch(
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root, self._makeComponentWatcher(kind, hostname))
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def _makeComponentWatcher(self, kind, hostname):
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def watch(data, stat, event=None):
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return self._onComponentUpdate(kind, hostname, data, stat, event)
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return watch
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def _onComponentUpdate(self, kind, hostname, data, stat, event):
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if event:
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etype = event.type
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else:
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etype = None
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self.log.debug(
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"Registry %s got event %s for %s %s",
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self, etype, kind, hostname)
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if (etype in (None, EventType.CHANGED, EventType.CREATED) and
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data is not None):
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# Perform an in-place update of the cached component (if any)
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component = self._cached_components.get(kind, {}).get(hostname)
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d = json.loads(data.decode("utf-8"))
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self.log.info(
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"Component %s %s updated: %s",
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kind, hostname, d)
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if component:
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if (stat.version <= component._zstat.version):
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# Don't update to older data
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return
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component.updateFromDict(d)
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component._zstat = stat
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else:
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# Create a new component from the data structure
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# Get the correct kind of component
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# TODO (felix): KeyError on unknown component type?
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component_cls = self.COMPONENT_CLASSES[kind]
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# Pass in null ZK client to make a read-only component
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# instance.
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component = component_cls.fromDict(None, hostname, d)
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component.path = self._getComponentPath(kind, hostname)
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component._zstat = stat
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self._cached_components[kind][hostname] = component
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self._updateMinimumModelApi()
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elif (etype == EventType.DELETED or data is None):
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self.log.info(
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"Noticed %s component %s disappeared",
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kind, hostname)
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try:
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del self._cached_components[kind][hostname]
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except KeyError:
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# If it's already gone, don't care
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pass
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self._updateMinimumModelApi()
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# Return False to stop the datawatch
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return False
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def all(self, kind=None):
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"""Returns a list of components.
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If kind is None, then a list of tuples is returned, with each tuple
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being (kind, [list of components]).
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:arg kind str: The type of component to look up in the registry, or
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None to return all kinds
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"""
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if kind is None:
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return [(kind, list(components.values()))
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for (kind, components) in self._cached_components.items()]
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# Filter the cached components for the given kind
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return self._cached_components.get(kind, {}).values()
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def getMinimumModelApi(self):
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"""Get the minimum model API version of all currently connected
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components"""
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# Start with our own version in case we're the only component
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# and we haven't registered.
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version = MODEL_API
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for kind, components in self.all():
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for component in components:
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version = min(version, component.model_api)
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return version
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def _updateMinimumModelApi(self):
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if not self._init:
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return
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version = self.getMinimumModelApi()
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if version != self.model_api:
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self.log.info(f"System minimum data model version {version}; "
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f"this component {MODEL_API}")
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if self.model_api is None:
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if version < MODEL_API:
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self.log.info("The data model version of this component is "
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"newer than the rest of the system; this "
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"component will operate in compatability mode "
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"until the system is upgraded")
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elif version > MODEL_API:
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self.log.error("The data model version of this component is "
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"older than the rest of the system; "
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"exiting to prevent data corruption")
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sys.exit(1)
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else:
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if version > self.model_api:
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if version > MODEL_API:
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self.log.info("The data model version of this component "
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"is older than other components in the "
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"system, so other components will operate "
|
||||
"in a compability mode; upgrade this "
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"component as soon as possible to complete "
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"the system upgrade")
|
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elif version == MODEL_API:
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self.log.info("The rest of the system has been upgraded "
|
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"to the data model version of this "
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"component")
|
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elif version < self.model_api:
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self.log.error("A component with a data model version older "
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"than the rest of the system has been started; "
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"data corruption is very likely to occur.")
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# Should we exit here as well?
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self.model_api = version
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@ -0,0 +1,11 @@
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---
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||||
upgrade:
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||||
- |
|
||||
Due to an internal change in how Nodepool launchers communicate
|
||||
with each other, all launchers should be upgraded to the same
|
||||
version within a short period of time.
|
||||
|
||||
They will generally continue to work at different versions, but
|
||||
the mechanism that allows them to yield to specific providers when
|
||||
requested is being changed and so that will not function correctly
|
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unless they are upgraded near-simultaneously.
|
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Loading…
Reference in new issue