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"""The Landscape monitor plugin system."""
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from logging import info
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from twisted.internet.defer import succeed
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from landscape.lib.dbus_util import method
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from landscape.lib.log import log_failure
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from landscape.log import format_object
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from landscape.plugin import BrokerClientPluginRegistry, Plugin, BrokerPlugin
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BUS_NAME = "com.canonical.landscape.Monitor"
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OBJECT_PATH = "/com/canonical/landscape/Monitor"
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class MonitorDBusObject(BrokerPlugin):
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"""A DBUS object which provides an interface to the Landscape Monitor."""
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object_path = OBJECT_PATH
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ping = method(IFACE_NAME)(BrokerPlugin.ping)
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exit = method(IFACE_NAME)(BrokerPlugin.exit)
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message = method(IFACE_NAME)(BrokerPlugin.message)
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class MonitorPluginRegistry(BrokerClientPluginRegistry):
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from landscape.broker.client import BrokerClient
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class Monitor(BrokerClient):
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"""The central point of integration in the Landscape monitor."""
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def __init__(self, broker, reactor, config, bus,
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persist, persist_filename=None,
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super(MonitorPluginRegistry, self).__init__(broker)
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def __init__(self, reactor, config, persist, persist_filename=None,
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super(Monitor, self).__init__(reactor)
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self.reactor = reactor
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self.config = config
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self.persist = persist
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def exchange(self):
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"""Call C{exchange} on all plugins."""
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super(MonitorPluginRegistry, self).exchange()
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super(Monitor, self).exchange()
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class MonitorPlugin(Plugin):
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@cvar persist_name: If specified as a string, a C{_persist} attribute
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will be available after registration.
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XXX This class is no longer very useful and should be cleaned out
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def register(self, registry):
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super(MonitorPlugin, self).register(registry)
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if self.persist_name is not None:
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self._persist = registry.persist.root_at(self.persist_name)
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def call_on_accepted(self, type, callable, *args, **kwargs):
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def acceptance_changed(acceptance):
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return callable(*args, **kwargs)
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self.registry.reactor.call_on(("message-type-acceptance-changed",
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type), acceptance_changed)
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class DataWatcher(MonitorPlugin):
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A utility for plugins which send data to the Landscape server
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which does not constantly change. New messages will only be sent
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when the result of get_data() has changed since the last time it
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Subclasses should provide a get_data method, and message_type,
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message_key, and persist_name class attributes.
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def get_message(self):
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Construct a message with the latest data, or None, if the data
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has not changed since the last call.
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data = self.get_data()
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if self._persist.get("data") != data:
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self._persist.set("data", data)
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return {"type": self.message_type, self.message_key: data}
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def send_message(self, urgent):
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message = self.get_message()
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if message is not None:
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info("Queueing a message with updated data watcher info "
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"for %s.", format_object(self))
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result = self.registry.broker.send_message(message, urgent=urgent)
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def persist_data(message_id):
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result.addCallback(persist_data)
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result.addErrback(log_failure)
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def persist_data(self):
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Sub-classes that need to defer the saving of persistent data
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should override this method.
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def exchange(self, urgent=False):
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Conditionally add a message to the message store if new data
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return self.registry.broker.call_if_accepted(self.message_type,
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self.send_message, urgent)
added
removed
landscape/monitor/monitor.py
