def get_configured_log(
self, channel="test-zk-log", context_name="unit:mysql/0"):
"""Get a log channel configured with a zk handler.
"""
log = logging.getLogger(channel)
log.setLevel(logging.DEBUG)
handler = ZookeeperHandler(self.client, context_name)
yield handler.open()
log.addHandler(handler)
returnValue(log)
def get_configured_log(self,
channel="test-zk-log",
context_name="unit:mysql/0"):
"""Get a log channel configured with a zk handler.
"""
log = logging.getLogger(channel)
log.setLevel(logging.DEBUG)
handler = ZookeeperHandler(self.client, context_name)
yield handler.open()
log.addHandler(handler)
returnValue(log)
class BaseAgent(object, service.Service):
name = "juju-agent-unknown"
client = None
# Flag when enabling persistent topology watches, testing aid.
_watch_enabled = True
# Distributed debug log handler
_debug_log_handler = None
@classmethod
def run(cls):
"""Runs the agent as a unix daemon.
Main entry point for starting an agent, parses cli options, and setups
a daemon using twistd as per options.
"""
parser = argparse.ArgumentParser()
cls.setup_options(parser)
config = parser.parse_args(namespace=TwistedOptionNamespace())
runner = AgentRunner(config)
agent = cls()
agent.configure(config)
runner.application = agent.as_app()
runner.run()
@classmethod
def setup_options(cls, parser):
"""Configure the argparse cli parser for the agent."""
return cls.setup_default_options(parser)
@classmethod
def setup_default_options(cls, parser):
"""Setup default twistd daemon and agent options.
This method is intended as a utility for subclasses.
@param parser an argparse instance.
@type C{argparse.ArgumentParser}
"""
setup_twistd_options(parser, cls)
setup_default_agent_options(parser, cls)
def as_app(self):
"""
Return the agent as a C{twisted.application.service.Application}
"""
app = service.Application(self.name)
self.setServiceParent(app)
return app
def configure(self, options):
"""Configure the agent to handle its cli options.
Invoked called before the service is started.
@param options
@type C{TwistedOptionNamespace} an argparse namespace corresponding
to a dict.
"""
if not options.get("zookeeper_servers"):
raise NoConnection("No zookeeper connection configured.")
if not os.path.exists(options.get("juju_directory", "")):
raise JujuError(
"Invalid juju-directory %r, does not exist." % (
options.get("juju_directory")))
if options["session_file"] is None:
raise JujuError("No session file specified")
self.config = options
@inlineCallbacks
def _kill_existing_session(self):
try:
# We might have died suddenly, in which case the session may
# still be alive. If this is the case, shoot it in the head, so
# it doesn't interfere with our attempts to recreate our state.
# (We need to be able to recreate our state *anyway*, and it's
# much simpler to force ourselves to recreate it every time than
# it is to mess around partially recreating partial state.)
client_id = load_client_id(self.config["session_file"])
if client_id is None:
return
temp_client = yield ZookeeperClient().connect(
self.config["zookeeper_servers"], client_id=client_id)
yield temp_client.close()
except zookeeper.ZooKeeperException:
# We don't really care what went wrong; just that we're not able
# to connect using the old session, and therefore we should be ok
# to start a fresh one without transient state hanging around.
pass
@inlineCallbacks
def connect(self):
"""Return an authenticated connection to the juju zookeeper."""
yield self._kill_existing_session()
self.client = yield ManagedClient().connect(
self.config["zookeeper_servers"])
save_client_id(
self.config["session_file"], self.client.client_id)
principals = self.config.get("principals", ())
for principal in principals:
self.client.add_auth("digest", principal)
# bug work around to keep auth fast
if principals:
yield self.client.exists("/")
returnValue(self.client)
def start(self):
"""Callback invoked on the agent's startup.
The agent will already be connected to zookeeper. Subclasses are
responsible for implementing.
"""
raise NotImplementedError
def stop(self):
"""Callback invoked on when the agent is shutting down."""
pass
# Twisted IService implementation, used for delegates to maintain naming
# conventions.
@inlineCallbacks
def startService(self):
yield self.connect()
# Start the global settings watch prior to starting the agent.
# Allows for debug log to be enabled early.
if self.get_watch_enabled():
yield self.start_global_settings_watch()
yield self.start()
@inlineCallbacks
def stopService(self):
try:
yield self.stop()
finally:
if self.client and self.client.connected:
self.client.close()
session_file = self.config["session_file"]
if os.path.exists(session_file):
os.unlink(session_file)
def set_watch_enabled(self, flag):
"""Set boolean flag for whether this agent should watching zookeeper.
This is mainly used for testing, to allow for setting up the
various data scenarios, before enabling an agent watch which will
be observing state.
"""
self._watch_enabled = bool(flag)
def get_watch_enabled(self):
"""Returns a boolean if the agent should be settings state watches.
The meaning of this flag is typically agent specific, as each
agent has separate watches they'd like to establish on agent specific
state within zookeeper. In general if this flag is False, the agent
should refrain from establishing a watch on startup. This flag is
typically used by tests to isolate and test the watch behavior
independent of the agent startup, via construction of test data.
"""
return self._watch_enabled
def start_global_settings_watch(self):
"""Start watching the runtime state for configuration changes."""
self.global_settings_state = GlobalSettingsStateManager(self.client)
return self.global_settings_state.watch_settings_changes(
self.on_global_settings_change)
@inlineCallbacks
def on_global_settings_change(self, change):
"""On global settings change, take action.
"""
if (yield self.global_settings_state.is_debug_log_enabled()):
yield self.start_debug_log()
else:
self.stop_debug_log()
@inlineCallbacks
def start_debug_log(self):
"""Enable the distributed debug log handler.
"""
if self._debug_log_handler is not None:
returnValue(None)
context_name = self.get_agent_name()
self._debug_log_handler = ZookeeperHandler(
self.client, context_name)
yield self._debug_log_handler.open()
log_root = logging.getLogger()
log_root.addHandler(self._debug_log_handler)
def stop_debug_log(self):
"""Disable any configured debug log handler.
"""
if self._debug_log_handler is None:
return
handler, self._debug_log_handler = self._debug_log_handler, None
log_root = logging.getLogger()
log_root.removeHandler(handler)
def get_agent_name(self):
"""Return the agent's name and context such that it can be identified.
Subclasses should override this to provide additional context and
unique naming.
"""
return self.__class__.__name__
def test_open_with_nonexisting_container_path(self):
handler = ZookeeperHandler(self.client, "unit:mysql/0")
# should not raise exception
yield handler.open()
exists = yield self.client.exists("/logs")
self.assertTrue(exists)
def test_open_with_existing_container_path(self):
yield self.client.create("/logs")
handler = ZookeeperHandler(self.client, "unit:mysql/0")
# should not raise exception
yield handler.open()
class BaseAgent(object, service.Service):
name = "juju-agent-unknown"
client = None
# Flag when enabling persistent topology watches, testing aid.
_watch_enabled = True
# Distributed debug log handler
_debug_log_handler = None
@classmethod
def run(cls):
"""Runs the agent as a unix daemon.
Main entry point for starting an agent, parses cli options, and setups
a daemon using twistd as per options.
"""
parser = argparse.ArgumentParser()
cls.setup_options(parser)
config = parser.parse_args(namespace=TwistedOptionNamespace())
runner = AgentRunner(config)
agent = cls()
agent.configure(config)
runner.application = agent.as_app()
runner.run()
@classmethod
def setup_options(cls, parser):
"""Configure the argparse cli parser for the agent."""
return cls.setup_default_options(parser)
@classmethod
def setup_default_options(cls, parser):
"""Setup default twistd daemon and agent options.
This method is intended as a utility for subclasses.
@param parser an argparse instance.
@type C{argparse.ArgumentParser}
"""
setup_twistd_options(parser, cls)
setup_default_agent_options(parser, cls)
def as_app(self):
"""
Return the agent as a C{twisted.application.service.Application}
"""
app = service.Application(self.name)
self.setServiceParent(app)
return app
def configure(self, options):
"""Configure the agent to handle its cli options.
Invoked called before the service is started.
@param options
@type C{TwistedOptionNamespace} an argparse namespace corresponding
to a dict.
"""
if not options.get("zookeeper_servers"):
raise NoConnection("No zookeeper connection configured.")
if not os.path.exists(options.get("juju_directory", "")):
raise JujuError("Invalid juju-directory %r, does not exist." %
(options.get("juju_directory")))
self.config = options
@inlineCallbacks
def connect(self):
"""Return an authenticated connection to the juju zookeeper."""
hosts = self.config["zookeeper_servers"]
self.client = yield ZookeeperClient().connect(hosts)
principals = self.config.get("principals", ())
for principal in principals:
self.client.add_auth("digest", principal)
# bug work around to keep auth fast
if principals:
yield self.client.exists("/")
returnValue(self.client)
def start(self):
"""Callback invoked on the agent's startup.
The agent will already be connected to zookeeper. Subclasses are
responsible for implementing.
"""
raise NotImplementedError
def stop(self):
"""Callback invoked on when the agent is shutting down."""
pass
# Twisted IService implementation, used for delegates to maintain naming
# conventions.
@inlineCallbacks
def startService(self):
yield self.connect()
yield self.start()
if self.get_watch_enabled():
yield self.start_global_settings_watch()
@inlineCallbacks
def stopService(self):
try:
yield self.stop()
finally:
if self.client and self.client.connected:
self.client.close()
def set_watch_enabled(self, flag):
"""Set boolean flag for whether this agent should watching zookeeper.
This is mainly used for testing, to allow for setting up the
various data scenarios, before enabling an agent watch which will
be observing state.
"""
self._watch_enabled = bool(flag)
def get_watch_enabled(self):
"""Returns a boolean if the agent should be settings state watches.
The meaning of this flag is typically agent specific, as each
agent has separate watches they'd like to establish on agent specific
state within zookeeper. In general if this flag is False, the agent
should refrain from establishing a watch on startup. This flag is
typically used by tests to isolate and test the watch behavior
independent of the agent startup, via construction of test data.
"""
return self._watch_enabled
def start_global_settings_watch(self):
"""Start watching the runtime state for configuration changes."""
self.global_settings_state = GlobalSettingsStateManager(self.client)
return self.global_settings_state.watch_settings_changes(
self.on_global_settings_change)
@inlineCallbacks
def on_global_settings_change(self, change):
"""On global settings change, take action.
"""
if (yield self.global_settings_state.is_debug_log_enabled()):
yield self.start_debug_log()
else:
self.stop_debug_log()
@inlineCallbacks
def start_debug_log(self):
"""Enable the distributed debug log handler.
"""
if self._debug_log_handler is not None:
returnValue(None)
context_name = self.get_agent_name()
self._debug_log_handler = ZookeeperHandler(self.client, context_name)
yield self._debug_log_handler.open()
log_root = logging.getLogger()
log_root.addHandler(self._debug_log_handler)
def stop_debug_log(self):
"""Disable any configured debug log handler.
"""
if self._debug_log_handler is None:
return
handler, self._debug_log_handler = self._debug_log_handler, None
log_root = logging.getLogger()
log_root.removeHandler(handler)
def get_agent_name(self):
"""Return the agent's name and context such that it can be identified.
Subclasses should override this to provide additional context and
unique naming.
"""
return self.__class__.__name__
def test_open_with_nonexisting_container_path(self):
handler = ZookeeperHandler(self.client, "unit:mysql/0")
# should not raise exception
yield handler.open()
exists = yield self.client.exists("/logs")
self.assertTrue(exists)
def test_open_with_existing_container_path(self):
yield self.client.create("/logs")
handler = ZookeeperHandler(self.client, "unit:mysql/0")
# should not raise exception
yield handler.open()