# Copyright 2013 Rackspace, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import os
import random
import select
import threading
import time
from oslo_log import log
import pkg_resources
from stevedore import extension
from wsgiref import simple_server
from ironic_python_agent.api import app
from ironic_python_agent import encoding
from ironic_python_agent import errors
from ironic_python_agent.extensions import base
from ironic_python_agent import hardware
from ironic_python_agent import inspector
from ironic_python_agent import ironic_api_client
def _time():
"""Wraps time.time() for simpler testing."""
return time.time()
[docs]class IronicPythonAgentStatus(encoding.Serializable):
"""Represents the status of an agent."""
serializable_fields = ('started_at', 'version')
def __init__(self, started_at, version):
self.started_at = started_at
self.version = version
[docs]class IronicPythonAgentHeartbeater(threading.Thread):
"""Thread that periodically heartbeats to Ironic."""
# If we could wait at most N seconds between heartbeats (or in case of an
# error) we will instead wait r x N seconds, where r is a random value
# between these multipliers.
min_jitter_multiplier = 0.3
max_jitter_multiplier = 0.6
# Exponential backoff values used in case of an error. In reality we will
# only wait a portion of either of these delays based on the jitter
# multipliers.
initial_delay = 1.0
max_delay = 300.0
backoff_factor = 2.7
def __init__(self, agent):
"""Initialize the heartbeat thread.
:param agent: an :class:`ironic_python_agent.agent.IronicPythonAgent`
instance.
"""
super(IronicPythonAgentHeartbeater, self).__init__()
self.agent = agent
self.api = ironic_api_client.APIClient(agent.api_url,
agent.driver_name)
self.log = log.getLogger(__name__)
self.error_delay = self.initial_delay
self.reader = None
self.writer = None
[docs] def run(self):
"""Start the heartbeat thread."""
# The first heartbeat happens immediately
self.log.info('starting heartbeater')
interval = 0
self.agent.set_agent_advertise_addr()
self.reader, self.writer = os.pipe()
p = select.poll()
p.register(self.reader, select.POLLIN)
try:
while True:
if p.poll(interval * 1000):
if os.read(self.reader, 1) == 'a':
break
self.do_heartbeat()
interval_multiplier = random.uniform(
self.min_jitter_multiplier,
self.max_jitter_multiplier)
interval = self.agent.heartbeat_timeout * interval_multiplier
log_msg = 'sleeping before next heartbeat, interval: {0}'
self.log.info(log_msg.format(interval))
finally:
os.close(self.reader)
os.close(self.writer)
self.reader = None
self.writer = None
[docs] def do_heartbeat(self):
"""Send a heartbeat to Ironic."""
try:
self.api.heartbeat(
uuid=self.agent.get_node_uuid(),
advertise_address=self.agent.advertise_address
)
self.error_delay = self.initial_delay
self.log.info('heartbeat successful')
except Exception:
self.log.exception('error sending heartbeat')
self.error_delay = min(self.error_delay * self.backoff_factor,
self.max_delay)
[docs] def force_heartbeat(self):
os.write(self.writer, 'b')
[docs] def stop(self):
"""Stop the heartbeat thread."""
if self.writer is not None:
self.log.info('stopping heartbeater')
os.write(self.writer, 'a')
return self.join()
[docs]class IronicPythonAgent(base.ExecuteCommandMixin):
"""Class for base agent functionality."""
def __init__(self, api_url, advertise_address, listen_address,
ip_lookup_attempts, ip_lookup_sleep, network_interface,
lookup_timeout, lookup_interval, driver_name, standalone):
super(IronicPythonAgent, self).__init__()
self.ext_mgr = extension.ExtensionManager(
namespace='ironic_python_agent.extensions',
invoke_on_load=True,
propagate_map_exceptions=True,
invoke_kwds={'agent': self},
)
self.api_url = api_url
self.driver_name = driver_name
self.api_client = ironic_api_client.APIClient(self.api_url,
self.driver_name)
self.listen_address = listen_address
self.advertise_address = advertise_address
self.version = pkg_resources.get_distribution('ironic-python-agent')\
.version
self.api = app.VersionSelectorApplication(self)
self.heartbeater = IronicPythonAgentHeartbeater(self)
self.heartbeat_timeout = None
self.log = log.getLogger(__name__)
self.started_at = None
self.node = None
# lookup timeout in seconds
self.lookup_timeout = lookup_timeout
self.lookup_interval = lookup_interval
self.ip_lookup_attempts = ip_lookup_attempts
self.ip_lookup_sleep = ip_lookup_sleep
self.network_interface = network_interface
self.standalone = standalone
[docs] def get_status(self):
"""Retrieve a serializable status.
:returns: a :class:`ironic_python_agent.agent.IronicPythonAgent`
instance describing the agent's status.
"""
return IronicPythonAgentStatus(
started_at=self.started_at,
version=self.version
)
[docs] def set_agent_advertise_addr(self):
"""Set advertised IP address for the agent, if not already set.
If agent's advertised IP address is still default (None), try to
find a better one. If the agent's network interface is None, replace
that as well.
:raises: LookupAgentInterfaceError if a valid network interface cannot
be found.
:raises: LookupAgentIPError if an IP address could not be found
"""
if self.advertise_address[0] is not None:
return
if self.network_interface is None:
ifaces = self.get_agent_network_interfaces()
else:
ifaces = [self.network_interface]
attempts = 0
while (attempts < self.ip_lookup_attempts):
for iface in ifaces:
found_ip = hardware.dispatch_to_managers('get_ipv4_addr',
iface)
if found_ip is not None:
self.advertise_address = (found_ip,
self.advertise_address[1])
self.network_interface = iface
return
attempts += 1
time.sleep(self.ip_lookup_sleep)
raise errors.LookupAgentIPError('Agent could not find a valid IP '
'address.')
[docs] def get_agent_network_interfaces(self):
"""Get a list of all network interfaces available.
Excludes loopback connections.
:returns: list of network interfaces available.
:raises: LookupAgentInterfaceError if a valid interface could not
be found.
"""
iface_list = [iface.serialize()['name'] for iface in
hardware.dispatch_to_managers('list_network_interfaces')]
iface_list = [name for name in iface_list if 'lo' not in name]
if len(iface_list) == 0:
raise errors.LookupAgentInterfaceError('Agent could not find a '
'valid network interface.')
else:
return iface_list
[docs] def get_node_uuid(self):
"""Get UUID for Ironic node.
If the agent has not yet heartbeated to Ironic, it will not have
the UUID and this will raise an exception.
:returns: A string containing the UUID for the Ironic node.
:raises: UnknownNodeError if UUID is unknown.
"""
if self.node is None or 'uuid' not in self.node:
raise errors.UnknownNodeError()
return self.node['uuid']
[docs] def list_command_results(self):
"""Get a list of command results.
:returns: list of :class:`ironic_python_agent.extensions.base.
BaseCommandResult` objects.
"""
return list(self.command_results.values())
[docs] def get_command_result(self, result_id):
"""Get a specific command result by ID.
:returns: a :class:`ironic_python_agent.extensions.base.
BaseCommandResult` object.
:raises: RequestedObjectNotFoundError if command with the given ID
is not found.
"""
try:
return self.command_results[result_id]
except KeyError:
raise errors.RequestedObjectNotFoundError('Command Result',
result_id)
[docs] def force_heartbeat(self):
if not self.standalone:
self.heartbeater.force_heartbeat()
[docs] def run(self):
"""Run the Ironic Python Agent."""
# Get the UUID so we can heartbeat to Ironic. Raises LookupNodeError
# if there is an issue (uncaught, restart agent)
self.started_at = _time()
# Cached hw managers at runtime, not load time. See bug 1490008.
hardware.load_managers()
if not self.standalone:
# Inspection should be started before call to lookup, otherwise
# lookup will fail due to unknown MAC.
uuid = inspector.inspect()
content = self.api_client.lookup_node(
hardware_info=hardware.dispatch_to_managers(
'list_hardware_info'),
timeout=self.lookup_timeout,
starting_interval=self.lookup_interval,
node_uuid=uuid)
self.node = content['node']
self.heartbeat_timeout = content['heartbeat_timeout']
wsgi = simple_server.make_server(
self.listen_address[0],
self.listen_address[1],
self.api,
server_class=simple_server.WSGIServer)
if not self.standalone:
# Don't start heartbeating until the server is listening
self.heartbeater.start()
try:
wsgi.serve_forever()
except BaseException:
self.log.exception('shutting down')
if not self.standalone:
self.heartbeater.stop()