ironic-python-agent/ironic_python_agent/agent.py
Riccardo Pittau d525f8a07f Making ironic-python-agent able to stop with python 3.x
The agent stop function will write a byte string 'a' to the pipe
as a signal for the run function to end process.
The run function is expecting a literal string.
In python 2.x the byte string will automatically be converted to
literal, while python 3.x won't do the conversion, causing the
process to never stop.
This patch will fix that behavior, allowing the IPA to correctly
stop using python 3.x.

Story: 2004928
Task: 29308
Change-Id: Iad16e8bed2436d961dea8ddaec1c2724225b4097
2019-02-04 09:55:08 +01:00

408 lines
15 KiB
Python

# 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 collections
import os
import random
import select
import socket
import threading
import time
from wsgiref import simple_server
import netaddr
from oslo_concurrency import processutils
from oslo_config import cfg
from oslo_log import log
from oslo_utils import netutils
import pkg_resources
from six.moves.urllib import parse as urlparse
from stevedore import extension
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
from ironic_python_agent import utils
LOG = log.getLogger(__name__)
# Time(in seconds) to wait for any of the interfaces to be up
# before lookup of the node is attempted
NETWORK_WAIT_TIMEOUT = 60
# Time(in seconds) to wait before reattempt
NETWORK_WAIT_RETRY = 5
cfg.CONF.import_group('metrics', 'ironic_lib.metrics_utils')
cfg.CONF.import_group('metrics_statsd', 'ironic_lib.metrics_statsd')
Host = collections.namedtuple('Host', ['hostname', 'port'])
def _time():
"""Wraps time.time() for simpler testing."""
return time.time()
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
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 = agent.api_client
self.error_delay = self.initial_delay
self.reader = None
self.writer = None
def run(self):
"""Start the heartbeat thread."""
# The first heartbeat happens immediately
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).decode() == '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: {}'
LOG.info(log_msg.format(interval))
finally:
os.close(self.reader)
os.close(self.writer)
self.reader = None
self.writer = None
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
LOG.info('heartbeat successful')
except errors.HeartbeatConflictError:
LOG.warning('conflict error sending heartbeat')
self.error_delay = min(self.error_delay * self.backoff_factor,
self.max_delay)
except Exception:
LOG.exception('error sending heartbeat')
self.error_delay = min(self.error_delay * self.backoff_factor,
self.max_delay)
def force_heartbeat(self):
os.write(self.writer, b'b')
def stop(self):
"""Stop the heartbeat thread."""
if self.writer is not None:
LOG.info('stopping heartbeater')
os.write(self.writer, b'a')
return self.join()
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, standalone,
hardware_initialization_delay=0):
super(IronicPythonAgent, self).__init__()
if bool(cfg.CONF.keyfile) != bool(cfg.CONF.certfile):
LOG.warning("Only one of 'keyfile' and 'certfile' options is "
"defined in config file. Its value will be ignored.")
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
if self.api_url:
self.api_client = ironic_api_client.APIClient(self.api_url)
self.heartbeater = IronicPythonAgentHeartbeater(self)
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.heartbeat_timeout = None
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
self.hardware_initialization_delay = hardware_initialization_delay
# IPA will stop serving requests and exit after this is set to False
self.serve_api = True
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
)
def _get_route_source(self, dest):
"""Get the IP address to send packages to destination."""
try:
out, _err = utils.execute('ip', 'route', 'get', dest)
except (EnvironmentError, processutils.ProcessExecutionError) as e:
LOG.warning('Cannot get route to host %(dest)s: %(err)s',
{'dest': dest, 'err': e})
return
try:
source = out.strip().split('\n')[0].split('src')[1].split()[0]
if netaddr.IPAddress(source).is_link_local():
LOG.info('Ignoring link-local source to %(dest)s: %(rec)s',
{'dest': dest, 'rec': out})
return
return source
except IndexError:
LOG.warning('No route to host %(dest)s, route record: %(rec)s',
{'dest': dest, 'rec': out})
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: LookupAgentIPError if an IP address could not be found
"""
if self.advertise_address.hostname is not None:
return
found_ip = None
if self.network_interface is not None:
# TODO(dtantsur): deprecate this
found_ip = hardware.dispatch_to_managers('get_ipv4_addr',
self.network_interface)
else:
url = urlparse.urlparse(self.api_url)
ironic_host = url.hostname
# Try resolving it in case it's not an IP address
try:
ironic_host = socket.gethostbyname(ironic_host)
except socket.gaierror:
LOG.debug('Count not resolve %s, maybe no DNS', ironic_host)
for attempt in range(self.ip_lookup_attempts):
found_ip = self._get_route_source(ironic_host)
if found_ip:
break
time.sleep(self.ip_lookup_sleep)
if found_ip:
self.advertise_address = Host(hostname=found_ip,
port=self.advertise_address.port)
else:
raise errors.LookupAgentIPError('Agent could not find a valid IP '
'address.')
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']
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())
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)
def force_heartbeat(self):
if not self.standalone:
self.heartbeater.force_heartbeat()
def _wait_for_interface(self):
"""Wait until at least one interface is up."""
wait_till = time.time() + NETWORK_WAIT_TIMEOUT
while time.time() < wait_till:
interfaces = hardware.dispatch_to_managers(
'list_network_interfaces')
if not any(ifc.mac_address for ifc in interfaces):
LOG.debug('Network is not up yet. '
'No valid interfaces found, retrying ...')
time.sleep(NETWORK_WAIT_RETRY)
else:
break
else:
LOG.warning("No valid network interfaces found. "
"Node lookup will probably fail.")
def serve_ipa_api(self):
"""Serve the API until an extension terminates it."""
if netutils.is_ipv6_enabled():
# Listens to both IP versions, assuming IPV6_V6ONLY isn't enabled,
# (the default behaviour in linux)
simple_server.WSGIServer.address_family = socket.AF_INET6
server = simple_server.WSGIServer((self.listen_address.hostname,
self.listen_address.port),
simple_server.WSGIRequestHandler)
server.set_app(self.api)
if not self.standalone and self.api_url:
# Don't start heartbeating until the server is listening
self.heartbeater.start()
while self.serve_api:
try:
server.handle_request()
except BaseException as e:
msg = "Failed due to an unknown exception. Error %s" % e
LOG.exception(msg)
raise errors.IronicAPIError(msg)
LOG.info('shutting down')
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()
# Operator-settable delay before hardware actually comes up.
# Helps with slow RAID drivers - see bug 1582797.
if self.hardware_initialization_delay > 0:
LOG.info('Waiting %d seconds before proceeding',
self.hardware_initialization_delay)
time.sleep(self.hardware_initialization_delay)
if not self.standalone:
# Inspection should be started before call to lookup, otherwise
# lookup will fail due to unknown MAC.
uuid = None
if cfg.CONF.inspection_callback_url:
uuid = inspector.inspect()
if self.api_url:
self._wait_for_interface()
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)
LOG.debug('Received lookup results: %s', content)
self.node = content['node']
LOG.info('Lookup succeeded, node UUID is %s',
self.node['uuid'])
hardware.cache_node(self.node)
self.heartbeat_timeout = content['config']['heartbeat_timeout']
# Update config with values from Ironic
config = content.get('config', {})
if config.get('metrics'):
for opt, val in config.items():
setattr(cfg.CONF.metrics, opt, val)
if config.get('metrics_statsd'):
for opt, val in config.items():
setattr(cfg.CONF.metrics_statsd, opt, val)
elif cfg.CONF.inspection_callback_url:
LOG.info('No ipa-api-url configured, Heartbeat and lookup '
'skipped for inspector.')
else:
LOG.error('Neither ipa-api-url nor inspection_callback_url'
'found, please check your pxe append parameters.')
self.serve_ipa_api()
if not self.standalone and self.api_url:
self.heartbeater.stop()