Source code for ironic_python_agent.agent

# 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 socket
import threading
import time

from oslo_concurrency import processutils
from oslo_log import log
import pkg_resources
from six.moves.urllib import parse as urlparse
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
from ironic_python_agent import utils


LOG = log.getLogger(__name__)


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.error_delay = self.initial_delay self.reader = None self.writer = None
[docs] 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) == '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}' 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 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)
[docs] def force_heartbeat(self): os.write(self.writer, 'b')
[docs] def stop(self): """Stop the heartbeat thread.""" if self.writer is not None: 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.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 )
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: return out.strip().split('\n')[0].split('src')[1].strip() except IndexError: LOG.warning('No route to host %(dest)s, route record: %(rec)s', {'dest': dest, 'rec': out})
[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: LookupAgentIPError if an IP address could not be found """ if self.advertise_address[0] 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 = (found_ip, self.advertise_address[1]) else: raise errors.LookupAgentIPError('Agent could not find a valid IP ' 'address.')
[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: LOG.exception('shutting down') if not self.standalone: self.heartbeater.stop()

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