split out base and agent modules
This commit is contained in:
Russell Haering
parent
c62cf1a7fa
commit
ad70d89847
251
teeth_agent/agent.py
Normal file
251
teeth_agent/agent.py
Normal file
@ -0,0 +1,251 @@
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"""
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Copyright 2013 Rackspace, Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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"""
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import collections
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import random
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import socket
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import threading
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import time
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import urlparse
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from cherrypy import wsgiserver
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import pkg_resources
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from stevedore import driver
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import structlog
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from teeth_rest import encoding
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from teeth_rest import errors as rest_errors
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from teeth_agent import api
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from teeth_agent import base
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from teeth_agent import errors
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from teeth_agent import hardware
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from teeth_agent import overlord_agent_api
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class TeethAgentStatus(encoding.Serializable):
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def __init__(self, mode, started_at, version):
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self.mode = mode
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self.started_at = started_at
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self.version = version
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def serialize(self, view):
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"""Turn the status into a dict."""
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return collections.OrderedDict([
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('mode', self.mode),
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('started_at', self.started_at),
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('version', self.version),
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])
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class TeethAgentHeartbeater(threading.Thread):
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# If we could wait at most N seconds between heartbeats (or in case of an
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# error) we will instead wait r x N seconds, where r is a random value
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# between these multipliers.
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min_jitter_multiplier = 0.3
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max_jitter_multiplier = 0.6
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# Exponential backoff values used in case of an error. In reality we will
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# only wait a portion of either of these delays based on the jitter
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# multipliers.
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initial_delay = 1.0
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max_delay = 300.0
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backoff_factor = 2.7
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def __init__(self, agent):
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super(TeethAgentHeartbeater, self).__init__()
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self.agent = agent
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self.api = overlord_agent_api.APIClient(agent.api_url)
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self.log = structlog.get_logger(api_url=agent.api_url)
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self.stop_event = threading.Event()
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self.error_delay = self.initial_delay
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def run(self):
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# The first heartbeat happens now
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self.log.info('starting heartbeater')
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interval = 0
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while not self.stop_event.wait(interval):
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next_heartbeat_by = self.do_heartbeat()
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interval_multiplier = random.uniform(self.min_jitter_multiplier,
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self.max_jitter_multiplier)
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interval = (next_heartbeat_by - time.time()) * interval_multiplier
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self.log.info('sleeping before next heartbeat', interval=interval)
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def do_heartbeat(self):
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try:
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deadline = self.api.heartbeat(
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mac_addr=self.agent.get_agent_mac_addr(),
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url=self.agent.get_agent_url(),
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version=self.agent.version,
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mode=self.agent.mode_implementation.name)
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self.error_delay = self.initial_delay
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self.log.info('heartbeat successful')
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except Exception as e:
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self.log.error('error sending heartbeat', exception=e)
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deadline = time.time() + self.error_delay
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self.error_delay = min(self.error_delay * self.backoff_factor,
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self.max_delay)
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pass
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return deadline
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def stop(self):
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self.log.info('stopping heartbeater')
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self.stop_event.set()
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return self.join()
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class TeethAgent(object):
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def __init__(self, api_url, listen_address, advertise_address, mode_impl):
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self.api_url = api_url
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self.listen_address = listen_address
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self.advertise_address = advertise_address
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self.mode_implementation = mode_impl
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self.version = pkg_resources.get_distribution('teeth-agent').version
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self.api = api.TeethAgentAPIServer(self)
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self.command_results = collections.OrderedDict()
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self.heartbeater = TeethAgentHeartbeater(self)
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self.hardware = hardware.HardwareInspector()
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self.command_lock = threading.Lock()
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self.log = structlog.get_logger()
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self.started_at = None
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def get_status(self):
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"""Retrieve a serializable status."""
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return TeethAgentStatus(
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mode=self.mode_implementation.name,
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started_at=self.started_at,
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version=self.version
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)
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def get_agent_url(self):
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# If we put this behind any sort of proxy (ie, stunnel) we're going to
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# need to (re)think this.
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return 'http://{host}:{port}/'.format(host=self.advertise_address[0],
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port=self.advertise_address[1])
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def get_agent_mac_addr(self):
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return self.hardware.get_primary_mac_address()
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def list_command_results(self):
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return self.command_results.values()
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def get_command_result(self, result_id):
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try:
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return self.command_results[result_id]
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except KeyError:
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raise errors.RequestedObjectNotFoundError('Command Result',
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result_id)
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def execute_command(self, command_name, **kwargs):
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"""Execute an agent command."""
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with self.command_lock:
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if len(self.command_results) > 0:
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last_command = self.command_results.values()[-1]
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if not last_command.is_done():
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raise errors.CommandExecutionError('agent is busy')
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if command_name not in self.mode_implementation:
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raise errors.InvalidCommandError(command_name)
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try:
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command_fn = self.mode_implementation[command_name]
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result = command_fn(command_name, **kwargs)
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if not isinstance(result, base.BaseCommandResult):
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result = base.SyncCommandResult(command_name,
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kwargs,
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True,
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result)
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except rest_errors.InvalidContentError as e:
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# Any command may raise a InvalidContentError which will be
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# returned to the caller directly.
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raise e
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except Exception as e:
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# Other errors are considered command execution errors, and are
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# recorded as an
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result = base.SyncCommandResult(command_name, kwargs, False, e)
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self.command_results[result.id] = result
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return result
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def run(self):
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"""Run the Teeth Agent."""
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self.started_at = time.time()
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self.heartbeater.start()
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server = wsgiserver.CherryPyWSGIServer(self.listen_address, self.api)
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try:
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server.start()
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except BaseException as e:
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self.log.error('shutting down', exception=e)
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server.stop()
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self.heartbeater.stop()
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def _get_api_facing_ip_address(api_url):
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"""Note: this will raise an exception if anything goes wrong. That is
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expected to be fine, if we can't get to the agent API there isn't much
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point in starting up. Just crash and rely on the process manager to
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restart us in a sane fashion.
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"""
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api_addr = urlparse.urlparse(api_url)
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if api_addr.scheme not in ('http', 'https'):
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raise RuntimeError('API URL scheme must be one of \'http\' or '
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'\'https\'.')
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api_port = api_addr.port or {'http': 80, 'https': 443}[api_addr.scheme]
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api_host = api_addr.hostname
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conn = socket.create_connection((api_host, api_port))
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listen_ip = conn.getsockname()[0]
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conn.close()
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return listen_ip
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def _load_mode_implementation(mode_name):
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mgr = driver.DriverManager(
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namespace='teeth_agent.modes',
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name=mode_name,
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invoke_on_load=True,
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invoke_args=[],
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)
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return mgr.driver
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def build_agent(api_url,
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listen_host,
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listen_port,
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advertise_host,
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advertise_port):
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if not advertise_host:
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advertise_host = _get_api_facing_ip_address(api_url)
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if not listen_host:
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listen_host = advertise_host
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# TODO(russellhaering): Load this from the configuration API
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mode_name = 'standby'
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mode_implementation = _load_mode_implementation(mode_name)
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return TeethAgent(api_url,
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(listen_host, listen_port),
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(advertise_host, advertise_port),
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mode_implementation)
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@ -16,39 +16,14 @@ limitations under the License.
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import abc
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import collections
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import random
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import socket
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import threading
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import time
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import urlparse
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import uuid
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from cherrypy import wsgiserver
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import pkg_resources
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from stevedore import driver
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import structlog
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from teeth_rest import encoding
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from teeth_rest import errors as rest_errors
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from teeth_agent import api
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from teeth_agent import errors
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from teeth_agent import hardware
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from teeth_agent import overlord_agent_api
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class TeethAgentStatus(encoding.Serializable):
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def __init__(self, mode, started_at, version):
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self.mode = mode
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self.started_at = started_at
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self.version = version
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def serialize(self, view):
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"""Turn the status into a dict."""
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return collections.OrderedDict([
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('mode', self.mode),
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('started_at', self.started_at),
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('version', self.version),
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])
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class AgentCommandStatus(object):
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@ -143,207 +118,8 @@ class AsyncCommandResult(BaseCommandResult):
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pass
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class TeethAgentHeartbeater(threading.Thread):
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# If we could wait at most N seconds between heartbeats (or in case of an
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# error) we will instead wait r x N seconds, where r is a random value
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# between these multipliers.
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min_jitter_multiplier = 0.3
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max_jitter_multiplier = 0.6
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# Exponential backoff values used in case of an error. In reality we will
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# only wait a portion of either of these delays based on the jitter
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# multipliers.
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initial_delay = 1.0
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max_delay = 300.0
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backoff_factor = 2.7
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def __init__(self, agent):
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super(TeethAgentHeartbeater, self).__init__()
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self.agent = agent
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self.api = overlord_agent_api.APIClient(agent.api_url)
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self.log = structlog.get_logger(api_url=agent.api_url)
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self.stop_event = threading.Event()
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self.error_delay = self.initial_delay
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def run(self):
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# The first heartbeat happens now
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self.log.info('starting heartbeater')
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interval = 0
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while not self.stop_event.wait(interval):
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next_heartbeat_by = self.do_heartbeat()
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interval_multiplier = random.uniform(self.min_jitter_multiplier,
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self.max_jitter_multiplier)
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interval = (next_heartbeat_by - time.time()) * interval_multiplier
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self.log.info('sleeping before next heartbeat', interval=interval)
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def do_heartbeat(self):
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try:
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deadline = self.api.heartbeat(
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mac_addr=self.agent.get_agent_mac_addr(),
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url=self.agent.get_agent_url(),
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version=self.agent.version,
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mode=self.agent.mode_implementation.name)
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self.error_delay = self.initial_delay
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self.log.info('heartbeat successful')
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except Exception as e:
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self.log.error('error sending heartbeat', exception=e)
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deadline = time.time() + self.error_delay
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self.error_delay = min(self.error_delay * self.backoff_factor,
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self.max_delay)
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pass
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return deadline
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def stop(self):
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self.log.info('stopping heartbeater')
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self.stop_event.set()
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return self.join()
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class BaseAgentMode(dict):
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def __init__(self, name):
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super(BaseAgentMode, self).__init__()
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self.log = structlog.get_logger(agent_mode=name)
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self.name = name
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class TeethAgent(object):
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def __init__(self,
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listen_host,
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listen_port,
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advertise_host,
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advertise_port,
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api_url):
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self.listen_host = listen_host
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self.listen_port = listen_port
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self.advertise_host = advertise_host
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self.advertise_port = advertise_port
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self.api_url = api_url
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self.started_at = None
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self.mode_implementation = None
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self.version = pkg_resources.get_distribution('teeth-agent').version
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self.api = api.TeethAgentAPIServer(self)
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self.command_results = collections.OrderedDict()
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self.heartbeater = TeethAgentHeartbeater(self)
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self.hardware = hardware.HardwareInspector()
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self.command_lock = threading.Lock()
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self.log = structlog.get_logger()
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def get_status(self):
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"""Retrieve a serializable status."""
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return TeethAgentStatus(
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mode=self.mode_implementation.name,
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started_at=self.started_at,
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version=self.version
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)
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def get_agent_url(self):
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# If we put this behind any sort of proxy (ie, stunnel) we're going to
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# need to (re)think this.
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return 'http://{host}:{port}/'.format(host=self.advertise_host,
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port=self.advertise_port)
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def get_api_facing_ip_address(self):
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"""Note: this will raise an exception if anything goes wrong. That is
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expected to be fine, if we can't get to the agent API there isn't much
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point in starting up. Just crash and rely on the process manager to
|
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restart us in a sane fashion.
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"""
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api_addr = urlparse.urlparse(self.api_url)
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if api_addr.scheme not in ('http', 'https'):
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raise RuntimeError('API URL scheme must be one of \'http\' or '
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'\'https\'.')
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api_port = api_addr.port or {'http': 80, 'https': 443}[api_addr.scheme]
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api_host = api_addr.hostname
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self.log.info('attempting to resolve listen IP',
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api_host=api_host,
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api_port=api_port)
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conn = socket.create_connection((api_host, api_port))
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listen_ip = conn.getsockname()[0]
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conn.close()
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self.log.info('resolved listen IP', listen_ip=listen_ip)
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return listen_ip
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def load_mode_implementation(self, mode_name):
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mgr = driver.DriverManager(
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namespace='teeth_agent.modes',
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name=mode_name,
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invoke_on_load=True,
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invoke_args=[],
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)
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return mgr.driver
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def get_agent_mac_addr(self):
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return self.hardware.get_primary_mac_address()
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def list_command_results(self):
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return self.command_results.values()
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def get_command_result(self, result_id):
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try:
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return self.command_results[result_id]
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except KeyError:
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raise errors.RequestedObjectNotFoundError('Command Result',
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result_id)
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def execute_command(self, command_name, **kwargs):
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"""Execute an agent command."""
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with self.command_lock:
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if len(self.command_results) > 0:
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last_command = self.command_results.values()[-1]
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if not last_command.is_done():
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raise errors.CommandExecutionError('agent is busy')
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if command_name not in self.mode_implementation:
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raise errors.InvalidCommandError(command_name)
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try:
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command_fn = self.mode_implementation[command_name]
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result = command_fn(command_name, **kwargs)
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if not isinstance(result, BaseCommandResult):
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result = SyncCommandResult(command_name,
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kwargs,
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True,
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result)
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except rest_errors.InvalidContentError as e:
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# Any command may raise a InvalidContentError which will be
|
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# returned to the caller directly.
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raise e
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except Exception as e:
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# Other errors are considered command execution errors, and are
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# recorded as an
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result = SyncCommandResult(command_name, kwargs, False, e)
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self.command_results[result.id] = result
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return result
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def run(self):
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"""Run the Teeth Agent."""
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self.started_at = time.time()
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if not self.advertise_host:
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self.advertise_host = self.get_api_facing_ip_address()
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if not self.listen_host:
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self.listen_host = self.advertise_host
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self.mode_implementation = self.load_mode_implementation('standby')
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self.heartbeater.start()
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listen_address = (self.listen_host, self.listen_port)
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server = wsgiserver.CherryPyWSGIServer(listen_address, self.api)
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try:
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server.start()
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except BaseException as e:
|
||||
self.log.error('shutting down', exception=e)
|
||||
server.stop()
|
||||
|
||||
self.heartbeater.stop()
|
||||
|
||||
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Reference in New Issue
Block a user