240 lines
8.0 KiB
Python
240 lines
8.0 KiB
Python
# Copyright (c) 2011 Openstack, LLC.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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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, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""
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Handles all requests relating to schedulers.
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"""
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import novaclient
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from nova import db
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from nova import exception
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from nova import flags
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from nova import log as logging
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from nova import rpc
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from eventlet import greenpool
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FLAGS = flags.FLAGS
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flags.DEFINE_bool('enable_zone_routing',
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False,
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'When True, routing to child zones will occur.')
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LOG = logging.getLogger('nova.scheduler.api')
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def _call_scheduler(method, context, params=None):
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"""Generic handler for RPC calls to the scheduler.
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:param params: Optional dictionary of arguments to be passed to the
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scheduler worker
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:retval: Result returned by scheduler worker
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"""
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if not params:
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params = {}
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queue = FLAGS.scheduler_topic
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kwargs = {'method': method, 'args': params}
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return rpc.call(context, queue, kwargs)
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def get_zone_list(context):
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"""Return a list of zones assoicated with this zone."""
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items = _call_scheduler('get_zone_list', context)
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for item in items:
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item['api_url'] = item['api_url'].replace('\\/', '/')
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if not items:
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items = db.zone_get_all(context)
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return items
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def zone_get(context, zone_id):
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return db.zone_get(context, zone_id)
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def zone_delete(context, zone_id):
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return db.zone_delete(context, zone_id)
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def zone_create(context, data):
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return db.zone_create(context, data)
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def zone_update(context, zone_id, data):
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return db.zone_update(context, zone_id, data)
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def get_zone_capabilities(context):
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"""Returns a dict of key, value capabilities for this zone."""
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return _call_scheduler('get_zone_capabilities', context=context)
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def update_service_capabilities(context, service_name, host, capabilities):
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"""Send an update to all the scheduler services informing them
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of the capabilities of this service."""
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kwargs = dict(method='update_service_capabilities',
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args=dict(service_name=service_name, host=host,
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capabilities=capabilities))
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return rpc.fanout_cast(context, 'scheduler', kwargs)
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def _wrap_method(function, self):
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"""Wrap method to supply self."""
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def _wrap(*args, **kwargs):
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return function(self, *args, **kwargs)
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return _wrap
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def _process(func, zone):
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"""Worker stub for green thread pool. Give the worker
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an authenticated nova client and zone info."""
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nova = novaclient.OpenStack(zone.username, zone.password, zone.api_url)
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nova.authenticate()
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return func(nova, zone)
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def child_zone_helper(zone_list, func):
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"""Fire off a command to each zone in the list.
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The return is [novaclient return objects] from each child zone.
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For example, if you are calling server.pause(), the list will
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be whatever the response from server.pause() is. One entry
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per child zone called."""
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green_pool = greenpool.GreenPool()
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return [result for result in green_pool.imap(
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_wrap_method(_process, func), zone_list)]
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def _issue_novaclient_command(nova, zone, collection, method_name, item_id):
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"""Use novaclient to issue command to a single child zone.
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One of these will be run in parallel for each child zone."""
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manager = getattr(nova, collection)
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result = None
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try:
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try:
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result = manager.get(int(item_id))
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except ValueError, e:
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result = manager.find(name=item_id)
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except novaclient.NotFound:
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url = zone.api_url
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LOG.debug(_("%(collection)s '%(item_id)s' not found on '%(url)s'" %
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locals()))
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return None
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if method_name.lower() not in ['get', 'find']:
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result = getattr(result, method_name)()
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return result
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def wrap_novaclient_function(f, collection, method_name, item_id):
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"""Appends collection, method_name and item_id to the incoming
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(nova, zone) call from child_zone_helper."""
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def inner(nova, zone):
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return f(nova, zone, collection, method_name, item_id)
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return inner
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class RedirectResult(exception.Error):
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"""Used to the HTTP API know that these results are pre-cooked
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and they can be returned to the caller directly."""
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def __init__(self, results):
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self.results = results
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super(RedirectResult, self).__init__(
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message=_("Uncaught Zone redirection exception"))
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class reroute_compute(object):
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"""Decorator used to indicate that the method should
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delegate the call the child zones if the db query
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can't find anything."""
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def __init__(self, method_name):
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self.method_name = method_name
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def __call__(self, f):
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def wrapped_f(*args, **kwargs):
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collection, context, item_id = \
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self.get_collection_context_and_id(args, kwargs)
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try:
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# Call the original function ...
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return f(*args, **kwargs)
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except exception.InstanceNotFound, e:
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LOG.debug(_("Instance %(item_id)s not found "
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"locally: '%(e)s'" % locals()))
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if not FLAGS.enable_zone_routing:
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raise
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zones = db.zone_get_all(context)
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if not zones:
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raise
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# Ask the children to provide an answer ...
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LOG.debug(_("Asking child zones ..."))
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result = self._call_child_zones(zones,
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wrap_novaclient_function(_issue_novaclient_command,
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collection, self.method_name, item_id))
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# Scrub the results and raise another exception
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# so the API layers can bail out gracefully ...
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raise RedirectResult(self.unmarshall_result(result))
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return wrapped_f
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def _call_child_zones(self, zones, function):
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"""Ask the child zones to perform this operation.
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Broken out for testing."""
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return child_zone_helper(zones, function)
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def get_collection_context_and_id(self, args, kwargs):
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"""Returns a tuple of (novaclient collection name, security
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context and resource id. Derived class should override this."""
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context = kwargs.get('context', None)
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instance_id = kwargs.get('instance_id', None)
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if len(args) > 0 and not context:
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context = args[1]
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if len(args) > 1 and not instance_id:
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instance_id = args[2]
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return ("servers", context, instance_id)
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def unmarshall_result(self, zone_responses):
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"""Result is a list of responses from each child zone.
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Each decorator derivation is responsible to turning this
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into a format expected by the calling method. For
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example, this one is expected to return a single Server
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dict {'server':{k:v}}. Others may return a list of them, like
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{'servers':[{k,v}]}"""
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reduced_response = []
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for zone_response in zone_responses:
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if not zone_response:
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continue
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server = zone_response.__dict__
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for k in server.keys():
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if k[0] == '_' or k == 'manager':
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del server[k]
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reduced_response.append(dict(server=server))
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if reduced_response:
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return reduced_response[0] # first for now.
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return {}
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def redirect_handler(f):
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def new_f(*args, **kwargs):
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try:
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return f(*args, **kwargs)
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except RedirectResult, e:
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return e.results
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return new_f
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