x/python-ganttclient
Code Issues Proposed changes

Pep8 fixes

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This commit is contained in:
Rick Harris
2011-05-17 18:15:31 -05:00
parent 2000f6da7b
commit f099682915
3 changed files with 38 additions and 21 deletions
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30
nova/scheduler/least_cost.py
View File

@@ -13,16 +13,19 @@
# License for the specific language governing permissions and limitations
# under the License.
"""
Helpful docstring here
Least Cost Scheduler is a mechanism for choosing which host machines to
provision a set of resources to. The input of the least-cost-scheduler is a
set of objective-functions, called the 'cost-functions', a weight for each
cost-function, and a list of candidate hosts (gathered via FilterHosts).
The cost-function and weights are tabulated, and the host with the least cost
is then selected for provisioning.
"""
import collections
from nova import flags
from nova import log as logging
# TODO(sirp): this should be just `zone_aware` to match naming scheme
# TODO(sirp): perhaps all zone-aware stuff should go under a `zone_aware`
# module
from nova.scheduler import zone_aware_scheduler
from nova import utils
@@ -38,6 +41,8 @@ flags.DEFINE_list('least_cost_scheduler_cost_functions',
# cost_functions.py file (perhaps in a least_cost_scheduler directory)
flags.DEFINE_integer('noop_cost_fn_weight', 1,
'How much weight to give the noop cost function')
def noop_cost_fn(host):
"""Return a pre-weight cost of 1 for each host"""
return 1
@@ -45,6 +50,8 @@ def noop_cost_fn(host):
flags.DEFINE_integer('fill_first_cost_fn_weight', 1,
'How much weight to give the fill-first cost function')
def fill_first_cost_fn(host):
"""Prefer hosts that have less ram available, filter_hosts will exclude
hosts that don't have enough ram"""
@@ -68,7 +75,7 @@ class LeastCostScheduler(zone_aware_scheduler.ZoneAwareScheduler):
except exception.ClassNotFound:
raise exception.SchedulerCostFunctionNotFound(
cost_fn_str=cost_fn_str)
try:
weight = getattr(FLAGS, "%s_weight" % cost_fn.__name__)
except AttributeError:
@@ -82,17 +89,22 @@ class LeastCostScheduler(zone_aware_scheduler.ZoneAwareScheduler):
def weigh_hosts(self, num, request_spec, hosts):
"""Returns a list of dictionaries of form:
[ {weight: weight, hostname: hostname} ]"""
# FIXME(sirp): weigh_hosts should handle more than just instances
hostnames = [hostname for hostname, _ in hosts]
hostnames = [hostname for hostname, caps in hosts]
cost_fns = self.get_cost_fns()
costs = weighted_sum(domain=hosts, weighted_fns=cost_fns)
weighted = []
weight_log = []
for cost, hostname in zip(costs, hostnames):
weight_log.append("%s: %s" % (hostname, "%.2f" % cost))
weight_dict = dict(weight=cost, hostname=hostname)
weighted.append(weight_dict)
return weighted
LOG.debug(_("Weighted Costs => %s") % weight_log)
return weighted
def normalize_list(L):
@@ -110,7 +122,7 @@ def weighted_sum(domain, weighted_fns, normalize=True):
"""Use the weighted-sum method to compute a score for an array of objects.
Normalize the results of the objective-functions so that the weights are
meaningful regardless of objective-function's range.
domain - input to be scored
weighted_fns - list of weights and functions like:
[(weight, objective-functions)]

11
nova/scheduler/zone_aware_scheduler.py
View File

@@ -80,7 +80,7 @@ class ZoneAwareScheduler(driver.Scheduler):
LOG.debug(_("Casted to compute %(host)s for run_instance")
% locals())
else:
# TODO(sandy) Provision in child zone ...
# TODO(sandy) Provision in child zone ...
LOG.warning(_("Provision to Child Zone not supported (yet)")
% locals())
pass
@@ -117,11 +117,11 @@ class ZoneAwareScheduler(driver.Scheduler):
# Filter local hosts based on requirements ...
host_list = self.filter_hosts(num_instances, request_spec)
# then weigh the selected hosts.
# weighted = [{weight=weight, name=hostname}, ...]
# TODO(sirp): weigh_hosts should also be a function of 'topic' or
# resources, so that we can apply different objective functions to it
# then weigh the selected hosts.
# weighted = [{weight=weight, name=hostname}, ...]
weighted = self.weigh_hosts(num_instances, request_spec, host_list)
# Next, tack on the best weights from the child zones ...
@@ -145,8 +145,9 @@ class ZoneAwareScheduler(driver.Scheduler):
"""Derived classes must override this method and return
a list of hosts in [(hostname, capability_dict)] format."""
# NOTE(sirp): The default logic is the equivalent to AllHostsFilter
service_states = self.zone_manager.service_states
return [(host, services)
for host, services in self.zone_manager.service_states.iteritems()]
for host, services in service_states.iteritems()]
def weigh_hosts(self, num, request_spec, hosts):
"""Derived classes may override this to provide more sophisticated

18
nova/tests/test_least_cost_scheduler.py
View File

@@ -30,6 +30,7 @@ class FakeHost(object):
self.free_ram = free_ram
self.io = io
class WeightedSumTestCase(test.TestCase):
def test_empty_domain(self):
domain = []
@@ -50,14 +51,15 @@ class WeightedSumTestCase(test.TestCase):
(2, lambda h: h.io), # Avoid high I/O
]
costs = least_cost.weighted_sum(domain=hosts, weighted_fns=weighted_fns)
costs = least_cost.weighted_sum(
domain=hosts, weighted_fns=weighted_fns)
# Each 256 MB unit of free-ram contributes 0.5 points by way of:
# cost = weight * (score/max_score) = 1 * (256/512) = 0.5
# Each 100 iops of IO adds 0.5 points by way of:
# cost = 2 * (100/400) = 2 * 0.25 = 0.5
expected = [1.5, 2.5, 1.5]
self.assertEqual(expected, costs)
self.assertEqual(expected, costs)
# TODO(sirp): unify this with test_host_filter tests? possibility of sharing
@@ -65,6 +67,7 @@ class WeightedSumTestCase(test.TestCase):
class FakeZoneManager:
pass
class LeastCostSchedulerTestCase(test.TestCase):
def _host_caps(self, multiplier):
# Returns host capabilities in the following way:
@@ -116,7 +119,6 @@ class LeastCostSchedulerTestCase(test.TestCase):
#FLAGS.default_host_filter_driver = self.old_flag
super(LeastCostSchedulerTestCase, self).tearDown()
def assertWeights(self, expected, num, request_spec, hosts):
weighted = self.sched.weigh_hosts(num, request_spec, hosts)
self.assertDictListMatch(weighted, expected, approx_equal=True)
@@ -138,8 +140,9 @@ class LeastCostSchedulerTestCase(test.TestCase):
num = 1
request_spec = {}
hosts = self.sched.filter_hosts(num, request_spec)
expected = [ dict(weight=1, hostname=hostname) for hostname, caps in hosts]
expected = [dict(weight=1, hostname=hostname)
for hostname, caps in hosts]
self.assertWeights(expected, num, request_spec, hosts)
def test_cost_fn_weights(self):
@@ -152,7 +155,8 @@ class LeastCostSchedulerTestCase(test.TestCase):
request_spec = {}
hosts = self.sched.filter_hosts(num, request_spec)
expected = [ dict(weight=2, hostname=hostname) for hostname, caps in hosts]
expected = [dict(weight=2, hostname=hostname)
for hostname, caps in hosts]
self.assertWeights(expected, num, request_spec, hosts)
def test_fill_first_cost_fn(self):
@@ -164,7 +168,7 @@ class LeastCostSchedulerTestCase(test.TestCase):
num = 1
request_spec = {}
hosts = self.sched.filter_hosts(num, request_spec)
expected = []
for idx, (hostname, caps) in enumerate(hosts):
# Costs are normalized so over 10 hosts, each host with increasing