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Diffstat (limited to 'nova/scheduler/filters/__init__.py')
| -rw-r--r-- | nova/scheduler/filters/__init__.py | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/nova/scheduler/filters/__init__.py b/nova/scheduler/filters/__init__.py index 74e24b7bc3..785a13279e 100644 --- a/nova/scheduler/filters/__init__.py +++ b/nova/scheduler/filters/__init__.py @@ -16,8 +16,12 @@ """ Scheduler host filters """ +from oslo_log import log as logging + from nova import filters +LOG = logging.getLogger(__name__) + class BaseHostFilter(filters.BaseFilter): """Base class for host filters.""" @@ -53,6 +57,43 @@ class BaseHostFilter(filters.BaseFilter): raise NotImplementedError() +class CandidateFilterMixin: + """Mixing that helps to implement a Filter that needs to filter host by + Placement allocation candidates. + """ + + def filter_candidates(self, host_state, filter_func): + """Checks still viable allocation candidates by the filter_func and + keep only those that are passing it. + + :param host_state: HostState object holding the list of still viable + allocation candidates + :param filter_func: A callable that takes an allocation candidate and + returns a True like object if the candidate passed the filter or a + False like object if it doesn't. + """ + good_candidates = [] + for candidate in host_state.allocation_candidates: + LOG.debug( + f'{self.__class__.__name__} tries allocation candidate: ' + f'{candidate}', + ) + if filter_func(candidate): + LOG.debug( + f'{self.__class__.__name__} accepted allocation ' + f'candidate: {candidate}', + ) + good_candidates.append(candidate) + else: + LOG.debug( + f'{self.__class__.__name__} rejected allocation ' + f'candidate: {candidate}', + ) + + host_state.allocation_candidates = good_candidates + return good_candidates + + class HostFilterHandler(filters.BaseFilterHandler): def __init__(self): super(HostFilterHandler, self).__init__(BaseHostFilter) |