a26b7cfbe6
Partially addresses BP transformer-unit
Provide a new transformer to apply scaling conversions, either
replacing or emitted in addition to the original sample.
The target counters are identified either by name or by unit.
The scaling can be expressed as either a straight multiplicative
factor or as a string expression to be eval'd.
Configured as per usual via the pipeline.yaml, for example:
...
transformers:
- name: "unit_conversion"
parameters:
source:
unit: "°C"
target:
unit: "°F"
scale: "(volume * 1.8) + 32"
replace: True
Change-Id: I4c3f64376c6f994afd0b1a25dc399daabe2a2ec5
105 lines
3.8 KiB
Python
105 lines
3.8 KiB
Python
# -*- encoding: utf-8 -*-
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#
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# Copyright © 2013 Red Hat, Inc
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#
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# Author: Eoghan Glynn <eglynn@redhat.com>
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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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import copy
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from ceilometer import counter as ceilocounter
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from ceilometer.openstack.common import log
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from ceilometer import transformer
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LOG = log.getLogger(__name__)
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class ScalingTransformer(transformer.TransformerBase):
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"""Transformer to apply a scaling conversion.
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"""
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def __init__(self, source={}, target={}, replace=False, **kwargs):
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"""Initialize transformer with configured parameters.
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:param source: dict containing source counter unit
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:param target: dict containing target counter name, type,
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unit and scaling factor (a missing value
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connotes no change)
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:param replace: true if source counter is to be replaced
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(as opposed to an additive conversion)
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"""
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self.source = source
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self.target = target
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self.replace = replace
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self.preserved = None
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LOG.debug(_('scaling conversion transformer with source:'
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' %(source)s target: %(target)s replace:'
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' %(replace)s') % locals())
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super(ScalingTransformer, self).__init__(**kwargs)
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@staticmethod
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def _scale(counter, scale):
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"""Apply the scaling factor (either a straight multiplicative
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factor or else a string to be eval'd).
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"""
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ns = copy.deepcopy(counter._asdict())
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return ((eval(scale, {}, ns) if isinstance(scale, basestring)
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else counter.volume * scale) if scale else counter.volume)
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def _convert(self, counter):
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"""Transform the appropriate counter fields.
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"""
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scale = self.target.get('scale')
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return ceilocounter.Counter(
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name=self.target.get('name', counter.name),
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unit=self.target.get('unit', counter.unit),
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type=self.target.get('type', counter.type),
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volume=self._scale(counter, scale),
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user_id=counter.user_id,
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project_id=counter.project_id,
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resource_id=counter.resource_id,
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timestamp=counter.timestamp,
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resource_metadata=counter.resource_metadata
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)
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def _keep(self, counter, transformed):
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"""Either replace counter with the transformed version
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or preserve for flush() call to emit as an additional
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sample.
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"""
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if self.replace:
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counter = transformed
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else:
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self.preserved = transformed
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return counter
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def handle_sample(self, context, counter, source):
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"""Handle a sample, converting if necessary."""
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LOG.debug('handling counter %s', (counter,))
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if (self.source.get('unit', counter.unit) == counter.unit):
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transformed = self._convert(counter)
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LOG.debug(_('converted to: %s') % (transformed,))
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counter = self._keep(counter, transformed)
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return counter
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def flush(self, context, source):
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"""Emit the additional transformed counter in the non-replace
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case.
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"""
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counters = []
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if self.preserved:
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counters.append(self.preserved)
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self.preserved = None
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return counters
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