148 lines
4.3 KiB
Python
148 lines
4.3 KiB
Python
# 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 decimal
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import pint
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from horizon.utils import functions
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# Mapping of units from Ceilometer to Pint
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INFORMATION_UNITS = (
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('B', 'byte'),
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('KB', 'Kibyte'),
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('MB', 'Mibyte'),
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('GB', 'Gibyte'),
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('TB', 'Tibyte'),
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('PB', 'Pibyte'),
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('EB', 'Eibyte'),
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)
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TIME_UNITS = ('ns', 's', 'min', 'hr', 'day', 'week', 'month', 'year')
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ureg = pint.UnitRegistry()
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def is_supported(unit):
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"""Returns a bool indicating whether the unit specified is supported by
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this module.
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"""
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return unit in functions.get_keys(INFORMATION_UNITS) + TIME_UNITS
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def is_larger(unit_1, unit_2):
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"""Returns a boolean indicating whether unit_1 is larger than unit_2.
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E.g:
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>>> is_larger('KB', 'B')
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True
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>>> is_larger('min', 'day')
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False
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"""
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unit_1 = functions.value_for_key(INFORMATION_UNITS, unit_1)
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unit_2 = functions.value_for_key(INFORMATION_UNITS, unit_2)
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return ureg.parse_expression(unit_1) > ureg.parse_expression(unit_2)
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def convert(value, source_unit, target_unit, fmt=False):
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"""Converts value from source_unit to target_unit. Returns a tuple
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containing the converted value and target_unit. Having fmt set to True
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causes the value to be formatted to 1 decimal digit if it's a decimal or
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be formatted as integer if it's an integer.
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E.g:
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>>> convert(2, 'hr', 'min')
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(120.0, 'min')
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>>> convert(2, 'hr', 'min', fmt=True)
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(120, 'min')
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>>> convert(30, 'min', 'hr', fmt=True)
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(0.5, 'hr')
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"""
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orig_target_unit = target_unit
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source_unit = functions.value_for_key(INFORMATION_UNITS, source_unit)
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target_unit = functions.value_for_key(INFORMATION_UNITS, target_unit)
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q = ureg.Quantity(value, source_unit)
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q = q.to(ureg.parse_expression(target_unit))
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value = functions.format_value(q.magnitude) if fmt else q.magnitude
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return value, orig_target_unit
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def normalize(value, unit):
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"""Converts the value so that it belongs to some expected range.
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Returns the new value and new unit.
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E.g:
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>>> normalize(1024, 'KB')
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(1, 'MB')
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>>> normalize(90, 'min')
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(1.5, 'hr')
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>>> normalize(1.0, 'object')
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(1, 'object')
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"""
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if value < 0:
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raise ValueError('Negative value: %s %s.' % (value, unit))
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if unit in functions.get_keys(INFORMATION_UNITS):
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return _normalize_information(value, unit)
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elif unit in TIME_UNITS:
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return _normalize_time(value, unit)
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else:
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# Unknown unit, just return it
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return functions.format_value(value), unit
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def _normalize_information(value, unit):
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value = decimal.Decimal(str(value))
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while value < 1:
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prev_unit = functions.previous_key(INFORMATION_UNITS, unit)
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if prev_unit is None:
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break
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value, unit = convert(value, unit, prev_unit)
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while value >= 1024:
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next_unit = functions.next_key(INFORMATION_UNITS, unit)
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if next_unit is None:
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break
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value, unit = convert(value, unit, next_unit)
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return functions.format_value(value), unit
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def _normalize_time(value, unit):
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# Normalize time by converting to next higher unit when value is
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# at least 2 units
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value, unit = convert(value, unit, 's')
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if value >= 120:
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value, unit = convert(value, 's', 'min')
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if value >= 120:
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value, unit = convert(value, 'min', 'hr')
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if value >= 48:
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value, unit = convert(value, 'hr', 'day')
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if value >= 730:
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value, unit = convert(value, 'day', 'year')
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elif value >= 62:
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value, unit = convert(value, 'day', 'month')
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elif value >= 14:
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value, unit = convert(value, 'day', 'week')
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return functions.format_value(value), unit
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