75 lines
2.3 KiB
Python
75 lines
2.3 KiB
Python
# Copyright 2019 The Kubernetes Authors.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from decimal import Decimal, InvalidOperation
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def parse_quantity(quantity):
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"""
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Parse kubernetes canonical form quantity like 200Mi to a decimal number.
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Supported SI suffixes:
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base1024: Ki | Mi | Gi | Ti | Pi | Ei
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base1000: n | u | m | "" | k | M | G | T | P | E
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See https://github.com/kubernetes/apimachinery/blob/master/pkg/api/resource/quantity.go
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Input:
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quantity: string. kubernetes canonical form quantity
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Returns:
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Decimal
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Raises:
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ValueError on invalid or unknown input
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"""
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if isinstance(quantity, (int, float, Decimal)):
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return Decimal(quantity)
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exponents = {"n": -3, "u": -2, "m": -1, "K": 1, "k": 1, "M": 2,
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"G": 3, "T": 4, "P": 5, "E": 6}
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quantity = str(quantity)
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number = quantity
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suffix = None
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if len(quantity) >= 2 and quantity[-1] == "i":
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if quantity[-2] in exponents:
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number = quantity[:-2]
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suffix = quantity[-2:]
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elif len(quantity) >= 1 and quantity[-1] in exponents:
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number = quantity[:-1]
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suffix = quantity[-1:]
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try:
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number = Decimal(number)
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except InvalidOperation:
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raise ValueError("Invalid number format: {}".format(number))
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if suffix is None:
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return number
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if suffix.endswith("i"):
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base = 1024
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elif len(suffix) == 1:
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base = 1000
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else:
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raise ValueError("{} has unknown suffix".format(quantity))
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# handle SI inconsistency
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if suffix == "ki":
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raise ValueError("{} has unknown suffix".format(quantity))
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if suffix[0] not in exponents:
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raise ValueError("{} has unknown suffix".format(quantity))
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exponent = Decimal(exponents[suffix[0]])
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return number * (base ** exponent)
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