codekingpro/portable-devtools

1# Copyright 2019 The Kubernetes Authors.2#3# Licensed under the Apache License, Version 2.0 (the "License");4# you may not use this file except in compliance with the License.5# You may obtain a copy of the License at6#7#     http://www.apache.org/licenses/LICENSE-2.08#9# Unless required by applicable law or agreed to in writing, software10# distributed under the License is distributed on an "AS IS" BASIS,11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.12# See the License for the specific language governing permissions and13# limitations under the License.14from decimal import Decimal, InvalidOperation15 16_EXPONENTS = {17    "n": -3,18    "u": -2,19    "m": -1,20    "K": 1,21    "k": 1,22    "M": 2,23    "G": 3,24    "T": 4,25    "P": 5,26    "E": 6,27}28 29 30def parse_quantity(quantity):31    """32    Parse kubernetes canonical form quantity like 200Mi to a decimal number.33    Supported SI suffixes:34    base1024: Ki | Mi | Gi | Ti | Pi | Ei35    base1000: n | u | m | "" | k | M | G | T | P | E36 37    See https://github.com/kubernetes/apimachinery/blob/master/pkg/api/resource/quantity.go38 39    Input:40    quantity: string. kubernetes canonical form quantity41 42    Returns:43    Decimal44 45    Raises:46    ValueError on invalid or unknown input47    """48    if isinstance(quantity, (int, float, Decimal)):49        return Decimal(quantity)50 51    quantity = str(quantity)52    number = quantity53    suffix = None54    if len(quantity) >= 2 and quantity[-1] == "i":55        if quantity[-2] in _EXPONENTS:56            number = quantity[:-2]57            suffix = quantity[-2:]58    elif len(quantity) >= 1 and quantity[-1] in _EXPONENTS:59        number = quantity[:-1]60        suffix = quantity[-1:]61 62    try:63        number = Decimal(number)64    except InvalidOperation:65        raise ValueError("Invalid number format: {}".format(number))66 67    if suffix is None:68        return number69 70    if suffix.endswith("i"):71        base = 102472    elif len(suffix) == 1:73        base = 100074    else:75        raise ValueError("{} has unknown suffix".format(quantity))76 77    # handle SI inconsistency78    if suffix == "ki":79        raise ValueError("{} has unknown suffix".format(quantity))80 81    if suffix[0] not in _EXPONENTS:82        raise ValueError("{} has unknown suffix".format(quantity))83 84    exponent = Decimal(_EXPONENTS[suffix[0]])85    return number * (base ** exponent)86 87 88def format_quantity(quantity_value, suffix, quantize=None) -> str:89    """90    Takes a decimal and produces a string value in kubernetes' canonical quantity form,91    like "200Mi".Users can specify an additional decimal number to quantize the output.92 93    Example -  Relatively increase pod memory limits:94 95    # retrieve my_pod96    current_memory: Decimal = parse_quantity(my_pod.spec.containers[0].resources.limits.memory)97    desired_memory = current_memory * 1.298    desired_memory_str = format_quantity(desired_memory, suffix="Gi", quantize=Decimal(1))99    # patch pod with desired_memory_str100 101    'quantize=Decimal(1)' ensures that the result does not contain any fractional digits.102 103    Supported SI suffixes:104    base1024: Ki | Mi | Gi | Ti | Pi | Ei105    base1000: n | u | m | "" | k | M | G | T | P | E106 107    See https://github.com/kubernetes/apimachinery/blob/master/pkg/api/resource/quantity.go108 109    Input:110    quantity: Decimal.  Quantity as a number which is supposed to converted to a string111                        with SI suffix.112    suffix: string.     The desired suffix/unit-of-measure of the output string113    quantize: Decimal.  Can be used to round/quantize the value before the string114                        is returned. Defaults to None.115 116    Returns:117    string. Canonical Kubernetes quantity string containing the SI suffix.118 119    Raises:120    ValueError if the SI suffix is not supported.121    """122 123    if not suffix:124        return str(quantity_value)125 126    if suffix.endswith("i"):127        base = 1024128    elif len(suffix) == 1:129        base = 1000130    else:131        raise ValueError(f"{quantity_value} has unknown suffix")132 133    if suffix == "ki":134        raise ValueError(f"{quantity_value} has unknown suffix")135 136    if suffix[0] not in _EXPONENTS:137        raise ValueError(f"{quantity_value} has unknown suffix")138 139    different_scale = quantity_value / Decimal(base ** _EXPONENTS[suffix[0]])140    if quantize:141        different_scale = different_scale.quantize(quantize)142    return str(different_scale) + suffix143