Skip to content

Commit

Permalink
add function to parse canonical quantities (e.g. resources)
Browse files Browse the repository at this point in the history
This utility function is useful to parse values like the 200m or 300Gi
memory and cpu resources stored in kubernetes manifests.
It uses Decimal as output format as it usually represents typical input
values more accurately and reduces rounding errors.
  • Loading branch information
juliantaylor committed Aug 24, 2019
1 parent 08fefc3 commit e5b3e6a
Show file tree
Hide file tree
Showing 3 changed files with 174 additions and 0 deletions.
100 changes: 100 additions & 0 deletions kubernetes/test/test_quantity.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,100 @@
# coding: utf-8
# Copyright 2019 The Kubernetes Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from __future__ import absolute_import

import unittest
from kubernetes.utils import parse_quantity
from decimal import Decimal


class TestQuantity(unittest.TestCase):
def test_parse(self):
self.assertIsInstance(parse_quantity(2.2), Decimal)
tests = [
(2, 2),
(2, Decimal("2")),
(2., 2),
(Decimal("2.2"), Decimal("2.2")),
(2., Decimal(2)),
(Decimal("2."), 2),
("123", 123),
("2", 2),
("2m", Decimal("0.002")),
("223k", 223000),
("002M", 2 * 1000**2),
("2M", 2 * 1000**2),
("4123G", 4123 * 1000**3),
("2T", 2 * 1000**4),
("2P", 2 * 1000**5),
("2E", 2 * 1000**6),

("223Ki", 223 * 1024),
("002Mi", 2 * 1024**2),
("2Mi", 2 * 1024**2),
("2Gi", 2 * 1024**3),
("4123Gi", 4123 * 1024**3),
("2Ti", 2 * 1024**4),
("2Pi", 2 * 1024**5),
("2Ei", 2 * 1024**6),

("2.34Ki", Decimal("2.34") * 1024),
("2.34", Decimal("2.34")),
(".34", Decimal("0.34")),
("34.", 34),
(".34M", Decimal("0.34") * 1000**2),

("2e2K", Decimal("2e2") * 1000),
("2e2Ki", Decimal("2e2") * 1024),
("2e-2Ki", Decimal("2e-2") * 1024),
("2.34E1", Decimal("2.34E1")),
(".34e-2", Decimal("0.34e-2")),
]

for inp, out in tests:
self.assertEqual(parse_quantity(inp), out)
if isinstance(inp, (int, float, Decimal)):
self.assertEqual(parse_quantity(-1 * inp), -out)
else:
self.assertEqual(parse_quantity("-" + inp), -out)
self.assertEqual(parse_quantity("+" + inp), out)

def test_parse_invalid(self):
self.assertRaises(ValueError, parse_quantity, [])
self.assertRaises(ValueError, parse_quantity, "")
self.assertRaises(ValueError, parse_quantity, "-")
self.assertRaises(ValueError, parse_quantity, "i")
self.assertRaises(ValueError, parse_quantity, "2i")
self.assertRaises(ValueError, parse_quantity, "2e")
self.assertRaises(ValueError, parse_quantity, "2.2i")
self.assertRaises(ValueError, parse_quantity, "bla")
self.assertRaises(ValueError, parse_quantity, "Ki")
self.assertRaises(ValueError, parse_quantity, "M")
self.assertRaises(ValueError, parse_quantity, "2ki")
self.assertRaises(ValueError, parse_quantity, "2Ki ")
self.assertRaises(ValueError, parse_quantity, "20Ki ")
self.assertRaises(ValueError, parse_quantity, "20B")
self.assertRaises(ValueError, parse_quantity, "20Bi")
self.assertRaises(ValueError, parse_quantity, "20.2Bi")
self.assertRaises(ValueError, parse_quantity, "2MiKi")
self.assertRaises(ValueError, parse_quantity, "2MK")
self.assertRaises(ValueError, parse_quantity, "2MKi")
self.assertRaises(ValueError, parse_quantity, "234df")
self.assertRaises(ValueError, parse_quantity, "df234")
self.assertRaises(ValueError, parse_quantity, tuple())


if __name__ == '__main__':
unittest.main()
1 change: 1 addition & 0 deletions kubernetes/utils/__init__.py
Original file line number Diff line number Diff line change
Expand Up @@ -16,3 +16,4 @@

from .create_from_yaml import (FailToCreateError, create_from_dict,
create_from_yaml)
from .quantity import parse_quantity
73 changes: 73 additions & 0 deletions kubernetes/utils/quantity.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,73 @@
# Copyright 2019 The Kubernetes Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from decimal import Decimal, InvalidOperation


def parse_quantity(quantity):
"""
Parse kubernetes canonical form quantity like 200Mi to a decimal number.
Supported SI suffixes:
base1024: Ki | Mi | Gi | Ti | Pi | Ei
base1000: m | "" | k | M | G | T | P | E
Input:
quanity: string. kubernetes canonical form quantity
Returns:
Decimal
Raises:
ValueError on invalid or unknown input
"""
if isinstance(quantity, (int, float, Decimal)):
return Decimal(quantity)

exponents = {"m": -1, "K": 1, "k": 1, "M": 2,
"G": 3, "T": 4, "P": 5, "E": 6}

quantity = str(quantity)
number = quantity
suffix = None
if len(quantity) >= 2 and quantity[-1] == "i":
if quantity[-2] in exponents:
number = quantity[:-2]
suffix = quantity[-2:]
elif len(quantity) >= 1 and quantity[-1] in exponents:
number = quantity[:-1]
suffix = quantity[-1:]

try:
number = Decimal(number)
except InvalidOperation:
raise ValueError("Invalid number format: {}".format(number))

if suffix is None:
return number

if suffix.endswith("i"):
base = 1024
elif len(suffix) == 1:
base = 1000
else:
raise ValueError("{} has unknown suffix".format(quantity))

# handly SI inconsistency
if suffix == "ki":
raise ValueError("{} has unknown suffix".format(quantity))

if suffix[0] not in exponents:
raise ValueError("{} has unknown suffix".format(quantity))

exponent = Decimal(exponents[suffix[0]])
return number * (base ** exponent)

0 comments on commit e5b3e6a

Please sign in to comment.