e35cb361c8
Signed-off-by: Krzysztof Ostrowski <kostrows@redhat.com> Co-authored-by: Irbe Krumina <irbekrm@gmail.com>
59 lines
1.7 KiB
Go
59 lines
1.7 KiB
Go
/*
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Copyright 2020 The cert-manager Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package util
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import (
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"encoding/json"
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"fmt"
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"hash/fnv"
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"regexp"
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)
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// ComputeName hashes the given object and prefixes it with prefix.
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// The algorithm in use is Fowler–Noll–Vo hash function and is not
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// cryptographically secure. Using a cryptographically secure hash is
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// not necessary.
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func ComputeName(prefix string, obj interface{}) (string, error) {
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objectBytes, err := json.Marshal(obj)
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if err != nil {
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return "", err
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}
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hashF := fnv.New32()
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_, err = hashF.Write(objectBytes)
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if err != nil {
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return "", err
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}
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// we're shortening to stay under 64 as we use this in services
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// and pods down the road for ACME resources.
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prefix = DNSSafeShortenTo52Characters(prefix)
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return fmt.Sprintf("%s-%d", prefix, hashF.Sum32()), nil
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}
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// DNSSafeShortenTo52Characters shortens the input string to 52 chars and ensures the last char is an alpha-numeric character.
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func DNSSafeShortenTo52Characters(in string) string {
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if len(in) >= 52 {
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validCharIndexes := regexp.MustCompile(`[a-zA-Z\d]`).FindAllStringIndex(fmt.Sprintf("%.52s", in), -1)
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in = in[:validCharIndexes[len(validCharIndexes)-1][1]]
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}
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return in
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}
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