mirror of https://github.com/k3s-io/k3s
41 lines
1.3 KiB
Go
41 lines
1.3 KiB
Go
/*
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Copyright 2019 The Kubernetes 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 discovery
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import (
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"crypto/sha256"
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"encoding/base64"
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)
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// StorageVersionHash calculates the storage version hash for a
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// <group/version/kind> tuple.
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// WARNING: this function is subject to change. Clients shouldn't depend on
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// this function.
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func StorageVersionHash(group, version, kind string) string {
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gvk := group + "/" + version + "/" + kind
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if gvk == "" {
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return ""
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}
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bytes := sha256.Sum256([]byte(gvk))
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// Assuming there are N kinds in the cluster, and the hash is X-byte long,
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// the chance of colliding hash P(N,X) approximates to 1-e^(-(N^2)/2^(8X+1)).
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// P(10,000, 8) ~= 2.7*10^(-12), which is low enough.
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// See https://en.wikipedia.org/wiki/Birthday_problem#Approximations.
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return base64.StdEncoding.EncodeToString(
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bytes[:8])
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}
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