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@@ -23,4 +23,5 @@ test-report.json | |
junit*.xml | ||
*cov | ||
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*.test | ||
*.test | ||
kubeutils/testdata/fuzz/ |
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changelog: | ||
- type: NON_USER_FACING | ||
description: Fix and make santize faster |
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package kubeutils | ||
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import ( | ||
"bytes" | ||
"crypto/md5" | ||
"encoding/hex" | ||
"hash" | ||
"sync" | ||
) | ||
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// This is an extrememly important number for these shortened names. | ||
// It signifies the spot of separation from the original name and the hash. | ||
// It is used for many string building and parsing operations below. | ||
const magicNumber = 31 | ||
const totalSize = magicNumber*2 + 1 | ||
const encodedMd5 = 2 * md5.Size | ||
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const separator = '-' | ||
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// We can short-circuit the comparison if the first 31 characters are not equal. | ||
// Otherweise we need to compare the shortened version of the strings. | ||
func ShortenedEquals(shortened, standard string) bool { | ||
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// If the standard string is less than 63 characters, we can just compare the strings. | ||
if len(standard) <= totalSize { | ||
return shortened == standard | ||
} | ||
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// If the shortened string is less than or equal to 32 characters, we can just compare the strings. | ||
// Also if it's less than 32 the below checks may crash. | ||
if len(shortened) <= magicNumber+1 { | ||
return shortened == standard | ||
} | ||
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// Check the first 31 characters, if they're not equal we can exit early. | ||
if shortened[:magicNumber] != standard[:magicNumber] { | ||
return false | ||
} | ||
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// If 32nd character of the shortened string is not a '-' or the 32nd character of the standard string is not a '-' | ||
// we can exit early. | ||
// In theory this shouldn't be necessary, but this label can technically be modified by the user, | ||
// so it's safer to double check. | ||
if shortened[magicNumber] != separator { | ||
return false | ||
} | ||
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// Check the last 32 characters of the shortened string against the hash of the standard string. | ||
hashed := hashName(standard) | ||
return shortened[magicNumber+1:] == string(hashed[:magicNumber]) | ||
} | ||
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// shortenName is extrememly inefficient with it's allocation of slices for hashing. | ||
// We can re-use the arrays to avoid this allocation. However, this code may be called | ||
// from multiple go-routines simultaneously so we must house these objects in sync.Pools | ||
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// Pool of MD5 hashers to avoid allocation. | ||
var md5HasherPool = sync.Pool{ | ||
New: func() interface{} { | ||
return md5.New() | ||
}, | ||
} | ||
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// Pool of string builders to avoid allocation. | ||
var byteBufferPool = sync.Pool{ | ||
New: func() interface{} { | ||
b := &bytes.Buffer{} | ||
b.Grow(totalSize) | ||
return b | ||
}, | ||
} | ||
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// hashName returns a hash of the input string in base 16 format | ||
// This function is optimized for speed and memory usage. | ||
// It should aboid nearly all allocations by re-using the same buffers whenever possible. | ||
func hashName(name string) [encodedMd5]byte { | ||
hasher := md5HasherPool.Get().(hash.Hash) | ||
hasher.Reset() | ||
hasher.Write([]byte(name)) | ||
hashArray := [md5.Size]byte{} | ||
hash := hasher.Sum(hashArray[:0]) | ||
// Cannot use hex.EncodedLen() here because it's a func, but it just returns 2 * len(src) | ||
hashBufferArray := [encodedMd5]byte{} | ||
hex.Encode(hashBufferArray[:], hash) | ||
md5HasherPool.Put(hasher) | ||
return hashBufferArray | ||
} | ||
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// shortenName returns a shortened version of the input string. | ||
// It is based on the `kubeutils.SanitizeNameV2` function, but it | ||
// just does the shortening part. | ||
func ShortenName(name string) string { | ||
if len(name) > totalSize { | ||
hash := hashName(name) | ||
builder := byteBufferPool.Get().(*bytes.Buffer) | ||
builder.Reset() | ||
builder.Grow(totalSize) | ||
builder.WriteString(name[:magicNumber]) | ||
builder.WriteRune(separator) | ||
builder.Write(hash[:magicNumber]) | ||
name = builder.String() | ||
byteBufferPool.Put(builder) | ||
} | ||
return name | ||
} |
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package kubeutils | ||
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import ( | ||
"crypto/md5" | ||
"fmt" | ||
"testing" | ||
) | ||
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// This function is a copy of the old version of this function. | ||
// It is used to ensure parity with the old implementation. | ||
// https://github.com/solo-io/gloo-mesh-enterprise/blob/3953b2582ec63bb3cbde567bbc69e19b45ea8f35/pkg/labels/labels.go#L402C1-L409C2 | ||
func shortenName(name string) string { | ||
if len(name) > 63 { | ||
hash := md5.Sum([]byte(name)) | ||
name = fmt.Sprintf("%s-%x", name[:31], hash) | ||
name = name[:63] | ||
} | ||
return name | ||
} | ||
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func BenchmarkShortenEqual(b *testing.B) { | ||
b.Run("shorten name old", func(b *testing.B) { | ||
for i := 0; i < b.N; i++ { | ||
shortenName("jfdklanfkljasfhjhldacaslkhdfkjshfkjsadhfkjasdhgjadhgkdahfjkdahjfdsagdfhjdsagfhasjdfsdfasfsafsdf") | ||
} | ||
}) | ||
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b.Run("shortened equals--worst case", func(b *testing.B) { | ||
shortened := "jfdklanfkljasfhjhldacaslkhdfkjs-f1e0028d0fbfe9afbd1a8bb9b53848d" | ||
standard := "jfdklanfkljasfhjhldacaslkhdfkjshfkjsadhfkjasdhgjadhgkdahfjkdahjfdsagdfhjdsagfhasjdfsdfasfsafsdf" | ||
for i := 0; i < b.N; i++ { | ||
ShortenedEquals(shortened, standard) | ||
} | ||
}) | ||
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b.Run("shortened equals--different prefix", func(b *testing.B) { | ||
shortened := "jfdklanfkljasfhjhlxacaslkhdfkjs-f1e0028d0fbfe9afbd1a8bb9b53848d" | ||
standard := "jfdklanfkljasfhjhldacaslkhdfkjshfkjsadhfkjasdhgjadhgkdahfjkdahjfdsagdfhjdsagfhasjdfsdfasfsafsdf" | ||
for i := 0; i < b.N; i++ { | ||
ShortenedEquals(shortened, standard) | ||
} | ||
}) | ||
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b.Run("shortened equals--less than 63 characters", func(b *testing.B) { | ||
shortened := "hello" | ||
standard := "hello" | ||
for i := 0; i < b.N; i++ { | ||
ShortenedEquals(shortened, standard) | ||
} | ||
}) | ||
} | ||
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func FuzzShortNameParity(f *testing.F) { | ||
// Random string < 63 | ||
f.Add("hello") | ||
// Random string > 63 | ||
f.Add("jfdklanfkljasfhjhldacaslkhdfkjshfkjsadhfkjasdhgjadhgkdahfjkdahjfdsagdfhjdsagfhasjdfsdfasfsafsdf") | ||
f.Fuzz(func(t *testing.T, a string) { | ||
oldName := shortenName(a) | ||
newName := ShortenName(a) | ||
if oldName != newName { | ||
t.Fatalf("shortenName(%s) = %s, ShortenName(%s) = %s", a, oldName, a, newName) | ||
} | ||
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equal := ShortenedEquals(newName, a) | ||
if !equal { | ||
t.Fatalf("ShortenedEquals(%s, %s) = %t", newName, a, equal) | ||
} | ||
}) | ||
} | ||
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func TestShortenName(t *testing.T) { | ||
t.Run("shorten name < 63", func(t *testing.T) { | ||
name := "hello" | ||
shortened := ShortenName(name) | ||
if shortened != name { | ||
t.Fatalf("ShortenName(%s) = %s", name, shortened) | ||
} | ||
}) | ||
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t.Run("shorten name > 63", func(t *testing.T) { | ||
name := "jfdklanfkljasfhjhldacaslkhdfkjshfkjsadhfkjasdhgjadhgkdahfjkdahjfdsagdfhjdsagfhasjdfsdfasfsafsdf" | ||
shortened := ShortenName(name) | ||
if len(shortened) != 63 { | ||
t.Fatalf("ShortenName(%s) = %s", name, shortened) | ||
} | ||
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if shortened != "jfdklanfkljasfhjhldacaslkhdfkjs-f1e0028d0fbfe9afbd1a8bb9b53848d" { | ||
t.Fatalf("ShortenName(%s) = %s", name, shortened) | ||
} | ||
}) | ||
} | ||
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func TestShortenedEquals(t *testing.T) { | ||
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testCases := []struct { | ||
name string | ||
shortened string | ||
equal bool | ||
}{ | ||
{ | ||
name: "hello", | ||
shortened: "hello", | ||
equal: true, | ||
}, | ||
{ | ||
name: "jfdklanfkljasfhjhldacaslkhdfkjshfkjsadhfkjasdhgjadhgkdahfjkdahjfdsagdfhjdsagfhasjdfsdfasfsafsdf", | ||
shortened: "jfdklanfkljasfhjhldacaslkhdfkjs-f1e0028d0fbfe9afbd1a8bb9b53848d", | ||
equal: true, | ||
}, | ||
{ | ||
name: "jfdklanfkljasfhjhldacaslkhdfkjshfkjsadhfkjasdhgjadhgkdahfjkdahjfdsagdfhjdsagfhasjdfsdfasfsafsdf", | ||
shortened: "jfdklanfkljasfhjhldacaslkhdfkjs-f1e0028d0fbfe9afbd1a8bb9b53848", | ||
equal: false, | ||
}, | ||
{ | ||
name: "jfdklanfkljasfhjhldacaslkhdfkjshfkjsadhfkjasdhgjadhgkdahfjkdahjfdsagdfhjdsagfhasjdfsdfasfsafsdf", | ||
shortened: "jfdklanfkljasfhjhldacaslkhdfkjsf1e0028d0fbfe9afbd1a8bb9b53848ds", | ||
equal: false, | ||
}, | ||
{ | ||
name: "jfdklanfkljasfhjhldacaslkhdfkjshfkjsadhfkjasdhgjadhgkdahfjkdahjfdsagdfhjdsagfhasjdfsdfasfsafsdf", | ||
shortened: "jfdklanfkjasfhjhldacaslkhdfkjs-f1e0028d0fbfe9afbd1a8bb9b53848ds", | ||
equal: false, | ||
}, | ||
} | ||
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for _, tc := range testCases { | ||
t.Run(tc.name, func(t *testing.T) { | ||
equal := ShortenedEquals(tc.shortened, tc.name) | ||
if equal != tc.equal { | ||
t.Fatalf("ShortenedEquals(%s, %s) = %t", tc.shortened, tc.name, equal) | ||
} | ||
}) | ||
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} | ||
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} |
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