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Merge pull request #87 from prometheus/beorn7/fingerprint 

Unify fingerprinting aka signature calculation.
This commit is contained in:
Björn Rabenstein 2015-03-03 18:03:08 +01:00
parent de5f7a2db9 af21d456db
commit cbe3ef2442
5 changed files with 211 additions and 92 deletions
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34
model/metric.go
View File

@ -14,10 +14,8 @@
package model
import (
"encoding/binary"
"encoding/json"
"fmt"
"hash/fnv"
"sort"
"strings"
)
@ -66,37 +64,7 @@ func (m Metric) String() string {
// Fingerprint returns a Metric's Fingerprint.
func (m Metric) Fingerprint() Fingerprint {
labelNames := make([]string, 0, len(m))
maxLength := 0
for labelName, labelValue := range m {
labelNames = append(labelNames, string(labelName))
if len(labelName) > maxLength {
maxLength = len(labelName)
}
if len(labelValue) > maxLength {
maxLength = len(labelValue)
}
}
sort.Strings(labelNames)
summer := fnv.New64a()
buf := make([]byte, maxLength)
for _, labelName := range labelNames {
labelValue := m[LabelName(labelName)]
copy(buf, labelName)
summer.Write(buf[:len(labelName)])
summer.Write(separator)
copy(buf, labelValue)
summer.Write(buf[:len(labelValue)])
}
return Fingerprint(binary.LittleEndian.Uint64(summer.Sum(nil)))
return metricToFingerprint(m)
}
// Clone returns a copy of the Metric.

14
model/metric_test.go
View File

@ -22,7 +22,7 @@ func testMetric(t testing.TB) {
}{
{
input: Metric{},
fingerprint: 2676020557754725067,
fingerprint: 14695981039346656037,
},
{
input: Metric{
@ -30,31 +30,27 @@ func testMetric(t testing.TB) {
"occupation": "robot",
"manufacturer": "westinghouse",
},
fingerprint: 13260944541294022935,
fingerprint: 11310079640881077873,
},
{
input: Metric{
"x": "y",
},
fingerprint: 1470933794305433534,
fingerprint: 13948396922932177635,
},
// The following two demonstrate a bug in fingerprinting. They
// should not have the same fingerprint with a sane
// fingerprinting function. See
// https://github.com/prometheus/client_golang/issues/74 .
{
input: Metric{
"a": "bb",
"b": "c",
},
fingerprint: 3734646176939799877,
fingerprint: 3198632812309449502,
},
{
input: Metric{
"a": "b",
"bb": "c",
},
fingerprint: 3734646176939799877,
fingerprint: 5774953389407657638,
},
}

74
model/signature.go
View File

@ -63,10 +63,10 @@ func LabelsToSignature(labels map[string]string) uint64 {
hb := getHashAndBuf()
defer putHashAndBuf(hb)
for k, v := range labels {
hb.b.WriteString(k)
for labelName, labelValue := range labels {
hb.b.WriteString(labelName)
hb.b.WriteByte(SeparatorByte)
hb.b.WriteString(v)
hb.b.WriteString(labelValue)
hb.h.Write(hb.b.Bytes())
result ^= hb.h.Sum64()
hb.h.Reset()
@ -75,10 +75,34 @@ func LabelsToSignature(labels map[string]string) uint64 {
return result
}
// LabelValuesToSignature returns a unique signature (i.e., fingerprint) for the
// values of a given label set.
func LabelValuesToSignature(labels map[string]string) uint64 {
if len(labels) == 0 {
// metricToFingerprint works exactly as LabelsToSignature but takes a Metric as
// parameter (rather than a label map) and returns a Fingerprint.
func metricToFingerprint(m Metric) Fingerprint {
if len(m) == 0 {
return Fingerprint(emptyLabelSignature)
}
var result uint64
hb := getHashAndBuf()
defer putHashAndBuf(hb)
for labelName, labelValue := range m {
hb.b.WriteString(string(labelName))
hb.b.WriteByte(SeparatorByte)
hb.b.WriteString(string(labelValue))
hb.h.Write(hb.b.Bytes())
result ^= hb.h.Sum64()
hb.h.Reset()
hb.b.Reset()
}
return Fingerprint(result)
}
// SignatureForLabels works like LabelsToSignature but takes a Metric as
// parameter (rather than a label map) and only includes the labels with the
// specified LabelNames into the signature calculation.
func SignatureForLabels(m Metric, labels LabelNames) uint64 {
if len(m) == 0 || len(labels) == 0 {
return emptyLabelSignature
}
@ -86,8 +110,10 @@ func LabelValuesToSignature(labels map[string]string) uint64 {
hb := getHashAndBuf()
defer putHashAndBuf(hb)
for _, v := range labels {
hb.b.WriteString(v)
for _, label := range labels {
hb.b.WriteString(string(label))
hb.b.WriteByte(SeparatorByte)
hb.b.WriteString(string(m[label]))
hb.h.Write(hb.b.Bytes())
result ^= hb.h.Sum64()
hb.h.Reset()
@ -95,3 +121,33 @@ func LabelValuesToSignature(labels map[string]string) uint64 {
}
return result
}
// SignatureWithoutLabels works like LabelsToSignature but takes a Metric as
// parameter (rather than a label map) and excludes the labels with any of the
// specified LabelNames from the signature calculation.
func SignatureWithoutLabels(m Metric, labels map[LabelName]struct{}) uint64 {
if len(m) == 0 {
return emptyLabelSignature
}
var result uint64
hb := getHashAndBuf()
defer putHashAndBuf(hb)
for labelName, labelValue := range m {
if _, exclude := labels[labelName]; exclude {
continue
}
hb.b.WriteString(string(labelName))
hb.b.WriteByte(SeparatorByte)
hb.b.WriteString(string(labelValue))
hb.h.Write(hb.b.Bytes())
result ^= hb.h.Sum64()
hb.h.Reset()
hb.b.Reset()
}
if result == 0 {
return emptyLabelSignature
}
return result
}

180
model/signature_test.go
View File

@ -18,7 +18,7 @@ import (
"testing"
)
func testLabelsToSignature(t testing.TB) {
func TestLabelsToSignature(t *testing.T) {
var scenarios = []struct {
in map[string]string
out uint64
@ -42,57 +42,112 @@ func testLabelsToSignature(t testing.TB) {
}
}
func TestLabelToSignature(t *testing.T) {
testLabelsToSignature(t)
}
func TestEmptyLabelSignature(t *testing.T) {
input := []map[string]string{nil, {}}
var ms runtime.MemStats
runtime.ReadMemStats(&ms)
alloc := ms.Alloc
for _, labels := range input {
LabelsToSignature(labels)
func TestMetricToFingerprint(t *testing.T) {
var scenarios = []struct {
in Metric
out Fingerprint
}{
{
in: Metric{},
out: 14695981039346656037,
},
{
in: Metric{"name": "garland, briggs", "fear": "love is not enough"},
out: 12952432476264840823,
},
}
runtime.ReadMemStats(&ms)
for i, scenario := range scenarios {
actual := metricToFingerprint(scenario.in)
if got := ms.Alloc; alloc != got {
t.Fatal("expected LabelsToSignature with empty labels not to perform allocations")
}
}
func BenchmarkLabelToSignature(b *testing.B) {
for i := 0; i < b.N; i++ {
testLabelsToSignature(b)
}
}
func benchmarkLabelValuesToSignature(b *testing.B, l map[string]string, e uint64) {
for i := 0; i < b.N; i++ {
if a := LabelValuesToSignature(l); a != e {
b.Fatalf("expected signature of %d for %s, got %d", e, l, a)
if actual != scenario.out {
t.Errorf("%d. expected %d, got %d", i, scenario.out, actual)
}
}
}
func BenchmarkLabelValuesToSignatureScalar(b *testing.B) {
benchmarkLabelValuesToSignature(b, nil, 14695981039346656037)
func TestSignatureForLabels(t *testing.T) {
var scenarios = []struct {
in Metric
labels LabelNames
out uint64
}{
{
in: Metric{},
labels: nil,
out: 14695981039346656037,
},
{
in: Metric{"name": "garland, briggs", "fear": "love is not enough"},
labels: LabelNames{"fear", "name"},
out: 12952432476264840823,
},
{
in: Metric{"name": "garland, briggs", "fear": "love is not enough", "foo": "bar"},
labels: LabelNames{"fear", "name"},
out: 12952432476264840823,
},
{
in: Metric{"name": "garland, briggs", "fear": "love is not enough"},
labels: LabelNames{},
out: 14695981039346656037,
},
{
in: Metric{"name": "garland, briggs", "fear": "love is not enough"},
labels: nil,
out: 14695981039346656037,
},
}
for i, scenario := range scenarios {
actual := SignatureForLabels(scenario.in, scenario.labels)
if actual != scenario.out {
t.Errorf("%d. expected %d, got %d", i, scenario.out, actual)
}
}
}
func BenchmarkLabelValuesToSignatureSingle(b *testing.B) {
benchmarkLabelValuesToSignature(b, map[string]string{"first-label": "first-label-value"}, 2653746141194979650)
}
func TestSignatureWithoutLabels(t *testing.T) {
var scenarios = []struct {
in Metric
labels map[LabelName]struct{}
out uint64
}{
{
in: Metric{},
labels: nil,
out: 14695981039346656037,
},
{
in: Metric{"name": "garland, briggs", "fear": "love is not enough"},
labels: map[LabelName]struct{}{"fear": struct{}{}, "name": struct{}{}},
out: 14695981039346656037,
},
{
in: Metric{"name": "garland, briggs", "fear": "love is not enough", "foo": "bar"},
labels: map[LabelName]struct{}{"foo": struct{}{}},
out: 12952432476264840823,
},
{
in: Metric{"name": "garland, briggs", "fear": "love is not enough"},
labels: map[LabelName]struct{}{},
out: 12952432476264840823,
},
{
in: Metric{"name": "garland, briggs", "fear": "love is not enough"},
labels: nil,
out: 12952432476264840823,
},
}
func BenchmarkLabelValuesToSignatureDouble(b *testing.B) {
benchmarkLabelValuesToSignature(b, map[string]string{"first-label": "first-label-value", "second-label": "second-label-value"}, 8893559499616767364)
}
for i, scenario := range scenarios {
actual := SignatureWithoutLabels(scenario.in, scenario.labels)
func BenchmarkLabelValuesToSignatureTriple(b *testing.B) {
benchmarkLabelValuesToSignature(b, map[string]string{"first-label": "first-label-value", "second-label": "second-label-value", "third-label": "third-label-value"}, 1685970066862087833)
if actual != scenario.out {
t.Errorf("%d. expected %d, got %d", i, scenario.out, actual)
}
}
}
func benchmarkLabelToSignature(b *testing.B, l map[string]string, e uint64) {
@ -118,3 +173,46 @@ func BenchmarkLabelToSignatureDouble(b *testing.B) {
func BenchmarkLabelToSignatureTriple(b *testing.B) {
benchmarkLabelToSignature(b, map[string]string{"first-label": "first-label-value", "second-label": "second-label-value", "third-label": "third-label-value"}, 15738406913934009676)
}
func benchmarkMetricToFingerprint(b *testing.B, m Metric, e Fingerprint) {
for i := 0; i < b.N; i++ {
if a := metricToFingerprint(m); a != e {
b.Fatalf("expected signature of %d for %s, got %d", e, m, a)
}
}
}
func BenchmarkMetricToFingerprintScalar(b *testing.B) {
benchmarkMetricToFingerprint(b, nil, 14695981039346656037)
}
func BenchmarkMetricToFingerprintSingle(b *testing.B) {
benchmarkMetricToFingerprint(b, Metric{"first-label": "first-label-value"}, 5147259542624943964)
}
func BenchmarkMetricToFingerprintDouble(b *testing.B) {
benchmarkMetricToFingerprint(b, Metric{"first-label": "first-label-value", "second-label": "second-label-value"}, 18269973311206963528)
}
func BenchmarkMetricToFingerprintTriple(b *testing.B) {
benchmarkMetricToFingerprint(b, Metric{"first-label": "first-label-value", "second-label": "second-label-value", "third-label": "third-label-value"}, 15738406913934009676)
}
func TestEmptyLabelSignature(t *testing.T) {
input := []map[string]string{nil, {}}
var ms runtime.MemStats
runtime.ReadMemStats(&ms)
alloc := ms.Alloc
for _, labels := range input {
LabelsToSignature(labels)
}
runtime.ReadMemStats(&ms)
if got := ms.Alloc; alloc != got {
t.Fatal("expected LabelsToSignature with empty labels not to perform allocations")
}
}

1
model/timestamp.go
View File

@ -88,6 +88,7 @@ func (t Timestamp) String() string {
return strconv.FormatFloat(float64(t)/float64(second), 'f', -1, 64)
}
// MarshalJSON implements the json.Marshaler interface.
func (t Timestamp) MarshalJSON() ([]byte, error) {
return []byte(t.String()), nil
}