VictoriaMetrics/lib/storage/metric_name.go
Andrii Chubatiuk 9cfdbc582f
refactoring: changed prompb to prompbmarshal everythere where internal series transformations are happening (#7409)
### Describe Your Changes

doing similar changes for both vmagent and vminsert (like one in
https://github.com/VictoriaMetrics/VictoriaMetrics/pull/7399) ends up
with almost same implementations for each of packages instead of having
this shared code in one place. one of the reasons is the same Timeseries
and Labels structure from different prompb and prompbmarshal packages.
My proposal is to use structures from prompb package only to
marshal/unmarshal sent/received data, but for internal transformations
use only structures from prompbmarshal package

Another example, where it already can help to simplify code is streaming
aggregation pipeline for vmsingle (now it first marshals
prompb.Timeseries to storage.MetricRow and then if streaming aggregation
or deduplication is enabled it unmarshals all the series back but to
prompbmarshal.Timeseries)

### Checklist

The following checks are **mandatory**:

- [ ] My change adheres [VictoriaMetrics contributing
guidelines](https://docs.victoriametrics.com/contributing/).
2024-11-26 12:45:17 +01:00

844 lines
21 KiB
Go

package storage
import (
"bytes"
"fmt"
"runtime"
"sort"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/encoding"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/prompbmarshal"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/slicesutil"
)
const (
escapeChar = 0
tagSeparatorChar = 1
kvSeparatorChar = 2
)
// Tag represents a (key, value) tag for metric.
type Tag struct {
Key []byte
Value []byte
}
// Reset resets the tag.
func (tag *Tag) Reset() {
tag.Key = tag.Key[:0]
tag.Value = tag.Value[:0]
}
// Equal returns true if tag equals t
func (tag *Tag) Equal(t *Tag) bool {
return string(tag.Key) == string(t.Key) && string(tag.Value) == string(t.Value)
}
// Marshal appends marshaled tag to dst and returns the result.
func (tag *Tag) Marshal(dst []byte) []byte {
dst = marshalTagValue(dst, tag.Key)
dst = marshalTagValue(dst, tag.Value)
return dst
}
// Unmarshal unmarshals tag from src and returns the remaining data from src.
func (tag *Tag) Unmarshal(src []byte) ([]byte, error) {
var err error
src, tag.Key, err = unmarshalTagValue(tag.Key[:0], src)
if err != nil {
return src, fmt.Errorf("cannot unmarshal key: %w", err)
}
src, tag.Value, err = unmarshalTagValue(tag.Value[:0], src)
if err != nil {
return src, fmt.Errorf("cannot unmarshal value: %w", err)
}
return src, nil
}
func (tag *Tag) copyFrom(src *Tag) {
tag.Key = append(tag.Key[:0], src.Key...)
tag.Value = append(tag.Value[:0], src.Value...)
}
func marshalTagValueNoTrailingTagSeparator(dst []byte, src string) []byte {
dst = marshalTagValue(dst, bytesutil.ToUnsafeBytes(src))
// Remove trailing tagSeparatorChar
return dst[:len(dst)-1]
}
func marshalTagValue(dst, src []byte) []byte {
n1 := bytes.IndexByte(src, escapeChar)
n2 := bytes.IndexByte(src, tagSeparatorChar)
n3 := bytes.IndexByte(src, kvSeparatorChar)
if n1 < 0 && n2 < 0 && n3 < 0 {
// Fast path.
dst = append(dst, src...)
dst = append(dst, tagSeparatorChar)
return dst
}
// Slow path.
for _, ch := range src {
switch ch {
case escapeChar:
dst = append(dst, escapeChar, '0')
case tagSeparatorChar:
dst = append(dst, escapeChar, '1')
case kvSeparatorChar:
dst = append(dst, escapeChar, '2')
default:
dst = append(dst, ch)
}
}
dst = append(dst, tagSeparatorChar)
return dst
}
func unmarshalTagValue(dst, src []byte) ([]byte, []byte, error) {
n := bytes.IndexByte(src, tagSeparatorChar)
if n < 0 {
return src, dst, fmt.Errorf("cannot find the end of tag value")
}
b := src[:n]
src = src[n+1:]
for {
n := bytes.IndexByte(b, escapeChar)
if n < 0 {
dst = append(dst, b...)
return src, dst, nil
}
dst = append(dst, b[:n]...)
b = b[n+1:]
if len(b) == 0 {
return src, dst, fmt.Errorf("missing escaped char")
}
switch b[0] {
case '0':
dst = append(dst, escapeChar)
case '1':
dst = append(dst, tagSeparatorChar)
case '2':
dst = append(dst, kvSeparatorChar)
default:
return src, dst, fmt.Errorf("unsupported escaped char: %c", b[0])
}
b = b[1:]
}
}
// MetricName reperesents a metric name.
type MetricName struct {
MetricGroup []byte
// Tags are optional. They must be sorted by tag Key for canonical view.
// Use sortTags method.
Tags []Tag
}
// GetMetricName returns a MetricName from pool.
func GetMetricName() *MetricName {
v := mnPool.Get()
if v == nil {
return &MetricName{}
}
return v.(*MetricName)
}
// PutMetricName returns mn to the pool.
func PutMetricName(mn *MetricName) {
mn.Reset()
mnPool.Put(mn)
}
var mnPool sync.Pool
// Reset resets the mn.
func (mn *MetricName) Reset() {
mn.MetricGroup = mn.MetricGroup[:0]
mn.Tags = mn.Tags[:0]
}
// MoveFrom moves src to mn.
//
// The src is reset after the call.
func (mn *MetricName) MoveFrom(src *MetricName) {
*mn = *src
*src = MetricName{}
}
// CopyFrom copies src to mn.
func (mn *MetricName) CopyFrom(src *MetricName) {
if cap(mn.MetricGroup) > 0 {
mn.MetricGroup = append(mn.MetricGroup[:0], src.MetricGroup...)
mn.Tags = copyTags(mn.Tags[:0], src.Tags)
return
}
// Pre-allocate a single byte slice for MetricGroup + all the tags.
// This reduces the number of memory allocations for zero mn.
size := len(src.MetricGroup)
for i := range src.Tags {
tag := &src.Tags[i]
size += len(tag.Key)
size += len(tag.Value)
}
b := make([]byte, 0, size)
b = append(b, src.MetricGroup...)
mn.MetricGroup = b[:len(b):len(b)]
mn.Tags = make([]Tag, len(src.Tags))
for i := range src.Tags {
st := &src.Tags[i]
dt := &mn.Tags[i]
b = append(b, st.Key...)
dt.Key = b[len(b)-len(st.Key) : len(b) : len(b)]
b = append(b, st.Value...)
dt.Value = b[len(b)-len(st.Value) : len(b) : len(b)]
}
}
// AddTag adds new tag to mn with the given key and value.
func (mn *MetricName) AddTag(key, value string) {
if key == string(metricGroupTagKey) {
mn.MetricGroup = append(mn.MetricGroup, value...)
return
}
tag := mn.addNextTag()
tag.Key = append(tag.Key[:0], key...)
tag.Value = append(tag.Value[:0], value...)
}
// AddTagBytes adds new tag to mn with the given key and value.
func (mn *MetricName) AddTagBytes(key, value []byte) {
if string(key) == string(metricGroupTagKey) {
mn.MetricGroup = append(mn.MetricGroup, value...)
return
}
tag := mn.addNextTag()
tag.Key = append(tag.Key[:0], key...)
tag.Value = append(tag.Value[:0], value...)
}
func (mn *MetricName) addNextTag() *Tag {
if len(mn.Tags) < cap(mn.Tags) {
mn.Tags = mn.Tags[:len(mn.Tags)+1]
} else {
mn.Tags = append(mn.Tags, Tag{})
}
return &mn.Tags[len(mn.Tags)-1]
}
// ResetMetricGroup resets mn.MetricGroup
func (mn *MetricName) ResetMetricGroup() {
mn.MetricGroup = mn.MetricGroup[:0]
}
var metricGroupTagKey = []byte("__name__")
// RemoveTagsOn removes all the tags not included to onTags.
func (mn *MetricName) RemoveTagsOn(onTags []string) {
if !hasTag(onTags, metricGroupTagKey) {
mn.ResetMetricGroup()
}
tags := mn.Tags
mn.Tags = mn.Tags[:0]
if len(onTags) == 0 {
return
}
for i := range tags {
tag := &tags[i]
if hasTag(onTags, tag.Key) {
mn.AddTagBytes(tag.Key, tag.Value)
}
}
}
// RemoveTag removes a tag with the given tagKey
func (mn *MetricName) RemoveTag(tagKey string) {
if tagKey == "__name__" {
mn.ResetMetricGroup()
return
}
tags := mn.Tags
mn.Tags = mn.Tags[:0]
for i := range tags {
tag := &tags[i]
if string(tag.Key) != tagKey {
mn.AddTagBytes(tag.Key, tag.Value)
}
}
}
// RemoveTagsIgnoring removes all the tags included in ignoringTags.
func (mn *MetricName) RemoveTagsIgnoring(ignoringTags []string) {
if len(ignoringTags) == 0 {
return
}
if hasTag(ignoringTags, metricGroupTagKey) {
mn.ResetMetricGroup()
}
tags := mn.Tags
mn.Tags = mn.Tags[:0]
for i := range tags {
tag := &tags[i]
if !hasTag(ignoringTags, tag.Key) {
mn.AddTagBytes(tag.Key, tag.Value)
}
}
}
// GetTagValue returns tag value for the given tagKey.
func (mn *MetricName) GetTagValue(tagKey string) []byte {
if tagKey == "__name__" {
return mn.MetricGroup
}
tags := mn.Tags
for i := range tags {
tag := &tags[i]
if string(tag.Key) == tagKey {
return tag.Value
}
}
return nil
}
// SetTags sets tags from src with keys matching addTags.
//
// It adds prefix to copied label names.
// skipTags contains a list of tags, which must be skipped.
func (mn *MetricName) SetTags(addTags []string, prefix string, skipTags []string, src *MetricName) {
if len(addTags) == 1 && addTags[0] == "*" {
// Special case for copying all the tags except of skipTags from src to mn.
mn.setAllTags(prefix, skipTags, src)
return
}
bb := bbPool.Get()
for _, tagName := range addTags {
if containsString(skipTags, tagName) {
continue
}
if tagName == string(metricGroupTagKey) {
mn.MetricGroup = append(mn.MetricGroup[:0], src.MetricGroup...)
continue
}
var srcTag *Tag
for i := range src.Tags {
t := &src.Tags[i]
if string(t.Key) == tagName {
srcTag = t
break
}
}
if srcTag == nil {
mn.RemoveTag(tagName)
continue
}
bb.B = append(bb.B[:0], prefix...)
bb.B = append(bb.B, tagName...)
mn.SetTagBytes(bb.B, srcTag.Value)
}
bbPool.Put(bb)
}
var bbPool bytesutil.ByteBufferPool
// SetTagBytes sets tag with the given key to the given value.
func (mn *MetricName) SetTagBytes(key, value []byte) {
for i := range mn.Tags {
t := &mn.Tags[i]
if string(t.Key) == string(key) {
t.Value = append(t.Value[:0], value...)
return
}
}
mn.AddTagBytes(key, value)
}
func (mn *MetricName) setAllTags(prefix string, skipTags []string, src *MetricName) {
bb := bbPool.Get()
for _, tag := range src.Tags {
if containsString(skipTags, bytesutil.ToUnsafeString(tag.Key)) {
continue
}
bb.B = append(bb.B[:0], prefix...)
bb.B = append(bb.B, tag.Key...)
mn.SetTagBytes(bb.B, tag.Value)
}
bbPool.Put(bb)
}
func containsString(a []string, s string) bool {
for _, x := range a {
if x == s {
return true
}
}
return false
}
func hasTag(tags []string, key []byte) bool {
for _, t := range tags {
if t == string(key) {
return true
}
}
return false
}
// String returns user-readable representation of the metric name.
func (mn *MetricName) String() string {
var mnCopy MetricName
mnCopy.CopyFrom(mn)
mnCopy.sortTags()
var tags []string
for i := range mnCopy.Tags {
t := &mnCopy.Tags[i]
tags = append(tags, fmt.Sprintf("%s=%q", t.Key, t.Value))
}
tagsStr := strings.Join(tags, ",")
return fmt.Sprintf("%s{%s}", mnCopy.MetricGroup, tagsStr)
}
// Marshal appends marshaled mn to dst and returns the result.
//
// mn.sortTags must be called before calling this function
// in order to sort and de-duplcate tags.
func (mn *MetricName) Marshal(dst []byte) []byte {
// Calculate the required size and pre-allocate space in dst
dstLen := len(dst)
requiredSize := len(mn.MetricGroup) + 1
for i := range mn.Tags {
tag := &mn.Tags[i]
requiredSize += len(tag.Key) + len(tag.Value) + 2
}
dst = bytesutil.ResizeWithCopyMayOverallocate(dst, requiredSize)[:dstLen]
// Marshal MetricGroup
dst = marshalTagValue(dst, mn.MetricGroup)
// Marshal tags.
tags := mn.Tags
for i := range tags {
t := &tags[i]
dst = t.Marshal(dst)
}
return dst
}
// UnmarshalString unmarshals mn from s
func (mn *MetricName) UnmarshalString(s string) error {
b := bytesutil.ToUnsafeBytes(s)
err := mn.Unmarshal(b)
runtime.KeepAlive(s)
return err
}
// Unmarshal unmarshals mn from src.
func (mn *MetricName) Unmarshal(src []byte) error {
// Unmarshal MetricGroup.
var err error
src, mn.MetricGroup, err = unmarshalTagValue(mn.MetricGroup[:0], src)
if err != nil {
return fmt.Errorf("cannot unmarshal MetricGroup: %w", err)
}
mn.Tags = mn.Tags[:0]
for len(src) > 0 {
tag := mn.addNextTag()
var err error
src, err = tag.Unmarshal(src)
if err != nil {
return fmt.Errorf("cannot unmarshal tag: %w", err)
}
}
// There is no need in verifying for identical tag keys,
// since they must be handled by MetricName.sortTags before calling MetricName.Marshal.
return nil
}
// The maximum length of label name.
//
// Longer names are truncated.
const maxLabelNameLen = 256
// The maximum length of label value.
//
// Longer values are truncated.
var maxLabelValueLen = 1024
// SetMaxLabelValueLen sets the limit on the label value length.
//
// This function can be called before using the storage package.
//
// Label values with longer length are truncated.
func SetMaxLabelValueLen(n int) {
if n > 0 {
maxLabelValueLen = n
}
}
// The maximum number of labels per each timeseries.
var maxLabelsPerTimeseries = 30
// SetMaxLabelsPerTimeseries sets the limit on the number of labels
// per each time series.
//
// This function can be called before using the storage package.
//
// Superfluous labels are dropped.
func SetMaxLabelsPerTimeseries(maxLabels int) {
if maxLabels > 0 {
maxLabelsPerTimeseries = maxLabels
}
}
// MarshalMetricNameRaw marshals labels to dst and returns the result.
//
// The result must be unmarshaled with MetricName.UnmarshalRaw
func MarshalMetricNameRaw(dst []byte, labels []prompbmarshal.Label) []byte {
// Calculate the required space for dst.
dstLen := len(dst)
dstSize := dstLen
for i := range labels {
if i >= maxLabelsPerTimeseries {
trackDroppedLabels(labels, labels[i:])
break
}
label := &labels[i]
if len(label.Name) > maxLabelNameLen {
TooLongLabelNames.Add(1)
label.Name = label.Name[:maxLabelNameLen]
}
if len(label.Value) > maxLabelValueLen {
trackTruncatedLabels(labels, label)
label.Value = label.Value[:maxLabelValueLen]
}
if len(label.Value) == 0 {
// Skip labels without values, since they have no sense in prometheus.
continue
}
if string(label.Name) == "__name__" {
label.Name = label.Name[:0]
}
dstSize += len(label.Name)
dstSize += len(label.Value)
dstSize += 4
}
dst = bytesutil.ResizeWithCopyMayOverallocate(dst, dstSize)[:dstLen]
// Marshal labels to dst.
for i := range labels {
if i >= maxLabelsPerTimeseries {
break
}
label := &labels[i]
if len(label.Value) == 0 {
// Skip labels without values, since they have no sense in prometheus.
continue
}
dst = marshalStringFast(dst, label.Name)
dst = marshalStringFast(dst, label.Value)
}
return dst
}
var (
// MetricsWithDroppedLabels is the number of metrics with at least a single dropped label
MetricsWithDroppedLabels atomic.Uint64
// TooLongLabelNames is the number of too long label names
TooLongLabelNames atomic.Uint64
// TooLongLabelValues is the number of too long label values
TooLongLabelValues atomic.Uint64
)
func trackDroppedLabels(labels, droppedLabels []prompbmarshal.Label) {
MetricsWithDroppedLabels.Add(1)
select {
case <-droppedLabelsLogTicker.C:
// Do not call logger.WithThrottler() here, since this will result in increased CPU usage
// because labelsToString() will be called with each trackDroppedLabels call.
logger.Warnf("dropping %d labels for %s; dropped labels: %s; either reduce the number of labels for this metric "+
"or increase -maxLabelsPerTimeseries=%d command-line flag value",
len(droppedLabels), labelsToString(labels), labelsToString(droppedLabels), maxLabelsPerTimeseries)
default:
}
}
func trackTruncatedLabels(labels []prompbmarshal.Label, truncated *prompbmarshal.Label) {
TooLongLabelValues.Add(1)
select {
case <-truncatedLabelsLogTicker.C:
// Do not call logger.WithThrottler() here, since this will result in increased CPU usage
// because labelsToString() will be called with each trackTruncatedLabels call.
logger.Warnf("truncate value for label %s because its length=%d exceeds -maxLabelValueLen=%d; "+
"original labels: %s; either reduce the label value length or increase -maxLabelValueLen command-line flag value",
truncated.Name, len(truncated.Value), maxLabelValueLen, labelsToString(labels))
default:
}
}
var (
droppedLabelsLogTicker = time.NewTicker(5 * time.Second)
truncatedLabelsLogTicker = time.NewTicker(5 * time.Second)
)
func labelsToString(labels []prompbmarshal.Label) string {
labelsCopy := append([]prompbmarshal.Label{}, labels...)
sort.Slice(labelsCopy, func(i, j int) bool {
return string(labelsCopy[i].Name) < string(labelsCopy[j].Name)
})
var b []byte
b = append(b, '{')
for i, label := range labelsCopy {
if len(label.Name) == 0 {
b = append(b, "__name__"...)
} else {
b = append(b, label.Name...)
}
b = append(b, '=')
b = strconv.AppendQuote(b, string(label.Value))
if i < len(labels)-1 {
b = append(b, ',')
}
}
b = append(b, '}')
return string(b)
}
// marshalRaw marshals mn to dst and returns the result.
//
// The results may be unmarshaled with MetricName.UnmarshalRaw.
//
// This function is for testing purposes. MarshalMetricNameRaw must be used
// in prod instead.
func (mn *MetricName) marshalRaw(dst []byte) []byte {
dst = marshalBytesFast(dst, nil)
dst = marshalBytesFast(dst, mn.MetricGroup)
mn.sortTags()
for i := range mn.Tags {
tag := &mn.Tags[i]
dst = marshalBytesFast(dst, tag.Key)
dst = marshalBytesFast(dst, tag.Value)
}
return dst
}
// UnmarshalRaw unmarshals mn encoded with MarshalMetricNameRaw.
func (mn *MetricName) UnmarshalRaw(src []byte) error {
mn.Reset()
for len(src) > 0 {
tail, key, err := unmarshalBytesFast(src)
if err != nil {
return fmt.Errorf("cannot decode key: %w", err)
}
src = tail
tail, value, err := unmarshalBytesFast(src)
if err != nil {
return fmt.Errorf("cannot decode value: %w", err)
}
src = tail
if len(key) == 0 {
mn.MetricGroup = append(mn.MetricGroup[:0], value...)
} else {
mn.AddTagBytes(key, value)
}
}
return nil
}
func marshalStringFast(dst []byte, s string) []byte {
dst = encoding.MarshalUint16(dst, uint16(len(s)))
dst = append(dst, s...)
return dst
}
func marshalBytesFast(dst []byte, s []byte) []byte {
dst = encoding.MarshalUint16(dst, uint16(len(s)))
dst = append(dst, s...)
return dst
}
func unmarshalBytesFast(src []byte) ([]byte, []byte, error) {
if len(src) < 2 {
return src, nil, fmt.Errorf("cannot decode size form src=%X; it must be at least 2 bytes", src)
}
n := encoding.UnmarshalUint16(src)
src = src[2:]
if len(src) < int(n) {
return src, nil, fmt.Errorf("too short src=%X; it must be at least %d bytes", src, n)
}
return src[n:], src[:n], nil
}
// sortTags sorts tags in mn to canonical form needed for storing in the index.
//
// The sortTags tries moving job-like tag to mn.Tags[0], while instance-like tag to mn.Tags[1].
// See commonTagKeys list for job-like and instance-like tags.
// This guarantees that indexdb entries for the same (job, instance) are located
// close to each other on disk. This reduces disk seeks and disk read IO when metrics
// for a particular job and/or instance are read from the disk.
//
// The function also de-duplicates tags with identical keys in mn. The last tag value
// for duplicate tags wins.
//
// Tags sorting is quite slow, so try avoiding it by caching mn
// with sorted tags.
func (mn *MetricName) sortTags() {
if len(mn.Tags) == 0 {
return
}
cts := getCanonicalTags()
cts.tags = slicesutil.SetLength(cts.tags, len(mn.Tags))
dst := cts.tags
for i := range mn.Tags {
tag := &mn.Tags[i]
ct := &dst[i]
ct.key = normalizeTagKey(tag.Key)
ct.tag.copyFrom(tag)
}
cts.tags = dst
// Use sort.Stable instead of sort.Sort in order to preserve the order of tags with duplicate keys.
// The last tag value wins for tags with duplicate keys.
// Use sort.Stable instead of sort.SliceStable, since sort.SliceStable allocates a lot.
sort.Stable(&cts.tags)
j := 0
var prevKey []byte
for i := range cts.tags {
tag := &cts.tags[i].tag
if j > 0 && bytes.Equal(tag.Key, prevKey) {
// Overwrite the previous tag with duplicate key.
j--
} else {
prevKey = tag.Key
}
mn.Tags[j].copyFrom(tag)
j++
}
mn.Tags = mn.Tags[:j]
putCanonicalTags(cts)
}
func getCanonicalTags() *canonicalTags {
v := canonicalTagsPool.Get()
if v == nil {
return &canonicalTags{}
}
return v.(*canonicalTags)
}
func putCanonicalTags(cts *canonicalTags) {
cts.tags = cts.tags[:0]
canonicalTagsPool.Put(cts)
}
var canonicalTagsPool sync.Pool
type canonicalTags struct {
tags canonicalTagsSort
}
type canonicalTag struct {
key []byte
tag Tag
}
type canonicalTagsSort []canonicalTag
func (ts *canonicalTagsSort) Len() int { return len(*ts) }
func (ts *canonicalTagsSort) Less(i, j int) bool {
x := *ts
return string(x[i].key) < string(x[j].key)
}
func (ts *canonicalTagsSort) Swap(i, j int) {
x := *ts
x[i], x[j] = x[j], x[i]
}
func copyTags(dst, src []Tag) []Tag {
dstLen := len(dst)
dst = slicesutil.SetLength(dst, dstLen+len(src))
for i := range src {
dst[dstLen+i].copyFrom(&src[i])
}
return dst
}
var commonTagKeys = func() map[string][]byte {
lcm := map[string][]byte{
// job-like tags must go first in MetricName.Tags.
// This should improve data locality.
// They start with \x00\x00.
// Do not change values!
//
// TODO: add more job-like tags.
"namespace": []byte("\x00\x00\x00"),
"ns": []byte("\x00\x00\x01"),
"datacenter": []byte("\x00\x00\x08"),
"dc": []byte("\x00\x00\x09"),
"environment": []byte("\x00\x00\x0c"),
"env": []byte("\x00\x00\x0d"),
"cluster": []byte("\x00\x00\x10"),
"service": []byte("\x00\x00\x18"),
"job": []byte("\x00\x00\x20"),
"model": []byte("\x00\x00\x28"),
"type": []byte("\x00\x00\x30"),
"sensor_type": []byte("\x00\x00\x38"),
"SensorType": []byte("\x00\x00\x38"),
"db": []byte("\x00\x00\x40"),
// instance-like tags must go second in MetricName.Tags.
// This should improve data locality.
// They start with \x00\x01.
// Do not change values!
//
// TODO: add more instance-like tags.
"instance": []byte("\x00\x01\x00"),
"host": []byte("\x00\x01\x08"),
"server": []byte("\x00\x01\x10"),
"pod": []byte("\x00\x01\x18"),
"node": []byte("\x00\x01\x20"),
"device": []byte("\x00\x01\x28"),
"tenant": []byte("\x00\x01\x30"),
"client": []byte("\x00\x01\x38"),
"name": []byte("\x00\x01\x40"),
"measurement": []byte("\x00\x01\x48"),
}
// Generate Upper-case variants of lc
m := make(map[string][]byte, len(lcm)*2)
for k, v := range lcm {
s := strings.ToUpper(k[:1]) + k[1:]
m[k] = v
m[s] = v
}
return m
}()
func normalizeTagKey(key []byte) []byte {
tagKey := commonTagKeys[string(key)]
if tagKey == nil {
return key
}
return tagKey
}