VictoriaMetrics/lib/promscrape/discoveryutils/utils.go
Aliaksandr Valialkin c06e7a142c
lib/promscrape: optimize discoveryutils.SanitizeLabelName()
Cache sanitized label names and return them next time.
This reduces the number of allocations and speeds up the SanitizeLabelName()
function for common case when the number of unique label names is smaller than 100k
2022-08-27 00:17:45 +03:00

97 lines
2.3 KiB
Go

package discoveryutils
import (
"encoding/json"
"net"
"regexp"
"sort"
"strconv"
"sync"
"sync/atomic"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/prompbmarshal"
)
// SanitizeLabelName replaces anything that doesn't match
// client_label.LabelNameRE with an underscore.
//
// This has been copied from Prometheus sources at util/strutil/strconv.go
func SanitizeLabelName(name string) string {
m := sanitizedLabelNames.Load().(*sync.Map)
v, ok := m.Load(name)
if ok {
// Fast path - the sanitized label name is found in the cache.
sp := v.(*string)
return *sp
}
// Slow path - sanitize name and store it in the cache.
sanitizedName := invalidLabelCharRE.ReplaceAllString(name, "_")
// Make a copy of name in order to limit memory usage to the name length,
// since the name may point to bigger string.
s := string(append([]byte{}, name...))
sp := &sanitizedName
m.Store(s, sp)
n := atomic.AddUint64(&sanitizedLabelNamesLen, 1)
if n > 100e3 {
atomic.StoreUint64(&sanitizedLabelNamesLen, 0)
sanitizedLabelNames.Store(&sync.Map{})
}
return sanitizedName
}
var (
sanitizedLabelNames atomic.Value
sanitizedLabelNamesLen uint64
invalidLabelCharRE = regexp.MustCompile(`[^a-zA-Z0-9_]`)
)
func init() {
sanitizedLabelNames.Store(&sync.Map{})
}
// JoinHostPort returns host:port.
//
// Host may be dns name, ipv4 or ipv6 address.
func JoinHostPort(host string, port int) string {
portStr := strconv.Itoa(port)
return net.JoinHostPort(host, portStr)
}
// SortedLabels represents sorted labels.
type SortedLabels []prompbmarshal.Label
// GetByName returns the label with the given name from sls.
func (sls *SortedLabels) GetByName(name string) string {
for _, lb := range *sls {
if lb.Name == name {
return lb.Value
}
}
return ""
}
// UnmarshalJSON unmarshals JSON from data.
func (sls *SortedLabels) UnmarshalJSON(data []byte) error {
var m map[string]string
if err := json.Unmarshal(data, &m); err != nil {
return err
}
*sls = GetSortedLabels(m)
return nil
}
// GetSortedLabels returns SortedLabels built from m.
func GetSortedLabels(m map[string]string) SortedLabels {
a := make([]prompbmarshal.Label, 0, len(m))
for k, v := range m {
a = append(a, prompbmarshal.Label{
Name: k,
Value: v,
})
}
sort.Slice(a, func(i, j int) bool {
return a[i].Name < a[j].Name
})
return a
}