VictoriaMetrics/lib/promrelabel/relabel.go

573 lines
17 KiB
Go

package promrelabel
import (
"fmt"
"regexp"
"strconv"
"strings"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/prompbmarshal"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/regexutil"
"github.com/cespare/xxhash/v2"
)
// parsedRelabelConfig contains parsed `relabel_config`.
//
// See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#relabel_config
type parsedRelabelConfig struct {
SourceLabels []string
Separator string
TargetLabel string
RegexAnchored *regexp.Regexp
Modulus uint64
Replacement string
Action string
If *IfExpression
graphiteMatchTemplate *graphiteMatchTemplate
graphiteLabelRules []graphiteLabelRule
regex *regexutil.PromRegex
regexOriginal *regexp.Regexp
hasCaptureGroupInTargetLabel bool
hasCaptureGroupInReplacement bool
hasLabelReferenceInReplacement bool
}
// String returns human-readable representation for prc.
func (prc *parsedRelabelConfig) String() string {
return fmt.Sprintf("SourceLabels=%s, Separator=%s, TargetLabel=%s, Regex=%s, Modulus=%d, Replacement=%s, Action=%s, If=%s, graphiteMatchTemplate=%s, graphiteLabelRules=%s",
prc.SourceLabels, prc.Separator, prc.TargetLabel, prc.regexOriginal, prc.Modulus, prc.Replacement,
prc.Action, prc.If, prc.graphiteMatchTemplate, prc.graphiteLabelRules)
}
// Apply applies pcs to labels starting from the labelsOffset.
//
// If isFinalize is set, then FinalizeLabels is called on the labels[labelsOffset:].
//
// The returned labels at labels[labelsOffset:] are sorted.
func (pcs *ParsedConfigs) Apply(labels []prompbmarshal.Label, labelsOffset int, isFinalize bool) []prompbmarshal.Label {
var inStr string
relabelDebug := false
if pcs != nil {
relabelDebug = pcs.relabelDebug
if relabelDebug {
inStr = labelsToString(labels[labelsOffset:])
}
for _, prc := range pcs.prcs {
tmp := prc.apply(labels, labelsOffset)
if len(tmp) == labelsOffset {
// All the labels have been removed.
if pcs.relabelDebug {
logger.Infof("\nRelabel In: %s\nRelabel Out: DROPPED - all labels removed", inStr)
}
return tmp
}
labels = tmp
}
}
labels = removeEmptyLabels(labels, labelsOffset)
if isFinalize {
labels = FinalizeLabels(labels[:labelsOffset], labels[labelsOffset:])
}
SortLabels(labels[labelsOffset:])
if relabelDebug {
if len(labels) == labelsOffset {
logger.Infof("\nRelabel In: %s\nRelabel Out: DROPPED - all labels removed", inStr)
return labels
}
outStr := labelsToString(labels[labelsOffset:])
if inStr == outStr {
logger.Infof("\nRelabel In: %s\nRelabel Out: KEPT AS IS - no change", inStr)
} else {
logger.Infof("\nRelabel In: %s\nRelabel Out: %s", inStr, outStr)
}
// Drop labels
labels = labels[:labelsOffset]
}
return labels
}
func removeEmptyLabels(labels []prompbmarshal.Label, labelsOffset int) []prompbmarshal.Label {
src := labels[labelsOffset:]
needsRemoval := false
for i := range src {
label := &src[i]
if label.Name == "" || label.Value == "" {
needsRemoval = true
break
}
}
if !needsRemoval {
return labels
}
dst := labels[:labelsOffset]
for i := range src {
label := &src[i]
if label.Name != "" && label.Value != "" {
dst = append(dst, *label)
}
}
return dst
}
// RemoveMetaLabels removes all the `__meta_` labels from src and puts the rest of labels to dst.
//
// See https://www.robustperception.io/life-of-a-label fo details.
func RemoveMetaLabels(dst, src []prompbmarshal.Label) []prompbmarshal.Label {
for i := range src {
label := &src[i]
if strings.HasPrefix(label.Name, "__meta_") {
continue
}
dst = append(dst, *label)
}
return dst
}
// FinalizeLabels removes labels with "__" in the beginning (except of "__name__").
func FinalizeLabels(dst, src []prompbmarshal.Label) []prompbmarshal.Label {
for i := range src {
label := &src[i]
name := label.Name
if strings.HasPrefix(name, "__") && name != "__name__" {
continue
}
dst = append(dst, *label)
}
return dst
}
// apply applies relabeling according to prc.
//
// See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#relabel_config
func (prc *parsedRelabelConfig) apply(labels []prompbmarshal.Label, labelsOffset int) []prompbmarshal.Label {
src := labels[labelsOffset:]
if prc.If != nil && !prc.If.Match(labels) {
if prc.Action == "keep" {
// Drop the target on `if` mismatch for `action: keep`
return labels[:labelsOffset]
}
// Do not apply prc actions on `if` mismatch.
return labels
}
switch prc.Action {
case "graphite":
metricName := GetLabelValueByName(src, "__name__")
gm := graphiteMatchesPool.Get().(*graphiteMatches)
var ok bool
gm.a, ok = prc.graphiteMatchTemplate.Match(gm.a[:0], metricName)
if !ok {
// Fast path - name mismatch
graphiteMatchesPool.Put(gm)
return labels
}
// Slow path - extract labels from graphite metric name
bb := relabelBufPool.Get()
for _, gl := range prc.graphiteLabelRules {
bb.B = gl.grt.Expand(bb.B[:0], gm.a)
valueStr := string(bb.B)
labels = setLabelValue(labels, labelsOffset, gl.targetLabel, valueStr)
}
relabelBufPool.Put(bb)
graphiteMatchesPool.Put(gm)
return labels
case "replace":
// Store `replacement` at `target_label` if the `regex` matches `source_labels` joined with `separator`
replacement := prc.Replacement
bb := relabelBufPool.Get()
if prc.hasLabelReferenceInReplacement {
// Fill {{labelName}} references in the replacement
bb.B = fillLabelReferences(bb.B[:0], replacement, labels[labelsOffset:])
replacement = string(bb.B)
}
bb.B = concatLabelValues(bb.B[:0], src, prc.SourceLabels, prc.Separator)
if prc.RegexAnchored == defaultRegexForRelabelConfig && !prc.hasCaptureGroupInTargetLabel {
if replacement == "$1" {
// Fast path for the rule that copies source label values to destination:
// - source_labels: [...]
// target_label: foobar
valueStr := string(bb.B)
relabelBufPool.Put(bb)
return setLabelValue(labels, labelsOffset, prc.TargetLabel, valueStr)
}
if !prc.hasCaptureGroupInReplacement {
// Fast path for the rule that sets label value:
// - target_label: foobar
// replacement: something-here
relabelBufPool.Put(bb)
labels = setLabelValue(labels, labelsOffset, prc.TargetLabel, replacement)
return labels
}
}
if re := prc.regex; re.HasPrefix() && !re.MatchString(bytesutil.ToUnsafeString(bb.B)) {
// Fast path - regexp mismatch.
relabelBufPool.Put(bb)
return labels
}
match := prc.RegexAnchored.FindSubmatchIndex(bb.B)
if match == nil {
// Fast path - nothing to replace.
relabelBufPool.Put(bb)
return labels
}
sourceStr := bytesutil.ToUnsafeString(bb.B)
nameStr := prc.TargetLabel
if prc.hasCaptureGroupInTargetLabel {
nameStr = prc.expandCaptureGroups(nameStr, sourceStr, match)
}
valueStr := prc.expandCaptureGroups(replacement, sourceStr, match)
relabelBufPool.Put(bb)
return setLabelValue(labels, labelsOffset, nameStr, valueStr)
case "replace_all":
// Replace all the occurrences of `regex` at `source_labels` joined with `separator` with the `replacement`
// and store the result at `target_label`
bb := relabelBufPool.Get()
bb.B = concatLabelValues(bb.B[:0], src, prc.SourceLabels, prc.Separator)
sourceStr := string(bb.B)
relabelBufPool.Put(bb)
valueStr, ok := prc.replaceStringSubmatches(sourceStr, prc.Replacement, prc.hasCaptureGroupInReplacement)
if ok {
labels = setLabelValue(labels, labelsOffset, prc.TargetLabel, valueStr)
}
return labels
case "keep_if_equal":
// Keep the entry if all the label values in source_labels are equal.
// For example:
//
// - source_labels: [foo, bar]
// action: keep_if_equal
//
// Would leave the entry if `foo` value equals `bar` value
if areEqualLabelValues(src, prc.SourceLabels) {
return labels
}
return labels[:labelsOffset]
case "drop_if_equal":
// Drop the entry if all the label values in source_labels are equal.
// For example:
//
// - source_labels: [foo, bar]
// action: drop_if_equal
//
// Would drop the entry if `foo` value equals `bar` value.
if areEqualLabelValues(src, prc.SourceLabels) {
return labels[:labelsOffset]
}
return labels
case "keep":
// Keep the target if `source_labels` joined with `separator` match the `regex`.
if prc.RegexAnchored == defaultRegexForRelabelConfig {
// Fast path for the case with `if` and without explicitly set `regex`:
//
// - action: keep
// if: 'some{label=~"filters"}'
//
return labels
}
bb := relabelBufPool.Get()
bb.B = concatLabelValues(bb.B[:0], src, prc.SourceLabels, prc.Separator)
keep := prc.regex.MatchString(bytesutil.ToUnsafeString(bb.B))
relabelBufPool.Put(bb)
if !keep {
return labels[:labelsOffset]
}
return labels
case "drop":
// Drop the target if `source_labels` joined with `separator` don't match the `regex`.
if prc.RegexAnchored == defaultRegexForRelabelConfig {
// Fast path for the case with `if` and without explicitly set `regex`:
//
// - action: drop
// if: 'some{label=~"filters"}'
//
return labels[:labelsOffset]
}
bb := relabelBufPool.Get()
bb.B = concatLabelValues(bb.B[:0], src, prc.SourceLabels, prc.Separator)
drop := prc.regex.MatchString(bytesutil.ToUnsafeString(bb.B))
relabelBufPool.Put(bb)
if drop {
return labels[:labelsOffset]
}
return labels
case "hashmod":
// Calculate the `modulus` from the hash of `source_labels` joined with `separator` and store it at `target_label`
bb := relabelBufPool.Get()
bb.B = concatLabelValues(bb.B[:0], src, prc.SourceLabels, prc.Separator)
h := xxhash.Sum64(bb.B) % prc.Modulus
value := strconv.Itoa(int(h))
relabelBufPool.Put(bb)
return setLabelValue(labels, labelsOffset, prc.TargetLabel, value)
case "labelmap":
// Replace label names with the `replacement` if they match `regex`
for _, label := range src {
labelName, ok := prc.replaceFullString(label.Name, prc.Replacement, prc.hasCaptureGroupInReplacement)
if ok {
labels = setLabelValue(labels, labelsOffset, labelName, label.Value)
}
}
return labels
case "labelmap_all":
// Replace all the occurrences of `regex` at label names with `replacement`
for i := range src {
label := &src[i]
label.Name, _ = prc.replaceStringSubmatches(label.Name, prc.Replacement, prc.hasCaptureGroupInReplacement)
}
return labels
case "labeldrop":
// Drop labels with names matching the `regex`
dst := labels[:labelsOffset]
re := prc.regex
for _, label := range src {
if !re.MatchString(label.Name) {
dst = append(dst, label)
}
}
return dst
case "labelkeep":
// Keep labels with names matching the `regex`
dst := labels[:labelsOffset]
re := prc.regex
for _, label := range src {
if re.MatchString(label.Name) {
dst = append(dst, label)
}
}
return dst
case "uppercase":
bb := relabelBufPool.Get()
bb.B = concatLabelValues(bb.B[:0], src, prc.SourceLabels, prc.Separator)
valueStr := string(bb.B)
relabelBufPool.Put(bb)
valueStr = strings.ToUpper(valueStr)
labels = setLabelValue(labels, labelsOffset, prc.TargetLabel, valueStr)
return labels
case "lowercase":
bb := relabelBufPool.Get()
bb.B = concatLabelValues(bb.B[:0], src, prc.SourceLabels, prc.Separator)
valueStr := string(bb.B)
relabelBufPool.Put(bb)
valueStr = strings.ToLower(valueStr)
labels = setLabelValue(labels, labelsOffset, prc.TargetLabel, valueStr)
return labels
default:
logger.Panicf("BUG: unknown `action`: %q", prc.Action)
return labels
}
}
func (prc *parsedRelabelConfig) replaceFullString(s, replacement string, hasCaptureGroupInReplacement bool) (string, bool) {
prefix, complete := prc.regexOriginal.LiteralPrefix()
if complete && !hasCaptureGroupInReplacement {
if s == prefix {
return replacement, true
}
return s, false
}
if !strings.HasPrefix(s, prefix) {
return s, false
}
if replacement == "$1" {
// Fast path for commonly used rule for deleting label prefixes such as:
//
// - action: labelmap
// regex: __meta_kubernetes_node_label_(.+)
//
reStr := prc.regexOriginal.String()
if strings.HasPrefix(reStr, prefix) {
suffix := s[len(prefix):]
reSuffix := reStr[len(prefix):]
switch reSuffix {
case "(.*)":
return suffix, true
case "(.+)":
if len(suffix) > 0 {
return suffix, true
}
return s, false
}
}
}
if re := prc.regex; re.HasPrefix() && !re.MatchString(s) {
// Fast path - regex mismatch
return s, false
}
// Slow path - regexp processing
match := prc.RegexAnchored.FindStringSubmatchIndex(s)
if match == nil {
return s, false
}
bb := relabelBufPool.Get()
bb.B = prc.RegexAnchored.ExpandString(bb.B[:0], replacement, s, match)
result := string(bb.B)
relabelBufPool.Put(bb)
return result, true
}
func (prc *parsedRelabelConfig) replaceStringSubmatches(s, replacement string, hasCaptureGroupInReplacement bool) (string, bool) {
re := prc.regexOriginal
prefix, complete := re.LiteralPrefix()
if complete && !hasCaptureGroupInReplacement {
if !strings.Contains(s, prefix) {
return s, false
}
return strings.ReplaceAll(s, prefix, replacement), true
}
if !re.MatchString(s) {
return s, false
}
return re.ReplaceAllString(s, replacement), true
}
func (prc *parsedRelabelConfig) expandCaptureGroups(template, source string, match []int) string {
bb := relabelBufPool.Get()
bb.B = prc.RegexAnchored.ExpandString(bb.B[:0], template, source, match)
s := string(bb.B)
relabelBufPool.Put(bb)
return s
}
var relabelBufPool bytesutil.ByteBufferPool
func areEqualLabelValues(labels []prompbmarshal.Label, labelNames []string) bool {
if len(labelNames) < 2 {
logger.Panicf("BUG: expecting at least 2 labelNames; got %d", len(labelNames))
return false
}
labelValue := GetLabelValueByName(labels, labelNames[0])
for _, labelName := range labelNames[1:] {
v := GetLabelValueByName(labels, labelName)
if v != labelValue {
return false
}
}
return true
}
func concatLabelValues(dst []byte, labels []prompbmarshal.Label, labelNames []string, separator string) []byte {
if len(labelNames) == 0 {
return dst
}
for _, labelName := range labelNames {
label := GetLabelByName(labels, labelName)
if label != nil {
dst = append(dst, label.Value...)
}
dst = append(dst, separator...)
}
return dst[:len(dst)-len(separator)]
}
func setLabelValue(labels []prompbmarshal.Label, labelsOffset int, name, value string) []prompbmarshal.Label {
if label := GetLabelByName(labels[labelsOffset:], name); label != nil {
label.Value = value
return labels
}
labels = append(labels, prompbmarshal.Label{
Name: name,
Value: value,
})
return labels
}
// GetLabelByName returns label with the given name from labels.
func GetLabelByName(labels []prompbmarshal.Label, name string) *prompbmarshal.Label {
for i := range labels {
label := &labels[i]
if label.Name == name {
return label
}
}
return nil
}
// GetLabelValueByName returns value for label with the given name from labels.
//
// It returns empty string for non-existing label.
func GetLabelValueByName(labels []prompbmarshal.Label, name string) string {
label := GetLabelByName(labels, name)
if label == nil {
return ""
}
return label.Value
}
// CleanLabels sets label.Name and label.Value to an empty string for all the labels.
//
// This should help GC cleaning up label.Name and label.Value strings.
func CleanLabels(labels []prompbmarshal.Label) {
for i := range labels {
label := &labels[i]
label.Name = ""
label.Value = ""
}
}
func labelsToString(labels []prompbmarshal.Label) string {
labelsCopy := append([]prompbmarshal.Label{}, labels...)
SortLabels(labelsCopy)
mname := ""
for _, label := range labelsCopy {
if label.Name == "__name__" {
mname = label.Value
break
}
}
if mname != "" && len(labelsCopy) <= 1 {
return mname
}
b := []byte(mname)
b = append(b, '{')
for i, label := range labelsCopy {
if label.Name == "__name__" {
continue
}
b = append(b, label.Name...)
b = append(b, '=')
b = strconv.AppendQuote(b, label.Value)
if i+1 < len(labelsCopy) {
b = append(b, ',')
}
}
b = append(b, '}')
return string(b)
}
func fillLabelReferences(dst []byte, replacement string, labels []prompbmarshal.Label) []byte {
s := replacement
for len(s) > 0 {
n := strings.Index(s, "{{")
if n < 0 {
return append(dst, s...)
}
dst = append(dst, s[:n]...)
s = s[n+2:]
n = strings.Index(s, "}}")
if n < 0 {
dst = append(dst, "{{"...)
return append(dst, s...)
}
labelName := s[:n]
s = s[n+2:]
labelValue := GetLabelValueByName(labels, labelName)
dst = append(dst, labelValue...)
}
return dst
}
// SanitizeName replaces unsupported by Prometheus chars in metric names and label names with _.
//
// See https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels
func SanitizeName(name string) string {
return promSanitizer.Transform(name)
}
var promSanitizer = bytesutil.NewFastStringTransformer(func(s string) string {
return unsupportedPromChars.ReplaceAllString(s, "_")
})
var unsupportedPromChars = regexp.MustCompile(`[^a-zA-Z0-9_:]`)