mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-21 07:56:26 +01:00
937f382938
Unescape only `\n`, `\"` and `\\` sequences as Prometheus does. Other escape sequences shouldn't be unescaped.
367 lines
8.6 KiB
Go
367 lines
8.6 KiB
Go
package prometheus
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import (
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"fmt"
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"strings"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
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"github.com/VictoriaMetrics/metrics"
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"github.com/valyala/fastjson/fastfloat"
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)
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// Rows contains parsed Prometheus rows.
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type Rows struct {
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Rows []Row
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tagsPool []Tag
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}
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// Reset resets rs.
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func (rs *Rows) Reset() {
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// Reset items, so they can be GC'ed
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for i := range rs.Rows {
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rs.Rows[i].reset()
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}
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rs.Rows = rs.Rows[:0]
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for i := range rs.tagsPool {
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rs.tagsPool[i].reset()
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}
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rs.tagsPool = rs.tagsPool[:0]
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}
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// Unmarshal unmarshals Prometheus exposition text rows from s.
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//
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// See https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md#text-format-details
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//
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// s shouldn't be modified while rs is in use.
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func (rs *Rows) Unmarshal(s string) {
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rs.UnmarshalWithErrLogger(s, stdErrLogger)
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}
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func stdErrLogger(s string) {
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logger.ErrorfSkipframes(1, "%s", s)
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}
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// UnmarshalWithErrLogger unmarshal Prometheus exposition text rows from s.
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//
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// It calls errLogger for logging parsing errors.
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//
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// s shouldn't be modified while rs is in use.
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func (rs *Rows) UnmarshalWithErrLogger(s string, errLogger func(s string)) {
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noEscapes := strings.IndexByte(s, '\\') < 0
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rs.Rows, rs.tagsPool = unmarshalRows(rs.Rows[:0], s, rs.tagsPool[:0], noEscapes, errLogger)
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}
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// Row is a single Prometheus row.
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type Row struct {
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Metric string
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Tags []Tag
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Value float64
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Timestamp int64
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}
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func (r *Row) reset() {
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r.Metric = ""
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r.Tags = nil
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r.Value = 0
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r.Timestamp = 0
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}
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func skipTrailingComment(s string) string {
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n := strings.IndexByte(s, '#')
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if n < 0 {
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return s
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}
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return s[:n]
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}
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func skipLeadingWhitespace(s string) string {
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// Prometheus treats ' ' and '\t' as whitespace
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// according to https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md#text-format-details
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for len(s) > 0 && (s[0] == ' ' || s[0] == '\t') {
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s = s[1:]
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}
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return s
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}
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func skipTrailingWhitespace(s string) string {
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// Prometheus treats ' ' and '\t' as whitespace
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// according to https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md#text-format-details
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for len(s) > 0 && (s[len(s)-1] == ' ' || s[len(s)-1] == '\t') {
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s = s[:len(s)-1]
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}
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return s
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}
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func nextWhitespace(s string) int {
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n := strings.IndexByte(s, ' ')
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if n < 0 {
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return strings.IndexByte(s, '\t')
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}
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n1 := strings.IndexByte(s, '\t')
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if n1 < 0 || n1 > n {
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return n
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}
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return n1
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}
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func (r *Row) unmarshal(s string, tagsPool []Tag, noEscapes bool) ([]Tag, error) {
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r.reset()
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s = skipLeadingWhitespace(s)
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n := strings.IndexByte(s, '{')
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if n >= 0 {
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// Tags found. Parse them.
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r.Metric = skipTrailingWhitespace(s[:n])
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s = s[n+1:]
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tagsStart := len(tagsPool)
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var err error
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s, tagsPool, err = unmarshalTags(tagsPool, s, noEscapes)
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if err != nil {
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return tagsPool, fmt.Errorf("cannot unmarshal tags: %w", err)
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}
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if len(s) > 0 && s[0] == ' ' {
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// Fast path - skip whitespace.
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s = s[1:]
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}
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tags := tagsPool[tagsStart:]
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r.Tags = tags[:len(tags):len(tags)]
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} else {
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// Tags weren't found. Search for value after whitespace
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n = nextWhitespace(s)
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if n < 0 {
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return tagsPool, fmt.Errorf("missing value")
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}
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r.Metric = s[:n]
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s = s[n+1:]
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}
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if len(r.Metric) == 0 {
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return tagsPool, fmt.Errorf("metric cannot be empty")
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}
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s = skipLeadingWhitespace(s)
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s = skipTrailingComment(s)
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if len(s) == 0 {
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return tagsPool, fmt.Errorf("value cannot be empty")
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}
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n = nextWhitespace(s)
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if n < 0 {
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// There is no timestamp.
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v, err := fastfloat.Parse(s)
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if err != nil {
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return tagsPool, fmt.Errorf("cannot parse value %q: %w", s, err)
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}
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r.Value = v
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return tagsPool, nil
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}
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// There is a timestamp.
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v, err := fastfloat.Parse(s[:n])
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if err != nil {
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return tagsPool, fmt.Errorf("cannot parse value %q: %w", s[:n], err)
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}
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r.Value = v
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s = skipLeadingWhitespace(s[n+1:])
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if len(s) == 0 {
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// There is no timestamp - just a whitespace after the value.
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return tagsPool, nil
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}
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// There are some whitespaces after timestamp
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s = skipTrailingWhitespace(s)
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ts, err := fastfloat.Parse(s)
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if err != nil {
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return tagsPool, fmt.Errorf("cannot parse timestamp %q: %w", s, err)
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}
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if ts >= -1<<31 && ts < 1<<31 {
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// This looks like OpenMetrics timestamp in Unix seconds.
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// Convert it to milliseconds.
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//
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// See https://github.com/OpenObservability/OpenMetrics/blob/master/specification/OpenMetrics.md#timestamps
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ts *= 1000
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}
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r.Timestamp = int64(ts)
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return tagsPool, nil
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}
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var rowsReadScrape = metrics.NewCounter(`vm_protoparser_rows_read_total{type="promscrape"}`)
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func unmarshalRows(dst []Row, s string, tagsPool []Tag, noEscapes bool, errLogger func(s string)) ([]Row, []Tag) {
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dstLen := len(dst)
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for len(s) > 0 {
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n := strings.IndexByte(s, '\n')
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if n < 0 {
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// The last line.
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dst, tagsPool = unmarshalRow(dst, s, tagsPool, noEscapes, errLogger)
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break
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}
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dst, tagsPool = unmarshalRow(dst, s[:n], tagsPool, noEscapes, errLogger)
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s = s[n+1:]
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}
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rowsReadScrape.Add(len(dst) - dstLen)
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return dst, tagsPool
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}
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func unmarshalRow(dst []Row, s string, tagsPool []Tag, noEscapes bool, errLogger func(s string)) ([]Row, []Tag) {
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if len(s) > 0 && s[len(s)-1] == '\r' {
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s = s[:len(s)-1]
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}
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s = skipLeadingWhitespace(s)
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if len(s) == 0 {
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// Skip empty line
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return dst, tagsPool
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}
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if s[0] == '#' {
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// Skip comment
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return dst, tagsPool
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}
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if cap(dst) > len(dst) {
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dst = dst[:len(dst)+1]
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} else {
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dst = append(dst, Row{})
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}
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r := &dst[len(dst)-1]
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var err error
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tagsPool, err = r.unmarshal(s, tagsPool, noEscapes)
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if err != nil {
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dst = dst[:len(dst)-1]
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msg := fmt.Sprintf("cannot unmarshal Prometheus line %q: %s", s, err)
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errLogger(msg)
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invalidLines.Inc()
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}
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return dst, tagsPool
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}
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var invalidLines = metrics.NewCounter(`vm_rows_invalid_total{type="prometheus"}`)
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func unmarshalTags(dst []Tag, s string, noEscapes bool) (string, []Tag, error) {
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for {
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s = skipLeadingWhitespace(s)
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if len(s) > 0 && s[0] == '}' {
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// End of tags found.
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return s[1:], dst, nil
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}
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n := strings.IndexByte(s, '=')
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if n < 0 {
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return s, dst, fmt.Errorf("missing value for tag %q", s)
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}
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key := skipTrailingWhitespace(s[:n])
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s = skipLeadingWhitespace(s[n+1:])
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if len(s) == 0 || s[0] != '"' {
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return s, dst, fmt.Errorf("expecting quoted value for tag %q; got %q", key, s)
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}
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value := s[1:]
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if noEscapes {
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// Fast path - the line has no escape chars
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n = strings.IndexByte(value, '"')
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if n < 0 {
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return s, dst, fmt.Errorf("missing closing quote for tag value %q", s)
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}
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s = value[n+1:]
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value = value[:n]
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} else {
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// Slow path - the line contains escape chars
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n = findClosingQuote(s)
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if n < 0 {
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return s, dst, fmt.Errorf("missing closing quote for tag value %q", s)
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}
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value = unescapeValue(s[1:n])
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s = s[n+1:]
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}
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if len(key) > 0 {
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// Allow empty values (len(value)==0) - see https://github.com/VictoriaMetrics/VictoriaMetrics/issues/453
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if cap(dst) > len(dst) {
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dst = dst[:len(dst)+1]
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} else {
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dst = append(dst, Tag{})
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}
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tag := &dst[len(dst)-1]
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tag.Key = key
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tag.Value = value
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}
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s = skipLeadingWhitespace(s)
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if len(s) > 0 && s[0] == '}' {
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// End of tags found.
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return s[1:], dst, nil
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}
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if len(s) == 0 || s[0] != ',' {
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return s, dst, fmt.Errorf("missing comma after tag %s=%q", key, value)
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}
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s = s[1:]
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}
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}
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// Tag is a Prometheus tag.
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type Tag struct {
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Key string
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Value string
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}
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func (t *Tag) reset() {
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t.Key = ""
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t.Value = ""
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}
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func findClosingQuote(s string) int {
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if len(s) == 0 || s[0] != '"' {
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return -1
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}
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off := 1
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s = s[1:]
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for {
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n := strings.IndexByte(s, '"')
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if n < 0 {
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return -1
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}
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if prevBackslashesCount(s[:n])%2 == 0 {
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return off + n
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}
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off += n + 1
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s = s[n+1:]
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}
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}
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func unescapeValue(s string) string {
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n := strings.IndexByte(s, '\\')
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if n < 0 {
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// Fast path - nothing to unescape
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return s
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}
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b := make([]byte, 0, len(s))
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for {
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b = append(b, s[:n]...)
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s = s[n+1:]
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if len(s) == 0 {
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b = append(b, '\\')
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break
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}
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// label_value can be any sequence of UTF-8 characters, but the backslash (\), double-quote ("),
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// and line feed (\n) characters have to be escaped as \\, \", and \n, respectively.
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// See https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md
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switch s[0] {
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case '\\':
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b = append(b, '\\')
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case '"':
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b = append(b, '"')
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case 'n':
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b = append(b, '\n')
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default:
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b = append(b, '\\', s[0])
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}
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s = s[1:]
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n = strings.IndexByte(s, '\\')
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if n < 0 {
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b = append(b, s...)
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break
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}
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}
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return string(b)
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}
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func prevBackslashesCount(s string) int {
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n := 0
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for len(s) > 0 && s[len(s)-1] == '\\' {
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n++
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s = s[:len(s)-1]
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}
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return n
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}
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