mirror of https://github.com/prometheus/prometheus
472 lines
13 KiB
Go
472 lines
13 KiB
Go
// Copyright 2018 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//go:generate go get -u modernc.org/golex
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//go:generate golex -o=openmetricslex.l.go openmetricslex.l
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package textparse
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import (
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"errors"
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"fmt"
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"io"
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"math"
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"strings"
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"unicode/utf8"
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"github.com/prometheus/prometheus/model/exemplar"
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"github.com/prometheus/prometheus/model/histogram"
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"github.com/prometheus/prometheus/model/labels"
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"github.com/prometheus/prometheus/model/value"
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)
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type openMetricsLexer struct {
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b []byte
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i int
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start int
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err error
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state int
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}
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// buf returns the buffer of the current token.
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func (l *openMetricsLexer) buf() []byte {
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return l.b[l.start:l.i]
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}
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// next advances the openMetricsLexer to the next character.
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func (l *openMetricsLexer) next() byte {
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l.i++
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if l.i >= len(l.b) {
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l.err = io.EOF
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return byte(tEOF)
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}
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// Lex struggles with null bytes. If we are in a label value or help string, where
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// they are allowed, consume them here immediately.
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for l.b[l.i] == 0 && (l.state == sLValue || l.state == sMeta2 || l.state == sComment) {
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l.i++
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if l.i >= len(l.b) {
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l.err = io.EOF
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return byte(tEOF)
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}
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}
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return l.b[l.i]
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}
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func (l *openMetricsLexer) Error(es string) {
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l.err = errors.New(es)
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}
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// OpenMetricsParser parses samples from a byte slice of samples in the official
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// OpenMetrics text exposition format.
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// This is based on the working draft https://docs.google.com/document/u/1/d/1KwV0mAXwwbvvifBvDKH_LU1YjyXE_wxCkHNoCGq1GX0/edit
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type OpenMetricsParser struct {
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l *openMetricsLexer
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builder labels.ScratchBuilder
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series []byte
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text []byte
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mtype MetricType
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val float64
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ts int64
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hasTS bool
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start int
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offsets []int
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eOffsets []int
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exemplar []byte
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exemplarVal float64
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exemplarTs int64
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hasExemplarTs bool
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}
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// NewOpenMetricsParser returns a new parser of the byte slice.
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func NewOpenMetricsParser(b []byte) Parser {
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return &OpenMetricsParser{l: &openMetricsLexer{b: b}}
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}
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// Series returns the bytes of the series, the timestamp if set, and the value
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// of the current sample.
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func (p *OpenMetricsParser) Series() ([]byte, *int64, float64) {
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if p.hasTS {
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ts := p.ts
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return p.series, &ts, p.val
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}
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return p.series, nil, p.val
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}
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// Histogram returns (nil, nil, nil, nil) for now because OpenMetrics does not
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// support sparse histograms yet.
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func (p *OpenMetricsParser) Histogram() ([]byte, *int64, *histogram.Histogram, *histogram.FloatHistogram) {
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return nil, nil, nil, nil
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}
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// Help returns the metric name and help text in the current entry.
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// Must only be called after Next returned a help entry.
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// The returned byte slices become invalid after the next call to Next.
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func (p *OpenMetricsParser) Help() ([]byte, []byte) {
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m := p.l.b[p.offsets[0]:p.offsets[1]]
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// Replacer causes allocations. Replace only when necessary.
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if strings.IndexByte(yoloString(p.text), byte('\\')) >= 0 {
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// OpenMetrics always uses the Prometheus format label value escaping.
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return m, []byte(lvalReplacer.Replace(string(p.text)))
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}
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return m, p.text
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}
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// Type returns the metric name and type in the current entry.
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// Must only be called after Next returned a type entry.
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// The returned byte slices become invalid after the next call to Next.
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func (p *OpenMetricsParser) Type() ([]byte, MetricType) {
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return p.l.b[p.offsets[0]:p.offsets[1]], p.mtype
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}
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// Unit returns the metric name and unit in the current entry.
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// Must only be called after Next returned a unit entry.
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// The returned byte slices become invalid after the next call to Next.
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func (p *OpenMetricsParser) Unit() ([]byte, []byte) {
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// The Prometheus format does not have units.
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return p.l.b[p.offsets[0]:p.offsets[1]], p.text
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}
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// Comment returns the text of the current comment.
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// Must only be called after Next returned a comment entry.
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// The returned byte slice becomes invalid after the next call to Next.
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func (p *OpenMetricsParser) Comment() []byte {
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return p.text
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}
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// Metric writes the labels of the current sample into the passed labels.
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// It returns the string from which the metric was parsed.
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func (p *OpenMetricsParser) Metric(l *labels.Labels) string {
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// Copy the buffer to a string: this is only necessary for the return value.
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s := string(p.series)
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p.builder.Reset()
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p.builder.Add(labels.MetricName, s[:p.offsets[0]-p.start])
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for i := 1; i < len(p.offsets); i += 4 {
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a := p.offsets[i] - p.start
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b := p.offsets[i+1] - p.start
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c := p.offsets[i+2] - p.start
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d := p.offsets[i+3] - p.start
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value := s[c:d]
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// Replacer causes allocations. Replace only when necessary.
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if strings.IndexByte(s[c:d], byte('\\')) >= 0 {
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value = lvalReplacer.Replace(value)
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}
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p.builder.Add(s[a:b], value)
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}
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p.builder.Sort()
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*l = p.builder.Labels()
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return s
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}
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// Exemplar writes the exemplar of the current sample into the passed exemplar.
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// It returns whether an exemplar exists. As OpenMetrics only ever has one
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// exemplar per sample, every call after the first (for the same sample) will
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// always return false.
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func (p *OpenMetricsParser) Exemplar(e *exemplar.Exemplar) bool {
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if len(p.exemplar) == 0 {
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return false
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}
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// Allocate the full immutable string immediately, so we just
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// have to create references on it below.
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s := string(p.exemplar)
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e.Value = p.exemplarVal
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if p.hasExemplarTs {
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e.HasTs = true
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e.Ts = p.exemplarTs
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}
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p.builder.Reset()
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for i := 0; i < len(p.eOffsets); i += 4 {
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a := p.eOffsets[i] - p.start
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b := p.eOffsets[i+1] - p.start
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c := p.eOffsets[i+2] - p.start
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d := p.eOffsets[i+3] - p.start
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p.builder.Add(s[a:b], s[c:d])
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}
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p.builder.Sort()
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e.Labels = p.builder.Labels()
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// Wipe exemplar so that future calls return false.
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p.exemplar = p.exemplar[:0]
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return true
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}
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// nextToken returns the next token from the openMetricsLexer.
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func (p *OpenMetricsParser) nextToken() token {
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tok := p.l.Lex()
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return tok
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}
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func (p *OpenMetricsParser) parseError(exp string, got token) error {
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e := p.l.i + 1
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if len(p.l.b) < e {
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e = len(p.l.b)
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}
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return fmt.Errorf("%s, got %q (%q) while parsing: %q", exp, p.l.b[p.l.start:e], got, p.l.b[p.start:e])
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}
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// Next advances the parser to the next sample. It returns false if no
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// more samples were read or an error occurred.
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func (p *OpenMetricsParser) Next() (Entry, error) {
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var err error
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p.start = p.l.i
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p.offsets = p.offsets[:0]
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p.eOffsets = p.eOffsets[:0]
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p.exemplar = p.exemplar[:0]
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p.exemplarVal = 0
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p.hasExemplarTs = false
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switch t := p.nextToken(); t {
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case tEOFWord:
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if t := p.nextToken(); t != tEOF {
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return EntryInvalid, errors.New("unexpected data after # EOF")
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}
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return EntryInvalid, io.EOF
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case tEOF:
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return EntryInvalid, errors.New("data does not end with # EOF")
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case tHelp, tType, tUnit:
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switch t2 := p.nextToken(); t2 {
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case tMName:
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p.offsets = append(p.offsets, p.l.start, p.l.i)
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default:
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return EntryInvalid, p.parseError("expected metric name after "+t.String(), t2)
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}
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switch t2 := p.nextToken(); t2 {
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case tText:
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if len(p.l.buf()) > 1 {
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p.text = p.l.buf()[1 : len(p.l.buf())-1]
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} else {
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p.text = []byte{}
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}
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default:
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return EntryInvalid, fmt.Errorf("expected text in %s", t.String())
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}
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switch t {
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case tType:
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switch s := yoloString(p.text); s {
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case "counter":
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p.mtype = MetricTypeCounter
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case "gauge":
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p.mtype = MetricTypeGauge
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case "histogram":
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p.mtype = MetricTypeHistogram
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case "gaugehistogram":
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p.mtype = MetricTypeGaugeHistogram
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case "summary":
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p.mtype = MetricTypeSummary
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case "info":
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p.mtype = MetricTypeInfo
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case "stateset":
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p.mtype = MetricTypeStateset
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case "unknown":
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p.mtype = MetricTypeUnknown
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default:
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return EntryInvalid, fmt.Errorf("invalid metric type %q", s)
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}
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case tHelp:
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if !utf8.Valid(p.text) {
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return EntryInvalid, fmt.Errorf("help text %q is not a valid utf8 string", p.text)
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}
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}
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switch t {
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case tHelp:
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return EntryHelp, nil
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case tType:
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return EntryType, nil
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case tUnit:
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m := yoloString(p.l.b[p.offsets[0]:p.offsets[1]])
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u := yoloString(p.text)
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if len(u) > 0 {
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if !strings.HasSuffix(m, u) || len(m) < len(u)+1 || p.l.b[p.offsets[1]-len(u)-1] != '_' {
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return EntryInvalid, fmt.Errorf("unit %q not a suffix of metric %q", u, m)
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}
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}
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return EntryUnit, nil
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}
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case tMName:
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p.offsets = append(p.offsets, p.l.i)
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p.series = p.l.b[p.start:p.l.i]
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t2 := p.nextToken()
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if t2 == tBraceOpen {
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p.offsets, err = p.parseLVals(p.offsets)
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if err != nil {
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return EntryInvalid, err
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}
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p.series = p.l.b[p.start:p.l.i]
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t2 = p.nextToken()
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}
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p.val, err = p.getFloatValue(t2, "metric")
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if err != nil {
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return EntryInvalid, err
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}
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p.hasTS = false
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switch t2 := p.nextToken(); t2 {
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case tEOF:
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return EntryInvalid, errors.New("data does not end with # EOF")
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case tLinebreak:
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break
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case tComment:
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if err := p.parseComment(); err != nil {
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return EntryInvalid, err
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}
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case tTimestamp:
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p.hasTS = true
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var ts float64
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// A float is enough to hold what we need for millisecond resolution.
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if ts, err = parseFloat(yoloString(p.l.buf()[1:])); err != nil {
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return EntryInvalid, fmt.Errorf("%w while parsing: %q", err, p.l.b[p.start:p.l.i])
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}
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if math.IsNaN(ts) || math.IsInf(ts, 0) {
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return EntryInvalid, fmt.Errorf("invalid timestamp %f", ts)
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}
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p.ts = int64(ts * 1000)
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switch t3 := p.nextToken(); t3 {
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case tLinebreak:
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case tComment:
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if err := p.parseComment(); err != nil {
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return EntryInvalid, err
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}
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default:
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return EntryInvalid, p.parseError("expected next entry after timestamp", t3)
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}
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default:
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return EntryInvalid, p.parseError("expected timestamp or # symbol", t2)
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}
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return EntrySeries, nil
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default:
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err = p.parseError("expected a valid start token", t)
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}
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return EntryInvalid, err
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}
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func (p *OpenMetricsParser) parseComment() error {
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var err error
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// Parse the labels.
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p.eOffsets, err = p.parseLVals(p.eOffsets)
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if err != nil {
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return err
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}
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p.exemplar = p.l.b[p.start:p.l.i]
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// Get the value.
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p.exemplarVal, err = p.getFloatValue(p.nextToken(), "exemplar labels")
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if err != nil {
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return err
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}
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// Read the optional timestamp.
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p.hasExemplarTs = false
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switch t2 := p.nextToken(); t2 {
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case tEOF:
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return errors.New("data does not end with # EOF")
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case tLinebreak:
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break
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case tTimestamp:
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p.hasExemplarTs = true
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var ts float64
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// A float is enough to hold what we need for millisecond resolution.
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if ts, err = parseFloat(yoloString(p.l.buf()[1:])); err != nil {
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return fmt.Errorf("%w while parsing: %q", err, p.l.b[p.start:p.l.i])
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}
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if math.IsNaN(ts) || math.IsInf(ts, 0) {
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return fmt.Errorf("invalid exemplar timestamp %f", ts)
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}
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p.exemplarTs = int64(ts * 1000)
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switch t3 := p.nextToken(); t3 {
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case tLinebreak:
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default:
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return p.parseError("expected next entry after exemplar timestamp", t3)
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}
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default:
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return p.parseError("expected timestamp or comment", t2)
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}
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return nil
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}
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func (p *OpenMetricsParser) parseLVals(offsets []int) ([]int, error) {
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first := true
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for {
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t := p.nextToken()
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switch t {
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case tBraceClose:
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return offsets, nil
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case tComma:
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if first {
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return nil, p.parseError("expected label name or left brace", t)
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}
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t = p.nextToken()
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if t != tLName {
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return nil, p.parseError("expected label name", t)
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}
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case tLName:
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if !first {
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return nil, p.parseError("expected comma", t)
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}
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default:
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if first {
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return nil, p.parseError("expected label name or left brace", t)
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}
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return nil, p.parseError("expected comma or left brace", t)
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}
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first = false
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// t is now a label name.
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offsets = append(offsets, p.l.start, p.l.i)
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if t := p.nextToken(); t != tEqual {
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return nil, p.parseError("expected equal", t)
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}
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if t := p.nextToken(); t != tLValue {
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return nil, p.parseError("expected label value", t)
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}
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if !utf8.Valid(p.l.buf()) {
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return nil, fmt.Errorf("invalid UTF-8 label value: %q", p.l.buf())
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}
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// The openMetricsLexer ensures the value string is quoted. Strip first
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// and last character.
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offsets = append(offsets, p.l.start+1, p.l.i-1)
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}
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}
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func (p *OpenMetricsParser) getFloatValue(t token, after string) (float64, error) {
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if t != tValue {
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return 0, p.parseError(fmt.Sprintf("expected value after %v", after), t)
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}
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val, err := parseFloat(yoloString(p.l.buf()[1:]))
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if err != nil {
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return 0, fmt.Errorf("%w while parsing: %q", err, p.l.b[p.start:p.l.i])
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}
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// Ensure canonical NaN value.
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if math.IsNaN(p.exemplarVal) {
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val = math.Float64frombits(value.NormalNaN)
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}
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return val, nil
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}
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