Method startLabelName

expfmt/text_parse.go:273–320

startLabelName represents the state where the next byte read from p.buf is the start of a label name (or whitespace leading up to it).

()

// startLabelName represents the state where the next byte read from p.buf is
// the start of a label name (or whitespace leading up to it).
func (p *TextParser) startLabelName() stateFn {
	if p.skipBlankTab(); p.err != nil {
		return nil // Unexpected end of input.
	}
	if p.currentByte == '}' {
		if p.skipBlankTab(); p.err != nil {
			return nil // Unexpected end of input.
		}
		return p.readingValue
	}
	if p.readTokenAsLabelName(); p.err != nil {
		return nil // Unexpected end of input.
	}
	if p.currentToken.Len() == 0 {
		p.parseError(fmt.Sprintf("invalid label name for metric %q", p.currentMF.GetName()))
		return nil
	}
	p.currentLabelPair = &dto.LabelPair{Name: proto.String(p.currentToken.String())}
	if p.currentLabelPair.GetName() == string(model.MetricNameLabel) {
		p.parseError(fmt.Sprintf("label name %q is reserved", model.MetricNameLabel))
		return nil
	}
	// Special summary/histogram treatment. Don't add 'quantile' and 'le'
	// labels to 'real' labels.
	if !(p.currentMF.GetType() == dto.MetricType_SUMMARY && p.currentLabelPair.GetName() == model.QuantileLabel) &&
		!(p.currentMF.GetType() == dto.MetricType_HISTOGRAM && p.currentLabelPair.GetName() == model.BucketLabel) {
		p.currentMetric.Label = append(p.currentMetric.Label, p.currentLabelPair)
	}
	if p.skipBlankTabIfCurrentBlankTab(); p.err != nil {
		return nil // Unexpected end of input.
	}
	if p.currentByte != '=' {
		p.parseError(fmt.Sprintf("expected '=' after label name, found %q", p.currentByte))
		return nil
	}
	// Check for duplicate label names.
	labels := make(map[string]struct{})
	for _, l := range p.currentMetric.Label {
		lName := l.GetName()
		if _, exists := labels[lName]; !exists {
			labels[lName] = struct{}{}
		} else {
			p.parseError(fmt.Sprintf("duplicate label names for metric %q", p.currentMF.GetName()))
			return nil
		}
	}
	return p.startLabelValue
}

// startLabelValue represents the state where the next byte read from p.buf is
// the start of a (quoted) label value (or whitespace leading up to it).