Function MetricFamilyToText

expfmt/text_create.go:78–293

MetricFamilyToText converts a MetricFamily proto message into text format and writes the resulting lines to 'out'. It returns the number of bytes written and any error encountered. The output will have the same order as the input, no further sorting is performed. Furthermore, this function assumes t

(out io.Writer, in *dto.MetricFamily)

//
// This method fulfills the type 'prometheus.encoder'.
func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err error) {
	// Fail-fast checks.
	if len(in.Metric) == 0 {
		return 0, fmt.Errorf("MetricFamily has no metrics: %s", in)
	}
	name := in.GetName()
	if name == "" {
		return 0, fmt.Errorf("MetricFamily has no name: %s", in)
	}

	// Try the interface upgrade. If it doesn't work, we'll use a
	// bufio.Writer from the sync.Pool.
	w, ok := out.(enhancedWriter)
	if !ok {
		b := bufPool.Get().(*bufio.Writer)
		b.Reset(out)
		w = b
		defer func() {
			bErr := b.Flush()
			if err == nil {
				err = bErr
			}
			bufPool.Put(b)
		}()
	}

	var n int

	// Comments, first HELP, then TYPE.
	if in.Help != nil {
		n, err = w.WriteString("# HELP ")
		written += n
		if err != nil {
			return written, err
		}
		n, err = writeName(w, name)
		written += n
		if err != nil {
			return written, err
		}
		err = w.WriteByte(' ')
		written++
		if err != nil {
			return written, err
		}
		n, err = writeEscapedString(w, *in.Help, false)
		written += n
		if err != nil {
			return written, err
		}
		err = w.WriteByte('\n')
		written++
		if err != nil {
			return written, err
		}
	}
	n, err = w.WriteString("# TYPE ")
	written += n