Yolo, add units.

Signed-off-by: bwplotka <[email protected]>

Author: bwplotka

prometheus/counter.go

@@ -85,9 +85,10 @@ type CounterVecOpts struct {
 // Both internal tracking values are added up in the Write method. This has to
 // be taken into account when it comes to precision and overflow behavior.
 func NewCounter(opts CounterOpts) Counter {
-	desc := NewDesc(
+	desc := V2.NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
+		opts.Unit,
 		nil,
 		opts.ConstLabels,
 	)
@@ -203,6 +204,7 @@ func (v2) NewCounterVec(opts CounterVecOpts) *CounterVec {
 	desc := V2.NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
+		opts.Unit,
 		opts.VariableLabels,
 		opts.ConstLabels,
 	)

prometheus/desc.go

@@ -47,6 +47,8 @@ type Desc struct {
 	fqName string
 	// help provides some helpful information about this metric.
 	help string
+	// unit is a OpenMetrics unit.
+	unit string
 	// constLabelPairs contains precalculated DTO label pairs based on
 	// the constant labels.
 	constLabelPairs []*dto.LabelPair
@@ -76,7 +78,7 @@ type Desc struct {
 // For constLabels, the label values are constant. Therefore, they are fully
 // specified in the Desc. See the Collector example for a usage pattern.
 func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *Desc {
-	return V2.NewDesc(fqName, help, UnconstrainedLabels(variableLabels), constLabels)
+	return V2.NewDesc(fqName, help, "", UnconstrainedLabels(variableLabels), constLabels)
 }
 
 // NewDesc allocates and initializes a new Desc. Errors are recorded in the Desc
@@ -89,10 +91,14 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 //
 // For constLabels, the label values are constant. Therefore, they are fully
 // specified in the Desc. See the Collector example for a usage pattern.
-func (v2) NewDesc(fqName, help string, variableLabels ConstrainableLabels, constLabels Labels) *Desc {
+func (v2) NewDesc(fqName, help, unit string, variableLabels ConstrainableLabels, constLabels Labels) *Desc {
+	if variableLabels == nil {
+		variableLabels = UnconstrainedLabels(nil)
+	}
 	d := &Desc{
 		fqName:         fqName,
 		help:           help,
+		unit:           unit,
 		variableLabels: variableLabels.compile(),
 	}
 	if !model.IsValidMetricName(model.LabelValue(fqName)) {

prometheus/gauge.go

@@ -76,9 +76,10 @@ type GaugeVecOpts struct {
 // scenarios for Gauges and Counters, where the former tends to be Set-heavy and
 // the latter Inc-heavy.
 func NewGauge(opts GaugeOpts) Gauge {
-	desc := NewDesc(
+	desc := V2.NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
+		opts.Unit,
 		nil,
 		opts.ConstLabels,
 	)
@@ -161,6 +162,7 @@ func (v2) NewGaugeVec(opts GaugeVecOpts) *GaugeVec {
 	desc := V2.NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
+		opts.Unit,
 		opts.VariableLabels,
 		opts.ConstLabels,
 	)

prometheus/histogram.go

@@ -371,6 +371,7 @@ type HistogramOpts struct {
 	Namespace string
 	Subsystem string
 	Name      string
+	Unit      string
 
 	// Help provides information about this Histogram.
 	//
@@ -522,9 +523,10 @@ type HistogramVecOpts struct {
 // for each bucket.
 func NewHistogram(opts HistogramOpts) Histogram {
 	return newHistogram(
-		NewDesc(
+		V2.NewDesc(
 			BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 			opts.Help,
+			opts.Unit,
 			nil,
 			opts.ConstLabels,
 		),
@@ -1188,6 +1190,7 @@ func (v2) NewHistogramVec(opts HistogramVecOpts) *HistogramVec {
 	desc := V2.NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
+		opts.Unit,
 		opts.VariableLabels,
 		opts.ConstLabels,
 	)

prometheus/metric.go

@@ -74,6 +74,7 @@ type Opts struct {
 	Namespace string
 	Subsystem string
 	Name      string
+	Unit      string
 
 	// Help provides information about this metric.
 	//

prometheus/registry.go

@@ -685,6 +685,10 @@ func processMetric(
 		metricFamily = &dto.MetricFamily{}
 		metricFamily.Name = proto.String(desc.fqName)
 		metricFamily.Help = proto.String(desc.help)
+		if desc.unit != "" {
+			metricFamily.Unit = proto.String(desc.unit)
+		}
+
 		// TODO(beorn7): Simplify switch once Desc has type.
 		switch {
 		case dtoMetric.Gauge != nil:

prometheus/summary.go

@@ -576,6 +576,7 @@ func (v2) NewSummaryVec(opts SummaryVecOpts) *SummaryVec {
 	desc := V2.NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
+		"", // TODO
 		opts.VariableLabels,
 		opts.ConstLabels,
 	)

prometheus/wrap.go

@@ -204,7 +204,7 @@ func wrapDesc(desc *Desc, prefix string, labels Labels) *Desc {
 		constLabels[ln] = lv
 	}
 	// NewDesc will do remaining validations.
-	newDesc := V2.NewDesc(prefix+desc.fqName, desc.help, desc.variableLabels, constLabels)
+	newDesc := V2.NewDesc(prefix+desc.fqName, desc.help, desc.unit, desc.variableLabels, constLabels)
 	// Propagate errors if there was any. This will override any errer
 	// created by NewDesc above, i.e. earlier errors get precedence.
 	if desc.err != nil {