Merge pull request prometheus#13299 from vesari/add-unit-parser

protobuf: add unit parser

model/textparse/openmetricsparse.go

@@ -136,7 +136,6 @@ func (p *OpenMetricsParser) Type() ([]byte, model.MetricType) {
 // Must only be called after Next returned a unit entry.
 // The returned byte slices become invalid after the next call to Next.
 func (p *OpenMetricsParser) Unit() ([]byte, []byte) {
-	// The Prometheus format does not have units.
 	return p.l.b[p.offsets[0]:p.offsets[1]], p.text
 }
 

model/textparse/protobufparse.go

@@ -269,10 +269,11 @@ func (p *ProtobufParser) Type() ([]byte, model.MetricType) {
 	return n, model.MetricTypeUnknown
 }
 
-// Unit always returns (nil, nil) because units aren't supported by the protobuf
-// format.
+// Unit returns the metric unit in the current entry.
+// Must only be called after Next returned a unit entry.
+// The returned byte slices become invalid after the next call to Next.
 func (p *ProtobufParser) Unit() ([]byte, []byte) {
-	return nil, nil
+	return p.metricBytes.Bytes(), []byte(p.mf.GetUnit())
 }
 
 // Comment always returns nil because comments aren't supported by the protobuf
@@ -422,6 +423,16 @@ func (p *ProtobufParser) Next() (Entry, error) {
 		default:
 			return EntryInvalid, fmt.Errorf("unknown metric type for metric %q: %s", name, p.mf.GetType())
 		}
+		unit := p.mf.GetUnit()
+		if len(unit) > 0 {
+			if p.mf.GetType() == dto.MetricType_COUNTER && strings.HasSuffix(name, "_total") {
+				if !strings.HasSuffix(name[:len(name)-6], unit) || len(name)-6 < len(unit)+1 || name[len(name)-6-len(unit)-1] != '_' {
+					return EntryInvalid, fmt.Errorf("unit %q not a suffix of counter %q", unit, name)
+				}
+			} else if !strings.HasSuffix(name, unit) || len(name) < len(unit)+1 || name[len(name)-len(unit)-1] != '_' {
+				return EntryInvalid, fmt.Errorf("unit %q not a suffix of metric %q", unit, name)
+			}
+		}
 		p.metricBytes.Reset()
 		p.metricBytes.WriteString(name)
 

model/textparse/protobufparse_test.go

@@ -58,6 +58,7 @@ metric: <
 		`name: "go_memstats_alloc_bytes_total"
 help: "Total number of bytes allocated, even if freed."
 type: COUNTER
+unit: "bytes"
 metric: <
   counter: <
     value: 1.546544e+06
@@ -665,6 +666,7 @@ func TestProtobufParse(t *testing.T) {
 				{
 					m:    "go_memstats_alloc_bytes_total",
 					help: "Total number of bytes allocated, even if freed.",
+					unit: "bytes",
 				},
 				{
 					m:   "go_memstats_alloc_bytes_total",