Remove logic adding unit to metrics name (#877)

vesari · web-flow · commit e4c38a0aea47 · 2026-02-24T09:23:43.000Z
* Remove withUnit flag and automatic adding of unit to metric name, change tests accordingly

Signed-off-by: Arianna Vespri &lt;arianna.vespri@yahoo.it&gt;

* Remove redundant tests and comments for OM creation

Signed-off-by: Arianna Vespri &lt;arianna.vespri@yahoo.it&gt;

* fix fmt number in test

Signed-off-by: Arianna Vespri &lt;arianna.vespri@yahoo.it&gt;

---------

Signed-off-by: Arianna Vespri &lt;arianna.vespri@yahoo.it&gt;
diff --git a/expfmt/encode_test.go b/expfmt/encode_test.go
@@ -248,6 +248,7 @@ foo_metric 1.234
 			metric: metric1,
 			format: FmtOpenMetrics_0_0_1,
 			expOut: `# TYPE foo_metric unknown
+# UNIT foo_metric seconds
 foo_metric 1.234
 `,
 		},
@@ -256,24 +257,16 @@ foo_metric 1.234
 			metric: metric1,
 			format: FmtOpenMetrics_1_0_0,
 			expOut: `# TYPE foo_metric unknown
+# UNIT foo_metric seconds
 foo_metric 1.234
 `,
 		},
-		// 7: Simple Counter FmtOpenMetrics_0_0_1 unit opted in
-		{
-			metric:  metric1,
-			format:  FmtOpenMetrics_0_0_1,
-			options: []EncoderOption{WithUnit()},
-			expOut: `# TYPE foo_metric_seconds unknown
-# UNIT foo_metric_seconds seconds
-foo_metric_seconds 1.234
-`,
-		},
-		// 8: Simple Counter FmtOpenMetrics_1_0_0 unit opted out
+		// 7: Simple Counter FmtOpenMetrics_1_0_0
 		{
 			metric: metric1,
 			format: FmtOpenMetrics_1_0_0,
 			expOut: `# TYPE foo_metric unknown
+# UNIT foo_metric seconds
 foo_metric 1.234
 `,
 		},
diff --git a/expfmt/openmetrics_create.go b/expfmt/openmetrics_create.go
@@ -30,7 +30,6 @@ import (
 
 type encoderOption struct {
 	withCreatedLines bool
-	withUnit         bool
 }
 
 type EncoderOption func(*encoderOption)
@@ -51,17 +50,6 @@ func WithCreatedLines() EncoderOption {
 	}
 }
 
-// WithUnit is an EncoderOption enabling a set unit to be written to the output
-// and to be added to the metric name, if it's not there already, as a suffix.
-// Without opting in this way, the unit will not be added to the metric name and,
-// on top of that, the unit will not be passed onto the output, even if it
-// were declared in the *dto.MetricFamily struct, i.e. even if in.Unit !=nil.
-func WithUnit() EncoderOption {
-	return func(t *encoderOption) {
-		t.withUnit = true
-	}
-}
-
 // MetricFamilyToOpenMetrics converts a MetricFamily proto message into the
 // OpenMetrics text format and writes the resulting lines to 'out'. It returns
 // the number of bytes written and any error encountered. The output will have
@@ -99,15 +87,6 @@ func WithUnit() EncoderOption {
 //     its type will be set to `unknown` in that case to avoid invalid OpenMetrics
 //     output.
 //
-//   - According to the OM specs, the `# UNIT` line is optional, but if populated,
-//     the unit has to be present in the metric name as its suffix:
-//     (see https://github.com/prometheus/OpenMetrics/blob/v1.0.0/specification/OpenMetrics.md#unit).
-//     However, in order to accommodate any potential scenario where such a change in the
-//     metric name is not desirable, the users are here given the choice of either explicitly
-//     opt in, in case they wish for the unit to be included in the output AND in the metric name
-//     as a suffix (see the description of the WithUnit function above),
-//     or not to opt in, in case they don't want for any of that to happen.
-//
 //   - No support for the following (optional) features: info type,
 //     stateset type, gaugehistogram type.
 //
@@ -151,9 +130,6 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 	if metricType == dto.MetricType_COUNTER && strings.HasSuffix(compliantName, "_total") {
 		compliantName = name[:len(name)-6]
 	}
-	if toOM.withUnit && in.Unit != nil && !strings.HasSuffix(compliantName, "_"+*in.Unit) {
-		compliantName = compliantName + "_" + *in.Unit
-	}
 
 	// Comments, first HELP, then TYPE.
 	if in.Help != nil {
@@ -217,7 +193,7 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 	if err != nil {
 		return written, err
 	}
-	if toOM.withUnit && in.Unit != nil {
+	if in.Unit != nil {
 		n, err = w.WriteString("# UNIT ")
 		written += n
 		if err != nil {
diff --git a/expfmt/openmetrics_create_test.go b/expfmt/openmetrics_create_test.go
@@ -399,7 +399,7 @@ summary_name_created{name_1="value 1",name_2="value 2"} 12345.6
 					},
 				},
 			},
-			options: []EncoderOption{WithCreatedLines(), WithUnit()},
+			options: []EncoderOption{WithCreatedLines()},
 			out: `# HELP request_duration_microseconds The response latency.
 # TYPE request_duration_microseconds histogram
 # UNIT request_duration_microseconds microseconds
@@ -449,6 +449,7 @@ request_duration_microseconds_created 12345.6
 			},
 			out: `# HELP request_duration_microseconds The response latency.
 # TYPE request_duration_microseconds histogram
+# UNIT request_duration_microseconds microseconds
 request_duration_microseconds_bucket{le="100.0"} 123
 request_duration_microseconds_bucket{le="120.0"} 412
 request_duration_microseconds_bucket{le="144.0"} 592
@@ -613,13 +614,12 @@ foos_total 42.0
 				Unit:   proto.String("seconds"),
 				Metric: []*dto.Metric{},
 			},
-			options: []EncoderOption{WithUnit()},
 			out: `# HELP name_seconds doc string
 # TYPE name_seconds counter
 # UNIT name_seconds seconds
 `,
 		},
-		// 15: Histogram plus unit, but unit not opted in.
+		// 15: Histogram plus unit
 		{
 			in: &dto.MetricFamily{
 				Name: proto.String("request_duration_microseconds"),
@@ -659,6 +659,7 @@ foos_total 42.0
 			},
 			out: `# HELP request_duration_microseconds The response latency.
 # TYPE request_duration_microseconds histogram
+# UNIT request_duration_microseconds microseconds
 request_duration_microseconds_bucket{le="100.0"} 123
 request_duration_microseconds_bucket{le="120.0"} 412
 request_duration_microseconds_bucket{le="144.0"} 592
@@ -668,35 +669,7 @@ request_duration_microseconds_sum 1.7560473e+06
 request_duration_microseconds_count 2693
 `,
 		},
-		// 16: No metric, unit opted in, no unit in name.
-		{
-			in: &dto.MetricFamily{
-				Name:   proto.String("name_total"),
-				Help:   proto.String("doc string"),
-				Type:   dto.MetricType_COUNTER.Enum(),
-				Unit:   proto.String("seconds"),
-				Metric: []*dto.Metric{},
-			},
-			options: []EncoderOption{WithUnit()},
-			out: `# HELP name_seconds doc string
-# TYPE name_seconds counter
-# UNIT name_seconds seconds
-`,
-		},
-		// 17: No metric, unit opted in, BUT unit == nil.
-		{
-			in: &dto.MetricFamily{
-				Name:   proto.String("name_total"),
-				Help:   proto.String("doc string"),
-				Type:   dto.MetricType_COUNTER.Enum(),
-				Metric: []*dto.Metric{},
-			},
-			options: []EncoderOption{WithUnit()},
-			out: `# HELP name doc string
-# TYPE name counter
-`,
-		},
-		// 18: Counter, timestamp given, unit opted in, _total suffix.
+		// 16: Counter, timestamp given, unit given, _total suffix.
 		{
 			in: &dto.MetricFamily{
 				Name: proto.String("some_measure_total"),
@@ -737,15 +710,14 @@ request_duration_microseconds_count 2693
 					},
 				},
 			},
-			options: []EncoderOption{WithUnit()},
-			out: `# HELP some_measure_seconds some testing measurement
-# TYPE some_measure_seconds counter
-# UNIT some_measure_seconds seconds
-some_measure_seconds_total{labelname="val1",basename="basevalue"} 42.0
-some_measure_seconds_total{labelname="val2",basename="basevalue"} 0.23 1.23456789e+06
+			out: `# HELP some_measure some testing measurement
+# TYPE some_measure counter
+# UNIT some_measure seconds
+some_measure_total{labelname="val1",basename="basevalue"} 42.0
+some_measure_total{labelname="val2",basename="basevalue"} 0.23 1.23456789e+06
 `,
 		},
-		// 11: Gauge histogram.
+		// 17: Gauge histogram.
 		{
 			in: &dto.MetricFamily{
 				Name: proto.String("name"),
