fix comments for unit support

Signed-off-by: Arianna Vespri <[email protected]>

Author: vesari

expfmt/openmetrics_create.go

@@ -47,12 +47,15 @@ import (
 // Prometheus to OpenMetrics or vice versa:
 //
 //   - Counters are expected to have the `_total` suffix in their metric name. In
-//     the output, the suffix will be truncated from the `# TYPE` and `# HELP`
-//     line. A counter with a missing `_total` suffix is not an error. However,
+//     the output, the suffix will be truncated from the `# TYPE`, `# HELP` and `# UNIT`
+//     lines. A counter with a missing `_total` suffix is not an error. However,
 //     its type will be set to `unknown` in that case to avoid invalid OpenMetrics
 //     output.
 //
-//   - No support for the following (optional) features: `# UNIT` line, `_created`
+//   - 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/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#unit)
+//
+//   - No support for the following (optional) features: `_created`
 //     line, info type, stateset type, gaugehistogram type.
 //
 //   - The size of exemplar labels is not checked (i.e. it's possible to create

go.mod

@@ -32,4 +32,4 @@ require (
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 )
 
-replace github.com/prometheus/client_model => github.com/vesari/client_model v0.0.0-20231118150741-19723af61627
+replace github.com/prometheus/client_model => github.com/vesari/client_model v0.0.0-20231202151802-003f160da988

go.sum

@@ -42,8 +42,8 @@ github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncj
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
-github.com/vesari/client_model v0.0.0-20231118150741-19723af61627 h1:pJsecGZFkJIN3ipp7fS8hLDK0Dcnk2JVxXds3Dev3dQ=
-github.com/vesari/client_model v0.0.0-20231118150741-19723af61627/go.mod h1:dTiFglRmd66nLR9Pv9f0mZi7B7fk5Pm3gvsjB5tr+kI=
+github.com/vesari/client_model v0.0.0-20231202151802-003f160da988 h1:uGmTMMEergUEb2pEH90ZLVSBGvDqN16P12UsBjEQp0Y=
+github.com/vesari/client_model v0.0.0-20231202151802-003f160da988/go.mod h1:dTiFglRmd66nLR9Pv9f0mZi7B7fk5Pm3gvsjB5tr+kI=
 github.com/xhit/go-str2duration/v2 v2.1.0 h1:lxklc02Drh6ynqX+DdPyp5pCKLUQpRT8bp8Ydu2Bstc=
 github.com/xhit/go-str2duration/v2 v2.1.0/go.mod h1:ohY8p+0f07DiV6Em5LKB0s2YpLtXVyJfNt1+BlmyAsU=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=