engine: fix version parsing

engine.go

@@ -4,8 +4,6 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
-	"runtime"
-	"strings"
 	"sync"
 	"time"
 
@@ -169,35 +167,34 @@ func (e *Engine) reportVersionOnce(t time.Time) {
 	// configure it after creation time with e.g. the Register function. So
 	// instead we try to do it at the moment you try to send your first metric.
 	e.once.Do(func() {
-		vsn := strings.TrimPrefix(runtime.Version(), "go")
-		parts := strings.Split(vsn, ".")
-		// We don't want to report weird compiled Go versions like tip.
-		// len(parts) may equal 2 because an older Go version might be "go1.13"
-		// instead of "go1.13.1"
-		if len(parts) == 2 || len(parts) == 3 {
-			e.Handler.HandleMeasures(t,
-				Measure{
-					Name: "go_version",
-					Fields: []Field{{
-						Name:  "value",
-						Value: intValue(1),
-					}},
-					Tags: []Tag{
-						{"go_version", vsn},
-					},
+		measures := []Measure{
+			{
+				Name: "stats_version",
+				Fields: []Field{{
+					Name:  "value",
+					Value: intValue(1),
+				}},
+				Tags: []Tag{
+					{"stats_version", version.Version},
 				},
-				Measure{
-					Name: "stats_version",
-					Fields: []Field{{
-						Name:  "value",
-						Value: intValue(1),
-					}},
-					Tags: []Tag{
-						{"stats_version", version.Version},
-					},
+			},
+		}
+		// We don't want to report weird compiled Go versions like "devel" with
+		// a commit SHA. Splitting on periods does not work as well for
+		// filtering these
+		if !version.DevelGoVersion() {
+			measures = append(measures, Measure{
+				Name: "go_version",
+				Fields: []Field{{
+					Name:  "value",
+					Value: intValue(1),
+				}},
+				Tags: []Tag{
+					{"go_version", version.GoVersion()},
 				},
-			)
+			})
 		}
+		e.Handler.HandleMeasures(t, measures...)
 	})
 }
 

netstats/listener_test.go

@@ -3,12 +3,11 @@ package netstats
 import (
 	"net"
 	"reflect"
-	"runtime"
-	"strings"
 	"testing"
 
 	stats "github.com/segmentio/stats/v5"
 	"github.com/segmentio/stats/v5/statstest"
+	"github.com/segmentio/stats/v5/version"
 )
 
 func TestListener(t *testing.T) {
@@ -63,11 +62,12 @@ func TestListenerError(t *testing.T) {
 
 	lstn.Close()
 
-	vsn := strings.TrimPrefix(runtime.Version(), "go")
-	parts := strings.Split(vsn, ".")
 	measures := h.Measures()
-	measurePassed := false
-	if len(parts) == 2 || len(parts) == 3 {
+	t.Run("CheckGoVersionEmitted", func(t *testing.T) {
+		if version.DevelGoVersion() {
+			t.Skip("No metrics emitted if compiled with Go devel version")
+		}
+		measurePassed := false
 		for _, measure := range measures {
 			if measure.Name != "go_version" {
 				continue
@@ -76,15 +76,15 @@ func TestListenerError(t *testing.T) {
 				if tag.Name != "go_version" {
 					continue
 				}
-				if tag.Value == vsn {
+				if tag.Value == version.GoVersion() {
 					measurePassed = true
 				}
 			}
 		}
-	}
-	if !measurePassed {
-		t.Errorf("did not find correct tag for measure: %#v\n", measures)
-	}
+		if !measurePassed {
+			t.Errorf("did not find correct 'go_version' tag for measure: %#v\n", measures)
+		}
+	})
 	var foundMetric stats.Measure
 	for i := range measures {
 		if measures[i].Name == "netstats.test.conn.error" {

version/version.go

@@ -1,3 +1,35 @@
 package version
 
+import (
+	"runtime"
+	"strings"
+	"sync"
+)
+
 const Version = "5.3.0"
+
+var (
+	vsnOnce sync.Once
+	vsn     string
+)
+
+func isDevel(vsn string) bool {
+	return strings.Count(vsn, " ") > 2 || strings.HasPrefix(vsn, "devel")
+}
+
+// GoVersion reports the Go version, in a format that is consumable by metrics
+// tools.
+func GoVersion() string {
+	vsnOnce.Do(func() {
+		vsn = strings.TrimPrefix(runtime.Version(), "go")
+	})
+	return vsn
+}
+
+// DevelGoVersion reports whether the version of Go that compiled or ran this
+// library is a development ("tip") version. This is useful to distinguish
+// because tip versions include a commit SHA and change frequently, so are less
+// useful for metric reporting.
+func DevelGoVersion() bool {
+	return isDevel(GoVersion())
+}

version/version_test.go

@@ -0,0 +1,12 @@
+package version
+
+import "testing"
+
+func TestDevel(t *testing.T) {
+	if isDevel("1.23.4") {
+		t.Errorf("expected 1.23.4 to return false; got true")
+	}
+	if !isDevel("devel go1.24-d1d9312950 Wed Jan 1 21:18:59 2025 -0800 darwin/arm64") {
+		t.Errorf("expected tip version to return true; got false")
+	}
+}