engine: report go version on startup

.github/workflows/golangci-lint.yml

@@ -18,7 +18,6 @@ jobs:
   lint:
     name: lint
     runs-on: ubuntu-latest
-    continue-on-error: true
     steps:
       - uses: actions/setup-go@v5
         with:

Makefile

@@ -0,0 +1,8 @@
+test:
+	go test -trimpath ./...
+
+ci:
+	go test -race -trimpath ./...
+
+lint:
+	golangci-lint run --config .golangci.yml

README.md

@@ -183,7 +183,7 @@ Monitoring
 
 > 🚧 Go metrics reported with the `procstats` package were previously tagged with a
 > `version` label that reported the Go runtime version. This label was renamed to
-> `go_version` in v5.6.0.
+> `go_version` in v4.6.0.
 
 The
 [github.com/segmentio/stats/procstats](https://godoc.org/github.com/segmentio/stats/procstats)
@@ -385,3 +385,16 @@ func main() {
     // ...
 }
 ```
+
+### Addendum
+
+By default, the stats library will report the running go version when you
+invoke NewEngine() as a metric:
+
+- `go_version` with value 1 and a `tag` set to the current version.
+- `stats_version` with value ` and a `tag` set to the tag value of
+  segmentio/stats.
+
+Set `STATS_DISABLE_GO_VERSION_REPORTING` to `true` in your environment, or set
+`stats.GoVersionReportingEnabled` to `false` before collecting any metrics, to
+disable this behavior.

cmd/dogstatsd/main.go

@@ -12,7 +12,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 	"github.com/segmentio/stats/v5/datadog"
 )
 

context.go

@@ -6,7 +6,7 @@ import (
 )
 
 // ContextWithTags returns a new child context with the given tags.  If the
-// parent context already has tags set on it, they are _not_ propegated into
+// parent context already has tags set on it, they are _not_ propagated into
 // the context children.
 func ContextWithTags(ctx context.Context, tags ...Tag) context.Context {
 	// initialize the context reference and return a new context

datadog/append.go

@@ -4,7 +4,7 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 func appendMetric(b []byte, m Metric) []byte {

datadog/client.go

@@ -8,7 +8,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 
 	"golang.org/x/sys/unix"
 )

datadog/client_test.go

@@ -11,7 +11,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 
 	"github.com/stretchr/testify/assert"
 )

datadog/event.go

@@ -3,7 +3,7 @@ package datadog
 import (
 	"fmt"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 // EventPriority is an enumeration providing the available datadog event

datadog/event_test.go

@@ -1,7 +1,7 @@
 package datadog
 
 import (
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 var testEvents = []struct {

datadog/metric.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"sync"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 // MetricType is an enumeration providing symbols to represent the different

datadog/metric_test.go

@@ -3,7 +3,7 @@ package datadog
 import (
 	"testing"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 var testMetrics = []struct {

datadog/parse.go

@@ -5,7 +5,7 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 // Adapted from https://github.com/DataDog/datadog-agent/blob/6789e98a1e41e98700fa1783df62238bb23cb454/pkg/dogstatsd/parser.go#L141

datadog/serializer.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 // Datagram format: https://docs.datadoghq.com/developers/dogstatsd/datagram_shell

datadog/serializer_test.go

@@ -4,7 +4,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 var testMeasures = []struct {

datadog/server_test.go

@@ -11,10 +11,13 @@ import (
 	"testing"
 	"time"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 func TestServer(t *testing.T) {
+	initValue := stats.GoVersionReportingEnabled
+	stats.GoVersionReportingEnabled = false
+	defer func() { stats.GoVersionReportingEnabled = initValue }()
 	engine := stats.NewEngine("datadog.test", nil)
 
 	a := uint32(0)
@@ -97,6 +100,7 @@ func TestServer(t *testing.T) {
 }
 
 func startUDPTestServer(t *testing.T, handler Handler) (addr string, closer io.Closer) {
+	t.Helper()
 	conn, err := net.ListenPacket("udp", "127.0.0.1:0")
 	if err != nil {
 		t.Error(err)

engine.go

@@ -4,16 +4,20 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"runtime"
+	"strings"
 	"sync"
 	"time"
+
+	"github.com/segmentio/stats/v5/version"
 )
 
-// An Engine carries the context for producing metrics, it is configured by
+// An Engine carries the context for producing metrics. It is configured by
 // setting the exported fields or using the helper methods to create sub-engines
 // that inherit the configuration of the base they were created from.
 //
 // The program must not modify the engine's handler, prefix, or tags after it
-// started using it. If changes need to be made new engines must be created by
+// starts using them. If changes need to be made new engines must be created by
 // calls to WithPrefix or WithTags.
 type Engine struct {
 	// The measure handler that the engine forwards measures to.
@@ -26,7 +30,7 @@ type Engine struct {
 	//
 	// The list of tags has to be sorted. This is automatically managed by the
 	// helper methods WithPrefix, WithTags and the NewEngine function. A program
-	// that manipulates this field directly has to respect this requirement.
+	// that manipulates this field directly must respect this requirement.
 	Tags []Tag
 
 	// Indicates whether to allow duplicated tags from the tags list before sending.
@@ -41,16 +45,19 @@ type Engine struct {
 	// The cached values include the engine prefix in the measure names, which
 	// is why the cache must be local to the engine.
 	cache measureCache
+
+	once sync.Once
 }
 
 // NewEngine creates and returns a new engine configured with prefix, handler,
 // and tags.
 func NewEngine(prefix string, handler Handler, tags ...Tag) *Engine {
-	return &Engine{
+	e := &Engine{
 		Handler: handler,
 		Prefix:  prefix,
 		Tags:    SortTags(copyTags(tags)),
 	}
+	return e
 }
 
 // Register adds handler to eng.
@@ -144,7 +151,52 @@ func (eng *Engine) ClockAt(name string, start time.Time, tags ...Tag) *Clock {
 	}
 }
 
+var truthyValues = map[string]bool{
+	"true": true,
+	"TRUE": true,
+	"yes":  true,
+	"1":    true,
+	"on":   true,
+}
+
+var GoVersionReportingEnabled = !truthyValues[os.Getenv("STATS_DISABLE_GO_VERSION_REPORTING")]
+
 func (eng *Engine) measure(t time.Time, name string, value interface{}, ftype FieldType, tags ...Tag) {
+	if GoVersionReportingEnabled {
+		eng.once.Do(func() {
+			vsn := strings.TrimPrefix(runtime.Version(), "go")
+			parts := strings.Split(vsn, ".")
+			// this filters out weird compiled Go versions like tip. len(parts)
+			// may equal 2 because older Go version might be "go1.13"
+			if len(parts) == 2 || len(parts) == 3 {
+				eng.Handler.HandleMeasures(t, Measure{
+					Name: "go_version",
+					Fields: []Field{{
+						Name:  "go_version",
+						Value: intValue(1),
+					}},
+					Tags: []Tag{
+						{"go_version", vsn},
+					},
+				},
+					Measure{
+						Name: "stats_version",
+						Fields: []Field{{
+							Name:  "stats_version",
+							Value: intValue(1),
+						}},
+						Tags: []Tag{
+							{"stats_version", version.Version},
+						},
+					},
+				)
+			}
+		})
+	}
+	eng.measureOne(t, name, value, ftype, tags...)
+}
+
+func (eng *Engine) measureOne(t time.Time, name string, value interface{}, ftype FieldType, tags ...Tag) {
 	name, field := splitMeasureField(name)
 	mp := measureArrayPool.Get().(*[1]Measure)
 

engine_test.go

@@ -8,7 +8,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 	"github.com/segmentio/stats/v5/datadog"
 	"github.com/segmentio/stats/v5/influxdb"
 	"github.com/segmentio/stats/v5/prometheus"
@@ -74,14 +74,21 @@ func TestEngine(t *testing.T) {
 		},
 	}
 
-	for _, test := range tests {
-		testFunc := test.function
-		t.Run(test.scenario, func(t *testing.T) {
-			t.Parallel()
-			h := &statstest.Handler{}
-			testFunc(t, stats.NewEngine("test", h, stats.T("service", "test-service")))
-		})
-	}
+	initValue := stats.GoVersionReportingEnabled
+	stats.GoVersionReportingEnabled = false
+	defer func() { stats.GoVersionReportingEnabled = initValue }()
+	// Extra t.Run is necessary so above defer runs after parallel tests
+	// complete.
+	t.Run("subtests", func(t *testing.T) {
+		for _, test := range tests {
+			testFunc := test.function
+			t.Run(test.scenario, func(t *testing.T) {
+				t.Parallel()
+				h := &statstest.Handler{}
+				testFunc(t, stats.NewEngine("test", h, stats.T("service", "test-service")))
+			})
+		}
+	})
 }
 
 func testEngineWithPrefix(t *testing.T, eng *stats.Engine) {
@@ -369,7 +376,8 @@ func BenchmarkEngine(b *testing.B) {
 		},
 	}
 
-	for _, eng := range engines {
+	for i := range engines {
+		eng := &engines[i]
 		b.Run(eng.name, func(b *testing.B) {
 			tests := []struct {
 				scenario string

go.mod

@@ -2,8 +2,6 @@ module github.com/segmentio/stats/v5
 
 go 1.22.0
 
-toolchain go1.23.1
-
 require (
 	github.com/mdlayher/taskstats v0.0.0-20190313225729-7cbba52ee072
 	github.com/segmentio/fasthash v1.0.3

handler_test.go

@@ -4,7 +4,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 	"github.com/segmentio/stats/v5/statstest"
 
 	"github.com/stretchr/testify/assert"

httpstats/context.go

@@ -3,7 +3,7 @@ package httpstats
 import (
 	"net/http"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 // RequestWithTags returns a shallow copy of req with its context updated to

httpstats/context_test.go

@@ -6,17 +6,17 @@ import (
 	"net/http/httptest"
 	"testing"
 
-	"github.com/stretchr/testify/assert"
+	stats "github.com/segmentio/stats/v5"
 
-	"github.com/segmentio/stats/v5"
+	"github.com/stretchr/testify/assert"
 )
 
-// TestRequestContextTagPropegation verifies that the root ancestor tags are
+// TestRequestContextTagPropagation verifies that the root ancestor tags are
 // updated in the event the context or request has children.  It's nearly
 // identical to the context_test in the stats package itself, but we want to
 // keep this to ensure that changes to the request context code doesn't drift
 // and cause bugs.
-func TestRequestContextTagPropegation(t *testing.T) {
+func TestRequestContextTagPropagation(t *testing.T) {
 	// dummy request
 	x := httptest.NewRequest(http.MethodGet, "http://example.com/blah", nil)
 

httpstats/handler.go

@@ -6,7 +6,7 @@ import (
 	"net/http"
 	"time"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 )
 
 // NewHandler wraps h to produce metrics on the default engine for every request

httpstats/handler_test.go

@@ -7,7 +7,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/segmentio/stats/v5"
+	stats "github.com/segmentio/stats/v5"
 	"github.com/segmentio/stats/v5/statstest"
 )