simple span (#11)

Author: pkieltyka

Diff for: _examples/basic/main.go

@@ -3,11 +3,13 @@ package main
 import (
 	"context"
 	"log/slog"
+	"math/rand"
 	"net/http"
 	"os"
 	"os/signal"
 	"strconv"
 	"syscall"
+	"time"
 
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
@@ -61,6 +63,15 @@ func main() {
 			AppMetrics.RecordAppGauge(floatValue)
 			w.Write([]byte("Gauge recorded!"))
 		})
+		r.Get("/compute", func(w http.ResponseWriter, r *http.Request) {
+			span := AppMetrics.RecordSpan("compute", nil)
+			defer span.Stop()
+
+			// do random work for random tie,,
+			time.Sleep(time.Duration(rand.Intn(5)) * time.Second)
+
+			w.Write([]byte("Span recorded!"))
+		})
 	})
 
 	sig := make(chan os.Signal, 1)

Diff for: telemetry.go

@@ -172,6 +172,10 @@ func (n *Scope) RecordDurationWithResolution(measurement string, tags map[string
 	record.RecordDuration(elapsed)
 }
 
+func (n *Scope) RecordSpan(measurement string, tags map[string]string) tally.Stopwatch {
+	return n.scope.Timer(measurement + "_span").Start()
+}
+
 func newRootScope(opts tally.ScopeOptions, interval time.Duration) (tally.Scope, io.Closer) {
 	opts.CachedReporter = reporter
 	opts.Separator = prometheus.DefaultSeparator