tracing: Lower trace sample rate and make it configurable

Author: monstermunchkin

maintenance/tracing/tracing.go

@@ -5,6 +5,7 @@ package tracing
 import (
 	"net/http"
 	"os"
+	"strconv"
 	"strings"
 
 	"github.com/getsentry/sentry-go"
@@ -14,11 +15,23 @@ import (
 )
 
 func init() {
+	var tracesSampleRate float64 = 0.1
+
+	val := os.Getenv("SENTRY_TRACES_SAMPLE_RATE")
+	if val == "" {
+		var err error
+
+		tracesSampleRate, err = strconv.ParseFloat(val, 64)
+		if err != nil {
+			log.Fatalf("failed to parse SENTRY_TRACES_SAMPLE_RATE: %v", err)
+		}
+	}
+
 	err := sentry.Init(sentry.ClientOptions{
 		Dsn:              os.Getenv("SENTRY_DSN"),
 		Environment:      os.Getenv("ENVIRONMENT"),
 		EnableTracing:    true,
-		TracesSampleRate: 1.0,
+		TracesSampleRate: tracesSampleRate,
 		BeforeSendTransaction: func(event *sentry.Event, hint *sentry.EventHint) *sentry.Event {
 			// Drop request body.
 			if event.Request != nil {