metrics

cmd/cart/main.go

@@ -27,18 +27,17 @@ import (
 	"git.k6n.net/mats/platform/config"
 	"git.k6n.net/mats/platform/event"
 	"git.k6n.net/mats/platform/rabbit"
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/redis/go-redis/v9"
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 )
 
 var (
-	grainSpawns = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "cart_grain_spawned_total",
-		Help: "The total number of spawned grains",
-	})
+	// cartMetrics is the shared prometheus instrumentation for the
+	// cart actor pool and event log. Built once at process start; nil
+	// is not expected in production but the actor package's
+	// touch sites are nil-safe so a test binary can pass nil.
+	cartMetrics = actor.NewMetrics("cart")
 )
 
 func init() {
@@ -258,13 +257,14 @@ func main() {
 	)
 
 	diskStorage := actor.NewDiskStorage[cart.CartGrain](config.EnvString("CART_DIR", "data"), reg)
+	diskStorage.SetMetrics(cartMetrics)
 	poolConfig := actor.GrainPoolConfig[cart.CartGrain]{
 		MutationRegistry: reg,
 		Storage:          diskStorage,
+		Metrics:          cartMetrics,
 		Spawn: func(ctx context.Context, id uint64) (actor.Grain[cart.CartGrain], error) {
 			_, span := tracer.Start(ctx, fmt.Sprintf("Spawn cart id %d", id))
 			defer span.End()
-			grainSpawns.Inc()
 			ret := cart.NewCartGrain(id, time.Now())
 			// Set baseline lastChange at spawn; replay may update it to last event timestamp.