fix cpu usage reporting

worker/status.go

@@ -2,6 +2,7 @@ package worker
 
 import (
 	"context"
+	"time"
 
 	"github.com/mackerelio/go-osstat/cpu"
 	"github.com/mackerelio/go-osstat/memory"
@@ -14,13 +15,31 @@ func init() {
 	rpcServer.RegisterMethod("status", status)
 }
 
+var cpuBefore *cpu.Stats
+var cpuUsage uint64
+var cpuCount uint64
+
+func calcUsage() {
+	for {
+		cStats, _ := cpu.Get()
+		if cStats != nil {
+			cpuUsage = cStats.Total
+			cpuCount = uint64(cStats.CPUCount)
+
+			if cpuBefore != nil {
+				total := float64(cStats.Total - cpuBefore.Total)
+				cpuUsage = uint64(float64((cStats.User-cpuBefore.User)+(cStats.System-cpuBefore.System)) / total * 100)
+			}
+			cpuBefore = cStats
+		}
+		time.Sleep(time.Second)
+	}
+}
+
 func status(ctx context.Context, req rpc.Request) (any, error) {
 	s := types.WorkerStatus{}
-	cStats, _ := cpu.Get()
-	if cStats != nil {
-		s.CPUUsage = cStats.Total
-		s.CPUCount = uint64(cStats.CPUCount)
-	}
+	s.CPUUsage = cpuUsage
+	s.CPUCount = cpuCount
 	mStats, _ := memory.Get()
 	if mStats != nil {
 		s.MemoryUsage = uint64(float64(mStats.Used) / float64(mStats.Total) * 100)

worker/worker.go

@@ -60,6 +60,9 @@ func Start(_conf config.Config) {
 		exit = true
 		cancel()
 	}()
+
+	go calcUsage()
+
 	for {
 		if exit {
 			slog.InfoContext(ctx, "Done")