Refactor shutdown signals

main.go

@@ -2,11 +2,11 @@ package main
 
 import (
  "context"
+ "errors"
  "fmt"
  "net/http"
  "os"
  "os/signal"
- "syscall"
  "time"
 
  "golang.org/x/sync/errgroup"
@@ -28,30 +28,30 @@ func main() {
  panic(fmt.Sprintf("who watches the watchmen (%v)?", err))
  }
  log := zapr.NewLogger(zapLog)
+ if err := run(log); err != nil {
+ log.Error(err, "runtime error")
+ os.Exit(1)
+ }
+}
 
+func run(log logr.Logger) error {
  cfg, err := loadConfig(os.Args[1:])
  if err != nil {
- log.Error(err, "could not load config")
- os.Exit(1)
+ return fmt.Errorf("could not load config: %w", err)
  }
  client, err := getKubernetesClients(cfg.KubeConfigPath)
  if err != nil {
- log.Error(err, "could not create Kubernetes client", "path", cfg.KubeConfigPath)
- os.Exit(1)
+ return fmt.Errorf("could not create Kubernetes client: %w", err)
  }
 
- stopCh := make(chan os.Signal, 1)
- signal.Notify(stopCh, syscall.SIGTERM, syscall.SIGINT)
- defer signal.Stop(stopCh)
- ctx, cancel := context.WithCancel(context.Background())
+ ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
  defer cancel()
  g, ctx := errgroup.WithContext(ctx)
  ctx = logr.NewContext(ctx, log)
 
  g.Go(func() error {
  err := ttl.Run(ctx, client, cfg.Interval)
  if err != nil {
- fmt.Println(err)
  return err
  }
  return nil
@@ -61,29 +61,29 @@ func main() {
  handler.HandleFunc("/readyz", func(w http.ResponseWriter, req *http.Request) {
  w.WriteHeader(http.StatusOK)
  })
- server := http.Server{Addr: ":8080", Handler: handler}
- g.Go(server.ListenAndServe)
+ srv := http.Server{Addr: ":8080", Handler: handler}
+ g.Go(func() error {
+ if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+ return err
+ }
+ return nil
+ })
+ g.Go(func() error {
+ <-ctx.Done()
+ if err := srv.Shutdown(context.Background()); err != nil {
+ return err
+ }
+ return nil
+ })
 
  log.Info("running")
- select {
- case <-stopCh:
- break
- case <-ctx.Done():
- break
- }
- cancel()
+ <-ctx.Done()
  log.Info("shutting down")
-
- timeoutCtx, timeoutCancel := context.WithTimeout(context.Background(), 10*time.Second)
- defer timeoutCancel()
- if err := server.Shutdown(timeoutCtx); err != nil {
- log.Error(err, "error when shutting down HTTP server")
- }
-
  if err := g.Wait(); err != nil {
- log.Error(err, "shutdown error")
+ return fmt.Errorf("shutdown error: %w", err)
  }
  log.Info("gracefully shutdown")
+ return nil
 }
 
 type config struct {