func main()

in cmd/sidecar_mounter/main.go [44:119]
54 lines of code
12 McCabe index (conditional complexity)

func main() {
	klog.InitFlags(nil)
	flag.Parse()

	klog.Infof("Running Google Cloud Storage FUSE CSI driver sidecar mounter version %v", version)
	socketPathPattern := *volumeBasePath + "/*/socket"
	socketPaths, err := filepath.Glob(socketPathPattern)
	if err != nil {
		klog.Fatalf("failed to look up socket paths: %v", err)
	}

	mounter := sidecarmounter.New(*gcsfusePath)
	ctx, cancel := context.WithCancel(context.Background())

	for _, sp := range socketPaths {
		// sleep 1.5 seconds before launch the next gcsfuse to avoid
		// 1. different gcsfuse logs mixed together.
		// 2. memory usage peak.
		time.Sleep(1500 * time.Millisecond)
		mc := sidecarmounter.NewMountConfig(sp)
		if mc != nil {
			if err := mounter.Mount(ctx, mc); err != nil {
				mc.ErrWriter.WriteMsg(fmt.Sprintf("failed to mount bucket %q for volume %q: %v\n", mc.BucketName, mc.VolumeName, err))
			}
		}
	}

	c := make(chan os.Signal, 1)
	signal.Notify(c, syscall.SIGTERM)
	klog.Info("waiting for SIGTERM signal...")

	// Function that monitors the exit file used in regular sidecar containers.
	monitorExitFile := func() {
		ticker := time.NewTicker(5 * time.Second)
		for {
			<-ticker.C
			// If exit file is detected, send a syscall.SIGTERM signal to the signal channel.
			if _, err := os.Stat(*volumeBasePath + "/exit"); err == nil {
				klog.Info("all the other containers terminated in the Pod, exiting the sidecar container.")

				// After the Kubernetes native sidecar container feature is adopted,
				// we should propagate the SIGTERM signal outside of this goroutine.
				cancel()

				if err := os.Remove(*volumeBasePath + "/exit"); err != nil {
					klog.Error("failed to remove the exit file from emptyDir.")
				}

				c <- syscall.SIGTERM

				return
			}
		}
	}

	envVar := os.Getenv("NATIVE_SIDECAR")
	isNativeSidecar, err := strconv.ParseBool(envVar)
	if envVar != "" && err != nil {
		klog.Warningf(`env variable "%s" could not be converted to boolean`, envVar)
	}
	// When the pod contains a regular container, we monitor for the exit file.
	if !isNativeSidecar {
		go monitorExitFile()
	}

	<-c // blocking the process
	klog.Info("received SIGTERM signal, waiting for all the gcsfuse processes exit...")

	if isNativeSidecar {
		cancel()
	}

	mounter.WaitGroup.Wait()

	klog.Info("exiting sidecar mounter...")
}