[DATA-2672] simplify diskusage (viamrobotics#4300)

services/datamanager/builtin/file_deletion.go

@@ -24,20 +24,24 @@ var (
 var errAtSizeThreshold = errors.New("capture directory has reached or exceeded disk usage threshold for deletion")
 
 func shouldDeleteBasedOnDiskUsage(ctx context.Context, captureDirPath string, logger logging.Logger) (bool, error) {
-	usage := diskusage.NewDiskUsage(captureDirPath)
+	statfs, err := diskusage.Statfs(captureDirPath)
+	if err != nil {
+		logger.Debugf("diskusage.Statfs returned error: %s", err.Error())
+		return false, nil
+	}
 	// we get usage this way to ensure we get the amount of remaining space in the partition.
 	// calling usage.Usage() returns the usage of the whole disk, not the user partition
-	usedSpace := 1.0 - float64(usage.Available())/float64(usage.Size())
+	usedSpace := 1.0 - statfs.AvailablePercent()
 	if math.IsNaN(usedSpace) {
 		return false, nil
 	}
 	if usedSpace < fsThresholdToTriggerDeletion {
 		logger.Debugf("disk not full enough, exiting. Used space: %f, available space: %d, size: %d",
-			usedSpace, usage.Available(), usage.Size())
+			usedSpace, statfs.AvailableBytes, statfs.SizeBytes)
 		return false, nil
 	}
 	// Walk the dir to get capture stats
-	shouldDelete, err := exceedsDeletionThreshold(ctx, captureDirPath, float64(usage.Size()), logger)
+	shouldDelete, err := exceedsDeletionThreshold(ctx, captureDirPath, float64(statfs.SizeBytes), logger)
 	if err != nil && !shouldDelete {
 		logger.Warnf("Disk nearing capacity but data capture directory is below %f of that size, file deletion will not run",
 			captureDirToFSUsageRatio)

utils/diskusage/disk_usage.go

@@ -7,39 +7,27 @@ import "syscall"
 
 // DiskUsage contains usage data and provides user-friendly access methods.
 type DiskUsage struct {
-	stat *syscall.Statfs_t
+	// AvailableBytes is the total available bytes on file system to an unprivileged user.
+	AvailableBytes uint64
+	// SizeBytes is the total size of the file system in bytes.
+	SizeBytes uint64
 }
 
-// NewDiskUsage returns an object holding the disk usage of volumePath
-// or nil in case of error (invalid path, etc).
-func NewDiskUsage(volumePath string) *DiskUsage {
+// Statfs returns file system statistics.
+func Statfs(volumePath string) (DiskUsage, error) {
 	var stat syscall.Statfs_t
-	//nolint:errcheck,gosec
-	syscall.Statfs(volumePath, &stat)
-	return &DiskUsage{&stat}
+	if err := syscall.Statfs(volumePath, &stat); err != nil {
+		return DiskUsage{}, err
+	}
+	return DiskUsage{
+		AvailableBytes: stat.Bavail * uint64(stat.Bsize),
+		SizeBytes:      stat.Blocks * uint64(stat.Bsize),
+	}, nil
 }
 
-// Free returns total free bytes on file system.
-func (du *DiskUsage) Free() uint64 {
-	return du.stat.Bfree * uint64(du.stat.Bsize)
-}
-
-// Available return total available bytes on file system to an unprivileged user.
-func (du *DiskUsage) Available() uint64 {
-	return du.stat.Bavail * uint64(du.stat.Bsize)
-}
-
-// Size returns total size of the file system.
-func (du *DiskUsage) Size() uint64 {
-	return du.stat.Blocks * uint64(du.stat.Bsize)
-}
-
-// Used returns total bytes used in file system.
-func (du *DiskUsage) Used() uint64 {
-	return du.Size() - du.Free()
-}
-
-// Usage returns percentage of use on the file system.
-func (du *DiskUsage) Usage() float32 {
-	return float32(du.Used()) / float32(du.Size())
+// AvailablePercent returns the percentage (0.0-1.0) of the disk available
+// to an unprivileged user
+// see `man statfs` for how the underlying values are derived on your platform.
+func (du DiskUsage) AvailablePercent() float64 {
+	return float64(du.AvailableBytes) / float64(du.SizeBytes)
 }