refactor(storage): standardize size limits to use GB units

lib/config/parse.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"fmt"
+	"math"
 	"strconv"
 	"strings"
 )
@@ -39,6 +40,46 @@ func parseInt(value string, min int) (int, error) {
 	return int(parsed64), nil
 }
 
+const bytesPerGigabyte = 1024 * 1024 * 1024
+
+func parseGigabytes(value string, min float64) (int64, error) {
+	raw := strings.TrimSpace(value)
+	lower := strings.ToLower(raw)
+	if strings.HasSuffix(lower, "gb") {
+		raw = strings.TrimSpace(raw[:len(raw)-2])
+	}
+	parsed, err := strconv.ParseFloat(raw, 64)
+	if err != nil {
+		return 0, fmt.Errorf("must be a number of GB")
+	}
+	if parsed < min {
+		return 0, fmt.Errorf("must be at least %s", trimTrailingZeros(min))
+	}
+	bytes := parsed * bytesPerGigabyte
+	if bytes > math.MaxInt64 {
+		return 0, fmt.Errorf("is too large")
+	}
+	return int64(math.Round(bytes)), nil
+}
+
+func formatGigabytesFromBytes(bytes int64) string {
+	if bytes <= 0 {
+		return "0"
+	}
+	value := float64(bytes) / bytesPerGigabyte
+	return trimTrailingZeros(value)
+}
+
+func trimTrailingZeros(value float64) string {
+	text := strconv.FormatFloat(value, 'f', 3, 64)
+	text = strings.TrimRight(text, "0")
+	text = strings.TrimRight(text, ".")
+	if text == "" {
+		return "0"
+	}
+	return text
+}
+
 func formatBool(value bool) string {
 	if value {
 		return "true"