feat(logs): add support for days unit (d) in --since/until filters for logs

internal/cli/logs/duration.go

@@ -0,0 +1,66 @@
+package logs
+
+import (
+	"fmt"
+	"math/big"
+	"strings"
+	"time"
+)
+
+// Duration is an extended standard time.Duration that also supports days as a unit.
+type Duration = time.Duration
+
+// ParseDuration parses a Go duration with the additional unit d, meaning exactly 24 hours.
+// Days can be fractional or combined with other units, such as "1.5d" or "2d3h".
+func ParseDuration(value string) (Duration, error) {
+	if !strings.Contains(value, "d") {
+		return time.ParseDuration(value)
+	}
+
+	rest := value
+	var normalised strings.Builder
+	if len(rest) > 0 && (rest[0] == '-' || rest[0] == '+') {
+		normalised.WriteByte(rest[0])
+		rest = rest[1:]
+	}
+	for len(rest) > 0 {
+		// Each component is a decimal number followed by a unit. Only the leading sign is allowed.
+		numberEnd := 0
+		for numberEnd < len(rest) && (isDigit(rest[numberEnd]) || rest[numberEnd] == '.') {
+			numberEnd++
+		}
+		unitEnd := numberEnd
+		for unitEnd < len(rest) && !isDigit(rest[unitEnd]) && rest[unitEnd] != '.' {
+			unitEnd++
+		}
+		if numberEnd == 0 || unitEnd == numberEnd {
+			return 0, fmt.Errorf("time: invalid duration '%s'", value)
+		}
+		number, unit := rest[:numberEnd], rest[numberEnd:unitEnd]
+		if unit == "d" {
+			// Use exact decimal arithmetic to avoid float rounding and retain nanosecond precision.
+			days, ok := new(big.Rat).SetString(number)
+			if !ok {
+				return 0, fmt.Errorf("time: invalid duration '%s'", value)
+			}
+			days.Mul(days, new(big.Rat).SetInt64(int64(24*time.Hour)))
+			nanoseconds := new(big.Int).Quo(days.Num(), days.Denom())
+			normalised.WriteString(nanoseconds.String())
+			normalised.WriteString("ns")
+		} else {
+			normalised.WriteString(rest[:unitEnd])
+		}
+		rest = rest[unitEnd:]
+	}
+
+	// The standard parser validates the remaining units and checks the total for overflow.
+	duration, err := time.ParseDuration(normalised.String())
+	if err != nil {
+		return 0, fmt.Errorf("time: invalid duration '%s': %w", value, err)
+	}
+	return duration, nil
+}
+
+func isDigit(c byte) bool {
+	return c >= '0' && c <= '9'
+}