modifying docker --since and --until to support nanoseconds and time zones

Signed-off-by: Mike Brown <brownwm@us.ibm.com>

timeutils/utils.go

@@ -1,36 +1,124 @@
 package timeutils
 
 import (
+	"fmt"
+	"math"
 	"strconv"
 	"strings"
 	"time"
 )
 
+// These are additional predefined layouts for use in Time.Format and Time.Parse
+// with --since and --until parameters for `docker logs` and `docker events`
+const (
+	rFC3339Local     = "2006-01-02T15:04:05"           // RFC3339 with local timezone
+	rFC3339NanoLocal = "2006-01-02T15:04:05.999999999" // RFC3339Nano with local timezone
+	dateWithZone     = "2006-01-02Z07:00"              // RFC3339 with time at 00:00:00
+	dateLocal        = "2006-01-02"                    // RFC3339 with local timezone and time at 00:00:00
+)
+
 // GetTimestamp tries to parse given string as golang duration,
 // then RFC3339 time and finally as a Unix timestamp. If
 // any of these were successful, it returns a Unix timestamp
 // as string otherwise returns the given value back.
 // In case of duration input, the returned timestamp is computed
 // as the given reference time minus the amount of the duration.
-func GetTimestamp(value string, reference time.Time) string {
+func GetTimestamp(value string, reference time.Time) (string, error) {
 	if d, err := time.ParseDuration(value); value != "0" && err == nil {
-		return strconv.FormatInt(reference.Add(-d).Unix(), 10)
+		return strconv.FormatInt(reference.Add(-d).Unix(), 10), nil
 	}
 
 	var format string
+	var parseInLocation bool
+
+	// if the string has a Z or a + or three dashes use parse otherwise use parseinlocation
+	parseInLocation = !(strings.ContainsAny(value, "zZ+") || strings.Count(value, "-") == 3)
+
 	if strings.Contains(value, ".") {
-		format = time.RFC3339Nano
+		if parseInLocation {
+			format = rFC3339NanoLocal
+		} else {
+			format = time.RFC3339Nano
+		}
+	} else if strings.Contains(value, "T") {
+		// we want the number of colons in the T portion of the timestamp
+		tcolons := strings.Count(value, ":")
+		// if parseInLocation is off and we have a +/- zone offset (not Z) then
+		// there will be an extra colon in the input for the tz offset subract that
+		// colon from the tcolons count
+		if !parseInLocation && !strings.ContainsAny(value, "zZ") && tcolons > 0 {
+			tcolons--
+		}
+		if parseInLocation {
+			switch tcolons {
+			case 0:
+				format = "2006-01-02T15"
+			case 1:
+				format = "2006-01-02T15:04"
+			default:
+				format = rFC3339Local
+			}
+		} else {
+			switch tcolons {
+			case 0:
+				format = "2006-01-02T15Z07:00"
+			case 1:
+				format = "2006-01-02T15:04Z07:00"
+			default:
+				format = time.RFC3339
+			}
+		}
+	} else if parseInLocation {
+		format = dateLocal
 	} else {
-		format = time.RFC3339
+		format = dateWithZone
 	}
 
-	loc := time.FixedZone(time.Now().Zone())
-	if len(value) < len(format) {
-		format = format[:len(value)]
+	var t time.Time
+	var err error
+
+	if parseInLocation {
+		t, err = time.ParseInLocation(format, value, time.FixedZone(time.Now().Zone()))
+	} else {
+		t, err = time.Parse(format, value)
 	}
-	t, err := time.ParseInLocation(format, value, loc)
+
 	if err != nil {
-		return value
+		// if there is a `-` then its an RFC3339 like timestamp otherwise assume unixtimestamp
+		if strings.Contains(value, "-") {
+			return "", err // was probably an RFC3339 like timestamp but the parser failed with an error
+		}
+		return value, nil // unixtimestamp in and out case (meaning: the value passed at the command line is already in the right format for passing to the server)
 	}
-	return strconv.FormatInt(t.Unix(), 10)
+
+	return fmt.Sprintf("%d.%09d", t.Unix(), int64(t.Nanosecond())), nil
+}
+
+// ParseTimestamps returns seconds and nanoseconds from a timestamp that has the
+// format "%d.%09d", time.Unix(), int64(time.Nanosecond()))
+// if the incoming nanosecond portion is longer or shorter than 9 digits it is
+// converted to nanoseconds.  The expectation is that the seconds and
+// seconds will be used to create a time variable.  For example:
+//     seconds, nanoseconds, err := ParseTimestamp("1136073600.000000001",0)
+//     if err == nil since := time.Unix(seconds, nanoseconds)
+// returns seconds as def(aultSeconds) if value == ""
+func ParseTimestamps(value string, def int64) (int64, int64, error) {
+	if value == "" {
+		return def, 0, nil
+	}
+	sa := strings.SplitN(value, ".", 2)
+	s, err := strconv.ParseInt(sa[0], 10, 64)
+	if err != nil {
+		return s, 0, err
+	}
+	if len(sa) != 2 {
+		return s, 0, nil
+	}
+	n, err := strconv.ParseInt(sa[1], 10, 64)
+	if err != nil {
+		return s, n, err
+	}
+	// should already be in nanoseconds but just in case convert n to nanoseonds
+	n = int64(float64(n) * math.Pow(float64(10), float64(9-len(sa[1]))))
+	return s, n, nil
 }