cmd/lncli: add fwdinghistory support for relative times

- introduces new parser in `cmd/lncli/arg_parse.go`
- converts start_time and end_time flags to strings
- adds default value for end_time

cmd/lncli/arg_parse.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"regexp"
+	"strconv"
+	"time"
+)
+
+// reTimeRange matches systemd.time-like short negative timeranges, e.g. "-200s".
+var reTimeRange = regexp.MustCompile(`^-\d{1,18}[s|m|h|d|w|M|y]$`)
+
+// secondsPer allows translating s(seconds), m(minutes), h(ours), d(ays),
+// w(eeks), M(onths) and y(ears) into corresponding seconds.
+var secondsPer = map[string]int64{
+	"s": 1,
+	"m": 60,
+	"h": 3600,
+	"d": 86400,
+	"w": 604800,
+	"M": 2630016,  // 30.44 days
+	"y": 31557600, // 365.25 days
+}
+
+// parseTime parses UNIX timestamps or short timeranges inspired by sytemd (when starting with "-"),
+// e.g. "-1M" for one month (30.44 days) ago.
+func parseTime(s string, base time.Time) (uint64, error) {
+	if reTimeRange.MatchString(s) {
+		last := len(s) - 1
+
+		d, err := strconv.ParseInt(s[1:last], 10, 64)
+		if err != nil {
+			return uint64(0), err
+		}
+
+		mul := secondsPer[string(s[last])]
+		return uint64(base.Unix() - d*mul), nil
+	}
+
+	return strconv.ParseUint(s, 10, 64)
+}

cmd/lncli/arg_parse_test.go

@@ -0,0 +1,88 @@
+package main
+
+import (
+	"testing"
+	"time"
+)
+
+var now = time.Date(2017, 11, 10, 7, 8, 9, 1234, time.UTC)
+
+var partTimeTests = []struct {
+	in          string
+	expected    uint64
+	errExpected bool
+}{
+	{
+		"12345",
+		uint64(12345),
+		false,
+	},
+	{
+		"-0s",
+		uint64(now.Unix()),
+		false,
+	},
+	{
+		"-1s",
+		uint64(time.Date(2017, 11, 10, 7, 8, 8, 1234, time.UTC).Unix()),
+		false,
+	},
+	{
+		"-2h",
+		uint64(time.Date(2017, 11, 10, 5, 8, 9, 1234, time.UTC).Unix()),
+		false,
+	},
+	{
+		"-3d",
+		uint64(time.Date(2017, 11, 7, 7, 8, 9, 1234, time.UTC).Unix()),
+		false,
+	},
+	{
+		"-4w",
+		uint64(time.Date(2017, 10, 13, 7, 8, 9, 1234, time.UTC).Unix()),
+		false,
+	},
+	{
+		"-5M",
+		uint64(now.Unix() - 30.44*5*24*60*60),
+		false,
+	},
+	{
+		"-6y",
+		uint64(now.Unix() - 365.25*6*24*60*60),
+		false,
+	},
+	{
+		"-999999999999999999s",
+		uint64(now.Unix() - 999999999999999999),
+		false,
+	},
+	{
+		"-9999999999999999991s",
+		0,
+		true,
+	},
+	{
+		"-7z",
+		0,
+		true,
+	},
+}
+
+// Test that parsing absolute and relative times works.
+func TestParseTime(t *testing.T) {
+	for _, test := range partTimeTests {
+		actual, err := parseTime(test.in, now)
+		if test.errExpected == (err == nil) {
+			t.Fatalf("unexpected error for %s:\n%v\n", test.in, err)
+		}
+		if actual != test.expected {
+			t.Fatalf(
+				"for %s actual and expected do not match:\n%d\n%d\n",
+				test.in,
+				actual,
+				test.expected,
+			)
+		}
+	}
+}

cmd/lncli/commands.go

@@ -2708,9 +2708,12 @@ var forwardingHistoryCommand = cli.Command{
 	Query the HTLC switch's internal forwarding log for all completed
 	payment circuits (HTLCs) over a particular time range (--start_time and
 	--end_time). The start and end times are meant to be expressed in
-	seconds since the Unix epoch. If --start_time isn't provided,
-	then 24 hours ago is used.  If --end_time isn't provided,
-	then the current time is used.
+	seconds since the Unix epoch.
+	Alternatively negative time ranges can be used, e.g. "-3d". Supports
+	s(seconds), m(minutes), h(ours), d(ays), w(eeks), M(onths), y(ears).
+	Month equals 30.44 days, year equals 365.25 days.
+	If --start_time isn't provided, then 24 hours ago is used. If
+	--end_time isn't provided, then the current time is used.
 
 	The max number of events returned is 50k. The default number is 100,
 	callers can use the --max_events param to modify this value.
@@ -2720,15 +2723,15 @@ var forwardingHistoryCommand = cli.Command{
 	entry. Using this callers can manually paginate within a time slice.
 	`,
 	Flags: []cli.Flag{
-		cli.Int64Flag{
+		cli.StringFlag{
 			Name: "start_time",
-			Usage: "the starting time for the query, expressed in " +
-				"seconds since the unix epoch",
+			Usage: "the starting time for the query " +
+				`as unix timestamp or relative e.g. "-1w"`,
 		},
-		cli.Int64Flag{
+		cli.StringFlag{
 			Name: "end_time",
-			Usage: "the end time for the query, expressed in " +
-				"seconds since the unix epoch",
+			Usage: "the end time for the query " +
+				`as unix timestamp or relative e.g. "-1w"`,
 		},
 		cli.Int64Flag{
 			Name:  "index_offset",
@@ -2753,31 +2756,34 @@ func forwardingHistory(ctx *cli.Context) error {
 		err                    error
 	)
 	args := ctx.Args()
+	now := time.Now()
 
 	switch {
 	case ctx.IsSet("start_time"):
-		startTime = ctx.Uint64("start_time")
+		startTime, err = parseTime(ctx.String("start_time"), now)
 	case args.Present():
-		startTime, err = strconv.ParseUint(args.First(), 10, 64)
-		if err != nil {
-			return fmt.Errorf("unable to decode start_time %v", err)
-		}
+		startTime, err = parseTime(args.First(), now)
 		args = args.Tail()
 	default:
 		now := time.Now()
 		startTime = uint64(now.Add(-time.Hour * 24).Unix())
 	}
+	if err != nil {
+		return fmt.Errorf("unable to decode start_time: %v", err)
+	}
 
 	switch {
 	case ctx.IsSet("end_time"):
-		endTime = ctx.Uint64("end_time")
+		endTime, err = parseTime(ctx.String("end_time"), now)
 	case args.Present():
-		endTime, err = strconv.ParseUint(args.First(), 10, 64)
+		endTime, err = parseTime(args.First(), now)
+		args = args.Tail()
+	default:
+		endTime = uint64(now.Unix())
+	}
 	if err != nil {
 		return fmt.Errorf("unable to decode end_time: %v", err)
 	}
-		args = args.Tail()
-	}
 
 	switch {
 	case ctx.IsSet("index_offset"):