feat(clock): add ntp clock

iyear · iyear · commit 230fc61585bf · 2022-11-22T22:28:41.000+08:00
diff --git a/clock/ntp.go b/clock/ntp.go
@@ -0,0 +1,51 @@
+package clock
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/beevik/ntp"
+	"github.com/gotd/td/clock"
+)
+
+var _ clock.Clock = (*ntpClock)(nil)
+
+const defaultNTP = "pool.ntp.org"
+
+type ntpClock struct {
+	offset time.Duration
+}
+
+func (n *ntpClock) Now() time.Time {
+	return time.Now().Add(n.offset)
+}
+
+func (n *ntpClock) Timer(d time.Duration) clock.Timer {
+	return clock.System.Timer(d)
+}
+
+func (n *ntpClock) Ticker(d time.Duration) clock.Ticker {
+	return clock.System.Ticker(d)
+}
+
+// NewNTP creates new NTP clock.
+func NewNTP(ntpHost ...string) (clock.Clock, error) {
+	var host string
+	switch len(ntpHost) {
+	case 0:
+		host = defaultNTP
+	case 1:
+		host = ntpHost[0]
+	default:
+		return nil, fmt.Errorf("too many ntp hosts")
+	}
+
+	resp, err := ntp.Query(host)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ntpClock{
+		offset: resp.ClockOffset,
+	}, nil
+}
diff --git a/clock/ntp_example_test.go b/clock/ntp_example_test.go
@@ -0,0 +1,24 @@
+package clock_test
+
+import (
+	"log"
+
+	"github.com/gotd/contrib/clock"
+	"github.com/gotd/td/telegram"
+)
+
+func ExampleNewNTP() {
+	c, err := clock.NewNTP() // or clock.NewNTP("my.ntp.host")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	client, err := telegram.ClientFromEnvironment(telegram.Options{
+		Clock: c,
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	_ = client
+}
diff --git a/go.mod b/go.mod
@@ -3,6 +3,7 @@ module github.com/gotd/contrib
 go 1.18
 
 require (
+	github.com/beevik/ntp v0.3.0
 	github.com/cenkalti/backoff/v4 v4.1.3
 	github.com/cockroachdb/pebble v0.0.0-20220107203702-aa376a819bf6
 	github.com/gen2brain/dlgs v0.0.0-20211108104213-bade24837f0b
diff --git a/go.sum b/go.sum
@@ -56,6 +56,8 @@ github.com/armon/go-radix v0.0.0-20180808171621-7fddfc383310/go.mod h1:ufUuZ+zHj
 github.com/armon/go-radix v1.0.0 h1:F4z6KzEeeQIMeLFa97iZU6vupzoecKdU5TX24SNppXI=
 github.com/armon/go-radix v1.0.0/go.mod h1:ufUuZ+zHj4x4TnLV4JWEpy2hxWSpsRywHrMgIH9cCH8=
 github.com/aymerick/raymond v2.0.3-0.20180322193309-b565731e1464+incompatible/go.mod h1:osfaiScAUVup+UC9Nfq76eWqDhXlp+4UYaA8uhTBO6g=
+github.com/beevik/ntp v0.3.0 h1:xzVrPrE4ziasFXgBVBZJDP0Wg/KpMwk2KHJ4Ba8GrDw=
+github.com/beevik/ntp v0.3.0/go.mod h1:hIHWr+l3+/clUnF44zdK+CWW7fO8dR5cIylAQ76NRpg=
 github.com/benbjohnson/clock v1.1.0 h1:Q92kusRqC1XV2MjkWETPvjJVqKetz1OzxZB7mHJLju8=
 github.com/benbjohnson/clock v1.1.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
