Move telegram to separate module

telegram/dialer.go

@@ -0,0 +1,53 @@
+package telegram
+
+import (
+	"io"
+	"net"
+	"time"
+
+	"github.com/juju/errors"
+
+	"github.com/9seconds/mtg/config"
+	"github.com/9seconds/mtg/wrappers"
+)
+
+const telegramKeepAlive = 30 * time.Second
+
+type tgDialer struct {
+	net.Dialer
+
+	conf *config.Config
+}
+
+func (t *tgDialer) dial(addr string) (net.Conn, error) {
+	connRaw, err := t.Dialer.Dial("tcp", addr)
+	if err != nil {
+		return nil, errors.Annotate(err, "Cannot connect to Telegram")
+	}
+	conn := connRaw.(*net.TCPConn)
+
+	if err = conn.SetKeepAlive(true); err != nil {
+		return nil, errors.Annotate(err, "Cannot establish keepalive connection")
+	}
+	if err = conn.SetKeepAlivePeriod(telegramKeepAlive); err != nil {
+		return nil, errors.Annotate(err, "Cannot set keepalive timeout")
+	}
+
+	return conn, nil
+}
+
+func (t *tgDialer) dialRWC(addr string) (io.ReadWriteCloser, error) {
+	conn, err := t.dial(addr)
+	if err != nil {
+		return nil, err
+	}
+
+	return wrappers.NewTimeoutRWC(conn, t.conf.TimeoutRead, t.conf.TimeoutWrite), nil
+}
+
+func newDialer(conf *config.Config) *tgDialer {
+	return &tgDialer{
+		Dialer: net.Dialer{Timeout: conf.TimeoutRead},
+		conf:   conf,
+	}
+}