package notifications import ( "encoding/base64" "fmt" "github.com/spf13/cobra" "net/smtp" "os" "time" t "github.com/containrrr/watchtower/pkg/types" log "github.com/sirupsen/logrus" "strconv" ) const ( emailType = "email" ) // Implements Notifier, logrus.Hook // The default logrus email integration would have several issues: // - It would send one email per log output // - It would only send errors // We work around that by holding on to log entries until the update cycle is done. type emailTypeNotifier struct { From, To string Server, User, Password string Port int tlsSkipVerify bool entries []*log.Entry logLevels []log.Level } func newEmailNotifier(c *cobra.Command, acceptedLogLevels []log.Level) t.Notifier { flags := c.PersistentFlags() from, _ := flags.GetString("notification-email-from") to, _ := flags.GetString("notification-email-to") server, _ := flags.GetString("notification-email-server") user, _ := flags.GetString("notification-email-server-user") password, _ := flags.GetString("notification-email-server-password") port, _ := flags.GetInt("notification-email-server-port") tlsSkipVerify, _ := flags.GetBool("notification-email-server-tls-skip-verify") n := &emailTypeNotifier{ From: from, To: to, Server: server, User: user, Password: password, Port: port, tlsSkipVerify: tlsSkipVerify, logLevels: acceptedLogLevels, } log.AddHook(n) return n } func (e *emailTypeNotifier) buildMessage(entries []*log.Entry) []byte { emailSubject := "Watchtower updates" if hostname, err := os.Hostname(); err == nil { emailSubject += " on " + hostname } body := "" for _, entry := range entries { body += entry.Time.Format("2006-01-02 15:04:05") + " (" + entry.Level.String() + "): " + entry.Message + "\r\n" // We don't use fields in watchtower, so don't bother sending them. } t := time.Now() header := make(map[string]string) header["From"] = e.From header["To"] = e.To header["Subject"] = emailSubject header["Date"] = t.Format(time.RFC1123Z) header["MIME-Version"] = "1.0" header["Content-Type"] = "text/plain; charset=\"utf-8\"" header["Content-Transfer-Encoding"] = "base64" message := "" for k, v := range header { message += fmt.Sprintf("%s: %s\r\n", k, v) } encodedBody := base64.StdEncoding.EncodeToString([]byte(body)) //RFC 2045 base64 encoding demands line no longer than 76 characters. for _, line := range SplitSubN(encodedBody, 76) { message += "\r\n" + line } return []byte(message) } func (e *emailTypeNotifier) sendEntries(entries []*log.Entry) { // Do the sending in a separate goroutine so we don't block the main process. msg := e.buildMessage(entries) go func() { var auth smtp.Auth if e.User != "" { auth = smtp.PlainAuth("", e.User, e.Password, e.Server) } err := SendMail(e.Server+":"+strconv.Itoa(e.Port), e.tlsSkipVerify, auth, e.From, []string{e.To}, msg) if err != nil { // Use fmt so it doesn't trigger another email. fmt.Println("Failed to send notification email: ", err) } }() } func (e *emailTypeNotifier) StartNotification() { if e.entries == nil { e.entries = make([]*log.Entry, 0, 10) } } func (e *emailTypeNotifier) SendNotification() { if e.entries != nil && len(e.entries) != 0 { e.sendEntries(e.entries) } e.entries = nil } func (e *emailTypeNotifier) Levels() []log.Level { return e.logLevels } func (e *emailTypeNotifier) Fire(entry *log.Entry) error { if e.entries != nil { e.entries = append(e.entries, entry) } else { // Log output generated outside a cycle is sent immediately. e.sendEntries([]*log.Entry{entry}) } return nil }