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watchtower/notifications/email.go

120 lines
3.1 KiB
Go

package notifications
import (
"encoding/base64"
"fmt"
"net/smtp"
"os"
"strconv"
log "github.com/Sirupsen/logrus"
"github.com/urfave/cli"
)
const (
emailType = "email"
)
// Implements typeNotifier, 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
entries []*log.Entry
}
func newEmailNotifier(c *cli.Context) typeNotifier {
n := &emailTypeNotifier{
From: c.GlobalString("notification-email-from"),
To: c.GlobalString("notification-email-to"),
Server: c.GlobalString("notification-email-server"),
User: c.GlobalString("notification-email-server-user"),
Password: c.GlobalString("notification-email-server-password"),
Port: c.GlobalInt("notification-email-server-port"),
}
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.
}
header := make(map[string]string)
header["From"] = e.From
header["To"] = e.To
header["Subject"] = emailSubject
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)
}
message += "\r\n" + base64.StdEncoding.EncodeToString([]byte(body))
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() {
auth := smtp.PlainAuth("", e.User, e.Password, e.Server)
err := smtp.SendMail(e.Server+":"+strconv.Itoa(e.Port), 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 {
// TODO: Make this configurable.
return []log.Level{
log.PanicLevel,
log.FatalLevel,
log.ErrorLevel,
log.WarnLevel,
log.InfoLevel,
}
}
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
}