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mirror of https://github.com/containrrr/watchtower.git synced 2024-12-12 09:04:17 +02:00
watchtower/pkg/notifications/email.go
2019-07-21 22:22:30 +02:00

139 lines
3.7 KiB
Go

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
}