Notifications: Add Message-ID header to outgoing emails (#83752)

* Add Message-ID header to outgoing emails

* change message-id format

* parse adddresses with name

pkg/services/notifications/smtp.go

@@ -8,10 +8,12 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"net/mail"
 	"net/textproto"
 	"strconv"
 	"strings"
 
+	"github.com/google/uuid"
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/propagation"
@@ -101,6 +103,15 @@ func (sc *SmtpClient) buildEmail(ctx context.Context, msg *Message) *gomail.Mess
 	m.SetHeader("To", msg.To...)
 	m.SetHeader("Subject", msg.Subject)
 
+	from, err := mail.ParseAddress(msg.From)
+	if err == nil {
+		at := strings.LastIndex(from.Address, "@")
+		if at >= 0 {
+			domain := from.Address[at+1:]
+			m.SetHeader("Message-ID", fmt.Sprintf("<%s@%s>", uuid.NewString(), domain))
+		}
+	}
+
 	if sc.cfg.EnableTracing {
 		otel.GetTextMapPropagator().Inject(ctx, gomailHeaderCarrier{m})
 	}

pkg/services/notifications/smtp_test.go

@@ -31,7 +31,7 @@ func TestBuildMail(t *testing.T) {
 
 	message := &Message{
 		To:      []string{"to@address.com"},
-		From:    "from@address.com",
+		From:    "Mr. Foo <from@address.com>",
 		Subject: "Some subject",
 		Body: map[string]string{
 			"text/html":  "Some HTML body",
@@ -52,7 +52,8 @@ func TestBuildMail(t *testing.T) {
 		require.NoError(t, err)
 
 		assert.Contains(t, buf.String(), "Foo-Header: foo_value")
-		assert.Contains(t, buf.String(), "From: from@address.com")
+		assert.Contains(t, buf.String(), "From: Mr. Foo <from@address.com>")
+		assert.Regexp(t, "Message-ID: <.*@address.com>", buf.String())
 		assert.Contains(t, buf.String(), "Some HTML body")
 		assert.Contains(t, buf.String(), "Some plain text body")
 		assert.Less(t, strings.Index(buf.String(), "Some plain text body"), strings.Index(buf.String(), "Some HTML body"))