Add a From field to mailer config.

Fixes #1351.

cmd/config.go

@@ -118,6 +118,7 @@ type Config struct {
 		Port     string
 		Username string
 		Password string
+		From     string
 
 		CertLimit int
 		NagTimes  []string

cmd/expiration-mailer/main.go

@@ -247,7 +247,7 @@ func main() {
 		tmpl, err := template.New("expiry-email").Parse(string(emailTmpl))
 		cmd.FailOnError(err, "Could not parse email template")
 
-		mailClient := mail.New(c.Mailer.Server, c.Mailer.Port, c.Mailer.Username, c.Mailer.Password)
+		mailClient := mail.New(c.Mailer.Server, c.Mailer.Port, c.Mailer.Username, c.Mailer.Password, c.Mailer.From)
 
 		nagCheckInterval := defaultNagCheckInterval
 		if s := c.Mailer.NagCheckInterval; s != "" {

mail/mailer.go

@@ -64,13 +64,13 @@ func isASCII(str string) bool {
 
 // New constructs a Mailer to represent an account on a particular mail
 // transfer agent.
-func New(server, port, username, password string) MailerImpl {
+func New(server, port, username, password, from string) MailerImpl {
 	auth := smtp.PlainAuth("", username, password, server)
 	return MailerImpl{
 		Server:      server,
 		Port:        port,
 		Auth:        auth,
-		From:        username,
+		From:        from,
 		clk:         clock.Default(),
 		csprgSource: realSource{},
 	}

mail/mailer_test.go

@@ -24,7 +24,9 @@ func (f fakeSource) generate() *big.Int {
 
 func TestGenerateMessage(t *testing.T) {
 	fc := clock.NewFake()
-	m := MailerImpl{From: "send@email.com", clk: fc, csprgSource: fakeSource{}}
+	m := New("", "", "", "", "send@email.com")
+	m.clk = fc
+	m.csprgSource = fakeSource{}
 	messageBytes, err := m.generateMessage([]string{"recv@email.com"}, "test subject", "this is the body\n")
 	test.AssertNotError(t, err, "Failed to generate email body")
 	message := string(messageBytes)
@@ -44,8 +46,7 @@ func TestGenerateMessage(t *testing.T) {
 }
 
 func TestFailNonASCIIAddress(t *testing.T) {
-	fc := clock.NewFake()
-	m := MailerImpl{From: "send@email.com", clk: fc, csprgSource: fakeSource{}}
+	m := New("", "", "", "", "send@email.com")
 	_, err := m.generateMessage([]string{"遗憾@email.com"}, "test subject", "this is the body\n")
 	test.AssertError(t, err, "Allowed a non-ASCII to address incorrectly")
 }