feature: implement email sending settings

The back office proxy supoports skipping the user resolution and
overriding the email's sender and the email's default recipients, and
the idea of these changes is for MBOP to support the same things too.

RHCLOUD-29047

internal/handlers/send_email.go

@@ -36,21 +36,42 @@ func SendEmails(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
+		// The user might have wanted to override the sender that goes in the "from" field of the email.
+		var fromAddress string
+		if emails.EmailSender != "" {
+			fromAddress = emails.EmailSender
+		} else {
+			fromAddress = config.Get().FromEmail
+		}
+
 		for _, email := range emails.Emails {
 			// creating a copy in order to pass it down into sub-functions
 			email := email
 
-			err := mailer.LookupEmailsForUsernames(r.Context(), &email)
-			if err != nil {
-				l.Log.Error(err, "error translating usernames")
-				continue
+			// Lookup the emails for the given usernames unless the client specified otherwise.
+			if !emails.SkipUsersResolution {
+				err := mailer.LookupEmailsForUsernames(r.Context(), &email)
+				if err != nil {
+					l.Log.Error(err, "error translating usernames")
+					continue
+				}
+
+				if len(email.Recipients) == 0 {
+					email.Recipients = []string{config.Get().ToEmail}
+				}
 			}
 
+			// Should the user not specify any recipients, we need to determine if we should use the "default
+			// recipient" the user might have specified, or the default one that we set up in the configuration.
 			if len(email.Recipients) == 0 {
-				email.Recipients = []string{config.Get().ToEmail}
+				if emails.DefaultRecipient != "" {
+					email.Recipients = []string{emails.DefaultRecipient}
+				} else {
+					email.Recipients = []string{config.Get().ToEmail}
+				}
 			}
 
-			err = sender.SendEmail(r.Context(), &email)
+			err = sender.SendEmail(r.Context(), &email, fromAddress)
 			if err != nil {
 				l.Log.Error(err, "Error sending email", "email", email)
 			}

internal/models/mail.go

@@ -8,7 +8,10 @@ import (
 )
 
 type Emails struct {
-	Emails []Email `json:"emails,omitempty"`
+	Emails              []Email `json:"emails,omitempty"`
+	EmailSender         string  `json:"emailSender,omitempty"`
+	DefaultRecipient    string  `json:"defaultRecipient,omitempty"`
+	SkipUsersResolution bool    `json:"skipUsersResolution,omitempty"`
 }
 
 // taken from the BOP openapi spec

internal/service/mailer/aws_ses_mailer.go

@@ -49,9 +49,9 @@ type awsSESEmailer struct {
 	client *ses.Client
 }
 
-func (s *awsSESEmailer) SendEmail(ctx context.Context, email *models.Email) error {
+func (s *awsSESEmailer) SendEmail(ctx context.Context, email *models.Email, fromAddress string) error {
 	out, err := s.client.SendEmail(ctx, &ses.SendEmailInput{
-		FromEmailAddress: aws.String(config.Get().FromEmail),
+		FromEmailAddress: aws.String(fromAddress),
 		Destination: &sesTypes.Destination{
 			ToAddresses:  email.Recipients,
 			CcAddresses:  email.CcList,

internal/service/mailer/mailer_interface.go

@@ -11,7 +11,7 @@ import (
 )
 
 type Emailer interface {
-	SendEmail(ctx context.Context, email *models.Email) error
+	SendEmail(ctx context.Context, email *models.Email, fromAddress string) error
 }
 
 func NewMailer() (Emailer, error) {

internal/service/mailer/print_mailer.go

@@ -12,19 +12,20 @@ type printEmailer struct{}
 
 var _ = (Emailer)(&printEmailer{})
 
-func (p printEmailer) SendEmail(_ context.Context, email *models.Email) error {
+func (p printEmailer) SendEmail(_ context.Context, email *models.Email, fromAddress string) error {
 	l := 50
 	if len(email.Body) < 50 {
 		l = len(email.Body)
 	}
 
-	fmt.Printf(`To: %v
+	fmt.Printf(`From: %v
+To: %v
 CC: %v
 BCC: %v
 Subject: %v
 BodyType: %v
 Message: %v...(truncated to 50 chars)
-`, email.Recipients, email.CcList, email.BccList, email.Subject, email.BodyType, email.Body[:l])
+`, fromAddress, email.Recipients, email.CcList, email.BccList, email.Subject, email.BodyType, email.Body[:l])
 
 	return nil
 }