Inversion of Control for smtpd.Server

Allow more control over how Server is instaniated so that it can be unit
tested.

inbucket.go

@@ -94,6 +94,9 @@ func main() {
 		fmt.Fprintf(pidf, "%v\n", os.Getpid())
 	}
 
+	// Grab our datastore
+	ds := smtpd.DefaultFileDataStore()
+
 	// Start HTTP server
 	go web.Start()
 
@@ -102,7 +105,7 @@ func main() {
 	go pop3Server.Start()
 
 	// Startup SMTP server, block until it exits
-	smtpServer = smtpd.New()
+	smtpServer = smtpd.NewSmtpServer(config.GetSmtpConfig(), ds)
 	smtpServer.Start()
 
 	// Wait for active connections to finish

smtpd/listener.go

@@ -46,9 +46,7 @@ var expErrorsHist = new(expvar.String)
 var expWarnsHist = new(expvar.String)
 
 // Init a new Server object
-func New() *Server {
-	ds := DefaultFileDataStore()
-	cfg := config.GetSmtpConfig()
+func NewSmtpServer(cfg config.SmtpConfig, ds DataStore) *Server {
 	return &Server{dataStore: ds, domain: cfg.Domain, maxRecips: cfg.MaxRecipients,
 		maxIdleSeconds: cfg.MaxIdleSeconds, maxMessageBytes: cfg.MaxMessageBytes,
 		storeMessages: cfg.StoreMessages, domainNoStore: strings.ToLower(cfg.DomainNoStore),