Extract startServer method from main()

cmd/idp.go

@@ -33,6 +33,7 @@ import (
 
 	"github.com/go-openapi/runtime/client"
 	"github.com/gorilla/csrf"
+	"github.com/knadh/koanf"
 	hydra "github.com/ory/hydra-client-go/client"
 	log "github.com/sirupsen/logrus"
 
@@ -145,22 +146,32 @@ func main() {
 		logger.Fatalf("could not initialize request error handling: %v", err)
 	}
 
+	handlerChain := tracing(logging(hsts(errorMiddleware(csrfProtect(router)))))
+
+	startServer(ctx, handlerChain, logger, config)
+}
+
+func startServer(ctx context.Context, handlerChain http.Handler, logger *log.Logger, config *koanf.Koanf) {
+	clientCertificateCAFile := config.MustString("security.client.ca-file")
+	serverName := config.String("server.name")
+	serverPort := config.Int("server.port")
+
 	clientCertPool := x509.NewCertPool()
-	pemBytes, err := ioutil.ReadFile(config.MustString("security.client.ca-file"))
+	pemBytes, err := ioutil.ReadFile(clientCertificateCAFile)
 	if err != nil {
 		logger.Fatalf("could not load client CA certificates: %v", err)
 	}
 	clientCertPool.AppendCertsFromPEM(pemBytes)
 
 	tlsConfig := &tls.Config{
-		ServerName: config.String("server.name"),
+		ServerName: serverName,
 		MinVersion: tls.VersionTLS12,
 		ClientAuth: tls.VerifyClientCertIfGiven,
 		ClientCAs:  clientCertPool,
 	}
 	server := &http.Server{
-		Addr:         fmt.Sprintf("%s:%d", config.String("server.name"), config.Int("server.port")),
-		Handler:      tracing(logging(hsts(errorMiddleware(csrfProtect(router))))),
+		Addr:         fmt.Sprintf("%s:%d", serverName, serverPort),
+		Handler:      handlerChain,
 		ReadTimeout:  20 * time.Second,
 		WriteTimeout: 20 * time.Second,
 		IdleTimeout:  30 * time.Second,