Add custom http listener support

pkg/app/app.go

@@ -3,6 +3,7 @@ package app
 import (
 	"context"
 	"errors"
+	"net"
 	"net/http"
 
 	"github.com/rs/zerolog"
@@ -25,10 +26,11 @@ type App struct {
 }
 
 type AppHTTP struct {
-	Funcs        []srv.HTTPFunc
-	Middleware   []http.Handler
-	HealthChecks []srv.HealthCheckFunc
-	httpDone     <-chan interface{}
+	Funcs          []srv.HTTPFunc        // Handle funcs to serve
+	Middleware     []http.Handler        // Optional middleware. Next handler called by app framework.
+	HealthChecks   []srv.HealthCheckFunc // Health-check functions to be called by health endpoint
+	CustomListener net.Listener          // Optional listener for http server
+	httpDone       <-chan interface{}
 }
 
 type (
@@ -85,6 +87,7 @@ func (a *App) initHTTP() {
 			HandleFuncs:      a.HTTP.Funcs,
 			Middleware:       a.HTTP.Middleware,
 			HealthCheckFuncs: a.HTTP.HealthChecks,
+			CustomListener:   a.HTTP.CustomListener,
 		},
 	)
 	a.shutdownFuncs = append(a.shutdownFuncs, httpShutdown)