Allow calling root route on app

Fixes #64

Previously calling a root registered route would result in an error
message "Not Found" suggesting the route hadn't been registed, yet when
listing the routes, `fn routes list myapp` you could see the `/` route.

You can now successfully call a root registered route with `fn call
myapp /`

api/server/runner.go

@@ -94,9 +94,14 @@ func (s *Server) handleRequest(c *gin.Context, enqueue models.Enqueue) {
 		payload = strings.NewReader(reqPayload)
 	}
 
+	r, routeExists := c.Get(api.Path)
+	if !routeExists {
+		r = "/"
+	}
+
 	reqRoute := &models.Route{
 		AppName: c.MustGet(api.AppName).(string),
-		Path:    path.Clean(c.MustGet(api.Path).(string)),
+		Path:    path.Clean(r.(string)),
 	}
 
 	s.FireBeforeDispatch(ctx, reqRoute)

api/server/runner_test.go

@@ -124,6 +124,7 @@ func TestRouteRunnerExecution(t *testing.T) {
 			{Name: "myapp", Config: models.Config{}},
 		},
 		[]*models.Route{
+			{Path: "/", AppName: "myapp", Image: "funcy/hello", Headers: map[string][]string{"X-Function": {"Test"}}},
 			{Path: "/myroute", AppName: "myapp", Image: "funcy/hello", Headers: map[string][]string{"X-Function": {"Test"}}},
 			{Path: "/myerror", AppName: "myapp", Image: "funcy/error", Headers: map[string][]string{"X-Function": {"Test"}}},
 		}, nil, nil,
@@ -141,10 +142,12 @@ func TestRouteRunnerExecution(t *testing.T) {
 		expectedCode    int
 		expectedHeaders map[string][]string
 	}{
+		{"/r/myapp/", ``, "GET", http.StatusOK, map[string][]string{"X-Function": {"Test"}}},
 		{"/r/myapp/myroute", ``, "GET", http.StatusOK, map[string][]string{"X-Function": {"Test"}}},
 		{"/r/myapp/myerror", ``, "GET", http.StatusInternalServerError, map[string][]string{"X-Function": {"Test"}}},
 
 		// Added same tests again to check if time is reduced by the auth cache
+		{"/r/myapp/", ``, "GET", http.StatusOK, map[string][]string{"X-Function": {"Test"}}},
 		{"/r/myapp/myroute", ``, "GET", http.StatusOK, map[string][]string{"X-Function": {"Test"}}},
 		{"/r/myapp/myerror", ``, "GET", http.StatusInternalServerError, map[string][]string{"X-Function": {"Test"}}},
 	} {

api/server/server.go

@@ -327,6 +327,7 @@ func (s *Server) bindHandlers(ctx context.Context) {
 
 	engine.DELETE("/tasks", s.handleTaskRequest)
 	engine.GET("/tasks", s.handleTaskRequest)
+	engine.Any("/r/:app", s.handleRunnerRequest)
 	engine.Any("/r/:app/*route", s.handleRunnerRequest)
 
 	// This final route is used for extensions, see Server.Add