Fixed a bug where a double "/" would be added to the load balancers' path.

The previous version would concatenate `areaEtcdKey(area) + "/" + registryLoadBalancerDirectory`. This would result in a path like: "registry/area-name//__lb" instead of the correct one "registry/area-name/__lb", since areaEtcdKey returns a "/"-terminated value". The result was that the `servers` map would always be empty, even when a load balancer was available.

The fix uses path.Join(), instead of just removing the `+ "/" +`. This is because this function is more robust to errors. In fact, path.Joins returns a correct path even when the arguments are something like "a/" and "/b" (which after the fix is no longer the case, anyway). The return in this example would still be "a/b" and not "a//b", like it would happen with this bug. This should solve the bug and be more bug-resistant also for the future.

Author: FilippoMuschera

internal/registration/registry.go

@@ -2,9 +2,6 @@ package registration
 
 import (
 	"fmt"
-	"github.com/hexablock/vivaldi"
-	"github.com/serverledge-faas/serverledge/internal/node"
-	"golang.org/x/exp/maps"
 	"log"
 	"net"
 	"path"
@@ -14,6 +11,10 @@ import (
 	"sync"
 	"time"
 
+	"github.com/hexablock/vivaldi"
+	"github.com/serverledge-faas/serverledge/internal/node"
+	"golang.org/x/exp/maps"
+
 	"github.com/serverledge-faas/serverledge/internal/config"
 	"github.com/serverledge-faas/serverledge/utils"
 	"go.etcd.io/etcd/client/v3"
@@ -194,7 +195,8 @@ func GetOneNodeInArea(area string, includeSelf bool) (NodeRegistration, error) {
 }
 
 func GetLBInArea(area string) (map[string]NodeRegistration, error) {
-	baseDir := areaEtcdKey(area) + "/" + registryLoadBalancerDirectory
+	prefix := areaEtcdKey(area)
+	baseDir := path.Join(prefix, registryLoadBalancerDirectory)
 
 	ctx, _ := context.WithTimeout(context.Background(), 3*time.Second)