fix url path join

main.go

@@ -9,6 +9,7 @@ import (
 	log "github.com/sirupsen/logrus"
 	"io"
 	"net/http"
+	"net/url"
 	"os"
 	"path"
 	"regexp"
@@ -93,8 +94,14 @@ func main() {
 			continue
 		}
 
-		log.Debugf("checking mirror %s (%s)", repo.Servers[0], path.Join(repo.Servers[0], "../../../lastupdate"))
-		resp, err := http.Get(path.Join(repo.Servers[0], "../../../lastupdate"))
+		pURL, err := url.Parse(repo.Servers[0])
+		if err != nil {
+			log.Warnf("error parsing mirror url: %v", err)
+		}
+		pURL.Path = path.Join(pURL.Path, "../../../lastupdate")
+
+		log.Debugf("checking mirror %s (%s)", repo.Servers[0], pURL.String())
+		resp, err := http.Get(pURL.String())
 		if err != nil {
 			log.Warnf("error getting mirror lastupdate: %v", err)
 			continue