fixing file log for multiple locations

Former-commit-id: 53cbecbc1e745fd497fc26b8c4172c7df1eade7f

kong/plugins/filelog/fd_util.lua

@@ -1,13 +1,13 @@
 local _M = {}
 
-local fd = nil
+local fd = {}
 
-function _M.get_fd()
-  return fd
+function _M.get_fd(conf_path)
+  return fd[conf_path]
 end
 
-function _M.set_fd(file_descriptor)
-  fd = file_descriptor
+function _M.set_fd(conf_path, file_descriptor)
+  fd[conf_path] = file_descriptor
 end
 
 return _M

kong/plugins/filelog/log.lua

@@ -26,10 +26,10 @@ int fprintf(FILE *stream, const char *format, ...);
 local function log(premature, conf, message)
   local message = cjson.encode(message).."\n"
 
-  local f = fd_util.get_fd()
+  local f = fd_util.get_fd(conf.path)
   if not f then
     f = ffi.C.fopen(conf.path, "a+")
-    fd_util.set_fd(f)
+    fd_util.set_fd(conf.path, f)
   end
 
   ffi.C.fprintf(f, message)