anchor.diff:                       end, AssignedInfo),
       gen_json({[{<<"assigned_info">>, JSON}]}).
   
  +
   %% @doc Format a history list
   %%
   -spec(histories(list(#history{})) ->
  
positive.code:          bad_nodes/1, system_info_and_nodes_stat/1, node_stat/2,
           compact_status/1, du/2, credential/2, users/1, endpoints/1,
           buckets/1, bucket_by_access_key/1,
           acls/1, whereis/1, histories/1
          ]).
  
  -define(output_ok(),           gen_json({[{result, <<"OK">>}]})).
  
negative.code:     gen_json({[{<<"buckets">>, JSON}]}).
  
  
  %% @doc Format a acl list
  %%
  -spec(acls(acls()) ->
               string()).
  acls(ACLs) ->
      JSON = lists:map(fun(#bucket_acl_info{user_id = UserId, permissions = Permissions}) ->
                               {[{<<"user_id">>,   UserId},
                                 {<<"permissions">>, Permissions}
                                ]}
                       end, ACLs),
      gen_json({[{<<"acls">>, JSON}]}).
  
  
  cluster_status(Stats) ->
      JSON = lists:map(fun(Items) ->
                               ClusterId = leo_misc:get_value('cluster_id', Items),
                               DCId = leo_misc:get_value('dc_id', Items),
                               Status = leo_misc:get_value('status', Items),
                               NumOfStorages = leo_misc:get_value('members', Items),
                               UpdatedAt = leo_misc:get_value('updated_at', Items),
  
                               {[{<<"cluster_id">>, list_to_binary(ClusterId)},
                                 {<<"dc_id">>,      list_to_binary(atom_to_list(DCId))},
                                 {<<"status">>,     list_to_binary(atom_to_list(Status))},
                                 {<<"num_of_storages">>, NumOfStorages},
                                 {<<"updated_at">>,      list_to_binary(UpdatedAt)}
                                ]}
                       end, Stats),
      gen_json({[{<<"cluster_stats">>, JSON}]}).
  
  
  %% @doc Format an assigned file
  %%
  -spec(whereis(list()) ->
  