aliases

[Licenser]

I found it to be a commone sep to do something like this:

{mapping, "data_dir", "riak_core.platform_data_dir",
 [{default, "{{platform_data_dir}}"},
  {datatype, string}]}.

{translation,
 "fifo_db.db_path",
 fun(Conf) ->
         cuttlefish_util:conf_get_value("data_dir", Conf)
 end
}.

{translation,
 "leveldb.data_root",
 fun(Conf) ->
         cuttlefish_util:conf_get_value("data_dir", Conf)
 end
}.

{translation,
 "hanoidb.data_root",
 fun(Conf) ->
         cuttlefish_util:conf_get_value("data_dir", Conf)
 end
}.

{translation,
 "bitcask.data_root",
 fun(Conf) ->
         cuttlefish_util:conf_get_value("data_dir", Conf)
 end
}.

aka hide the detailed setting under a simplified name for a system. So what would be great is if there would be something like {alias, "hanoidb.data_root"} which would then act as a 'default' for hanoidb.data_root (as example).

So this would simplify the above code to:

{mapping, "data_dir", "riak_core.platform_data_dir",
 [{default, "{{platform_data_dir}}"},
  {datatype, string},
  {alias, "fifo_db.db_path"},
  {alias, "leveldb.data_root"},
  {alias, "hanoidb.data_root"},
  {alias, "bitcask.data_root"}]}.

which is kind of sweet ;)

[joedevivo]

I'm going to mull this over the weekend. I think it (or something similar) will solve some problems I've also had. Part of the mulling will be trying to remember what those problems were.

[Licenser]

mull away! If you want I can make a PR for this too but I wanted to discuss it before investing more time then just coming up with crazy stuff ;)

[joedevivo]

This is covered now with the little publicized "right hand substitutions" feature. It would work like this:

{mapping, "data_dir", "riak_core.platform_data_dir",
 [{default, "{{platform_data_dir}}"},
  {datatype, directory}]}.

{mapping, "hanoi.data_root", "hanoidb.data_root",
 [{default, "#(data_dir)/hanoi"},
  {datatype, directory}]}.

then you could also override in your .conf file like this:

data_dir = /wherever
hanoi.data_root = #(data_dir)/some_other_hanoi_path