Asimov
Config file: global variables vs "config getcher" function
Hi all,
This is a general programming question, not specific to Elixir. I do my fare share of scripting in LUA. Specifically I code IVR on freeswitch / Asterisk. So a common scenario I have is that there is a bunch of configurations parameters that I have to load in memory every time I run a script (e.g. every time a call hits the IVR). I am coding a project now where the number of configuration parameters is quite large (about 200) - please do not focus on the why of this, that is not the aim of the question.
So, what I usually do is to have a config.lua somehere where I define all these parameters as global variables:
__parameter001__ = value01
__parameter001__ = value02
__parameter_N__ = value_N
Not elegant but it does the job. So, I was thinking, would it be more efficient to have a “config getcher” fuction? Something like this :
function get_parameter(parameter)
if(parameter == '__parameter001__')then return value01;
elseif(parameter == '__parameter002__')then return value02;
elseif(parameter == '__parameter_N__')then return value_N;
else return 'no_value_set';
end;
end
In my code I would simply call this function everytime I need a parameter value:
my_parameter = get_parameter('__parameter001__');
So, instead of loading a lot of global variables I would be calling a function every time to get the value of a parameter.
My question is: is this something sensible to do? Should I just simply keep loading the parameters in memory?
I know this is not an Elixir question and my example is LUA based but I believe this is language independent discussion. Also, this forum is much more professional than any LUA forum out there (that I know of), so I’d love to know your opinion.
Thank you!
Most Liked
dimitarvp
I don’t see why not. Can’t comment on Lua in particular but in Elixir I’d just load these into a Map and then store it and use it like so:
defmodule MyConfig do
@config_key :my_config
def load(file_path) do
# load your configuration parameters into an Elixir map.
# ...your code here...
# then, assuming your map with the loaded config is called `cfg`:
:persistent_term.put(@config_key, cfg)
end
def get(param), do: :persistent_term.get(@config_key) |> Map.get(param)
end
That way, you are putting that 200+ keyed map in an in-memory cache that does not get copied when accessed and you have a hyper-fast config map.
(This approach assumes that you’d change that config map rather rarely, by the way.)
dimitarvp
I’d advise you to do a quick read on Erlang’s :persistent_term module. It’s absolutely perfect for rarely (or never) changing data.
Glad to help.








