[erlang-questions] specifying OS-level environment variables

[Sergej Jurečko]

I would put a default value into vm.args

-env Variable Value

and start your app with: -args_file path/to/vm.args


regards,
Sergej

> On 30 Nov 2016, at 11:35, Ivan Uemlianin <ivan@REDACTED> wrote:
> 
> Dear All
> 
> I am writing an erlang application, and one of its dependencies requires an OS environment variable to be set.  For sake of argument:
> 
>    XYZ_HOME = /path/to/lib/
> 
> What is the best way to express this requirement to the user?  I can think of two ways.  Are there other, better, ways?
> 
> 1. Just put it in the documentation, along with other system requirements: "Needs XYZ_HOME to be set otherwise won't work."
> 
> 2. Put a "sensible default" in the .app.src and/or sys.config, document these application configs, and during application startup use os:putenv, e.g.:
> 
>    {ok, XYZ_HOME} = application:get_env(myapp, xyz_home),
>    os:putenv("XYZ_HOME", XYZ_HOME),
> 
> The first doesn't seem very friendly and I shouldn't think will be very effective.  Is the second a correct use case for os:putenv?
> 
> Is there a third way that is even better?
> 
> With thanks and best wishes
> 
> Ivan
> 
> 
> -- 
> ============================================================
> Ivan A. Uemlianin PhD
> Llaisdy
> Speech Technology Research and Development
> 
>                    ivan@REDACTED
>                        @llaisdy
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> 
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