[erlang-questions] specifying OS-level environment variables

[Ivan Uemlianin]

Dear Sergej

Excellent thanks.  That looks like the tight way to do it.

Best wishes

Ivan


On 30/11/2016 12:12, Sergej Jurečko wrote:
> 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
>>                          llaisdy.wordpress.com
>>               github.com/llaisdy
>>                      www.linkedin.com/in/ivanuemlianin
>>
>>                         festina lente
>> ============================================================
>>
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-- 
============================================================
Ivan A. Uemlianin PhD
Llaisdy
Speech Technology Research and Development

                     ivan@REDACTED
                         @llaisdy
                          llaisdy.wordpress.com
               github.com/llaisdy
                      www.linkedin.com/in/ivanuemlianin

                         festina lente
============================================================