Reading ubuntu environment variables in elixir production app

Are you using relx to build your releases? Or distillery? Or the new elixir releases?

I’m using the new elixir releases, I’m following this documentation. hexdox mix task release

Here’s my compilation script on the server

git pull origin cd ~/deploy/my_app MIX_ENV=prod mix deps.get --only prod && MIX_ENV=prod mix clean && MIX_ENV=prod mix compile && sudo MIX_ENV=prod mix release my_app &&

For a release you should just do System.get_env/1 in the config/release.exs, that’s it.

Or a config provider.

It is not clear what you are doing and in which file.

To be honest, so far I have not seen the error you are citing.

RELX_REPLACE_OS_VARS is a very old environment variable, it was changed to REPLACE_OS_VARS=true a while ago, maybe that will help?

Generally though you want to switch to using a releases.exs file as described here: mix release — Mix v1.20.2

I tried that and I’m getting a nil which is very strange

Can you reproduce it in a minimal project on GitHub and provide explanation how you build and run it in the README?

Thank you, this is my first elixir project hence the mis-steps. I’ve removed all the references and the rest is per the tutorial suggested.

Okay, let me do it

I realised git will not necessarily illustrate my problem so let me try to be articulate as possible. Here’s my releases.exs

import Config

config :my_app,
  secret_key_base: System.fetch_env!("SECRET_KEY_BASE"),
  variable: System.fetch_env!("VARIABLE") #or System.get_env("VARIABLE")

In my function,

System.get_env("VARIABLE") # Nil
Application.get_env(:my_app, :variable) #NIL
System.fetch_env!("VARIABLE") #{"init terminating in do_boot",{#{'__exception__'=>true,'__struct__'=>'Elixir.ArgumentError',message=><<"could not fetch environment variable \"VARIABLE\" because it is not set">>}

However, printenv in Ubuntu and nano /etc/environment show the environment variable VARIABLE set

Another strange thing is that when I go into the interactive shell iex, System.get_env("VARIABLE") prints out the value

Do you start the app in the very same terminal as you do the printenv? Do you rebuild your app after changing the config?