Handling environment variables in Elixir?

I will tell you my experience of using it may help.

I create a condition in runtime:

# runtime.exs
if config_env() == :prod do

  amqp_url =
    System.get_env("AMQP_URL") ||
      raise """
          enviroment variable AMQP_URL is missing
      """

  config :pioneer_rpc,
    connection_string: amqp_url

# other config
end

I run the application itself as a system process and specify EnviromentFile=pathToEnvFile in the app.service config

example:

server@server ~> cat /etc/systemd/system/app.service
[Unit]
Description=test
After=network.target

[Service]
Restart=on-failure
EnvironmentFile=/etc/app/env.conf

WorkingDirectory=/opt/app

ExecStart=/opt/app/_build/prod/rel/app/bin/app start
ExecStop=/opt/app/_build/prod/rel/app/bin/app stop

[Install]
WantedBy=multi-user.target

Next, the property can be accessed using Application.get_env(:connection_string).

Have you verified that the call in runtime.exs is actually looking for a .env file in the project root (which iex can see) rather than in the config directory?

Are you running iex -S mix or just plain iex? Just running iex won’t evaluate any of your project files such as the configuration.

I figured it out. I put the environment variables within the :prod scope. Working normally now that I moved it outside :prod. Thanks all!