Loading the endpoint configuration from the system environment - environment-variables

Question

I have the following endpoint initialization in lib/flashcards_web/endpoint.ex:
#doc """
Callback invoked for dynamically configuring the endpoint.
It receives the endpoint configuration and checks if
configuration should be loaded from the system environment.
"""
def init(_key, config) do
if config[:load_from_system_env] do
port = System.get_env("PORT") || raise "expected the PORT environment variable to be set"
jwt_token_ttl_minutes =
"USER_SESSION_MINUTES"
|> System.get_env
|> String.to_integer
|| raise "expected the USER_SESSION_MINUTES environment variable to be set"
config =
config
|> Keyword.put(:http, [:inet6, port: port])
|> Keyword.put(:jwt_token_ttl_minutes, jwt_token_ttl_minutes)
{:ok, config}
else
{:ok, config}
end
end
and the required load_from_system_env: true line in config/dev.exs:
# For development, we disable any cache and enable
# debugging and code reloading.
#
# The watchers configuration can be used to run external
# watchers to your application. For example, we use it
# with brunch.io to recompile .js and .css sources.
config :flashcards, FlashcardsWeb.Endpoint,
http: [port: 4000],
debug_errors: true,
code_reloader: true,
check_origin: false,
watchers: [node: ["node_modules/brunch/bin/brunch", "watch", "--stdin",
cd: Path.expand("../assets", __DIR__)]],
load_from_system_env: true
However when running
PORT=4000 USER_SESSION_MINUTES=1 iex -S mix phx.server
I get:
iex(1)> Application.get_env(:flashcards, FlashcardsWeb.Endpoint)[:jwt_token_ttl_minutes]
nil
Am I missing something here?

Answer 1

Found the solution to access the dynamic endpoint configuration.
The docs mention that a config/2 function is automatically generated at the endpoint.
The dynamic endpoint configuration can therefore be accessed as follows:
iex(2)> FlashcardsWeb.Endpoint.config(:jwt_token_ttl_minutes)
1