mblagusz
Runtime configuration for a dependent library
We are in the process of moving some shared functionality (mail sending) into a separate application that’s a dependency of our main app. That is, a shared library.
The problem we’re running into is that the mail configuration currently lives inside config/runtime.exs in our main application. If we move it to config/runtime.exs inside the dependent library, then Application.get_env(:mailer, …) doesn’t find it anymore. It would seem that only the “main” runtime.exs file is being loaded by mix run.
I see some libraries use files like config/prod.exs, but I want the shared configuration to read environment variables at startup. Is there a pattern that will let me do this?
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LostKobrakai
Not just runtime.exs. All config can only come from the top level mix project you’re on. Config of dependencies is ignored.
mayel
Not only that, but it is generally discouraged to use the config for libraries (see the infobox at Config — Elixir v1.16.2).
I personally consider one’s “internal” dependencies to be an exception, and so this is my approach to runtime config for such libraries:
in the main app’s runtime.exs:
[SubApp1.RuntimeConfig]
|> Enum.each(&apply(&1, :config))
in the dependency (at lib/runtime_config.exs):
defmodule SubApp1.RuntimeConfig do
def config do
import Config
config :sub_app1,
key: System.get_env("SUB_APP1_key", "default_val")Last Post!
mayel
Yeah that’s why I only suggested it for “internal” libraries, with the advantage of keeping the config in the same repo as the code rather than copy/pasting it all in runtime.exs but YYMV…
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