Usage of Mix.env() discouraged in Phoenix router?

Questions & Help Questions
, ,
1

Hi!

I’m curious about the usage of Mix.env() in Phoenix router. Bamboo recommends to add a conditional route for :dev environment to see emails that are kept in memory when using Bamboo.LocalAdapter.

# In your Router
defmodule MyApp.Router do
  use Phoenix.Router # or use Plug.Router if you're not using Phoenix

  if Mix.env == :dev do
    # If using Phoenix
    forward "/sent_emails", Bamboo.SentEmailViewerPlug

    # If using Plug.Router, make sure to add the `to`
    forward "/sent_emails", to: Bamboo.SentEmailViewerPlug
  end
end

Others have asked similar questions here and the conclusion seems to be that it’s not a bad practice because routes are compiled. But since Mix is a build tool, I’m wondering if this holds true when using releases for example, so it will be a better idea to use Application config values.

2

The Mix.env call won’t land in your release, because that if expression is executed when compiling the module to a beam file – a.k.a. when creating the release. Only the resulting beam files are included in the release itself. Therefore it’s not problematic in terms of Mix being not available at runtime.

3

Thanks! That was my intuition too :slightly_smiling_face: