Get current environment name

Question

In Phoenix Framework, how can I get the current environment\'s name ?

I\'ve already tried reading env variables with System.get_env(\"MIX_ENV\")

Answer 1

Mix.env() doesn't work in production or other environments where you use compiled releases (built using Exrm / Distillery) or when Mix just isn't available.

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The solution is to specify it in your config/config.exs file:

config :your_app, env: Mix.env()

You can then get the environment atom in your application like this:

Application.get_env(:your_app, :env)
#=> :prod

Answer 2

Now in each environment config file (e.g. prod.exs) generated by default, you'll see the environment atom being set at the last line:

config :your_app, :environment, :prod

You can then use Application.get_env(:your_app, :environment) to get it.

You can do the same in any custom environment config you create.

Answer 3

You can use Mix.env/0:

iex(1)> Mix.env
:dev

Answer 4

An alternative to putting the Mix.env/0 into your applications configuration is to use a module attribute. This also works in production because module attributes are evaluate at compile time.

defmodule MyModule do
  @env Mix.env()

  def env, do: @env
end

If you only need the environment in a specific place - for example when starting up the application supervisor - this tends to be the easier solution.