Reads and parses the application's Mix config.

Usage

In order to get values, you may first add dynamic configuration to config/prod.exs:

config :confix,
  base_app: :my_project # defaults to Mix app, so it's usually not needed

config :my_project,
  feature_x_enabled: {:system, "FEATURE_X_ENABLED", type: :boolean, default: false}

config :my_project, MyProject.Web.Endpoint,
  pubsub: [url: {:system, "REDIS_URL"}]

You may get these values in your own code:

iex> Confix.get(:feature_x_enabled)
false
iex> System.put_env("FEATURE_X_ENABLED", "1")
:ok
iex> Confix.get(:feature_x_enabled)
true
iex> System.put_env("REDIS_URL", "redis://localhost:6379")
:ok
iex> Confix.get_in(MyProject.Web.Endpoint, [:pubsub, :url])
"redis://localhost:6379"

You may also want to parse arbitrary configuration that doesn't come from Mix:

iex> System.put_env("ADAPTER_URL", "http://example.com")
:ok
iex> Confix.parse({:system, "ADAPTER_URL"})
"http://example.com"
iex> Confix.deep_parse(adapter: [url: {:system, "ADAPTER_URL"}])
[adapter: [url: "http://example.com"]]

Sometimes however the place where you'd like system tuples to be read lies outside your own code and in 3rd party applications that don't natively support them. That could be (and actually is) the case of MyProject.Web.Endpoint on examples above - the Redis adapter for Phoenix PubSub doesn't properly parse the system tuples. In such cases, 3rd party config can be easily patched with Confix.Application.

Usage in modules

You may also use Confix in your own modules in order to have quick means for getting config associated with that particular module:

defmodule MyProject.MyHTTPClient do
  use Confix

  def call do
    url = config!(:url)

    # ...
  end
end

Syntax

System tuples may have the following syntax:

{:system, "ENV_VAR"}
{:system, "ENV_VAR", default: "xyz"}
{:system, "ENV_VAR", type: :integer}
{:system, "ENV_VAR", type: :boolean, default: true}
{:system, ["ENV_VAR_1", "ENV_VAR_2"]}