distillery v2.0.8 Mix.Releases.Config.Provider behaviour View Source

This defines the behaviour for custom configuration providers.

Link to this section Summary

Functions

Given a file path, this function expands it to an absolute path, while also expanding any environment variable references in the path

Callbacks

init(args)

Called when the provider is initialized

Link to this section Functions

expand_path(path)

Given a file path, this function expands it to an absolute path, while also expanding any environment variable references in the path.

Examples

iex> var = String.replace("Elixir.Mix.Releases.Config.Provider", ".", "_")
...> System.put_env(var, "hello")
...> {:ok, "var/hello/test"} = Elixir.Mix.Releases.Config.Provider.expand_path("var/${" <> var <> "}/test")

iex> {:ok, "/" <> _} = Elixir.Mix.Releases.Config.Provider.expand_path("~/")

iex> {:error, :unclosed_var_expansion} = Elixir.Mix.Releases.Config.Provider.expand_path("var/${FOO/test")

Link to this section Callbacks

init(args)

init(args :: [term()]) :: :ok | no_return()

Called when the provider is initialized.

Providers are invoked pre-boot, in a dedicated VM, with all application code loaded, and kernel, stdlib, compiler, and elixir applications started. Providers must use this callback to push configuration into the application environment, which will be persisted to a final sys.config for the release itself.

The arguments given to init/1 are the same as given in the config_providers setting in your release configuration file.