API for reading config files defined with Config.

As a provider

Config.Reader can also be used as a Config.Provider. A config provider is used during releases to customize how applications are configured. When used as a provider, it expects a single argument: the configuration path (as outlined in Config.Provider.config_path/0) for the file to be read and loaded during the system boot.

For example, if you expect the target system to have a config file in an absolute path, you can add this inside the def project portion of your mix.exs:

releases: [
  demo: [
    config_providers: [
      {Config.Reader, "/etc/config.exs"}
    ]
  ]
]

Or if you want to read a custom path inside the release:

config_providers: [{Config.Reader, {:system, "RELEASE_ROOT", "/config.exs"}}]

You can also pass a keyword list of options to the reader, where the :path is a required key:

config_providers: [
  {Config.Reader,
   path: "/etc/config.exs",
   env: :prod,
   imports: :disabled}
]

Remember Mix already loads config/runtime.exs by default. For more examples and scenarios, see the Config.Providers module.