View Source Config.Reader (Elixir v1.17.0)

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.Provider module.

Summary

Functions

eval!(file, contents, opts \\ [])

Evaluates the configuration contents for the given file.

merge(config1, config2)

Merges two configurations.

read!(file, opts \\ [])

Reads the configuration file.

read_imports!(file, opts \\ [])

Reads the given configuration file and returns the configuration with its imports.

Functions

eval!(file, contents, opts \\ [])

(since 1.11.0)

@spec eval!(Path.t(), binary(), keyword()) :: keyword()

Evaluates the configuration contents for the given file.

Accepts the same options as read!/2.

merge(config1, config2)

(since 1.9.0)

@spec merge(keyword(), keyword()) :: keyword()

Merges two configurations.

The configurations are merged together with the values in the second one having higher preference than the first in case of conflicts. In case both values are set to keyword lists, it deep merges them.

Examples

iex> Config.Reader.merge([app: [k: :v1]], [app: [k: :v2]])
[app: [k: :v2]]

iex> Config.Reader.merge([app: [k: [v1: 1, v2: 2]]], [app: [k: [v2: :a, v3: :b]]])
[app: [k: [v1: 1, v2: :a, v3: :b]]]

iex> Config.Reader.merge([app1: []], [app2: []])
[app1: [], app2: []]

read!(file, opts \\ [])

(since 1.9.0)

@spec read!(
  Path.t(),
  keyword()
) :: keyword()

Reads the configuration file.

Options

:imports - a list of already imported paths or :disabled to disable imports
:env - the environment the configuration file runs on. See Config.config_env/0 for sample usage
:target - the target the configuration file runs on. See Config.config_target/0 for sample usage

read_imports!(file, opts \\ [])

(since 1.9.0)

@spec read_imports!(
  Path.t(),
  keyword()
) :: {keyword(), [Path.t()]}

Reads the given configuration file and returns the configuration with its imports.

Accepts the same options as read!/2. Although note the :imports option cannot be disabled in read_imports!/2.