Mix.Config
A simple configuration API and functions for managing config files.
This module is deprecated, use the modules Config
and Config.Reader
from Elixir's standard library instead.
Setting configuration
Most commonly, this module is used to define your own configuration:
use Mix.Config config :root_key, key1: "value1", key2: "value2" import_config "#{Mix.env()}.exs"
use Mix.Config
will import the functions config/2
, config/3
and import_config/1
to help you manage your configuration.
Evaluating configuration
Once a configuration is written to a file, the functions in this module can be used to read and merge said configuration. The eval!/2
function allows you to evaluate a given configuration file and the merge/2
function allows you to deep merge the results of multiple configurations. Those functions should not be invoked by users writing configurations but rather by library authors.
Examples
The most common use of Mix.Config
is to define application configuration so that Application.get_env/3
and other Application
functions can be used to retrieve or further change them.
Application config files are typically placed in the config/
directory of your Mix projects. For example, the following config
# config/config.exs config :my_app, :key, "value"
will be automatically loaded by Mix and persisted into the :my_app
's application environment, which can be accessed in its source code as follows:
"value" = Application.fetch_env!(:my_app, :key1)
Summary
Functions
- config(root_key, opts) deprecated
Configures the given
root_key
.- config(root_key, key, opts) deprecated
Configures the given
key
for the givenroot_key
.- eval!(file, imported_paths \\ []) deprecated
Evaluates the given configuration file.
- import_config(path_or_wildcard) deprecated
Imports configuration from the given file or files.
- merge(config1, config2) deprecated
Merges two configurations.
- persist(config) deprecated
Persists the given configuration by modifying the configured applications environment.
- read!(file, imported_paths \\ []) deprecated
Reads the configuration file.
Functions
config(root_key, opts)
Configures the given root_key
.
Keyword lists are always deep merged.
Examples
The given opts
are merged into the existing configuration for the given root_key
. Conflicting keys are overridden by the ones specified in opts
. For example, the application configuration below
config :logger, level: :warn, backends: [:console] config :logger, level: :info, truncate: 1024
will have a final configuration for :logger
of:
[level: :info, backends: [:console], truncate: 1024]
config(root_key, key, opts)
Configures the given key
for the given root_key
.
Keyword lists are always deep merged.
Examples
The given opts
are merged into the existing values for key
in the given root_key
. Conflicting keys are overridden by the ones specified in opts
. For example, the application configuration below
config :ecto, Repo, log_level: :warn, adapter: Ecto.Adapters.Postgres config :ecto, Repo, log_level: :info, pool_size: 10
will have a final value of the configuration for the Repo
key in the :ecto
application of:
[log_level: :info, pool_size: 10, adapter: Ecto.Adapters.Postgres]
eval!(file, imported_paths \\ [])
Evaluates the given configuration file.
It accepts a list of imported_paths
that should raise if attempted to be imported again (to avoid recursive imports).
It returns a tuple with the configuration and the imported paths.
import_config(path_or_wildcard)
Imports configuration from the given file or files.
If path_or_wildcard
is a wildcard, then all the files matching that wildcard will be imported; if no file matches the wildcard, no errors are raised. If path_or_wildcard
is not a wildcard but a path to a single file, then that file is imported; in case the file doesn't exist, an error is raised.
If path/wildcard is a relative path/wildcard, it will be expanded relatively to the directory the current configuration file is in.
Examples
This is often used to emulate configuration across environments:
import_config "#{Mix.env()}.exs"
Or to import files from children in umbrella projects:
import_config "../apps/*/config/config.exs"
merge(config1, config2)
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> Mix.Config.merge([app: [k: :v1]], [app: [k: :v2]]) [app: [k: :v2]] iex> Mix.Config.merge([app: [k: [v1: 1, v2: 2]]], [app: [k: [v2: :a, v3: :b]]]) [app: [k: [v1: 1, v2: :a, v3: :b]]] iex> Mix.Config.merge([app1: []], [app2: []]) [app1: [], app2: []]
persist(config)
Persists the given configuration by modifying the configured applications environment.
config
should be a list of {app, app_config}
tuples or a %{app => app_config}
map where app
are the applications to be configured and app_config
are the configuration (as key-value pairs) for each of those applications.
Returns the configured applications.
Examples
Mix.Config.persist(logger: [level: :error], my_app: [my_config: 1]) #=> [:logger, :my_app]
read!(file, imported_paths \\ [])
Specs
read!(Path.t(), [Path.t()]) :: keyword()
Reads the configuration file.
The same as eval!/2
but only returns the configuration in the given file, without returning the imported paths.
It exists for convenience purposes. For example, you could invoke it inside your mix.exs
to read some external data you decided to move to a configuration file:
subsystem: Mix.Config.read!("rel/subsystem.exs")
© 2012 Plataformatec
Licensed under the Apache License, Version 2.0.
https://hexdocs.pm/mix/1.11.2/Mix.Config.html