Mix v1.8.1 Mix.Config View Source
Module for defining, reading and merging app configurations.
Most commonly, this module is used to define your own configuration:
use Mix.Config
config :plug,
key1: "value1",
key2: "value2"
import_config "#{Mix.env}.exs"All config/* macros, including import_config/1, are used
to help define such configuration files.
Furthermore, this module provides functions like read!/1,
merge/2 and friends which help manipulate configurations
in general.
Configuration set using Mix.Config will set the application environment, so
that Application.get_env/3 and other Application functions can be used
at run or compile time to retrieve or change the configuration.
For example, the :key1 value from the application :plug (see example above) can be
retrieved with:
"value1" = Application.fetch_env!(:plug, :key1)Link to this section Summary
Functions
Configures the given application.
Configures the given key for the given application.
Evaluates the given configuration file.
Imports configuration from the given file or files.
Merges two configurations.
Persists the given configuration by modifying the configured applications environment.
Link to this section Functions
Configures the given application.
Keyword lists are always deep merged.
Examples
The given opts are merged into the existing configuration
for the given app. Conflicting keys are overridden by the
ones specified in opts. For example, the declaration below:
config :lager,
log_level: :warn,
mode: :truncate
config :lager,
log_level: :info,
threshold: 1024Will have a final configuration of:
[log_level: :info, mode: :truncate, threshold: 1024]This final configuration can be retrieved at run or compile time:
Application.get_all_env(:lager)Configures the given key for the given application.
Keyword lists are always deep merged.
Examples
The given opts are merged into the existing values for key
in the given app. Conflicting keys are overridden by the
ones specified in opts. For example, given the two configurations
below:
config :ecto, Repo,
log_level: :warn,
adapter: Ecto.Adapters.Postgres
config :ecto, Repo,
log_level: :info,
pool_size: 10the final value of the configuration for the Repo key in the :ecto
application will be:
[log_level: :info, pool_size: 10, adapter: Ecto.Adapters.Postgres]This final value can be retrieved at runtime or compile time with:
Application.get_env(:ecto, Repo)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.
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"Merges two configurations.
The configuration of each application is merged together with the values in the second one having higher preference than the first in case of conflicts.
Examples
iex> Mix.Config.merge([app: [k: :v1]], [app: [k: :v2]])
[app: [k: :v2]]
iex> Mix.Config.merge([app1: []], [app2: []])
[app1: [], app2: []]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]