One configuration to rule all data sources
Anyway Config is a configuration library for Ruby gems and applications.
As a library author, you can benefit from using Anyway Config by providing a better UX for your end-users:
- Zero-code configuration — no more boilerplate initializers.
- Per-environment and local settings support out-of-the-box.
For application developers, Anyway Config could be useful to:
- Keep configuration organized and use named configs instead of bloated
.env
/settings.yml
/whatever. - Free code of ENV/credentials/secrets dependency and use configuration classes instead—your code should not rely on configuration data sources.
NOTE: this readme shows documentation for 2.x version. For version 1.x see the 1-4-stable branch.
- Main concepts
- Installation
- Usage
- Using with Rails applications
- Using with Ruby applications
- Environment variables
- Type coercion
- Local configuration
- Data loaders
- Source tracing
- Pattern matching
- Test helpers
- OptionParser integration
- RBS support
Anyway Config abstractize the configuration layer by introducing configuration classes which describe available parameters and their defaults. For example:
module Influxer
class Config < Anyway::Config
attr_config(
host: "localhost",
username: "root",
password: "root"
)
end
end
Using Ruby classes to represent configuration allows you to add helper methods and computed parameters easily, makes the configuration testable.
The anyway_config
gem takes care of loading parameters from different sources (YAML, credentials/secrets, environment variables, etc.). Internally, we use a pipeline pattern and provide the Loaders API to manage and extend its functionality.
Check out the libraries using Anyway Config for more examples:
Adding to a gem:
# my-cool-gem.gemspec
Gem::Specification.new do |spec|
# ...
spec.add_dependency "anyway_config", ">= 2.0.0"
# ...
end
Or adding to your project:
# Gemfile
gem "anyway_config", "~> 2.0"
- Ruby (MRI) >= 2.5.0
- JRuby >= 9.2.9
Using configuration classes allows you to make configuration data a bit more than a bag of values: you can define a schema for your configuration, provide defaults, add validations and additional helper methods.
Anyway Config provides a base class to inherit from with a few DSL methods:
require "anyway_config"
module MyCoolGem
class Config < Anyway::Config
attr_config user: "root", password: "root", host: "localhost"
end
end
Here attr_config
creates accessors and populates the default values. If you don't need default values you can write:
attr_config :user, :password, host: "localhost", options: {}
NOTE: it's safe to use non-primitive default values (like Hashes or Arrays) without worrying about their mutation: the values would be deeply duplicated for each config instance.
Then, create an instance of the config class and use it:
MyCoolGem::Config.new.user #=> "root"
Bonus:: if you define attributes with boolean default values (false
or true
), Anyway Config would automatically add a corresponding predicate method. For example:
attr_config :user, :password, debug: false
MyCoolGem::Config.new.debug? #=> false
MyCoolGem::Config.new(debug: true).debug? #=> true
NOTE: since v2.0 accessors created by attr_config
are not attr_accessor
, i.e. they do not populate instance variables. If you used instance variables before to override readers, you must switch to using super
or values
store:
class MyConfig < Anyway::Config
attr_config :host, :port, :url, :meta
# override writer to handle type coercion
def meta=(val)
super JSON.parse(val)
end
# or override reader to handle missing values
def url
super || (self.url = "#{host}:#{port}")
end
# untill v2.1, it will still be possible to read instance variables,
# i.e. the following code would also work
def url
@url ||= "#{host}:#{port}"
end
end
We recommend to add a feature check and support both v1.x and v2.0 in gems for the time being:
# Check for the class method added in 2.0, e.g., `.on_load`
if respond_to?(:on_load)
def url
super || (self.url = "#{host}:#{port}")
end
else
def url
@url ||= "#{host}:#{port}"
end
end
Anyway Config relies on the notion of config name to populate data.
By default, Anyway Config uses the config class name to infer the config name using the following rules:
- if the class name has a form of
<Module>::Config
then use the module name (SomeModule::Config => "somemodule"
) - if the class name has a form of
<Something>Config
then use the class name prefix (SomeConfig => "some"
)
NOTE: in both cases, the config name is a downcased module/class prefix, not underscored.
You can also specify the config name explicitly (it's required in cases when your class name doesn't match any of the patterns above):
module MyCoolGem
class Config < Anyway::Config
config_name :cool
attr_config user: "root", password: "root", host: "localhost", options: {}
end
end
By default, Anyway Config uses upper-cased config name as a prefix for env variable names (e.g.
config_name :my_app
will result to parsing MY_APP_
prefix).
You can set env prefix explicitly:
module MyCoolGem
class Config < Anyway::Config
config_name :cool_gem
env_prefix :really_cool # now variables, starting wih `REALLY_COOL_`, will be parsed
attr_config user: "root", password: "root", host: "localhost", options: {}
end
end
Sometimes it's useful to set some parameters explicitly during config initialization.
You can do that by passing a Hash into .new
method:
config = MyCoolGem::Config.new(
user: "john",
password: "rubyisnotdead"
)
# The value would not be overridden from other sources (such as YML file, env)
config.user == "john"
There are #clear
and #reload
methods that do exactly what they state.
NOTE: #reload
also accepts an optional Hash for explicit values.
You can also fetch configuration without pre-defined schema:
# load data from config/my_app.yml,
# credentials.my_app, secrets.my_app (if using Rails), ENV["MY_APP_*"]
#
# Given MY_APP_VALUE=42
config = Anyway::Config.for(:my_app)
config["value"] #=> 42
# you can specify the config file path or env prefix
config = Anyway::Config.for(:my_app, config_path: "my_config.yml", env_prefix: "MYAPP")
This feature is similar to Rails.application.config_for
but more powerful:
Feature | Rails | Anyway Config |
---|---|---|
Load data from config/app.yml |
✅ | ✅ |
Load data from secrets |
❌ | ✅ |
Load data from credentials |
❌ | ✅ |
Load data from environment | ❌ | ✅ |
Load data from other sources | ❌ | ✅ |
Local config files | ❌ | ✅ |
Type coercion | ❌ | ✅ |
Source tracing | ❌ | ✅ |
Return Hash with indifferent access | ❌ | ✅ |
Support ERB* within config/app.yml |
✅ | ✅ |
Raise if file doesn't exist | ✅ | ❌ |
Works without Rails | 😀 | ✅ |
* Make sure that ERB is loaded
Anyway Config provides basic ways of ensuring that the configuration is valid.
There is a built-in required
class method to define the list of parameters that must be present in the
configuration after loading (where present means non-nil
and non-empty for strings):
class MyConfig < Anyway::Config
attr_config :api_key, :api_secret, :debug
required :api_key, :api_secret
end
MyConfig.new(api_secret: "") #=> raises Anyway::Config::ValidationError
Required
method supports additional env
parameter which indicates necessity to run validations under specified
environments. Env
parameter could be present in symbol, string, array or hash formats:
class EnvConfig < Anyway::Config
required :password, env: "production"
required :maps_api_key, env: :production
required :smtp_host, env: %i[production staging]
required :aws_bucket, env: %w[production staging]
required :anycable_rpc_host, env: {except: :development}
required :anycable_redis_url, env: {except: %i[development test]}
required :anycable_broadcast_adapter, env: {except: %w[development test]}
end
If your current Anyway::Settings.current_environment
is mismatch keys that specified
Anyway::Config::ValidationError
error will be raised.
If you need more complex validation or need to manipulate with config state right after it has been loaded, you can use on load callbacks and #raise_validation_error
method:
class MyConfig < Anyway::Config
attr_config :api_key, :api_secret, :mode
# on_load macro accepts symbol method names
on_load :ensure_mode_is_valid
# or block
on_load do
# the block is evaluated in the context of the config
raise_validation_error("API key and/or secret could be blank") if
api_key.blank? || api_secret.blank?
end
def ensure_mode_is_valid
unless %w[production test].include?(mode)
raise_validation_error "Unknown mode; #{mode}"
end
end
end
NOTE: version 2.x supports Rails >= 5.0; for Rails 4.x use version 1.x of the gem.
We recommend going through Data population and Organizing configs sections first, and then use Rails generators to make your application Anyway Config-ready.
Your config is filled up with values from the following sources (ordered by priority from low to high):
- YAML configuration files:
RAILS_ROOT/config/my_cool_gem.yml
.
Rails environment is used as the namespace (required); supports ERB
:
test:
host: localhost
port: 3002
development:
host: localhost
port: 3000
NOTE: You can override the environment name for configuration files via the ANYWAY_ENV
environment variable or by setting it explicitly in the code: Anyway::Settings.current_environment = "some_other_env"
.
⚡️ This feature will be turned on by default in the future releases. You can turn it on now via config.anyway_config.future.use :unwrap_known_environments
.
If the YML does not have keys that are one of the "known" Rails environments (development, production, test)—the same configuration will be available in all environments, similar to non-Rails behavior:
host: localhost
port: 3002
# These values will be active in all environments
To extend the list of known environments, use the setting in the relevant part of your Rails code:
Rails.application.config.anyway_config.known_environments << "staging"
If your YML defines at least a single "environmental" top-level, you have to separate all your settings per-environment. You can't mix and match:
staging:
host: localhost # This value will be loaded when Rails.env.staging? is true
port: 3002 # This value will not be loaded at all
To provide default values you can use YAML anchors, but they do not deep-merge settings, so Anyway Config provides a way to define a special top-level key for default values like this:
config.anyway_config.default_environmental_key = "default"
After that, Anyway Config will start reading settings under the "default"
key and then merge environmental settings into them.
default:
server: # This values will be loaded in all environments by default
host: localhost
port: 3002
staging:
server:
host: staging.example.com # This value will override the defaults when Rails.env.staging? is true
# port will be set to the value from the defaults — 3002
You can specify the lookup path for YAML files in one of the following ways:
- By setting
config.anyway_config.default_config_path
to a target directory path:
config.anyway_config.default_config_path = "/etc/configs"
config.anyway_config.default_config_path = Rails.root.join("etc", "configs")
- By setting
config.anyway_config.default_config_path
to a Proc, which accepts a config name and returns the path:
config.anyway_config.default_config_path = ->(name) { Rails.root.join("data", "configs", "#{name}.yml") }
- By overriding a specific config YML file path via the
<NAME>_CONF
env variable, e.g.,MYCOOLGEM_CONF=path/to/cool.yml
- (Rails <7.1) Rails secrets:
Rails.application.secrets.my_cool_gem
(ifsecrets.yml
present).
# config/secrets.yml
development:
my_cool_gem:
port: 4444
NOTE: If you want to use secrets with Rails 7.1 (still supported, but deprecated) you must add the corresponding loader manually: Anyway.loaders.insert_after :yml, :secrets, Anyway::Rails::Loaders::Secrets
.
- Rails credentials:
Rails.application.credentials.my_cool_gem
(if supported):
my_cool_gem:
host: secret.host
NOTE: You can backport Rails 6 per-environment credentials to Rails 5.2 app using this patch.
- Environment variables:
ENV['MYCOOLGEM_*']
.
You can store application-level config classes in app/configs
folder just like any other Rails entities.
However, in that case you won't be able to use them during the application initialization (i.e., in config/**/*.rb
files).
Since that's a pretty common scenario, we provide a way to do that via a custom autoloader for config/configs
folder.
That means, that you can put your configuration classes into config/configs
folder, use them anywhere in your code without explicitly requiring them.
Consider an example: setting the Action Mailer hostname for Heroku review apps.
We have the following config to fetch the Heroku provided metadata:
# This data is provided by Heroku Dyno Metadadata add-on.
class HerokuConfig < Anyway::Config
attr_config :app_id, :app_name,
:dyno_id, :release_version,
:slug_commit
def hostname
"#{app_name}.herokuapp.com"
end
end
Then in config/application.rb
you can do the following:
config.action_mailer.default_url_options = {host: HerokuConfig.new.hostname}
You can configure the configs folder path:
# The path must be relative to Rails root
config.anyway_config.autoload_static_config_path = "path/to/configs"
NOTE: Configs loaded from the autoload_static_config_path
are not reloaded in development. We call them static. So, it makes sense to keep only configs necessary for initialization in this folder. Other configs, dynamic, could be stored in app/configs
.
Or you can store everything in app/configs
by setting config.anyway_config.autoload_static_config_path = "app/configs"
.
NOTE 2: Since static configs are loaded before initializers, it's not possible to use custom inflection Rules (usually defined in config/initializers/inflections.rb
) to resolve constant names from files. If you rely on custom inflection rules (see, for example, #81), we recommend configuration Rails inflector before initialization as well:
# config/application.rb
# ...
require_relative "initializers/inflections"
module SomeApp
class Application < Rails::Application
# ...
end
end
Anyway Config provides Rails generators to create new config classes:
rails g anyway:install
—creates anApplicationConfig
class (the base class for all config classes) and updates.gitignore
You can specify the static configs path via the --configs-path
option:
rails g anyway:install --configs-path=config/settings
# or to keep everything in app/configs
rails g anyway:install --configs-path=app/configs
rails g anyway:config <name> param1 param2 ...
—creates a named configuration class and optionally the corresponding YAML file; createsapplication_config.rb
is missing.
The generator command for the Heroku example above would be:
$ rails g anyway:config heroku app_id app_name dyno_id release_version slug_commit
generate anyway:install
rails generate anyway:install
create config/configs/application_config.rb
append .gitignore
create config/configs/heroku_config.rb
Would you like to generate a heroku.yml file? (Y/n) n
You can also specify the --app
option to put the newly created class into app/configs
folder.
Alternatively, you can call rails g anyway:app_config name param1 param2 ...
.
NOTE: The generated ApplicationConfig
class uses a singleton pattern along with delegate_missing_to
to re-use the same instance across the application. However, the delegation can lead to unexpected behaviour and break Anyway Config internals if you have attributes named as Anyway::Config
class methods. See #120.
Anyway Config activates Rails-specific features automatically on the gem load only if Rails has been already required (we check for the Rails::VERSION
constant presence). However, in some cases you may want to use Anyway Config before Rails initialization (e.g., in config/puma.rb
when starting a Puma web server).
By default, Anyway Config sets up a hook (via TracePoint API) and waits for Rails to be loaded to require the Rails extensions (require "anyway/rails"
). In case you load Rails after Anyway Config, you will see a warning telling you about that. Note that config classes loaded before Rails are not populated from Rails-specific data sources (e.g., credentials).
You can disable the warning by setting Anyway::Rails.disable_postponed_load_warning = true
in your application. Also, you can disable the hook completely by calling Anyway::Rails.tracer.disable
.
The default data loading mechanism for non-Rails applications is the following (ordered by priority from low to high):
- YAML configuration files:
./config/<config-name>.yml
.
In pure Ruby apps, we also can load data under specific environments (test
, development
, production
, etc.).
If you want to enable this feature you must specify Anyway::Settings.current_environment
variable for load config under specific environment.
Anyway::Settings.current_environment = "development"
You can also specify the ANYWAY_ENV=development
environment variable to set the current environment for configuration.
YAML files should be in this format:
development:
host: localhost
port: 3000
If Anyway::Settings.current_environment
is missed we assume that the YAML contains values for a single environment:
host: localhost
port: 3000
ERB
is supported if erb
is loaded (thus, you need to call require "erb"
somewhere before loading configuration).
You can specify the lookup path for YAML files in one of the following ways:
- By setting
Anyway::Settings.default_config_path
to a target directory path:
Anyway::Settings.default_config_path = "/etc/configs"
- By setting
Anyway::Settings.default_config_path
to a Proc, which accepts a config name and returns the path:
Anyway::Settings.default_config_path = ->(name) { Rails.root.join("data", "configs", "#{name}.yml") }
- By overriding a specific config YML file path via the
<NAME>_CONF
env variable, e.g.,MYCOOLGEM_CONF=path/to/cool.yml
- Environment variables:
ENV['MYCOOLGEM_*']
.
Environmental variables for your config should start with your config name, upper-cased.
For example, if your config name is "mycoolgem", then the env var "MYCOOLGEM_PASSWORD" is used as config.password
.
By default, environment variables are automatically type cast (rules are case-insensitive):
"true"
,"t"
,"yes"
and"y"
totrue
;"false"
,"f"
,"no"
and"n"
tofalse
;"nil"
and"null"
tonil
(do you really need it?);"123"
to123
and"3.14"
to3.14
.
Type coercion can be customized or disabled.
Anyway Config supports nested (hashed) env variables—just separate keys with double-underscore.
For example, "MYCOOLGEM_OPTIONS__VERBOSE" is parsed as config.options["verbose"]
.
Array values are also supported:
# Suppose ENV["MYCOOLGEM_IDS"] = '1,2,3'
config.ids #=> [1,2,3]
If you want to provide a text-like env variable which contains commas then wrap it into quotes:
MYCOOLGEM = "Nif-Nif, Naf-Naf and Nouf-Nouf"
🆕 v2.2.0
You can define custom type coercion rules to convert string data to config values. To do that, use .coerce_types
method:
class CoolConfig < Anyway::Config
config_name :cool
attr_config port: 8080,
host: "localhost",
user: {name: "admin", password: "admin"}
coerce_types port: :string, user: {dob: :date}
end
ENV["COOL_USER__DOB"] = "1989-07-01"
config = CoolConfig.new
config.port == "8080" # Even though we defined the default value as int, it's converted into a string
config.user["dob"] == Date.new(1989, 7, 1) #=> true
Type coercion is especially useful to deal with array values:
# To define an array type, provide a hash with two keys:
# - type — elements type
# - array: true — mark the parameter as array
coerce_types list: {type: :string, array: true}
You can use type: nil
in case you don't want to coerce values, just convert a value into an array:
# From AnyCable config (sentinels could be represented via strings or hashes)
coerce_types redis_sentinels: {type: nil, array: true}
It's also could be useful to explicitly define non-array types (to avoid confusion):
coerce_types non_list: :string
Finally, it's possible to disable auto-casting for a particular config completely:
class CoolConfig < Anyway::Config
attr_config port: 8080,
host: "localhost",
user: {name: "admin", password: "admin"}
disable_auto_cast!
end
ENV["COOL_PORT"] = "443"
CoolConfig.new.port == "443" #=> true
IMPORTANT: Values provided explicitly (via attribute writers) are not coerced. Coercion is only happening during the load phase.
The following types are supported out-of-the-box: :string
, :integer
, :float
, :date
, :datetime
, :uri
, :boolean
.
You can use custom deserializers by passing a callable object instead of a type name:
COLOR_TO_HEX = lambda do |raw|
case raw
when "red"
"#ff0000"
when "green"
"#00ff00"
when "blue"
"#0000ff"
end
end
class CoolConfig < Anyway::Config
attr_config :color
coerce_types color: COLOR_TO_HEX
end
CoolConfig.new({color: "red"}).color #=> "#ff0000"
It's useful to have a personal, user-specific configuration in development, which extends the project-wide one.
We support this by looking at local files when loading the configuration data:
<config_name>.local.yml
files (next to* the global<config_name>.yml
)config/credentials/local.yml.enc
(for Rails >= 7.1, generate it viarails local_credentials:edit
; for Rails >= 6.0, <7.1 you can also userails credentials:edit -e local
).
* If the YAML config path is not a default one (i.e., set via <CONFIG_NAME>_CONF
), we look up the local
config at this location, too.
Local configs are meant for using in development and only loaded if Anyway::Settings.use_local_files
is true
(which is true by default if RACK_ENV
or RAILS_ENV
env variable is equal to "development"
).
NOTE: in Rails apps you can use Rails.application.configuration.anyway_config.use_local_files
.
Don't forget to add *.local.yml
(and config/credentials/local.*
) to your .gitignore
.
NOTE: local YAML configs for a Rails app must be environment-free (i.e., you shouldn't have top-level development:
key).
Anyway Config can pull configuration data from Doppler. All you need is to specify the DOPPLER_TOKEN
environment variable with the service token, associated with the specific content (read more about service tokens).
You can also configure Doppler loader manually if needed:
# Add loader
Anyway.loaders.append :Doppler, Anyway::Loaders::Doppler
# Configure API URL and token (defaults are shown)
Anyway::Loaders::Doppler.download_url = "https://api.doppler.com/v3/configs/config/secrets/download"
Anyway::Loaders::Doppler.token = ENV["DOPPLER_TOKEN"]
NOTE: You can opt-out from Doppler loader by specifying theANYWAY_CONFIG_DISABLE_DOPPLER=true
env var (in case you have the DOPPLER_TOKEN
env var, but don't want to use it with Anyway Config).
Anyway Config allows you to keep your configuration also in encrypted .ejson
files. More information
about EJSON format you can read here.
Configuration will be loaded only if you have ejson
executable in your PATH. Easiest way to do this - install ejson
as a gem into project:
# Gemfile
gem "ejson"
Loading order of configuration is next:
config/secrets.local.ejson
(see Local files for more information)config/<environment>/secrets.ejson
(if you have any multi-environment setup, e.g Rails environments)config/secrets.ejson
Example of config/secrets.ejson
file content for your MyConfig
:
{
"_public_key": "0843d33f0eee994adc66b939fe4ef569e4c97db84e238ff581934ee599e19d1a",
"my":
{
"_username": "root",
"password": "EJ[1:IC1d347GkxLXdZ0KrjGaY+ljlsK1BmK7CobFt6iOLgE=:Z55OYS1+On0xEBvxUaIOdv/mE2r6lp44:T7bE5hkAbazBnnH6M8bfVcv8TOQJAgUDQffEgw==]"
}
}
To debug any problems with loading configurations from .ejson
files you can directly call ejson decrypt
:
ejson decrypt config/secrets.ejson
You can customize the JSON namespace under which a loader searches for configuration via loader_options
:
class MyConfig < Anyway::Config
# To look under the key "foo" instead of the default key of "my"
loader_options ejson_namespace: "foo"
# Or to disable namespacing entirely, and instead search in the root object
loader_options ejson_namespace: false
end
You can provide your own data loaders or change the existing ones using the Loaders API (which is very similar to Rack middleware builder):
# remove env loader => do not load params from ENV
Anyway.loaders.delete :env
# add custom loader before :env (it's better to keep the ENV loader the last one)
Anyway.loaders.insert_before :env, :my_loader, MyLoader
Loader is a callable Ruby object (module/class responding to .call
or lambda/proc), which call
method
accepts the following keyword arguments:
def call(
name:, # config name
env_prefix:, # prefix for env vars if any
config_path:, # path to YML config
local:, # true|false, whether to load local configuration
**options # custom options can be passed via Anyway::Config.loader_options example: "custom", option: "blah"
)
#=> must return Hash with configuration data
end
You can use Anyway::Loaders::Base
as a base class for your loader and define a #call
method.
For example, the Chamber loader could be written as follows:
class ChamberConfigLoader < Base
def call(name:, **_opts)
Chamber.to_hash[name] || {}
rescue Chamber::Errors::DecryptionFailure => e
warn "Couldn't decrypt Chamber settings: #{e.message}"
{}
end
end
# Don't forget to register it
Anyway.loaders.insert_before :env, :chamber, ChamberConfigLoader
In order to support source tracing, you need to wrap the resulting Hash via the #trace!
method with metadata:
def call(name:, **_opts)
trace!(:chamber) do
Chamber.to_hash[name] || {}
rescue Chamber::Errors::DecryptionFailure => e
warn "Couldn't decrypt Chamber settings: #{e.message}"
{}
end
end
Since Anyway Config loads data from multiple source, it could be useful to know where a particular value came from.
Each Anyway::Config
instance contains tracing information which you can access via #to_source_trace
method:
conf = ExampleConfig.new
conf.to_source_trace
# returns the following hash
{
"host" => {value: "test.host", source: {type: :yml, path: "config/example.yml"}},
"user" => {
"name" => {value: "john", source: {type: :env, key: "EXAMPLE_USER__NAME"}},
"password" => {value: "root", source: {type: :credentials, store: "config/credentials/production.enc.yml"}}
},
"port" => {value: 9292, source: {type: :defaults}}
}
# if you change the value manually in your code,
# that would be reflected in the trace
conf.host = "anyway.host"
conf.to_source_trace["host"]
#=> {type: :user, called_from: "/path/to/caller.rb:15"}
You can disable tracing functionality by setting Anyway::Settings.tracing_enabled = false
or config.anyway_config.tracing_enabled = false
in Rails.
You can use pp
to print a formatted information about the config including the sources trace.
Example:
pp CoolConfig.new
# #<CoolConfig
# config_name="cool"
# env_prefix="COOL"
# values:
# port => 3334 (type=load),
# host => "test.host" (type=yml path=./config/cool.yml),
# user =>
# name => "john" (type=env key=COOL_USER__NAME),
# password => "root" (type=yml path=./config/cool.yml)>
You can use config instances in Ruby 2.7+ pattern matching:
case AWSConfig.new
in bucket:, region: "eu-west-1"
setup_eu_storage(bucket)
in bucket:, region: "us-east-1"
setup_us_storage(bucket)
end
If the attribute wasn't populated, the key won't be returned for pattern matching, i.e. you can do something line:
aws_configured =
case AWSConfig.new
in access_key_id:, secret_access_key:
true
else
false
end
We provide the with_env
test helper to test code in the context of the specified environment variables values:
describe HerokuConfig, type: :config do
subject { described_class.new }
specify do
# Ensure that the env vars are set to the specified
# values within the block and reset to the previous values
# outside of it.
with_env(
"HEROKU_APP_NAME" => "kin-web-staging",
"HEROKU_APP_ID" => "abc123",
"HEROKU_DYNO_ID" => "ddyy",
"HEROKU_RELEASE_VERSION" => "v0",
"HEROKU_SLUG_COMMIT" => "3e4d5a"
) do
is_expected.to have_attributes(
app_name: "kin-web-staging",
app_id: "abc123",
dyno_id: "ddyy",
release_version: "v0",
slug_commit: "3e4d5a"
)
end
end
end
If you want to delete the env var, pass nil
as the value.
This helper is automatically included to RSpec if RAILS_ENV
or RACK_ENV
env variable is equal to "test". It's only available for the example with the tag type: :config
or with the path spec/configs/...
.
You can add it manually by requiring "anyway/testing/helpers"
and including the Anyway::Testing::Helpers
module (into RSpec configuration or Minitest test class).
It's possible to use config as option parser (e.g., for CLI apps/libraries). It uses
optparse
under the hood.
Example usage:
class MyConfig < Anyway::Config
attr_config :host, :log_level, :concurrency, :debug, server_args: {}
# specify which options shouldn't be handled by option parser
ignore_options :server_args
# provide description for options
describe_options(
concurrency: "number of threads to use"
)
# mark some options as flag
flag_options :debug
# extend an option parser object (i.e. add banner or version/help handlers)
extend_options do |parser, config|
parser.banner = "mycli [options]"
parser.on("--server-args VALUE") do |value|
config.server_args = JSON.parse(value)
end
parser.on_tail "-h", "--help" do
puts parser
end
end
end
config = MyConfig.new
config.parse_options!(%w[--host localhost --port 3333 --log-level debug])
config.host # => "localhost"
config.port # => 3333
config.log_level # => "debug"
# Get the instance of OptionParser
config.option_parser
NOTE: values are automatically type cast using the same rules as for environment variables.
If you want to specify the type explicitly, you can do that using describe_options
:
describe_options(
# In this case, you should specify a hash with `type`
# and (optionally) `desc` keys
concurrency: {
desc: "number of threads to use",
type: String
}
)
Anyway Config comes with Ruby type signatures (RBS).
To use them with Steep, add the following your Steepfile
:
library "pathname"
library "optparse"
library "anyway_config"
We also provide an API to generate a type signature for your config class:
class MyGem::Config < Anyway::Config
attr_config :host, port: 8080, tags: [], debug: false
coerce_types host: :string, port: :integer,
tags: {type: :string, array: true}
required :host
end
Then calling MyGem::Config.to_rbs
will return the following signature:
module MyGem
interface _Config
def host: () -> String
def host=: (String) -> void
def port: () -> String?
def port=: (String) -> void
def tags: () -> Array[String]?
def tags=: (Array[String]) -> void
def debug: () -> bool
def debug?: () -> bool
def debug=: (bool) -> void
end
class Config < Anyway::Config
include _Config
end
end
When we use on_load
callback with a block, we switch the context (via instance_eval
), and we need to provide type hints for the type checker. Here is an example:
class MyConfig < Anyway::Config
on_load do
# @type self : MyConfig
raise_validation_error("host is invalid") if host.start_with?("localhost")
end
end
Yeah, a lot of annotations 😞 Welcome to the type-safe world!
Bug reports and pull requests are welcome on GitHub at https://github.com/palkan/anyway_config.
The gem is available as open source under the terms of the MIT License.