Blinkist::Config

This GEM allows you to access configuration stores with different adapters. Here're some examples of usage:

Using the ENV

# First setup the Config to use the ENV as config store

Diplomat.configure do |config|
  config.url = "http://172.17.0.1:8500"
end

Blinkist::Config.env = ENV["RAILS_ENV"]
Blinkist::Config.app_name = "my_nice_app"
Blinkist::Config.adapter_type = :env
Blinkist::Config.error_handler = :strict

my_config_value = Blinkist::Config.get! "some/folder/config"

# This is being translated to ENV["SOME_FOLDER_CONFIG"]

Error handling

When configured with Blinkist::Config.error_handler = :strict (as recommended) reading a configuration entry for which the value is missing (for example missing enviroment variables) will cause Blinkist::Config::ValueMissingError to be raised.

There is also an alternative mode Blinkist::Config.error_handler = :heuristic which will raise exceptions only when Blinkist::Config.env == "production".

This alternative mode is also the default for compatibility.

Having a default value

If you don't want Blinkist::Config.get! to scream at you for missing configuration entries then you canprovide a default value as a second paramter to get!:

my_config_value = Blinkist::Config.get! "some/folder/config", "default value"

# If ENV["SOME_FOLDER_CONFIG"] is nil, "default value" will be returned

Using Diplomat & Consul

If you want to use Consul's key value store, simply use our diplomat adapter.

• https://www.consul.io/
• https://github.com/WeAreFarmGeek/diplomat

The GEM expects consul to listen to http://172.17.0.1:8500

# First setup the Config to use the ENV as config store
Blinkist::Config.env = ENV["RAILS_ENV"]
Blinkist::Config.app_name = "my_nice_app"
Blinkist::Config.adapter_type = ENV["CONSUL_AVAILABLE"] == "true" ? :diplomat : :env

my_config_value = Blinkist::Config.get! "some/folder/config"

# This is will try to get a value from Consul's KV store at "my_nice_app/some/folder/config"

Using Diplomat with a folder scope

# Here we setting a scope outside of the app

my_config_value = Blinkist::Config.get! "another/config", scope: "global"

# This will replace `my_nice_app` with `global` and try to resolve "global/another/config"
# With :env the scope will simply be ignored

Using AWS SSM

If you want to use EC2's key value store SSM, simply use our aws_ssm adapter. It'll automatically try to decrypt all keys.

The GEM expects the code to run in an AWS environment with properly set up IAM.

Blinkist::Config.env = ENV["RAILS_ENV"]
Blinkist::Config.app_name = "my_nice_app"
Blinkist::Config.adapter_type = ENV["SSM_AVAILABLE"] == "true" ? :aws_ssm : :env

my_config_value = Blinkist::Config.get! "some/folder/config"

# This is will try to get a parameter from SSM at "/application/my_nice_app/some/folder/config"

# You can also preload all parameters to avoid later calls to SSM
Blinkist::Config.preload
Blinkist::Config.preload scope: "global" # in case you need also another scope being preloaded

Using SSM with a folder scope

# Here we setting a scope outside of the app

my_config_value = Blinkist::Config.get! "another/config", scope: "global"

# This will replace `my_nice_app` with `global` and try to resolve "/application/global/another/config"

Installation

Add this line to your application's Gemfile:

gem "blinkist-config"

Usage

You have to set up the GEM before you can use it. The basic setup requires this

Blinkist::Config.env = "production" || "test" || "development"
Blinkist::Config.app_name = "your_app_name" # Used only with diplomat adapter
Blinkist::Config.adapter_type = :diplomat || :env

It's best to drop a config.rb into your app and load this file before every other file. In Rails you can link it into your application.rb

require_relative "boot"
require_relative "config"

require "rails"
# ...

Development

You can build this project easily with docker compose.

docker-compose run rake

This will execute rake and run all specs by auto correcting the code with rubocop.

If you're ready to tag a new version, do this

docker-compose run gem bump -t -v major|minor|patch

To deploy to rubygems.org do this then

docker-compose run gem release

You'll have to have proper rights to access rubygems.org

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/blinkist/blinkist-config.

License

The gem is available as open source under the terms of the MIT License.