RrxConfig

Ruby on Rails application configuration support.

Installation

Install the gem and add to the application's Gemfile by executing:

$ bundle add rrx_config

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install rrx_config

Usage

This gem loads runtime application configuration from JSON provided by an external source. Configurations are stored as immutable Ruby Data objects.

For example, with the JSON config

{
  "some_config": {
    "value": "foo"
  },
  "other_config_value": "bar"
}

The config would be accessed like this:

def my_code
  if RrxConfig.some_config.value == 'foo'
    do_something RrxConfig.other_config_value
  end
end

You can test for optional values using standard mechanisms:

optional_stuff if RrxConfig.respond_to?(:optional_thing)
deep_optional_stuff if RrxConfig.optional_thing.include?(:deep_thoughts)

optional_flag = RrxConfig.try(:optional).try(:flag) || DEFAULT_FLAG

# Root-level configs can also be tested with the xxxx? syntax
optional_stuff if RrxConfig.optional_thing?

Configuration Sources

Environment

Set the RRX_CONFIG environment variable to the required JSON configuration

AWS

Loads configuration from an AWS secret that contains the required JSON configuration. Recommended when deploying on AWS. By default will use the implicit AWS context that is assigned by the instance role.

Set the RRX_CONFIG_AWS_SECRET environment variable to the name of the secret to read.

For local integration testing, set RRX_AWS_PROFILE to use local AWS credentials. The profile must be configured in the local AWS client (typically ~/.aws/credentials).

Local File Configuration

For development purposes, the gem will also check for the following files:

• {rails_root}/spec/spec_config.json if RAILS_ENV=test
• {rails_root}/local_config.json

Database Support

If the loaded config contains a root-level database item then it will be used to configure the application database instead of database.yml.

AWS RDS IAM Authentication

The gem also adds support for AWS RDS authentication using IAM to MySQL/MariaDB databases. If the RDS instance and user account has been configured correctly, replace the password argument with iam: true. This is supported using the database configuration or database.yml.

The gem will automatically download the required CA certificates and set the necessary client options.

Using JSON configuration:

{
  "database": {
    "adapter": "mysql2",
    "host": "rds-db-address...rds.amazonaws.com",
    "port": 3306,
    "username": "my_app_user",
    "iam": true
  }
}

Using database.yml:

production:
  adapter: mysql2
  host: rds-db-address...rds.amazonaws.com
  port: 3306
  username: my_app_user
  iam: true

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/rails-rrx/rrx_config. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

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

Code of Conduct

Everyone interacting in the RrxConfig project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.