AwsSu

AwsSu is a gem developed for a specific use case, where the user has an ID setup in an AWS master account and wants to assume a role in another account that they have permission to assume.

Add this line to your application's Gemfile:

  gem 'aws_su'

And then execute:

$ bundle

Or install it yourself as:

$ gem install aws_su

Implemented as a Ruby Module, the gem can be included into any class that needs to authenticate and assume a role prior to calling one of the aws client methods like so:

    require 'aws_su'
    
    class RunAwsSu
      include AwsSu
    end
    
    run_aws_su = RunAwsSu.new
    run_aws_su.authenticate(
      profile: 'ds-nonprod',
      duration: '28800',
      region: 'eu-west-2'
    )
    run_aws_su.ec2_client.describe_vpcs

The gem expects to find the standard aws secrets files:

• ~/.aws/credentials
• ~/.aws/config

With the former containing the master account secrets:

   aws_access_key_id = XXXXXXXXXXXXXX
   aws_secret_access_key = XXXXXXXXXXXXXXXXXXXX

And the latter containing the details of the role to be assumed:

    [profile my-profile]
    source_profile=master
    mfa_serial=arn:aws:iam::1234567890:mfa/bradley.atkins@bjss.com
    role_arn=arn:aws:iam::1234567890:role/MY-NONPROD-TESTER-ROLE

AwsSu also configures the current shell with the necessary environment variables to allow system calls to be made without further authentication:

  system('aws ec2 describe-vpcs --region eu-west-2')

Clients currently supported are:

• ec2_client
• elb_client
• iam_client
• sqs_client

After you use the authenticator, running the AWS CLI from the command line is possible via the assumed role if you add this function to your ~/.bashrc or ~/bash_profile file:

    function awssu() {
        while read line
        do
            export "${line}"
        done < ~/.awssudo
        export AWS_DEFAULT_REGION="${1:-eu-west-2}" # Change to your default region
    }

If you have a valid session still available then you can enter:

    awssu eu-west-1

The region is optional and will default to eu-west-2 unless you change the default in the function.

This will call the function which will export the contents of the environment variables and then you can run the CLI without further authentication.

After checking out the repo, run bin/setup to install dependencies. Then, run rake test 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 tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at The Github Repository. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

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

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