ExAws.STS

Service module for https://github.com/ex-aws/ex_aws.

Installation

The package can be installed by adding :ex_aws_sts to your list of dependencies in mix.exs along with :ex_aws.

def deps do
  [
    {:ex_aws, "~> 2.2"},
    {:ex_aws_sts, "~> 2.2"},
  ]
end

Documentation can be found at https://hexdocs.pm/ex_aws_sts.

Role based authentication

Using the :awscli_auth_adapter option of ex_aws is supported, but requires additional dependencies:

{:sweet_xml, "~> 0.6"}
{:configparser_ex, "~> 2.0"}

Using AWS CLI config file with source profile

ExAws.STS allows to authentication based on role_arn and source_profile as specified in the awscli config file.

When specified in your ~/.aws/config you can set

config :ex_aws,
  secret_access_key: [{:awscli, "profile_name", 30}],
  access_key_id: [{:awscli, "profile_name", 30}],
  awscli_auth_adapter: ExAws.STS.AuthCache.AssumeRoleCredentialsAdapter

and if the profile profile_name sets a role_arn then this will make ExAws issue an AssumeRoleCredentials request to fetch the access_key_id and secret_access_key.

Using AWS CLI config from ENV vars

It is possible to inject the credentials by configuration, for example, by using ENV vars. This is very useful for containerized applications.

In order to do that, just place in the config the block awscli_credentials with your profile_name as key and the corresponding values. Then under access_key_id and secret_access_key just make a reference to the profile, so it will be used to ask for the credentials automatically.

config :ex_aws,
  access_key_id: [{:awscli, "default", 30}],
  secret_access_key: [{:awscli, "default", 30}],
  awscli_auth_adapter: ExAws.STS.AuthCache.AssumeRoleCredentialsAdapter,
  awscli_credentials: %{
    "default" => %{
      role_arn: {:system, "AWS_ROLE_ARN"},
      access_key_id: {:system, "AWS_ACCESS_KEY_ID"},
      secret_access_key: {:system, "AWS_SECRET_ACCESS_KEY"},
      source_profile: "default"
    }
  }

Using Web Identity tokens from ENV vars

Similarly, it is possible to use a web identity token to perform the assume role operation. It currently uses the following env vars to obtain it:

AWS_WEB_IDENTITY_TOKEN_FILE: path of the file with the web identity token AWS_ROLE_ARN: role to be assumed

config :ex_aws,
  secret_access_key: [{:awscli, "profile_name", 30}],
  access_key_id: [{:awscli, "profile_name", 30}],
  awscli_auth_adapter: ExAws.STS.AuthCache.AssumeRoleWebIdentityAdapter

License

The MIT License (MIT)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.