New ExAws IAM service module

I wrote an IAM service module for ExAws. You can find it on GitHub.

It’s a work in progress, but I think I have the internal API figured out. Currently, the following services are supported:

* CreateAccessKey
* CreateUser
* DeleteAccessKey
* DeleteUser
* GetAccessKeyLastUsed
* GetUser
* ListAccessKeys
* ListUsers
* UpdateAccessKey
* UpdateUser

The API aims to be easy to use. For example:

1. You can pass params as atoms and the lib converts them into the AWS IAM query format.
2. Each operation has its own parser that translates the XML response into its equivalent map in Elixir.
3. Helper functions are available to convert some responses into a data structure.

op = Iam.create_user("my_user", path: "/my/path/")

IO.inspect(op)
%ExAws.Operation.Query{
  action: "CreateUser",
  params: %{
    "Action" => "CreateUser",
    "Path" => "/my/path/",
    "UserName" => "my_user",
    "Version" => "2010-05-08"
  },
  parser: &ExAws.Iam.Parsers.User.create/2,
  path: "/my/path/",
  service: :iam
}

user = op |> ExAws.request() |> Iam.to_user()

IO.inspect(user)
%ExAws.Iam.User{
  arn: "arn:aws:iam::085326204011:user/my/path/my_user",
  create_date: "2018-10-18T15:47:08Z",
  path: "/my/path/",
  user_id: "AIDAIH3RMDWGIGEXAMPLE",
  username: "my_user"
}

Extending the library is straightforward. For example, adding a new operation is as easy as:

def create_group(name, opts \\ []) do
  :create_group
  |> to_params(opts, [group_name: name])
  |> to_op() 
end
Iam.create_group("my_group", path: "/my/path/")

You may need to write a parser, and, obviously, some tests, but it’s as easy as that.

I’ve not released the lib yet as I’d like to wait for some feedback before doing so.