AWS SDK for Rubyにてcredentialsのprofile指定とassume role方法についてわかりづらかったので記載

↓profileはaws-cliで下記のように作成した際のもの

$ aws configure --profile hoge

profile指定

Clientの引数に渡すだけ
例：EC2

ec2 = Aws::EC2::Client.new(
  profile: "hoge",
  # ...
)

assume role

require 'aws-sdk-core'
require 'aws-sdk-ec2'

role_credentials = Aws::AssumeRoleCredentials.new(
  client: Aws::STS::Client.new(opts),
  role_arn: "arn:aws:iam::xxxxxxxxxxxx:role/hoge_role",
  role_session_name: hoge
)

ec2 = Aws::EC2::Client.new(
  credentials: role_credentials,
  # ...
)