Installation

We can install the AWS SDK for Ruby with rubygems as:

gem install aws-sdk

Or can be used as bundler by adding:
 gem 'aws-sdk', '~> 1.0' 

Basic Configuration

Configuring to use AWS services:

AWS.config(access_key_id: '...', secret_access_key: '...') 

Or can be configure for a particular service as:-

EC2 = AWS::EC2.new(access_key_id: '...', secret_access_key: '...)

CW = AWS::CloudWatch.new(access_key_id: '...', secret_access_key: '...)    

IAM = AWS::IAM.new(access_key_id: '...', secret_access_key: '...) 

Basic Usage

Each service provides a service interface and a client.

ec2 = AWS.ec2 #=> AWS::EC2
ec2.client #=> AWS::EC2::Client 

The client provides one method for each API operation.  The client methods
accept a hash of request params and return a response with a hash of
response data. The service interfaces provide a higher level abstration built using the client. 

Example: list instance tags using a client 

resp = EC2.client.describe_tags(filters: [{ name: "resource-id", values: ["i-12345678"] }])
resp[:tag_set].first