Amazon Simple Storage Service
Developer Guide (API Version 2006-03-01)

Making Requests Using IAM User Temporary Credentials - AWS SDK for Ruby

An IAM user or an AWS account can request temporary security credentials using AWS SDK for Ruby and use them to access Amazon S3. These credentials expire after the session duration. By default, the session duration is one hour. If you use IAM user credentials, you can specify the duration (from 1 to 36 hours) when requesting the temporary security credentials. For information about requesting temporary security credentials, see Making Requests.


If you obtain temporary security credentials using your AWS account security credentials, the temporary security credentials are valid for only one hour. You can specify session duration only if you use IAM user credentials to request a session.

The following Ruby example creates a temporary user to list the items in a specified bucket for one hour. To use this example, you must have AWS credentials that have the necessary permissions to create new AWS Security Token Service (AWS STS) clients, and list Amazon S3 buckets.

require 'aws-sdk-core' require 'aws-sdk-s3' require 'aws-sdk-iam' USAGE = <<DOC Usage: assumerole_create_bucket_policy.rb -b BUCKET -u USER [-r REGION] [-d] [-h] Assumes a role for USER to list items in BUCKET for one hour. BUCKET is required and must already exist. USER is required and if not found, is created. If REGION is not supplied, defaults to us-west-2. -d gives you extra (debugging) information. -h displays this message and quits. DOC $debug = false def print_debug(s) if $debug puts s end end def get_user(region, user_name, create) user = nil iam = 'us-west-2') begin user = iam.create_user(user_name: user_name) iam.wait_until(:user_exists, user_name: user_name) print_debug("Created new user #{user_name}") rescue Aws::IAM::Errors::EntityAlreadyExists print_debug("Found user #{user_name} in region #{region}") end end # main region = 'us-west-2' user_name = '' bucket_name = '' i = 0 while i < ARGV.length case ARGV[i] when '-b' i += 1 bucket_name = ARGV[i] when '-u' i += 1 user_name = ARGV[i] when '-r' i += 1 region = ARGV[i] when '-d' puts 'Debugging enabled' $debug = true when '-h' puts USAGE exit 0 else puts 'Unrecognized option: ' + ARGV[i] puts USAGE exit 1 end i += 1 end if bucket_name == '' puts 'You must supply a bucket name' puts USAGE exit 1 end if user_name == '' puts 'You must supply a user name' puts USAGE exit 1 end #Identify the IAM user that is allowed to list Amazon S3 bucket items for an hour. user = get_user(region, user_name, true) # Create a new Amazon STS client and get temporary credentials. This uses a role that was already created. creds = client: region), role_arn: "arn:aws:iam::111122223333:role/assumedrolelist", role_session_name: "assumerole-s3-list" ) # Create an Amazon S3 resource with temporary credentials. s3 = region, credentials: creds) puts "Contents of '%s':" % bucket_name puts ' Name => GUID' s3.bucket(bucket_name).objects.limit(50).each do |obj| puts " #{obj.key} => #{obj.etag}" end