AWS SDK for Ruby - Version 2

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This is version 2 of the aws-sdk gem. Version 1 can be found in the aws-sdk-v1 branch.

Links of Interest

NameError: uninitialized constant AWS

If you receive this error, you likely have upgraded to version 2 of the aws-sdk gem unintentionally. Version 2 uses the Aws namespace, not AWS. This allows version 1 and version 2 to be used in the same application.


The AWS SDK for Ruby is available as the aws-sdk gem from RubyGems. Please use a major version when expressing a dependency on aws-sdk.

gem 'aws-sdk', '~> 2'


You need to configure :credentials and a :region to make API calls. It is recommended that you provide these via your environment. This makes it easier to rotate credentials and it keeps your secrets out of source control.

The SDK searches the following locations for credentials:

  • The shared credentials ini file at ~/.aws/credentials (more information)
  • From an instance profile when running on EC2

The SDK searches the following locations for a region:


The region is used to construct an SSL endpoint. If you need to connect to a non-standard endpoint, you may specify the :endpoint option.

Configuration Options

You can configure default credentials and region via Aws.config. In version 2, Aws.config is a vanilla Ruby hash, not a method like it was in version 1. The Aws.config hash takes precedence over environment variables.

require 'aws-sdk'

  region: 'us-west-2',
  credentials:'akid', 'secret')

Valid region and credentials options are:

You may also pass configuration options directly to resource and client constructors. These options take precedence over the environment and Aws.config defaults.

# resource constructors
ec2 ='us-west-2', credentials: credentials)

# client constructors
ec2 ='us-west-2', credentials: credentials)

Please take care to never commit credentials to source control. We strongly recommended loading credentials from an external source.

require 'aws-sdk'
require 'json'
creds = JSON.load('secrets.json'))
Aws.config[:credentials] =['AccessKeyId'], creds['SecretAccessKey'])

API Clients (aws-sdk-core gem)

Construct a service client to make API calls. Each client provides a 1-to-1 mapping of methods to API operations. Refer to the API documentation for a complete list of available methods.

# list buckets in Amazon S3
s3 =
resp = s3.list_buckets
#=> ["bucket-1", "bucket-2", ...]

API methods accept a hash of additional request parameters and return structured response data.

# list the first two objects in a bucket
resp = s3.list_objects(bucket: 'aws-sdk-core', max_keys: 2)
resp.contents.each do |object|
  puts "#{object.key} => #{object.etag}"

Paging Responses

Many AWS operations limit the number of results returned with each response. To make it easy to get the next page of results, every AWS response object is enumerable:

# yields one response object per API call made, this will enumerate
# EVERY object in the named bucket
s3.list_objects(bucket:'aws-sdk').each do |response|

If you prefer to control paging yourself, response objects have helper methods that control paging:

# make a request that returns a truncated response
resp = s3.list_objects(bucket:'aws-sdk')

resp.last_page? #=> false
resp.next_page? #=> true
resp = resp.next_page # send a request for the next response page
resp = resp.next_page until resp.last_page?


Waiters are utility methods that poll for a particular state. To invoke a waiter, call #wait_until on a client:

  ec2.wait_until(:instance_running, instance_ids:['i-12345678'])
  puts "instance running"
rescue Aws::Waiters::Errors::WaiterFailed => error
  puts "failed waiting for instance running: #{error.message}"

Waiters have sensible default polling intervals and maximum attempts. You can configure these per call to #wait_until. You can also register callbacks that are triggered before each polling attempt and before waiting. See the API documentation for more examples and for a list of supported waiters per service.

Resource Interfaces (aws-sdk-resources gem)

Resource interfaces are object oriented classes that represent actual resources in AWS. Resource interfaces built on top of API clients and provide additional functionality.

s3 =

# reference an existing bucket by name
bucket = s3.bucket('aws-sdk')

# enumerate every object in a bucket
bucket.objects.each do |obj|
  puts "#{obj.key} => #{obj.etag}"

# batch operations, delete objects in batches of 1k
bucket.objects(prefix: '/tmp-files/').delete

# single object operations
obj = bucket.object('hello')
obj.put(body:'Hello World!')

REPL - AWS Interactive Console

The aws-sdk-core gem ships with a REPL that provides a simple way to test the Ruby SDK. You can access the REPL by running aws.rb from the command line.

$ aws.rb
Aws> ec2.describe_instances.reservations.first.instances.first
[Aws::EC2::Client 200 0.216615 0 retries] describe_instances()
 state=<struct  code=16, name="running">,

You can enable HTTP wire logging by setting the verbose flag:

$ aws.rb -v

In the REPL, every service class has a helper that returns a new client object. Simply downcase the service module name for the helper:

  • Aws::S3 => s3
  • Aws::EC2 => ec2
  • etc


This project uses semantic versioning. You can safely express a dependency on a major version and expect all minor and patch versions to be backwards compatible.

Supported Services

Service Name Service Class API Version
AWS Application Discovery Service ApplicationDiscoveryService 2015-11-01
AWS Certificate Manager ACM 2015-12-08
AWS CloudFormation CloudFormation 2010-05-15
AWS CloudTrail CloudTrail 2013-11-01
AWS CodeCommit CodeCommit 2015-04-13
AWS CodeDeploy CodeDeploy 2014-10-06
AWS CodePipeline CodePipeline 2015-07-09
AWS Config ConfigService 2014-11-12
AWS Data Pipeline DataPipeline 2012-10-29
AWS Database Migration Service DatabaseMigrationService 2016-01-01
AWS Device Farm DeviceFarm 2015-06-23
AWS Direct Connect DirectConnect 2012-10-25
AWS Directory Service DirectoryService 2015-04-16
AWS Elastic Beanstalk ElasticBeanstalk 2010-12-01
AWS Identity and Access Management IAM 2010-05-08
AWS Import/Export ImportExport 2010-06-01
AWS IoT IoT 2015-05-28
AWS IoT Data Plane IoTDataPlane 2015-05-28
AWS Key Management Service KMS 2014-11-01
AWS Lambda LambdaPreview 2014-11-11
AWS Lambda Lambda 2015-03-31
AWS Marketplace Commerce Analytics MarketplaceCommerceAnalytics 2015-07-01
AWS OpsWorks OpsWorks 2013-02-18
AWS Security Token Service STS 2011-06-15
AWS Storage Gateway StorageGateway 2013-06-30
AWS Support Support 2013-04-15
AWS WAF WAF 2015-08-24
AWSMarketplace Metering MarketplaceMetering 2016-01-14
Amazon API Gateway APIGateway 2015-07-09
Amazon CloudFront CloudFront 2016-01-28
Amazon CloudHSM CloudHSM 2014-05-30
Amazon CloudSearch CloudSearch 2013-01-01
Amazon CloudSearch Domain CloudSearchDomain 2013-01-01
Amazon CloudWatch CloudWatch 2010-08-01
Amazon CloudWatch Events CloudWatchEvents 2015-10-07
Amazon CloudWatch Logs CloudWatchLogs 2014-03-28
Amazon Cognito Identity CognitoIdentity 2014-06-30
Amazon Cognito Identity Provider CognitoIdentityProvider 2016-04-18
Amazon Cognito Sync CognitoSync 2014-06-30
Amazon DynamoDB DynamoDB 2012-08-10
Amazon DynamoDB Streams DynamoDBStreams 2012-08-10
Amazon EC2 Container Registry ECR 2015-09-21
Amazon EC2 Container Service ECS 2014-11-13
Amazon ElastiCache ElastiCache 2015-02-02
Amazon Elastic Compute Cloud EC2 2015-10-01
Amazon Elastic File System EFS 2015-02-01
Amazon Elastic MapReduce EMR 2009-03-31
Amazon Elastic Transcoder ElasticTranscoder 2012-09-25
Amazon Elasticsearch Service ElasticsearchService 2015-01-01
Amazon GameLift GameLift 2015-10-01
Amazon Glacier Glacier 2012-06-01
Amazon Inspector Inspector 2016-02-16
Amazon Kinesis Kinesis 2013-12-02
Amazon Kinesis Firehose Firehose 2015-08-04
Amazon Machine Learning MachineLearning 2014-12-12
Amazon Redshift Redshift 2012-12-01
Amazon Relational Database Service RDS 2014-10-31
Amazon Route 53 Route53 2013-04-01
Amazon Route 53 Domains Route53Domains 2014-05-15
Amazon Simple Email Service SES 2010-12-01
Amazon Simple Notification Service SNS 2010-03-31
Amazon Simple Queue Service SQS 2012-11-05
Amazon Simple Storage Service S3 2006-03-01
Amazon Simple Systems Management Service SSM 2014-11-06
Amazon Simple Workflow Service SWF 2012-01-25
Amazon SimpleDB SimpleDB 2009-04-15
Amazon WorkSpaces WorkSpaces 2015-04-08
Application Auto Scaling ApplicationAutoScaling 2016-02-06
Auto Scaling AutoScaling 2011-01-01
Elastic Load Balancing ElasticLoadBalancing 2012-06-01


This library is distributed under the Apache License, version 2.0

copyright 2013. amazon web services, inc. all rights reserved.

licensed under the apache license, version 2.0 (the "license");
you may not use this file except in compliance with the license.
you may obtain a copy of the license at

unless required by applicable law or agreed to in writing, software
distributed under the license is distributed on an "as is" basis,
without warranties or conditions of any kind, either express or implied.
see the license for the specific language governing permissions and
limitations under the license.