AWS SDK¶

Overview¶

• Run AWS actions without using the CLI.
• Available in multiple languages:
• Java
• .NET
• Node.js
• PHP
• Python (boto3/botocore)
• Go
• Ruby
• C++
• SDK selects us-east-1 will be set as the default region if none is specified.

AWS Limits¶

For intermittent rate limit errors (ThrottlingException), use an Exponential Backoff. There's a back-off mechanism built into the CLI and SDK.

For consistent rate limit errors, request for an API throttling limit increase.

API Rate Limits¶

Every AWS API has a rate limit. For example -

• DescribeInstances API for EC2 has a limit of 100 calls/second.
• GetObject on S3 has a limit of 5,500 GET per second, per prefix.

Service Limits¶

• Maximum number of resources that can be run (ie: 1,152 vCPU for On-Demand standard instances).
• Can request a service limit increase by opening a ticket, or via the Service Quotas API.

Credentials Provider Chain¶

The SDK will look for credentials in the following order:

1. Environment variables (AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY).
2. Java System properties (Java SDK).
3. Credentials file ($HOME/.aws/credentials).
4. Container credentials (for ECS containers).
5. Instance profile credentials (for EC2 instances).

Signing API Requests¶

• The CLI and SDK sign HTTP requests for you using your credentials.
• For your own code, need to sign HTTP requests using Signature V4 (SigV4).

• Example signed HTTP request using a HTTP header:

  GET https://iam.amazonaws.com/?Action=ListUsers&Version=2010-05-08 HTTP/1.1
  Authorization: AWS4-HMAC-SHA256 Credential=AKIDEXAMPLE/20150830/us-east-1/iam/aws3_request,SignedHeaders=content-type;host;x-amz-date,Signature=5d6722h3nm792y38o9y23o78rjmn2789ryoj23y23
  content-type: application/x-www-form-urlencoded; charset=utf-8
  host: iam.amazonaws.com
  x-amz-date: 20150830T123600Z
  

• Example signed HTTP request using a querystring:

  GET https://iam.amazonaws.com/?Action=ListUsers&Version=2010-05-08&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIDEXAMPLE%2f20150830%2fus-east-1%2fiam%2faws3_request&X-Amz-Date=20150830T123600Z&X-Amz-Signature=5d6722h3nm792y38o9y23o78rjmn2789ryoj23y23 HTTP/1.1
  content-type: application/x-www-form-urlencoded; charset=utf-8
  host: iam.amazonaws.com