How to retrieve temporary credentials using rest api or by using AssumeRole in AWS SDK

Hello

You cant get the credentials for your current role, so you need to call sts:AssumeRole API.

Here is an example with python boto3.

You can now use the s3_client to call S3 using the role you just assumed.

import boto3
sts_client = boto3.client('sts')

role_arn = "MyRoleArn"

role_credentials = sts_client.assume_role(
  RoleArn=role_arn,
  RoleSessionName='MySessionName',
)['Credentials']

print(f"{role_credentials}")

s3_client = boto3.client('s3',
    aws_access_key_id=role_credentials['AccessKeyId'],
    aws_secret_access_key=role_credentials['SecretAccessKey'],
    aws_session_token=role_credentials['SessionToken']
)

NOTE: Be super careful with logging because the role_credentials variable continues your actual credentials.

Hope this helps!

//Carl

Your question seems to indicate that you are running on an EC2 instance. If you are running code on EC2 instance, the recommended way to get credentials is to use roles for Amazon EC2..

Here is the link to documentation on using temporary credentials, including how to use them with SDKs: https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_temp_use-resources.html