python code to access s3 bucket from different account - Using Separate Boto3 Sessions/Profiles

This method is typically used to copy objects between buckets without saving them locally. 

 

import boto3

import io

# Source Account Credentials (can be loaded from .env file or config)

SOURCE_ACCESS_KEY = '...'

SOURCE_SECRET_KEY = '...'

SOURCE_BUCKET = 'my-source-bucket'

# Destination Account Credentials

DESTINATION_ACCESS_KEY = '...'

DESTINATION_SECRET_KEY = '...'

DESTINATION_BUCKET = 'their-destination-bucket'

OBJECT_KEY = 'path/to/object.txt'

# 1. Create a client for the source account

source_client = boto3.client(

    's3',

    aws_access_key_id=SOURCE_ACCESS_KEY,

    aws_secret_access_key=SOURCE_SECRET_KEY

)

# 2. Get the object data as a stream (file-like object)

source_object = source_client.get_object(Bucket=SOURCE_BUCKET, Key=OBJECT_KEY)

object_body = source_object['Body']

# 3. Create a client for the destination account

destination_client = boto3.client(

    's3',

    aws_access_key_id=DESTINATION_ACCESS_KEY,

    aws_secret_access_key=DESTINATION_SECRET_KEY

)

# 4. Upload the file-like object to the destination bucket

destination_client.upload_fileobj(

    object_body,

    DESTINATION_BUCKET,

    OBJECT_KEY,

    ExtraArgs={'ACL': 'bucket-owner-full-control'} # Ensure destination account owns the object

)

print(f"Successfully transferred {OBJECT_KEY} from {SOURCE_BUCKET} to {DESTINATION_BUCKET}.")