copy_batch_write_dynamodb.py

import os
import boto3

BATCH_SIZE = 25
REGION = 'us-west-2'
SRC_TABLE = os.environ['SRC']
SNK_TABLE = os.environ['SNK']

client = boto3.client('dynamodb', REGION)
tables = client.list_tables()['TableNames']

for table in (SRC_TABLE, SNK_TABLE):
	if table not in tables:
		raise(Exception(f'DynamoDB table does not exist: {table}'))

for resp in client.get_paginator('scan').paginate(TableName=SRC_TABLE):
	for n in range(0, len(resp['Items']), BATCH_SIZE):
		item_group = resp['Items'][n:n+BATCH_SIZE]
		req = {
			SNK_TABLE: [
				{'PutRequest': {'Item': i}}
				for i in item_group
			]
		}
		client.batch_write_item(RequestItems=req)