https://medium.com/@hang.c/processing-large-s3-files-with-aws-lambda-2c5840ae5c91

invoke_lambda.py

new_offset = offset + bodylines.offset
if new_offset < s3_object.content_length:
    new_event = {
        **event,
        "offset": new_offset,
        "fieldnames": fieldnames
    }
    invoke_lambda(context.function_name, new_event)


def invoke_lambda(function_name, event):
    payload = json.dumps(event).encode('utf-8')
    client = boto3.client('lambda')
    response = client.invoke(
        FunctionName=function_name,
        InvocationType='Event',
        ClientContext='string',
        Payload=payload
    )