The context here is simple, there's a lambda (lambda1) that creates a file asynchronously and then uploads it to S3.
Then, another lambda (lambda2) receives the soon-to-exist file name and needs to keep checking S3 until the file exists.
I don't think S3 triggers will work because lambda2 is invoked by a client request
1) Do I get charged for this kind of request between lambda and S3? I will be polling it until the object exists
2) What other way could I achieve this that doesn't incur charges?
3) What method do I use to check if a file exists in S3? (just try to get it and check status code?)