Amazon AWS: How Do I Programmatically Calculate My Spending?

Question

We are using Amazon's EC2 We would like to be able to write a program that calculates how much we spent between time to time?

We figured that it's possible to download the usage report and apply the pricing rules.. Is there any better way? Direct API? Is it possible to do it in real-time(the reports are somewhat delayed)

Usage-report: https://aws-portal.amazon.com/gp/aws/developer/account/index.html?action=usage-report

Answer 1

Unfortunately Amazon don't provide real-time data (and, in fact, you'll probably notice that the accuracy of Amazon's usage reports will vary within the current billing period), nor do they provide an API to query their current prices.

We currently do this for our systems and have found a combination of the following works well:

• Real time estimates: estimate charges based on monitoring data (number of instances, start date, terminate date, bandwidth and IO usage per-box monitored by a custom agent looking at /proc). We pessimistically over-estimate here.
• Recent estimate: replace total costs for real-time estimates with charges based on usage report.
• Bill: replace total costs based on actual bill

At each estimation stage we do a very primitive adjustment so the totals work out: we apply a credit/charge to bring the figure in line with the next level of estimate.

You can spend a LOT of effort trying to get these estimates as accurate as possible - it largely depends on how much data collection and maintenance overhead you're willing to bear.

We account for usage on a per-application basis (where each Instance may be reused within an instance-hour for multiple applications) so the collection overhead and maintenance of this code is worth it.