As part of AWS’s Free Usage Tier, Amazon SWF offers the following each month to new and existing customers:
1,000 workflow executions can be started at no charge
10,000 tasks, timers, signals, and markers can be used in aggregate at no charge
30,000 workflow-days can be used at no charge. A workflow-day refers to each 24-hour period that an execution is either open or retained in Amazon SWF.
Free Tier for data transfer is applicable as per AWS’s Free Usage Tier**
A workflow is a set of tasks executed in a certain order (sometimes with a set of conditional flows or loops). Each time that a workflow is executed, it is considered a distinct workflow execution. You pay for workflow executions when you start them (i.e. their first task becomes available for application hosts to execute) and for each 24-hour period until they are completed. The first 24 hours of workflow execution are free.
Tasks, Markers, Timers and Signals
Until a workflow execution is completed, your worker or client machines will execute additional tasks, may add “markers” (custom workflow execution log entries), start timers, or receive signals. For each of these you pay:
All charges are metered daily and billed monthly.
Data transfer “in” and “out” refers to transfer into and out of Amazon SWF. Data transferred between Amazon SWF and other AWS services (e.g. Amazon EC2 where workers and deciders may be deployed) within a single region is free of charge (i.e., $0.00 per GB). Data transferred between Amazon SWF and other AWS services in different regions will be charged at Internet Data Transfer rates on both sides of the transfer.
* Your free usage is calculated each month and automatically applied to your bill – free usage does not accumulate.
** As part of AWS’s Free Usage Tier, AWS customers will receive free 15 GB of data transfer out each month aggregated across all AWS services for one year.
*** Data transfer out rate tiers aggregate outbound data transfer across Amazon EC2, Amazon S3, Amazon RDS, Amazon SimpleDB, Amazon DynamoDB, Amazon SWF, Amazon SQS, Amazon SNS, AWS Storage Gateway, and Amazon VPC.
Example Cost Calculation
To illustrate Amazon SWF pricing, consider a simple video processing application with three tasks: download a video, encode it, and store the encoded video in Amazon S3. This application is used to encode 10,000 videos, each of which comprises a unique workflow execution. The workers and deciders in this application are all running on Amazon EC2 in the same region as Amazon SWF. The cost incurred for running 10,000 workflow executions of this workflow daily is $1.75 as follows:
$1.00 for starting 10,000 workflow executions (10,000 x $0.0001)
$0.75 for initiating tasks ($0.000025 per task x 3 tasks per workflow execution x 10,000 workflow executions)
We assume a video can be encoded and uploaded to S3 in less than 24 hours. As a result the workflow execution completes within 24 hours of being started and there is no ongoing workflow execution charge.
Let’s suppose you also want to have Amazon SWF retain information about the encoding workflow executions for 7 days after they complete. The cost for retaining information about the workflow executions is $0.35 ($0.000005 per day per execution x 7 workflow-days of retention x 10,000 workflow executions).
In total the Amazon SWF cost to coordinate the encoding and uploading of 10,000 videos and to retain information about the associated workflow executions and processing steps for 7 days is: $2.10 ($1.75 for running the workflow executions + $0.35 for retaining information on them).
AWS GovCloud Region
AWS GovCloud is an AWS Region designed to allow U.S. government agencies and contractors to move more sensitive workloads into the cloud by addressing their specific regulatory and compliance requirements. For pricing and more information on the new AWS GovCloud Region, please visit the AWS GovCloud web page.
“Of all the improvements obtained from using Amazon SWF for our computation platform, the most important is that it allowed us to quickly and efficiently start using the data for their true purpose: identifying cures for human diseases." -Dr. Brig Mecham