Limit the number of times a file can be downloaded

[charlesbrandt]

In local hosting environments, it's usually not necessary to limit the number of times a dataset is downloaded. However, in public cloud infrastructure, egress fees have the potential to contribute significant costs to the overall platform operation.

This issue explores the best way to allow system operators to control downloads. Some options include:

• fixed number of downloads per dataset (e.g. first download is free)
• disable downloads for extremely large datasets

This feature should be configurable for individual Bioloop instances.

This feature may be related to tracking and billing costs on a project by project basis. See also: #58

[deepakduggirala]

It's better to count the number of bytes downloaded by a user in a period of time (month) and have a quota as a limit for that period. Limiting the number of downloads will penalize the downloads of small datasets the same as large datasets.