Replace MongoDB

[mattfarina]

When MongoDB changed their license it made the case for us operating it, for the Helm Hub, to need to use something else. We can't use the newer versions, or so I'm told.

I would suggest replacing MongoDB with PostgreSQL. It now can handle documents and, if I understand what I read right, it's the foundation for the MongoDB API compliant service that Amazon operates.

In any case, the idea is to use a data store whose license we can and with versions getting updates for security and bugs.

[nwmac]

@mattfarina We are interested on using Monocular on the SUSE Stratos project (https://github.com/SUSE/stratos), but also can not use MongoDB due to the license change.

Would you consider refactoring Monocular to have a data-store abstraction layer under which different back-end repositories could be implemented?

Also, have you considered FoundationDB DocumentDB layer (https://www.foundationdb.org/blog/announcing-document-layer/)? Its Apache 2 licensed and offers API compatibility with MongoDB.

[mattfarina]

@nwmac We would consider FoundationDB

[dhrp]

Just jumping in; but

We can't use the newer versions, or so I'm told.

Why exactly is that? As far as I know projects using MongoDB, on any version, including the latest, is completely allowed. Effectively blocking any new release (helm/hub#212) seems unnecessary.