Sharing a graph database between Microservices

Question

Is there any way to share a neo4j / aws Neptune graph database between microservices while restricting the access to the specific parts of the graph database to only a specific microservice ? By doing so, will there be any performance impact ?

Answer 1

In Amazon Neptune, there is no way to have ACLs for a portion of a graph at the moment. You can have IAM users who have full access to a cluster or no access at all. (Allow All or Deny All). You would need to handle this at application layer. Fine grained access control would be a good feature to have, so you may want to place a feature request for that (via AWS Forums, for example).

If you rule out access control, and the only thing you need is to make micro services not impact each other, then you can create read replicas, and use that them in your micro services (whether sharing database across micro services is a good choice or not is a separate discussion). Two approaches there are:

1. Add enough replicas in your cluster and use the cluster-ro (reader) endpoints in your read only micro services. All micro services would share the read replicas, but with DNS round robin.
2. Add replicas for various use cases, and then use specific instance endpoints with specific micro services. The micro services would not impact each other, however, a drawback with this approach would be that your instance can get promoted to master in the event of crashes and that may be something that you'd need to handle or be ready for.