Best Practices for using Apollo Server with a Graph Database (Gremlin + CosmosDB)

[ntheile]

Hello Apollo Community 👋,

I am looking for best practices on how to use Apollo Server Federation with Gremlin and a gateway. I noticed a lot of the examples show how to fetch data from a REST API by using resolvers to fetch child data by ID (looping the children), but there is not a lot of examples on how to do it with a graph database.

For example, I want to share the Role type from the Role Service to the User Service. I want to simply re-use the type definition but not have the code hop back to the Role Service to resolve it. This is to avoid the extra queries. There could be a lot of extra queries if the user has a lot of roles. To sum it up, I want the User Service to resolve both the User and Role types via a Gremlin query without having to copy the Role Type to the User Service.

Here is the Gremlin query joining one User with many roles via an out edge.

Gremlin

g.V().hasLabel('user').has('id', '1234').out('roles')

User Type (in User Service port 4001)

type User @key(fields: "id") {
  id: ID! 
  name: String
  email: String
  roles: [Role]
}

Role Type (In Role Service port 4002)

type Role @key(fields: "id") {
  id: ID! 
  name: String  
}

Any guidance or links to articles would be greatly appreciated!

Thanks!