Sandboxing end-user/admin SPARQL endpoints

[namedgraph]

Because containers in the Docker network can by default access each other, a user of the end-user endpoint (fuseki-end-user) can potentially run such a federated query which will expose data from the admin (fuseki-admin) endpoint:

SELECT  *
WHERE
  { SERVICE <http://fuseki-admin:3030/ds>
      { GRAPH ?g { ?s  <http://xmlns.com/foaf/0.1/name>  ?o } }
  }
LIMIT   100

LinkedDataHub needs this federation for authorization queries. But the end-users having the same access is a security issue.

Some kind of authentication (even HTTP Basic) that the user does not have access to should work. Need to investigate Security in Fuseki2.