Federated Catalog Architecture¶

The Federated Catalog enables discovery of data offerings across all participants in the dataspace.

Overview¶

flowchart LR

    linkStyle default curvature:0;

    subgraph Participant_Ecosystem[Participant Ecosystem]
        direction TB
        ParticipantCP[Control Plane]
        ParticipantIH[Identity Hub]
        ParticipantDP[Data Plane]
        ParticipantVault["(Vault)"]
        ParticipantDB["(Database)"]
    end

    subgraph DSE_Services[DSE Federated Services]
        direction TB
        FedCatalog[Federated Catalog]
        ParticipantReg[Participant Registry]
        AuthIH[Authority Identity Hub]
    end

    subgraph VC_Issuers[VC Issuers]
        direction TB
        VcIssuerDID[DID Document]
    end

    FedCatalog --> ParticipantReg
    FedCatalog --> ParticipantIH
    FedCatalog --> ParticipantCP

    ParticipantCP --> AuthIH
    ParticipantCP --> VcIssuerDID

Components¶

Participant Registry¶

Maintains the list of all participants in the dataspace:

Stores participant DIDs
Provides participant discovery
Enables per-participant catalog crawling

Federated Catalog Crawler¶

Fetches catalogs from all registered participants:

Queries Participant Registry for DIDs
Resolves Control Plane URLs via Identity Hub
Periodic crawling based on configuration
In-memory caching of datasets

Provides VC-based filtering of catalog entries:

@Extension("VC-based Catalogue Filter Extension")
public class VcCatalogFilterExtension implements ServiceExtension {
    @Inject
    private PolicyEngine policyEngine;

    @Inject
    private IdentityService identityService;

    @Setting(description = "Authority did", key = "dse.authority.did", required = true)
    public String authorityDid;
}

Catalog Crawling Flow¶

Catalog Crawling Flow

Configuration¶

# Federated Catalog Crawler Configuration (from Terraform)
crawler:
  cache:
    executionPeriodSeconds: 10   # Crawl interval
    executionDelaySeconds: 10    # Initial delay before first crawl

VC-Based Filtering¶

The Federated Catalog Filter uses Verifiable Credentials for access control:

Catalog Filter Flow

Filter Types¶

VC-based: Filter based on Verifiable Credentials in participant's token
Policy-based: Evaluate ODRL policies via PolicyEngine
Participant-based: Match datasets by participant DID