Relationships

A relationship is a typed, directed link between a source item and a target item. Relationships form a graph layered on top of the catalog's items: they let you traverse from a service to its owners, from a deployment to the environment it targets, from a vulnerability to the artifacts it affects, and so on.

The catalog models relationships with three built-in kinds:

• RelationshipType — declares a type of connection (its semantic, plus the labels used to read it in each direction).
• RelationshipConstraint — declares which item kinds may participate as source and target of a given relationship type.
• Relationship — the actual instance linking two specific items through a relationship type.

All three are themselves catalog items, governed by Item Type Definitions under the mia-platform.eu/v1alpha1 group, and exposed at fixed paths on the Catalog API.

RelationshipType

A RelationshipType defines the vocabulary of a connection. It carries the labels used by the UI to phrase the relationship from each endpoint's perspective.

apiVersion: mia-platform.eu/v1alpha1
kind: RelationshipType
metadata:
  name: part-of.mia-platform.eu
spec:
  names:
    sourceToTarget: is part of
    targetToSource: contains

Required fields:

• spec.names.sourceToTarget — how the relationship reads from the source toward the target (e.g. "is part of", "depends on", "owns").
• spec.names.targetToSource — the reverse reading (e.g. "contains", "is a dependency of", "is owned by").

Built-in relationship types

The catalog ships with a small set of relationship types under the mia-platform.eu group:

Name	source → target	target → source	Typical use
ownership.mia-platform.eu	owns	is owned by	Connects a User or Team to the items they own. Surfaced by the UI as the item's owner.
follow.mia-platform.eu	follows	is followed by	Connects a User to an item they want to be notified about (see Campaigns).
part-of.mia-platform.eu	is part of	contains	Models containment (e.g. a Microservice is part of a Project).
dependency.mia-platform.eu	depends on	is a dependency of	Models runtime or build-time dependencies.
affect.mia-platform.eu	affects	is affected by	Connects a finding (e.g. a vulnerability) to the items it impacts.
origin.mia-platform.eu	originates from	is the origin of	Records provenance (e.g. an item ingested from a connector).

You can introduce custom relationship types by creating additional RelationshipType items.

RelationshipConstraint

A RelationshipConstraint declares which item kinds may legitimately participate in a relationship of a given type. It is the catalog's way to document the intended shape of the graph.

apiVersion: mia-platform.eu/v1alpha1
kind: RelationshipConstraint
metadata:
  name: ownership-team-owns-service
spec:
  relationshipTypeRef: urn:mia-platform-catalog:mia-platform.eu:v1alpha1:RelationshipType:ownership.mia-platform.eu
  sourceType: urn:mia-platform-catalog:mia-platform.eu:v1:Team
  targetType: urn:mia-platform-catalog:mia-platform.eu:v1:Service

Required fields:

• spec.relationshipTypeRef — URN of the relationship type the constraint is about.
• spec.sourceType (optional) — URN of an item type (a family selector: URN without the trailing :<name>) that the source must belong to.
• spec.targetType (optional) — same, for the target item type.

Omitting sourceType or targetType leaves the corresponding side unconstrained.

note

Constraints are permissive, not restrictive: the catalog does not reject a Relationship whose source/target kinds do not match any registered constraint. Constraints are intended to (a) document intent for humans and tooling, and (b) drive graph traversal heuristics in the Catalog Administration. They are not a validation gate.

Relationship

A Relationship is the actual edge: it pairs a source item URN with a target item URN through a relationship type URN.

apiVersion: mia-platform.eu/v1alpha1
kind: Relationship
metadata:
  name: api-gateway-owned-by-platform-team
spec:
  relationshipTypeRef: urn:mia-platform-catalog:mia-platform.eu:v1alpha1:RelationshipType:ownership.mia-platform.eu
  sourceRef: urn:mia-platform-catalog:mia-platform.eu:v1:Team:platform-team
  targetRef: urn:mia-platform-catalog:console.mia-platform.eu:v1:Service:api-gateway

Required fields:

• spec.relationshipTypeRef — URN of the RelationshipType.
• spec.sourceRef — URN of the source item.
• spec.targetRef — URN of the target item.

Validation

When a Relationship is created or updated, the catalog validates only the URN format of sourceRef and targetRef. It does not check that the referenced items actually exist, nor that their kinds satisfy any matching RelationshipConstraint. This is consistent with the broader item-reference policy: references are loosely coupled by design, so that items can be created in any order and dangling references can be repaired without coordinated writes.

Querying the graph

Once relationships exist, you can navigate them through:

• the Relationships tab of any item in the Catalog Administration, as a table or as a visual graph;
• the related operator of the Catalog Query Language, to express queries such as "all services owned by team X" or "all items affected by vulnerability Y".

See also

• Items: the entities relationships connect.
• Item Types: how to introduce new kinds that participate in the graph.
• Query Language: how to traverse relationships in queries.