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graflo.architecture.evolution.aspects.access

The access aspect: integer zone labels on declared types.

The lift adds one reserved field, access_zones: list[int], to each vertex type and edge relation the spec names. What a zone is and who opens it is not part of the graph: a caller stamps writes with zone ids and reads with a guard built from ANY_IN over the zones a reader opens.

Modules:

Name Description
plan

Planning the access aspect: a reserved access_zones field on named types.

Attributes

ACCESS_ZONES = 'access_zones' module-attribute

__all__ = ['ACCESS_ZONES', 'access_field', 'plan_access'] module-attribute

Functions:

access_field(merge='replace')

access_zones: a reserved list of zone ids, set by the writer's stamp.

Source code in graflo/architecture/evolution/aspects/access/plan.py 
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def access_field(merge: FieldMerge = "replace") -> Field:
    """``access_zones``: a reserved list of zone ids, set by the writer's stamp."""
    return Field(
        name=ACCESS_ZONES,
        type=FieldType.LIST,
        item_type=FieldType.INT,
        reserved=True,
        merge=merge,
        description=(
            "Ids of the access zones this element is visible in; set by the "
            "writer from its stamp."
        ),
    )

plan_access(manifest, *, vertices, edges)

The ops that label vertices and edges with access_zones.

A type that already declares the field keeps it when it is the same field; one declared with another type or merge mode is a contradiction (:func:~graflo.architecture.evolution.aspects.join.join).

Parameters:

Name Type Description Default
manifest GraphManifest

the manifest to lift, already finish_init()-ed, with the types and relations it names.

 required
vertices Mapping[str, FieldMerge]

vertex type -> merge mode of its zones.

 required
edges Mapping[str, FieldMerge]

edge relation -> merge mode of its zones.

 required

Raises:

Type Description
LiftError

nothing to label, a type or relation the manifest does not have, or a field that contradicts the aspect's.
Source code in graflo/architecture/evolution/aspects/access/plan.py 
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def plan_access(
    manifest: GraphManifest,
    *,
    vertices: Mapping[str, FieldMerge],
    edges: Mapping[str, FieldMerge],
) -> list[ManifestOp]:
    """The ops that label *vertices* and *edges* with ``access_zones``.

    A type that already declares the field keeps it when it is the same field;
    one declared with another type or merge mode is a contradiction
    (:func:`~graflo.architecture.evolution.aspects.join.join`).

    Args:
        manifest: the manifest to lift, already ``finish_init()``-ed, with the
            types and relations it names.
        vertices: vertex type -> merge mode of its zones.
        edges: edge relation -> merge mode of its zones.

    Raises:
        LiftError: nothing to label, a type or relation the manifest does not
            have, or a field that contradicts the aspect's.
    """
    if not vertices and not edges:
        raise LiftError(
            "the access aspect needs access_for or access_edges: it labels only "
            "the types a spec names"
        )
    schema = manifest.graph_schema
    if schema is None:
        raise LiftError("cannot lift a manifest with no schema block")
    return join(
        schema.core_schema,
        vertex_fields={
            name: [access_field(merge)] for name, merge in sorted(vertices.items())
        },
        relation_fields={
            relation: [access_field(merge)] for relation, merge in sorted(edges.items())
        },
    )