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package schema
import (
"context"
"errors"
"fmt"
"slices"
"strings"
core "github.com/authzed/spicedb/pkg/proto/core/v1"
)
// Graph is a struct holding reachability information.
type Graph struct {
arrowSet *ArrowSet
ts *TypeSystem
referenceInfoMap map[nsAndRel][]RelationReferenceInfo
}
// BuildGraph builds the graph of all reachable information in the schema.
func BuildGraph(ctx context.Context, r *CompiledSchemaResolver) (*Graph, error) {
arrowSet, err := buildArrowSet(ctx, r)
if err != nil {
return nil, err
}
ts := NewTypeSystem(r)
referenceInfoMap, err := preComputeRelationReferenceInfo(ctx, arrowSet, r, ts)
if err != nil {
return nil, err
}
return &Graph{
ts: ts,
arrowSet: arrowSet,
referenceInfoMap: referenceInfoMap,
}, nil
}
// Arrows returns the set of arrows found in the reachability graph.
func (g *Graph) Arrows() *ArrowSet {
return g.arrowSet
}
// RelationsReferencing returns all relations/permissions in the schema that reference the specified
// relation in some manner.
func (g *Graph) RelationsReferencing(namespaceName string, relationName string) []RelationReferenceInfo {
return g.referenceInfoMap[nsAndRel{
Namespace: namespaceName,
Relation: relationName,
}]
}
// ReferenceType is an enum describing what kind of relation reference we hold in a RelationReferenceInfo.
type ReferenceType int
const (
RelationInExpression ReferenceType = iota
RelationIsSubjectType
RelationIsTuplesetForArrow
RelationIsComputedUsersetForArrow
)
// RelationReferenceInfo holds the relation and metadata for a relation found in the full reachability graph.
type RelationReferenceInfo struct {
Relation *core.RelationReference
Type ReferenceType
Arrow *ArrowInformation
}
func relationsReferencing(ctx context.Context, arrowSet *ArrowSet, res FullSchemaResolver, ts *TypeSystem, namespaceName string, relationName string) ([]RelationReferenceInfo, error) {
foundReferences := make([]RelationReferenceInfo, 0)
for _, name := range res.AllDefinitionNames() {
def, err := ts.GetValidatedDefinition(ctx, name)
if err != nil {
return nil, err
}
for _, relation := range def.Namespace().Relation {
// Check for the use of the relation directly as part of any permissions in the same namespace.
if def.IsPermission(relation.Name) && name == namespaceName {
hasReference, err := expressionReferencesRelation(ctx, relation.GetUsersetRewrite(), relationName)
if err != nil {
return nil, err
}
if hasReference {
foundReferences = append(foundReferences, RelationReferenceInfo{
Relation: &core.RelationReference{
Namespace: name,
Relation: relation.Name,
},
Type: RelationInExpression,
})
}
continue
}
// Check for the use of the relation as a subject type on any relation in the entire schema.
isAllowed, err := def.IsAllowedDirectRelation(relation.Name, namespaceName, relationName)
if err != nil {
return nil, err
}
if isAllowed == DirectRelationValid {
foundReferences = append(foundReferences, RelationReferenceInfo{
Relation: &core.RelationReference{
Namespace: name,
Relation: relation.Name,
},
Type: RelationIsSubjectType,
})
}
}
}
// Add any arrow references.
key := namespaceName + "#" + relationName
foundArrows, _ := arrowSet.arrowsByFullTuplesetRelation.Get(key)
for _, arrow := range foundArrows {
arrow := arrow
foundReferences = append(foundReferences, RelationReferenceInfo{
Relation: &core.RelationReference{
Namespace: namespaceName,
Relation: arrow.ParentRelationName,
},
Type: RelationIsTuplesetForArrow,
Arrow: &arrow,
})
}
for _, tuplesetRelationKey := range arrowSet.reachableComputedUsersetRelationsByTuplesetRelation.Keys() {
values, ok := arrowSet.reachableComputedUsersetRelationsByTuplesetRelation.Get(tuplesetRelationKey)
if !ok {
continue
}
if slices.Contains(values, key) {
pieces := strings.Split(tuplesetRelationKey, "#")
foundReferences = append(foundReferences, RelationReferenceInfo{
Relation: &core.RelationReference{
Namespace: pieces[0],
Relation: pieces[1],
},
Type: RelationIsComputedUsersetForArrow,
})
}
}
return foundReferences, nil
}
type nsAndRel struct {
Namespace string
Relation string
}
func preComputeRelationReferenceInfo(ctx context.Context, arrowSet *ArrowSet, res FullSchemaResolver, ts *TypeSystem) (map[nsAndRel][]RelationReferenceInfo, error) {
nsAndRelToInfo := make(map[nsAndRel][]RelationReferenceInfo)
for _, namespaceName := range res.AllDefinitionNames() {
outerTS, err := ts.GetValidatedDefinition(ctx, namespaceName)
if err != nil {
return nil, err
}
for _, outerRelation := range outerTS.Namespace().Relation {
referenceInfos, err := relationsReferencing(ctx, arrowSet, res, ts, namespaceName, outerRelation.Name)
if err != nil {
return nil, err
}
nsAndRel := nsAndRel{
Namespace: namespaceName,
Relation: outerRelation.Name,
}
nsAndRelToInfo[nsAndRel] = referenceInfos
}
}
return nsAndRelToInfo, nil
}
func expressionReferencesRelation(ctx context.Context, rewrite *core.UsersetRewrite, relationName string) (bool, error) {
// TODO(jschorr): Precompute this and maybe create a visitor pattern to stop repeating this everywhere
switch rw := rewrite.RewriteOperation.(type) {
case *core.UsersetRewrite_Union:
return setOperationReferencesRelation(ctx, rw.Union, relationName)
case *core.UsersetRewrite_Intersection:
return setOperationReferencesRelation(ctx, rw.Intersection, relationName)
case *core.UsersetRewrite_Exclusion:
return setOperationReferencesRelation(ctx, rw.Exclusion, relationName)
default:
return false, errors.New("userset rewrite operation not implemented in expressionReferencesRelation")
}
}
func setOperationReferencesRelation(ctx context.Context, so *core.SetOperation, relationName string) (bool, error) {
for _, childOneof := range so.Child {
switch child := childOneof.ChildType.(type) {
case *core.SetOperation_Child_ComputedUserset:
if child.ComputedUserset.Relation == relationName {
return true, nil
}
case *core.SetOperation_Child_UsersetRewrite:
result, err := expressionReferencesRelation(ctx, child.UsersetRewrite, relationName)
if result || err != nil {
return result, err
}
case *core.SetOperation_Child_TupleToUserset:
// Nothing to do, handled above via arrow set
case *core.SetOperation_Child_XThis:
// Nothing to do
case *core.SetOperation_Child_XNil:
// Nothing to do
default:
return false, fmt.Errorf("unknown set operation child `%T` in setOperationReferencesRelation", child)
}
}
return false, nil
}
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