lookup_streaming.go

package lookup

import (
    "fmt"

    openfgapb "go.buf.build/openfga/go/openfga/api/openfga/v1"
    "golang.org/x/sync/errgroup"
)

func Lookup(req *openfgapb.LookupRequest, srv openfgapb.OpenFGAService_LookupServer) error {

    storeID := req.GetStoreId()
    modelID := req.GetAuthorizationModelId()
    targetObjectType := req.GetObjectType()
    targetRelation := req.GetRelation()
    targetUser := req.GetUser()

    // query all the relationship tuples for the given storeID and targetObjectType
    iter, err := database.QueryRelationships(storeID, targetObjectType)
    if err != nil {
        // handle error
    }

    g, ctx := errgroup.WithContext(srv.Context())
    g.SetLimit(100) // limit to 100 concurrent checks, for example

    for iter.Next() {
        var objectID string
        err := iter.Scan(&objectID)
        if err != nil {
            return err
        }

        fn := func() error {
            object := fmt.Sprintf("%s:%s", targetObjectType, objectID)
            allowed, err := Check(ctx, storeID, modelID, object, targetRelation, targetUser)
            if err != nil {
                return err
            }

            if allowed {
                err := srv.Send(&openfgapb.LookupResponse{
                    ObjectId: objectID,
                })
                if err != nil {
                    return err
                }
            }

            return nil
        }

        g.Go(fn)
    }

    return nil
}