func (g GremlinBackend) SetMetadata(i interface{}, k string, v interface{}) bool {
var e graphElement
var elType string
switch i.(type) {
case *Node:
e = i.(*Node).graphElement
elType = "V"
case *Edge:
e = i.(*Edge).graphElement
elType = "V"
}
properties, err := idToPropertiesString(e.ID)
if err != nil {
logging.GetLogger().Error("Error while retrieving a Node: %s", err.Error())
return false
}
encoder := gremlin.GremlinPropertiesEncoder{}
encoder.EncodeKVPair(k, v)
query := "g." + elType + "().has(" + properties + ").property(" + encoder.String() + ")"
_, err = g.client.Query(query)
if err != nil {
logging.GetLogger().Error("Gremlin query error: %s, %s", query, err.Error())
return false
}
return true
}
func idToPropertiesString(i Identifier) (string, error) {
properties := map[string]interface{}{
"_ID": string(i),
}
encoder := gremlin.GremlinPropertiesEncoder{}
err := encoder.Encode(properties)
if err != nil {
logging.GetLogger().Error("Error while retrieving a Node: %s", err.Error())
return "", err
}
return encoder.String(), nil
}
func toPropertiesString(e graphElement) ([]byte, error) {
properties := map[string]interface{}{
"_ID": string(e.ID),
}
for k, v := range e.metadatas {
if k == "_ID" {
return nil, errors.New("_ID is a reserved value, can not be overridden by metadata")
}
properties[k] = v
}
encoder := gremlin.GremlinPropertiesEncoder{}
err := encoder.Encode(properties)
return encoder.Bytes(), err
}
func toPropertiesString(e graphElement) ([]byte, error) {
properties := map[string]interface{}{
"_ID": string(e.ID),
"_host": e.host,
}
for k, v := range e.metadata {
if k[0] == '_' {
return nil, errors.New("Properties starting with _ are reserved")
}
properties[k] = v
}
encoder := gremlin.GremlinPropertiesEncoder{}
err := encoder.Encode(properties)
return encoder.Bytes(), err
}