// mergeSettings reads the relation settings node for the unit with the // supplied id, and sets a value in the Changed field keyed on the unit's // name. It returns the mgo/txn revision number of the settings node. func (w *relationUnitsWatcher) mergeSettings(changes *params.RelationUnitsChange, key string) (int64, error) { node, err := readSettings(w.st, key) if err != nil { return -1, err } name := (&relationScopeDoc{key}).unitName() settings := params.UnitSettings{Version: node.txnRevno} if changes.Changed == nil { changes.Changed = map[string]params.UnitSettings{name: settings} } else { changes.Changed[name] = settings } return node.txnRevno, nil }