// WatchRelationUnits returns a watcher that notifies of changes to the
// counterpart units in the relation for the given unit.
func (st *State) WatchRelationUnits(
relationTag names.RelationTag,
unitTag names.UnitTag,
) (watcher.RelationUnitsWatcher, error) {
var results params.RelationUnitsWatchResults
args := params.RelationUnits{
RelationUnits: []params.RelationUnit{{
Relation: relationTag.String(),
Unit: unitTag.String(),
}},
}
err := st.facade.FacadeCall("WatchRelationUnits", args, &results)
if err != nil {
return nil, err
}
if len(results.Results) != 1 {
return nil, fmt.Errorf("expected 1 result, got %d", len(results.Results))
}
result := results.Results[0]
if result.Error != nil {
return nil, result.Error
}
w := apiwatcher.NewRelationUnitsWatcher(st.facade.RawAPICaller(), result)
return w, nil
}
// Watch returns a watcher that notifies of changes to counterpart
// units in the relation.
func (ru *RelationUnit) Watch() (watcher.RelationUnitsWatcher, error) {
var results params.RelationUnitsWatchResults
args := params.RelationUnits{
RelationUnits: []params.RelationUnit{{
Relation: ru.relation.tag.String(),
Unit: ru.unit.tag.String(),
}},
}
err := ru.st.facade.FacadeCall("WatchRelationUnits", args, &results)
if err != nil {
return nil, err
}
if len(results.Results) != 1 {
return nil, fmt.Errorf("expected 1 result, got %d", len(results.Results))
}
result := results.Results[0]
if result.Error != nil {
return nil, result.Error
}
w := watcher.NewRelationUnitsWatcher(ru.st.facade.RawAPICaller(), result)
return w, nil
}