// getJoinedRelations finds out what relations the unit is *really* part of,
// working around the fact that pre-1.19 (1.18.1?) unit agents don't write a
// state dir for a relation until a remote unit joins.
func (u *Uniter) getJoinedRelations() (map[int]*uniter.Relation, error) {
var joinedRelationTags []string
for {
var err error
joinedRelationTags, err = u.unit.JoinedRelations()
if err == nil {
break
}
if params.IsCodeNotImplemented(err) {
logger.Infof("waiting for state server to be upgraded")
select {
case <-u.tomb.Dying():
return nil, tomb.ErrDying
case <-time.After(15 * time.Second):
continue
}
}
return nil, err
}
joinedRelations := make(map[int]*uniter.Relation)
for _, tag := range joinedRelationTags {
relation, err := u.st.Relation(tag)
if err != nil {
return nil, err
}
joinedRelations[relation.Id()] = relation
}
return joinedRelations, nil
}
// init reconciles the local relation state dirs with the remote state of
// the corresponding relations. It's only expected to be called while a
// *relations is being created.
func (r *relations) init() error {
joinedRelationTags, err := r.unit.JoinedRelations()
if err != nil {
return errors.Trace(err)
}
joinedRelations := make(map[int]*uniter.Relation)
for _, tag := range joinedRelationTags {
relation, err := r.st.Relation(tag)
if err != nil {
return errors.Trace(err)
}
joinedRelations[relation.Id()] = relation
}
knownDirs, err := relation.ReadAllStateDirs(r.relationsDir)
if err != nil {
return errors.Trace(err)
}
for id, dir := range knownDirs {
if rel, ok := joinedRelations[id]; ok {
if err := r.add(rel, dir); err != nil {
return errors.Trace(err)
}
} else if err := dir.Remove(); err != nil {
return errors.Trace(err)
}
}
for id, rel := range joinedRelations {
if _, ok := knownDirs[id]; ok {
continue
}
dir, err := relation.ReadStateDir(r.relationsDir, id)
if err != nil {
return errors.Trace(err)
}
if err := r.add(rel, dir); err != nil {
return errors.Trace(err)
}
}
return nil
}