Exemple #1
0
// addRelation causes the unit agent to join the supplied relation, and to
// store persistent state in the supplied dir.
func (u *Uniter) addRelation(rel *state.Relation, dir *relation.StateDir) error {
	log.Printf("worker/uniter: joining relation %q", rel)
	ru, err := rel.Unit(u.unit)
	if err != nil {
		return err
	}
	r := NewRelationer(ru, dir, u.relationHooks)
	w := u.unit.Watch()
	defer watcher.Stop(w, &u.tomb)
	for {
		select {
		case <-u.tomb.Dying():
			return tomb.ErrDying
		case _, ok := <-w.Changes():
			if !ok {
				return watcher.MustErr(w)
			}
			if err := r.Join(); err == state.ErrCannotEnterScopeYet {
				log.Printf("worker/uniter: cannot enter scope for relation %q; waiting for subordinate to be removed", rel)
				continue
			} else if err != nil {
				return err
			}
			log.Printf("worker/uniter: joined relation %q", rel)
			u.relationers[rel.Id()] = r
			return nil
		}
	}
	panic("unreachable")
}
func addRU(c *C, svc *state.Service, rel *state.Relation, principal *state.Unit) (*state.Unit, *state.RelationUnit) {
	// Given the service svc in the relation rel, add a unit of svc and create
	// a RelationUnit with rel. If principal is supplied, svc is assumed to be
	// subordinate and the unit will be created by temporarily entering the
	// relation's scope as the principal.
	var u *state.Unit
	if principal == nil {
		unit, err := svc.AddUnit()
		c.Assert(err, IsNil)
		u = unit
	} else {
		origUnits, err := svc.AllUnits()
		c.Assert(err, IsNil)
		pru, err := rel.Unit(principal)
		c.Assert(err, IsNil)
		err = pru.EnterScope(nil) // to create the subordinate
		c.Assert(err, IsNil)
		err = pru.LeaveScope() // to reset to initial expected state
		c.Assert(err, IsNil)
		newUnits, err := svc.AllUnits()
		c.Assert(err, IsNil)
		for _, unit := range newUnits {
			found := false
			for _, old := range origUnits {
				if unit.Name() == old.Name() {
					found = true
					break
				}
			}
			if !found {
				u = unit
				break
			}
		}
		c.Assert(u, NotNil)
	}
	preventUnitDestroyRemove(c, u)
	ru, err := rel.Unit(u)
	c.Assert(err, IsNil)
	return u, ru
}