// removeOps returns the operations necessary to remove the relation. If
// ignoreService is not empty, no operations affecting that service will be
// included; if departingUnit is not nil, this implies that the relation's
// services may be Dying and otherwise unreferenced, and may thus require
// removal themselves.
func (r *Relation) removeOps(ignoreService string, departingUnit *Unit) ([]txn.Op, error) {
relOp := txn.Op{
C: relationsC,
Id: r.doc.Key,
Remove: true,
}
if departingUnit != nil {
relOp.Assert = bson.D{{"life", Dying}, {"unitcount", 1}}
} else {
relOp.Assert = bson.D{{"life", Alive}, {"unitcount", 0}}
}
ops := []txn.Op{relOp}
for _, ep := range r.doc.Endpoints {
if ep.ServiceName == ignoreService {
continue
}
var asserts bson.D
hasRelation := bson.D{{"relationcount", bson.D{{"$gt", 0}}}}
if departingUnit == nil {
// We're constructing a destroy operation, either of the relation
// or one of its services, and can therefore be assured that both
// services are Alive.
asserts = append(hasRelation, isAliveDoc...)
} else if ep.ServiceName == departingUnit.ServiceName() {
// This service must have at least one unit -- the one that's
// departing the relation -- so it cannot be ready for removal.
cannotDieYet := bson.D{{"unitcount", bson.D{{"$gt", 0}}}}
asserts = append(hasRelation, cannotDieYet...)
} else {
// This service may require immediate removal.
services, closer := r.st.getCollection(servicesC)
defer closer()
svc := &Service{st: r.st}
hasLastRef := bson.D{{"life", Dying}, {"unitcount", 0}, {"relationcount", 1}}
removable := append(bson.D{{"_id", ep.ServiceName}}, hasLastRef...)
if err := services.Find(removable).One(&svc.doc); err == nil {
ops = append(ops, svc.removeOps(hasLastRef)...)
continue
} else if err != mgo.ErrNotFound {
return nil, err
}
// If not, we must check that this is still the case when the
// transaction is applied.
asserts = bson.D{{"$or", []bson.D{
{{"life", Alive}},
{{"unitcount", bson.D{{"$gt", 0}}}},
{{"relationcount", bson.D{{"$gt", 1}}}},
}}}
}
ops = append(ops, txn.Op{
C: servicesC,
Id: ep.ServiceName,
Assert: asserts,
Update: bson.D{{"$inc", bson.D{{"relationcount", -1}}}},
})
}
cleanupOp := r.st.newCleanupOp(cleanupRelationSettings, fmt.Sprintf("r#%d#", r.Id()))
return append(ops, cleanupOp), nil
}
// removeUnitOps returns the operations necessary to remove the supplied unit,
// assuming the supplied asserts apply to the unit document.
func (s *Service) removeUnitOps(u *Unit, asserts bson.D) ([]txn.Op, error) {
ops, err := u.destroyHostOps(s)
if err != nil {
return nil, err
}
observedFieldsMatch := bson.D{
{"charmurl", u.doc.CharmURL},
{"machineid", u.doc.MachineId},
}
ops = append(ops, txn.Op{
C: s.st.units.Name,
Id: u.doc.Name,
Assert: append(observedFieldsMatch, asserts...),
Remove: true,
},
removeConstraintsOp(s.st, u.globalKey()),
removeStatusOp(s.st, u.globalKey()),
annotationRemoveOp(s.st, u.globalKey()),
s.st.newCleanupOp(cleanupRemovedUnit, u.doc.Name),
)
if u.doc.CharmURL != nil {
decOps, err := settingsDecRefOps(s.st, s.doc.Name, u.doc.CharmURL)
if errors.IsNotFound(err) {
return nil, errRefresh
} else if err != nil {
return nil, err
}
ops = append(ops, decOps...)
}
if s.doc.Life == Dying && s.doc.RelationCount == 0 && s.doc.UnitCount == 1 {
hasLastRef := bson.D{{"life", Dying}, {"relationcount", 0}, {"unitcount", 1}}
return append(ops, s.removeOps(hasLastRef)...), nil
}
svcOp := txn.Op{
C: s.st.services.Name,
Id: s.doc.Name,
Update: bson.D{{"$inc", bson.D{{"unitcount", -1}}}},
}
if s.doc.Life == Alive {
svcOp.Assert = bson.D{{"life", Alive}, {"unitcount", bson.D{{"$gt", 0}}}}
} else {
svcOp.Assert = bson.D{
{"life", Dying},
{"$or", []bson.D{
{{"unitcount", bson.D{{"$gt", 1}}}},
{{"relationcount", bson.D{{"$gt", 0}}}},
}},
}
}
ops = append(ops, svcOp)
return ops, nil
}
func (s *Service) removeUnitOps(u *Unit) []txn.Op {
var ops []txn.Op
if u.doc.Principal != "" {
ops = append(ops, txn.Op{
C: s.st.units.Name,
Id: u.doc.Principal,
Assert: txn.DocExists,
Update: D{{"$pull", D{{"subordinates", u.doc.Name}}}},
})
} else if u.doc.MachineId != "" {
ops = append(ops, txn.Op{
C: s.st.machines.Name,
Id: u.doc.MachineId,
Assert: txn.DocExists,
Update: D{{"$pull", D{{"principals", u.doc.Name}}}},
})
}
ops = append(ops, txn.Op{
C: s.st.units.Name,
Id: u.doc.Name,
Assert: txn.DocExists,
Remove: true,
})
if s.doc.Life == Dying && s.doc.RelationCount == 0 && s.doc.UnitCount == 1 {
hasLastRef := D{{"life", Dying}, {"relationcount", 0}, {"unitcount", 1}}
return append(ops, s.removeOps(hasLastRef)...)
}
svcOp := txn.Op{
C: s.st.services.Name,
Id: s.doc.Name,
Update: D{{"$inc", D{{"unitcount", -1}}}},
}
if s.doc.Life == Alive {
svcOp.Assert = D{{"life", Alive}, {"unitcount", D{{"$gt", 0}}}}
} else {
svcOp.Assert = D{{"life", Dying}, {"unitcount", D{{"$gt", 1}}}}
}
return append(ops, svcOp)
}
// advanceLifecycle ensures that the machine's lifecycle is no earlier
// than the supplied value. If the machine already has that lifecycle
// value, or a later one, no changes will be made to remote state. If
// the machine has any responsibilities that preclude a valid change in
// lifecycle, it will return an error.
func (original *Machine) advanceLifecycle(life Life) (err error) {
containers, err := original.Containers()
if err != nil {
return err
}
if len(containers) > 0 {
return &HasContainersError{
MachineId: original.doc.Id,
ContainerIds: containers,
}
}
m := original
defer func() {
if err == nil {
// The machine's lifecycle is known to have advanced; it may be
// known to have already advanced further than requested, in
// which case we set the latest known valid value.
if m == nil {
life = Dead
} else if m.doc.Life > life {
life = m.doc.Life
}
original.doc.Life = life
}
}()
// op and
op := txn.Op{
C: m.st.machines.Name,
Id: m.doc.Id,
Update: bson.D{{"$set", bson.D{{"life", life}}}},
}
advanceAsserts := bson.D{
{"jobs", bson.D{{"$nin", []MachineJob{JobManageEnviron}}}},
{"$or", []bson.D{
{{"principals", bson.D{{"$size", 0}}}},
{{"principals", bson.D{{"$exists", false}}}},
}},
{"hasvote", bson.D{{"$ne", true}}},
}
// 3 attempts: one with original data, one with refreshed data, and a final
// one intended to determine the cause of failure of the preceding attempt.
for i := 0; i < 3; i++ {
// If the transaction was aborted, grab a fresh copy of the machine data.
// We don't write to original, because the expectation is that state-
// changing methods only set the requested change on the receiver; a case
// could perhaps be made that this is not a helpful convention in the
// context of the new state API, but we maintain consistency in the
// face of uncertainty.
if i != 0 {
if m, err = m.st.Machine(m.doc.Id); errors.IsNotFound(err) {
return nil
} else if err != nil {
return err
}
}
// Check that the life change is sane, and collect the assertions
// necessary to determine that it remains so.
switch life {
case Dying:
if m.doc.Life != Alive {
return nil
}
op.Assert = append(advanceAsserts, isAliveDoc...)
case Dead:
if m.doc.Life == Dead {
return nil
}
op.Assert = append(advanceAsserts, notDeadDoc...)
default:
panic(fmt.Errorf("cannot advance lifecycle to %v", life))
}
// Check that the machine does not have any responsibilities that
// prevent a lifecycle change.
if hasJob(m.doc.Jobs, JobManageEnviron) {
// (NOTE: When we enable multiple JobManageEnviron machines,
// this restriction will be lifted, but we will assert that the
// machine is not voting)
return fmt.Errorf("machine %s is required by the environment", m.doc.Id)
}
if m.doc.HasVote {
return fmt.Errorf("machine %s is a voting replica set member", m.doc.Id)
}
if len(m.doc.Principals) != 0 {
return &HasAssignedUnitsError{
MachineId: m.doc.Id,
UnitNames: m.doc.Principals,
}
}
// Run the transaction...
if err := m.st.runTransaction([]txn.Op{op}); err != txn.ErrAborted {
return err
}
// ...and retry on abort.
}
// In very rare circumstances, the final iteration above will have determined
// no cause of failure, and attempted a final transaction: if this also failed,
// we can be sure that the machine document is changing very fast, in a somewhat
// surprising fashion, and that it is sensible to back off for now.
return fmt.Errorf("machine %s cannot advance lifecycle: %v", m, ErrExcessiveContention)
}
// removeUnitOps returns the operations necessary to remove the supplied unit,
// assuming the supplied asserts apply to the unit document.
func (s *Service) removeUnitOps(u *Unit, asserts D) ([]txn.Op, error) {
var ops []txn.Op
if s.doc.Subordinate {
ops = append(ops, txn.Op{
C: s.st.units.Name,
Id: u.doc.Principal,
Assert: txn.DocExists,
Update: D{{"$pull", D{{"subordinates", u.doc.Name}}}},
})
} else if u.doc.MachineId != "" {
ops = append(ops, txn.Op{
C: s.st.machines.Name,
Id: u.doc.MachineId,
Assert: txn.DocExists,
Update: D{{"$pull", D{{"principals", u.doc.Name}}}},
})
}
observedFieldsMatch := D{
{"charmurl", u.doc.CharmURL},
{"machineid", u.doc.MachineId},
}
ops = append(ops, txn.Op{
C: s.st.units.Name,
Id: u.doc.Name,
Assert: append(observedFieldsMatch, asserts...),
Remove: true,
},
removeConstraintsOp(s.st, u.globalKey()),
removeStatusOp(s.st, u.globalKey()),
annotationRemoveOp(s.st, u.globalKey()),
)
if u.doc.CharmURL != nil {
decOps, err := settingsDecRefOps(s.st, s.doc.Name, u.doc.CharmURL)
if errors.IsNotFoundError(err) {
return nil, errRefresh
} else if err != nil {
return nil, err
}
ops = append(ops, decOps...)
}
if s.doc.Life == Dying && s.doc.RelationCount == 0 && s.doc.UnitCount == 1 {
hasLastRef := D{{"life", Dying}, {"relationcount", 0}, {"unitcount", 1}}
return append(ops, s.removeOps(hasLastRef)...), nil
}
svcOp := txn.Op{
C: s.st.services.Name,
Id: s.doc.Name,
Update: D{{"$inc", D{{"unitcount", -1}}}},
}
if s.doc.Life == Alive {
svcOp.Assert = D{{"life", Alive}, {"unitcount", D{{"$gt", 0}}}}
} else {
svcOp.Assert = D{
{"life", Dying},
{"$or", []D{
{{"unitcount", D{{"$gt", 1}}}},
{{"relationcount", D{{"$gt", 0}}}},
}},
}
}
return append(ops, svcOp), nil
}