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package mstate
import (
"errors"
"fmt"
"labix.org/v2/mgo"
"labix.org/v2/mgo/bson"
"launchpad.net/juju-core/charm"
"strconv"
)
// Service represents the state of a service.
type Service struct {
st *State
name string
}
// serviceDoc represents the internal state of a service in MongoDB.
type serviceDoc struct {
Name string `bson:"_id"`
CharmURL *charm.URL
Life Life
UnitSeq int
}
// Name returns the service name.
func (s *Service) Name() string {
return s.name
}
// CharmURL returns the charm URL this service is supposed to use.
func (s *Service) CharmURL() (url *charm.URL, err error) {
sdoc := &serviceDoc{}
sel := bson.D{{"_id", s.name}, {"life", Alive}}
err = s.st.services.Find(sel).One(sdoc)
if err != nil {
return nil, fmt.Errorf("can't get the charm URL of service %q: %v", s, err)
}
return sdoc.CharmURL, nil
}
// SetCharmURL changes the charm URL for the service.
func (s *Service) SetCharmURL(url *charm.URL) (err error) {
change := bson.D{{"$set", bson.D{{"charmurl", url}}}}
err = s.st.services.Update(bson.D{{"_id", s.name}}, change)
if err != nil {
return fmt.Errorf("can't set the charm URL of service %q: %v", s, err)
}
return nil
}
// Charm returns the service's charm.
func (s *Service) Charm() (*Charm, error) {
url, err := s.CharmURL()
if err != nil {
return nil, err
}
return s.st.Charm(url)
}
// String returns the service name.
func (s *Service) String() string {
return s.Name()
}
// newUnitName returns the next unit name.
func (s *Service) newUnitName() (string, error) {
sel := bson.D{{"_id", s.name}, {"life", Alive}}
change := mgo.Change{Update: bson.D{{"$inc", bson.D{{"unitseq", 1}}}}}
result := serviceDoc{}
_, err := s.st.services.Find(sel).Apply(change, &result)
if err != nil {
return "", err
}
name := s.name + "/" + strconv.Itoa(result.UnitSeq)
return name, nil
}
// addUnit adds the named unit, which is part of unitSet.
func (s *Service) addUnit(name string, principal string) (*Unit, error) {
udoc := unitDoc{
Name: name,
Service: s.name,
Principal: principal,
Life: Alive,
}
err := s.st.units.Insert(udoc)
if err != nil {
return nil, fmt.Errorf("can't add unit to service %q", s)
}
return newUnit(s.st, &udoc), nil
}
// AddUnit adds a new principal unit to the service.
func (s *Service) AddUnit() (unit *Unit, err error) {
ch, err := s.Charm()
if err != nil {
return nil, fmt.Errorf("can't add unit to service %q: %v", err)
}
if ch.Meta().Subordinate {
return nil, fmt.Errorf("cannot directly add units to subordinate service %q", s)
}
name, err := s.newUnitName()
if err != nil {
return nil, fmt.Errorf("can't add unit to service %q: %v", err)
}
return s.addUnit(name, "")
}
// AddUnitSubordinateTo adds a new subordinate unit to the service,
// subordinate to principal.
func (s *Service) AddUnitSubordinateTo(principal *Unit) (*Unit, error) {
ch, err := s.Charm()
if err != nil {
return nil, fmt.Errorf("can't add unit to service %q: %v", err)
}
if !ch.Meta().Subordinate {
return nil, fmt.Errorf("can't add unit of principal service %q as a subordinate of %q", s, principal)
}
if !principal.IsPrincipal() {
return nil, errors.New("a subordinate unit must be added to a principal unit")
}
name, err := s.newUnitName()
if err != nil {
return nil, fmt.Errorf("can't add unit to service %q: %v", err)
}
return s.addUnit(name, principal.Name())
}
// RemoveUnit removes the given unit from s.
func (s *Service) RemoveUnit(unit *Unit) error {
sel := bson.D{
{"_id", unit.Name()},
{"service", s.name},
{"life", Alive},
}
change := bson.D{{"$set", bson.D{{"life", Dying}}}}
err := s.st.units.Update(sel, change)
if err != nil {
return fmt.Errorf("can't remove unit %q: %v", unit, err)
}
return nil
}
func (s *Service) unitDoc(name string) (*unitDoc, error) {
udoc := &unitDoc{}
sel := bson.D{
{"_id", name},
{"service", s.name},
{"life", Alive},
}
err := s.st.units.Find(sel).One(udoc)
if err != nil {
return nil, err
}
return udoc, nil
}
// Unit returns the service's unit with name.
func (s *Service) Unit(name string) (*Unit, error) {
udoc, err := s.unitDoc(name)
if err != nil {
return nil, fmt.Errorf("can't get unit %q from service %q: %v", name, s.name, err)
}
return newUnit(s.st, udoc), nil
}
// AllUnits returns all units of the service.
func (s *Service) AllUnits() (units []*Unit, err error) {
docs := []unitDoc{}
sel := bson.D{{"service", s.name}, {"life", Alive}}
err = s.st.units.Find(sel).All(&docs)
if err != nil {
return nil, fmt.Errorf("can't get all units from service %q: %v", err)
}
for i := range docs {
units = append(units, newUnit(s.st, &docs[i]))
}
return units, nil
}
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