// Destroy ensures that the relation will be removed at some point; if no units
// are currently in scope, it will be removed immediately.
func (r *Relation) Destroy() (err error) {
defer trivial.ErrorContextf(&err, "cannot destroy relation %q", r)
defer func() {
if err == nil {
// This is a white lie; the document might actually be removed.
r.doc.Life = Dying
}
}()
rel := &Relation{r.st, r.doc}
// In this context, aborted transactions indicate that the number of units
// in scope have changed between 0 and not-0. The chances of 5 successive
// attempts each hitting this change -- which is itself an unlikely one --
// are considered to be extremely small.
for attempt := 0; attempt < 5; attempt++ {
ops, _, err := rel.destroyOps("")
if err == errAlreadyDying {
return nil
} else if err != nil {
return err
}
if err := rel.st.runner.Run(ops, "", nil); err != txn.ErrAborted {
return err
}
if err := rel.Refresh(); IsNotFound(err) {
return nil
} else if err != nil {
return err
}
}
return ErrExcessiveContention
}
// RemoveUnit removes the given unit from s.
func (s *Service) RemoveUnit(u *Unit) (err error) {
defer trivial.ErrorContextf(&err, "cannot remove unit %q", u)
if u.doc.Life != Dead {
return errors.New("unit is not dead")
}
if u.doc.Service != s.doc.Name {
return fmt.Errorf("unit is not assigned to service %q", s)
}
svc := &Service{s.st, s.doc}
unit := &Unit{u.st, u.doc}
for i := 0; i < 5; i++ {
ops := svc.removeUnitOps(unit)
if err := svc.st.runner.Run(ops, "", nil); err != txn.ErrAborted {
return err
}
if err := unit.Refresh(); IsNotFound(err) {
return nil
} else if err != nil {
return err
}
if err := svc.Refresh(); IsNotFound(err) {
return nil
} else if err != nil {
return err
}
}
return ErrExcessiveContention
}
// AddUnitSubordinateTo adds a new subordinate unit to the service, subordinate
// to principal. It does not verify relation state sanity or pre-existence of
// other subordinates of the same service; is deprecated; and only continues
// to exist for the convenience of certain tests, which are themselves due for
// overhaul.
func (s *Service) AddUnitSubordinateTo(principal *Unit) (unit *Unit, err error) {
log.Printf("state: Service.AddUnitSubordinateTo is DEPRECATED; subordinate units should be created only as a side-effect of a principal entering relation scope")
defer trivial.ErrorContextf(&err, "cannot add unit to service %q as a subordinate of %q", s, principal)
ch, _, err := s.Charm()
if err != nil {
return nil, err
}
if !ch.Meta().Subordinate {
return nil, fmt.Errorf("service is not a subordinate")
}
if !principal.IsPrincipal() {
return nil, fmt.Errorf("unit is not a principal")
}
name, ops, err := s.addUnitOps(principal.doc.Name, false)
if err != nil {
return nil, err
}
if err = s.st.runner.Run(ops, "", nil); err == nil {
return s.Unit(name)
} else if err != txn.ErrAborted {
return nil, err
}
if alive, err := isAlive(s.st.services, s.doc.Name); err != nil {
return nil, err
} else if !alive {
return nil, fmt.Errorf("service is not alive")
}
if alive, err := isAlive(s.st.units, principal.doc.Name); err != nil {
return nil, err
} else if !alive {
return nil, fmt.Errorf("principal unit is not alive")
}
return nil, fmt.Errorf("inconsistent state")
}
// validate returns an error if the state violates expectations.
func (st State) validate() (err error) {
defer trivial.ErrorContextf(&err, "invalid uniter state")
hasHook := st.Hook != nil
hasCharm := st.CharmURL != nil
switch st.Op {
case Install:
if hasHook {
return fmt.Errorf("unexpected hook info")
}
fallthrough
case Upgrade:
if !hasCharm {
return fmt.Errorf("missing charm URL")
}
case Continue, RunHook:
if !hasHook {
return fmt.Errorf("missing hook info")
} else if hasCharm {
return fmt.Errorf("unexpected charm URL")
}
default:
return fmt.Errorf("unknown operation %q", st.Op)
}
switch st.OpStep {
case Queued, Pending, Done:
default:
return fmt.Errorf("unknown operation step %q", st.OpStep)
}
if hasHook {
return st.Hook.Validate()
}
return nil
}
// AssignUnit places the unit on a machine. Depending on the policy, and the
// state of the environment, this may lead to new instances being launched
// within the environment.
func (st *State) AssignUnit(u *Unit, policy AssignmentPolicy) (err error) {
if !u.IsPrincipal() {
return fmt.Errorf("subordinate unit %q cannot be assigned directly to a machine", u)
}
defer trivial.ErrorContextf(&err, "cannot assign unit %q to machine", u)
var m *Machine
switch policy {
case AssignLocal:
m, err = st.Machine("0")
if err != nil {
return err
}
return u.AssignToMachine(m)
case AssignUnused:
if _, err = u.AssignToUnusedMachine(); err != noUnusedMachines {
return err
}
for {
// TODO(rog) take out a lease on the new machine
// so that we don't have a race here.
m, err := st.AddMachine(JobHostUnits)
if err != nil {
return err
}
err = u.assignToMachine(m, true)
if err == inUseErr {
// Someone else has grabbed the machine we've
// just allocated, so try again.
continue
}
return err
}
}
panic(fmt.Errorf("unknown unit assignment policy: %q", policy))
}
// RemoveMachine removes the machine with the the given id.
func (st *State) RemoveMachine(id string) (err error) {
defer trivial.ErrorContextf(&err, "cannot remove machine %s", id)
m, err := st.Machine(id)
if err != nil {
return err
}
if m.doc.Life != Dead {
return fmt.Errorf("machine is not dead")
}
sel := D{
{"_id", id},
{"life", Dead},
}
ops := []txn.Op{{
C: st.machines.Name,
Id: id,
Assert: sel,
Remove: true,
}}
if err := st.runner.Run(ops, "", nil); err != nil {
// If aborted, the machine is either dead or recreated.
return onAbort(err, nil)
}
return nil
}
// Write atomically writes to disk the relation state change in hi.
// It must be called after the respective hook was executed successfully.
// Write doesn't validate hi but guarantees that successive writes of
// the same hi are idempotent.
func (d *StateDir) Write(hi hook.Info) (err error) {
defer trivial.ErrorContextf(&err, "failed to write %q hook info for %q on state directory", hi.Kind, hi.RemoteUnit)
if hi.Kind == hook.RelationBroken {
return d.Remove()
}
name := strings.Replace(hi.RemoteUnit, "/", "-", 1)
path := filepath.Join(d.path, name)
if hi.Kind == hook.RelationDeparted {
if err = os.Remove(path); err != nil && !os.IsNotExist(err) {
return err
}
// If atomic delete succeeded, update own state.
delete(d.state.Members, hi.RemoteUnit)
return nil
}
di := diskInfo{&hi.ChangeVersion, hi.Kind == hook.RelationJoined}
if err := trivial.WriteYaml(path, &di); err != nil {
return err
}
// If write was successful, update own state.
d.state.Members[hi.RemoteUnit] = hi.ChangeVersion
if hi.Kind == hook.RelationJoined {
d.state.ChangedPending = hi.RemoteUnit
} else {
d.state.ChangedPending = ""
}
return nil
}
// DestroyUnits removes the specified units from the state.
func (conn *Conn) DestroyUnits(names ...string) (err error) {
defer trivial.ErrorContextf(&err, "cannot destroy units")
var units []*state.Unit
for _, name := range names {
unit, err := conn.State.Unit(name)
switch {
case state.IsNotFound(err):
return fmt.Errorf("unit %q is not alive", name)
case err != nil:
return err
case unit.Life() != state.Alive:
return fmt.Errorf("unit %q is not alive", name)
case unit.IsPrincipal():
units = append(units, unit)
default:
return fmt.Errorf("unit %q is a subordinate", name)
}
}
for _, unit := range units {
if err := unit.EnsureDying(); err != nil {
return err
}
}
return nil
}
// SetResolved marks the unit as having had any previous state transition
// problems resolved, and informs the unit that it may attempt to
// reestablish normal workflow. The resolved mode parameter informs
// whether to attempt to reexecute previous failed hooks or to continue
// as if they had succeeded before.
func (u *Unit) SetResolved(mode ResolvedMode) (err error) {
defer trivial.ErrorContextf(&err, "cannot set resolved mode for unit %q", u)
switch mode {
case ResolvedNone, ResolvedRetryHooks, ResolvedNoHooks:
default:
return fmt.Errorf("invalid error resolution mode: %q", mode)
}
assert := append(notDeadDoc, D{{"resolved", ResolvedNone}}...)
ops := []txn.Op{{
C: u.st.units.Name,
Id: u.doc.Name,
Assert: assert,
Update: D{{"$set", D{{"resolved", mode}}}},
}}
if err := u.st.runner.Run(ops, "", nil); err != nil {
if err == txn.ErrAborted {
// Find which assertion failed so we can give a
// more specific error.
u1, err := u.st.Unit(u.Name())
if err != nil {
return err
}
if u1.Life() != Alive {
return errNotAlive
}
return fmt.Errorf("already resolved")
}
return err
}
u.doc.Resolved = mode
return nil
}
// Validate returns an error if the supplied hook.Info does not represent
// a valid change to the relation state. Hooks must always be validated
// against the current state before they are run, to ensure that the system
// meets its guarantees about hook execution order.
func (s *State) Validate(hi hook.Info) (err error) {
defer trivial.ErrorContextf(&err, "inappropriate %q for %q", hi.Kind, hi.RemoteUnit)
if hi.RelationId != s.RelationId {
return fmt.Errorf("expected relation %d, got relation %d", s.RelationId, hi.RelationId)
}
if s.Members == nil {
return fmt.Errorf(`relation is broken and cannot be changed further`)
}
unit, kind := hi.RemoteUnit, hi.Kind
if kind == hook.RelationBroken {
if len(s.Members) == 0 {
return nil
}
return fmt.Errorf(`cannot run "relation-broken" while units still present`)
}
if s.ChangedPending != "" {
if unit != s.ChangedPending || kind != hook.RelationChanged {
return fmt.Errorf(`expected "relation-changed" for %q`, s.ChangedPending)
}
} else if _, joined := s.Members[unit]; joined && kind == hook.RelationJoined {
return fmt.Errorf("unit already joined")
} else if !joined && kind != hook.RelationJoined {
return fmt.Errorf("unit has not joined")
}
return nil
}
func (u *Uniter) init(name string) (err error) {
defer trivial.ErrorContextf(&err, "failed to initialize uniter for unit %q", name)
u.unit, err = u.st.Unit(name)
if err != nil {
return err
}
ename := u.unit.EntityName()
u.toolsDir = environs.AgentToolsDir(u.dataDir, ename)
if err := EnsureJujucSymlinks(u.toolsDir); err != nil {
return err
}
u.baseDir = filepath.Join(u.dataDir, "agents", ename)
u.relationsDir = filepath.Join(u.baseDir, "state", "relations")
if err := os.MkdirAll(u.relationsDir, 0755); err != nil {
return err
}
u.service, err = u.st.Service(u.unit.ServiceName())
if err != nil {
return err
}
u.relationers = map[int]*Relationer{}
u.relationHooks = make(chan hook.Info)
u.charm = charm.NewGitDir(filepath.Join(u.baseDir, "charm"))
u.bundles = charm.NewBundlesDir(filepath.Join(u.baseDir, "state", "bundles"))
u.deployer = charm.NewDeployer(filepath.Join(u.baseDir, "state", "deployer"))
u.sf = NewStateFile(filepath.Join(u.baseDir, "state", "uniter"))
u.rand = rand.New(rand.NewSource(time.Now().Unix()))
return nil
}
// Destroy ensures that the service and all its relations will be removed at
// some point; if the service has no units, and no relation involving the
// service has any units in scope, they are all removed immediately.
func (s *Service) Destroy() (err error) {
defer trivial.ErrorContextf(&err, "cannot destroy service %q", s)
defer func() {
if err != nil {
// This is a white lie; the document might actually be removed.
s.doc.Life = Dying
}
}()
svc := &Service{s.st, s.doc}
for i := 0; i < 5; i++ {
ops, err := svc.destroyOps()
switch {
case err == errRefresh:
case err == errAlreadyDying:
return nil
case err != nil:
return err
default:
if err := svc.st.runner.Run(ops, "", nil); err != txn.ErrAborted {
return err
}
}
if err := svc.Refresh(); IsNotFound(err) {
return nil
} else if err != nil {
return err
}
}
return ErrExcessiveContention
}
// ReadAllStateDirs loads and returns every StateDir persisted directly inside
// the supplied dirPath. If dirPath does not exist, no error is returned.
func ReadAllStateDirs(dirPath string) (dirs map[int]*StateDir, err error) {
defer trivial.ErrorContextf(&err, "cannot load relations state from %q", dirPath)
if _, err := os.Stat(dirPath); os.IsNotExist(err) {
return nil, nil
} else if err != nil {
return nil, err
}
fis, err := ioutil.ReadDir(dirPath)
if err != nil {
return nil, err
}
dirs = map[int]*StateDir{}
for _, fi := range fis {
// Entries with integer names must be directories containing StateDir
// data; all other names will be ignored.
relationId, err := strconv.Atoi(fi.Name())
if err != nil {
// This doesn't look like a relation.
continue
}
dir, err := ReadStateDir(dirPath, relationId)
if err != nil {
return nil, err
}
dirs[relationId] = dir
}
return dirs, nil
}
func verifyConfig(cfg *MachineConfig) (err error) {
defer trivial.ErrorContextf(&err, "invalid machine configuration")
if !state.IsMachineId(cfg.MachineId) {
return fmt.Errorf("invalid machine id")
}
if cfg.ProviderType == "" {
return fmt.Errorf("missing provider type")
}
if cfg.DataDir == "" {
return fmt.Errorf("missing var directory")
}
if cfg.Tools == nil {
return fmt.Errorf("missing tools")
}
if cfg.Tools.URL == "" {
return fmt.Errorf("missing tools URL")
}
if cfg.StateInfo == nil {
return fmt.Errorf("missing state info")
}
if len(cfg.StateInfo.CACert) == 0 {
return fmt.Errorf("missing CA certificate")
}
if cfg.StateServer {
if cfg.InstanceIdAccessor == "" {
return fmt.Errorf("missing instance id accessor")
}
if cfg.Config == nil {
return fmt.Errorf("missing environment configuration")
}
if cfg.StateInfo.EntityName != "" {
return fmt.Errorf("entity name must be blank when starting a state server")
}
if len(cfg.StateServerCert) == 0 {
return fmt.Errorf("missing state server certificate")
}
if len(cfg.StateServerKey) == 0 {
return fmt.Errorf("missing state server private key")
}
} else {
if len(cfg.StateInfo.Addrs) == 0 {
return fmt.Errorf("missing state hosts")
}
if cfg.StateInfo.EntityName != state.MachineEntityName(cfg.MachineId) {
return fmt.Errorf("entity name must match started machine")
}
}
for _, r := range cfg.StateInfo.Password {
if r == '\'' || r == '\\' || r < 32 {
return fmt.Errorf("password has disallowed characters")
}
}
return nil
}
// Relations returns a Relation for every relation the service is in.
func (s *Service) Relations() (relations []*Relation, err error) {
defer trivial.ErrorContextf(&err, "can't get relations for service %q", s)
docs := []relationDoc{}
err = s.st.relations.Find(D{{"endpoints.servicename", s.doc.Name}}).All(&docs)
if err != nil {
return nil, err
}
for _, v := range docs {
relations = append(relations, newRelation(s.st, &v))
}
return relations, nil
}
// ReadSettings returns a map holding the settings of the unit with the
// supplied name within this relation. An error will be returned if the
// relation no longer exists, or if the unit's service is not part of the
// relation, or the settings are invalid; but mere non-existence of the
// unit is not grounds for an error, because the unit settings are
// guaranteed to persist for the lifetime of the relation, regardless
// of the lifetime of the unit.
func (ru *RelationUnit) ReadSettings(uname string) (m map[string]interface{}, err error) {
defer trivial.ErrorContextf(&err, "cannot read settings for unit %q in relation %q", uname, ru.relation)
if !IsUnitName(uname) {
return nil, fmt.Errorf("%q is not a valid unit name", uname)
}
key, err := ru.key(uname)
if err != nil {
return nil, err
}
node, err := readSettings(ru.st, key)
if err != nil {
return nil, err
}
return node.Map(), nil
}
// ReadStateDir loads a StateDir from the subdirectory of dirPath named
// for the supplied RelationId. If the directory does not exist, no error
// is returned,
func ReadStateDir(dirPath string, relationId int) (d *StateDir, err error) {
d = &StateDir{
filepath.Join(dirPath, strconv.Itoa(relationId)),
State{relationId, map[string]int64{}, ""},
}
defer trivial.ErrorContextf(&err, "cannot load relation state from %q", d.path)
if _, err := os.Stat(d.path); os.IsNotExist(err) {
return d, nil
} else if err != nil {
return nil, err
}
fis, err := ioutil.ReadDir(d.path)
if err != nil {
return nil, err
}
for _, fi := range fis {
// Entries with names ending in "-" followed by an integer must be
// files containing valid unit data; all other names are ignored.
name := fi.Name()
i := strings.LastIndex(name, "-")
if i == -1 {
continue
}
svcName := name[:i]
unitId := name[i+1:]
if _, err := strconv.Atoi(unitId); err != nil {
continue
}
unitName := svcName + "/" + unitId
var info diskInfo
if err = trivial.ReadYaml(filepath.Join(d.path, name), &info); err != nil {
return nil, fmt.Errorf("invalid unit file %q: %v", name, err)
}
if info.ChangeVersion == nil {
return nil, fmt.Errorf(`invalid unit file %q: "changed-version" not set`, name)
}
d.state.Members[unitName] = *info.ChangeVersion
if info.ChangedPending {
if d.state.ChangedPending != "" {
return nil, fmt.Errorf("%q and %q both have pending changed hooks", d.state.ChangedPending, unitName)
}
d.state.ChangedPending = unitName
}
}
return d, nil
}
// SetAgentTools sets the tools that the agent is currently running.
func (u *Unit) SetAgentTools(t *Tools) (err error) {
defer trivial.ErrorContextf(&err, "cannot set agent tools for unit %q", u)
if t.Series == "" || t.Arch == "" {
return fmt.Errorf("empty series or arch")
}
ops := []txn.Op{{
C: u.st.units.Name,
Id: u.doc.Name,
Assert: notDeadDoc,
Update: D{{"$set", D{{"tools", t}}}},
}}
if err := u.st.runner.Run(ops, "", nil); err != nil {
return onAbort(err, errNotAlive)
}
tools := *t
u.doc.Tools = &tools
return nil
}
// AddUnit adds a new principal unit to the service.
func (s *Service) AddUnit() (unit *Unit, err error) {
defer trivial.ErrorContextf(&err, "cannot add unit to service %q", s)
name, ops, err := s.addUnitOps("", false)
if err != nil {
return nil, err
}
if err := s.st.runner.Run(ops, "", nil); err == txn.ErrAborted {
if alive, err := isAlive(s.st.services, s.doc.Name); err != nil {
return nil, err
} else if !alive {
return nil, fmt.Errorf("service is not alive")
}
return nil, fmt.Errorf("inconsistent state")
} else if err != nil {
return nil, err
}
return s.Unit(name)
}
// deathFailureReason returns an error indicating why the machine may have
// failed to advance its lifecycle to Dying or Dead. If deathFailureReason
// returns no error, it is possible that the condition that caused the txn
// failure no longer holds; it does not automatically indicate bad state.
func (m *Machine) deathFailureReason(life Life) (err error) {
if m, err = m.st.Machine(m.doc.Id); err != nil {
return err
}
defer trivial.ErrorContextf(&err, "machine %s cannot become %s", m, life)
for _, j := range m.doc.Jobs {
if j == JobManageEnviron {
// If and when we enable multiple JobManageEnviron machines, the
// restriction will become "there must be at least one machine
// with this job", and this will need to change.
return fmt.Errorf("required by environment")
}
}
if len(m.doc.Principals) != 0 {
return fmt.Errorf("unit %q is assigned to it", m.doc.Principals[0])
}
return nil
}
// SetAgentTools sets the tools that the agent is currently running.
func (m *Machine) SetAgentTools(t *Tools) (err error) {
defer trivial.ErrorContextf(&err, "cannot set agent tools for machine %v", m)
if t.Series == "" || t.Arch == "" {
return fmt.Errorf("empty series or arch")
}
ops := []txn.Op{{
C: m.st.machines.Name,
Id: m.doc.Id,
Assert: notDeadDoc,
Update: D{{"$set", D{{"tools", t}}}},
}}
if err := m.st.runner.Run(ops, "", nil); err != nil {
return onAbort(err, errNotAlive)
}
tools := *t
m.doc.Tools = &tools
return nil
}
// WaitAgentAlive blocks until the respective agent is alive.
func (u *Unit) WaitAgentAlive(timeout time.Duration) (err error) {
defer trivial.ErrorContextf(&err, "waiting for agent of unit %q", u)
ch := make(chan presence.Change)
u.st.pwatcher.Watch(u.globalKey(), ch)
defer u.st.pwatcher.Unwatch(u.globalKey(), ch)
for i := 0; i < 2; i++ {
select {
case change := <-ch:
if change.Alive {
return nil
}
case <-time.After(timeout):
return fmt.Errorf("still not alive after timeout")
case <-u.st.pwatcher.Dead():
return u.st.pwatcher.Err()
}
}
panic(fmt.Sprintf("presence reported dead status twice in a row for unit %q", u))
}
// addMachine implements AddMachine and InjectMachine.
func (st *State) addMachine(instanceId InstanceId, jobs []MachineJob) (m *Machine, err error) {
defer trivial.ErrorContextf(&err, "cannot add a new machine")
if len(jobs) == 0 {
return nil, fmt.Errorf("no jobs specified")
}
jset := make(map[MachineJob]bool)
for _, j := range jobs {
if jset[j] {
return nil, fmt.Errorf("duplicate job: %s", j)
}
jset[j] = true
}
seq, err := st.sequence("machine")
if err != nil {
return nil, err
}
id := strconv.Itoa(seq)
mdoc := machineDoc{
Id: id,
Life: Alive,
Jobs: jobs,
}
if instanceId != "" {
mdoc.InstanceId = instanceId
}
ops := []txn.Op{{
C: st.machines.Name,
Id: id,
Assert: txn.DocMissing,
Insert: mdoc,
}}
err = st.runner.Run(ops, "", nil)
if err != nil {
return nil, err
}
// Refresh to pick the txn-revno.
m = newMachine(st, &mdoc)
if err = m.Refresh(); err != nil {
return nil, err
}
return m, nil
}
// Units returns all the units that have been assigned to the machine.
func (m *Machine) Units() (units []*Unit, err error) {
defer trivial.ErrorContextf(&err, "cannot get units assigned to machine %v", m)
pudocs := []unitDoc{}
err = m.st.units.Find(D{{"machineid", m.doc.Id}}).All(&pudocs)
if err != nil {
return nil, err
}
for _, pudoc := range pudocs {
units = append(units, newUnit(m.st, &pudoc))
docs := []unitDoc{}
err = m.st.units.Find(D{{"principal", pudoc.Name}}).All(&docs)
if err != nil {
return nil, err
}
for _, doc := range docs {
units = append(units, newUnit(m.st, &doc))
}
}
return units, nil
}
// download fetches the supplied charm and checks that it has the correct sha256
// hash, then copies it into the directory. If a value is received on abort, the
// download will be stopped.
func (d *BundlesDir) download(sch *state.Charm, abort <-chan struct{}) (err error) {
defer trivial.ErrorContextf(&err, "failed to download charm %q from %q", sch.URL(), sch.BundleURL())
dir := d.downloadsPath()
if err := os.MkdirAll(dir, 0755); err != nil {
return err
}
burl := sch.BundleURL().String()
log.Printf("worker/uniter/charm: downloading %s from %s", sch.URL(), burl)
dl := downloader.New(burl, dir)
defer dl.Stop()
for {
select {
case <-abort:
log.Printf("worker/uniter/charm: download aborted")
return fmt.Errorf("aborted")
case st := <-dl.Done():
if st.Err != nil {
return st.Err
}
log.Printf("worker/uniter/charm: download complete")
defer st.File.Close()
hash := sha256.New()
if _, err = io.Copy(hash, st.File); err != nil {
return err
}
actualSha256 := hex.EncodeToString(hash.Sum(nil))
if actualSha256 != sch.BundleSha256() {
return fmt.Errorf(
"expected sha256 %q, got %q", sch.BundleSha256(), actualSha256,
)
}
log.Printf("worker/uniter/charm: download verified")
if err := os.MkdirAll(d.path, 0755); err != nil {
return err
}
return os.Rename(st.File.Name(), d.bundlePath(sch))
}
}
panic("unreachable")
}
// ClosePort sets the policy of the port with protocol and number to be closed.
func (u *Unit) ClosePort(protocol string, number int) (err error) {
port := Port{Protocol: protocol, Number: number}
defer trivial.ErrorContextf(&err, "cannot close port %v for unit %q", port, u)
ops := []txn.Op{{
C: u.st.units.Name,
Id: u.doc.Name,
Assert: notDeadDoc,
Update: D{{"$pull", D{{"ports", port}}}},
}}
err = u.st.runner.Run(ops, "", nil)
if err != nil {
return onAbort(err, errNotAlive)
}
newPorts := make([]Port, 0, len(u.doc.Ports))
for _, p := range u.doc.Ports {
if p != port {
newPorts = append(newPorts, p)
}
}
u.doc.Ports = newPorts
return nil
}
// ensureDead advances the specified entity's life status to Dead, if necessary.
// Preconditions can be supplied in assertOps; if the preconditions fail, the error
// will contain assertMsg. If the entity is not found, no error is returned.
func ensureDead(st *State, coll *mgo.Collection, id interface{}, desc string, assertOps []txn.Op, assertMsg string) (err error) {
defer trivial.ErrorContextf(&err, "cannot finish termination of %s %#v", desc, id)
ops := append(assertOps, txn.Op{
C: coll.Name,
Id: id,
Update: D{{"$set", D{{"life", Dead}}}},
})
if err = st.runner.Run(ops, "", nil); err == nil {
return nil
} else if err != txn.ErrAborted {
return err
}
var doc struct{ Life }
if err = coll.FindId(id).One(&doc); err == mgo.ErrNotFound {
return nil
} else if err != nil {
return err
} else if doc.Life != Dead {
return fmt.Errorf(assertMsg)
}
return nil
}
// fetchMetadata fetches a single atom of data from the ec2 instance metadata service.
// http://docs.amazonwebservices.com/AWSEC2/latest/UserGuide/AESDG-chapter-instancedata.html
func fetchMetadata(name string) (value string, err error) {
uri := fmt.Sprintf("%s/2011-01-01/meta-data/%s", metadataHost, name)
defer trivial.ErrorContextf(&err, "cannot get %q", uri)
for a := shortAttempt.Start(); a.Next(); {
var resp *http.Response
resp, err = http.Get(uri)
if err != nil {
continue
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
err = fmt.Errorf("bad http response %v", resp.Status)
continue
}
var data []byte
data, err = ioutil.ReadAll(resp.Body)
if err != nil {
continue
}
return strings.TrimSpace(string(data)), nil
}
return
}
// OpenPort sets the policy of the port with protocol and number to be opened.
func (u *Unit) OpenPort(protocol string, number int) (err error) {
port := Port{Protocol: protocol, Number: number}
defer trivial.ErrorContextf(&err, "cannot open port %v for unit %q", port, u)
ops := []txn.Op{{
C: u.st.units.Name,
Id: u.doc.Name,
Assert: notDeadDoc,
Update: D{{"$addToSet", D{{"ports", port}}}},
}}
err = u.st.runner.Run(ops, "", nil)
if err != nil {
return onAbort(err, errNotAlive)
}
found := false
for _, p := range u.doc.Ports {
if p == port {
break
}
}
if !found {
u.doc.Ports = append(u.doc.Ports, port)
}
return nil
}
// AddRelation creates a new relation with the given endpoints.
func (st *State) AddRelation(endpoints ...Endpoint) (r *Relation, err error) {
defer trivial.ErrorContextf(&err, "cannot add relation %q", relationKey(endpoints))
switch len(endpoints) {
case 1:
if endpoints[0].RelationRole != RolePeer {
return nil, fmt.Errorf("single endpoint must be a peer relation")
}
case 2:
if !endpoints[0].CanRelateTo(endpoints[1]) {
return nil, fmt.Errorf("endpoints do not relate")
}
default:
return nil, fmt.Errorf("cannot relate %d endpoints", len(endpoints))
}
ops := []txn.Op{}
var scope charm.RelationScope
for _, v := range endpoints {
if v.RelationScope == charm.ScopeContainer {
scope = charm.ScopeContainer
}
ops = append(ops, txn.Op{
C: st.services.Name,
Id: v.ServiceName,
Assert: isAliveDoc,
Update: D{{"$inc", D{{"relationcount", 1}}}},
})
}
if scope == charm.ScopeContainer {
for i := range endpoints {
endpoints[i].RelationScope = scope
}
}
id, err := st.sequence("relation")
if err != nil {
return nil, err
}
doc := relationDoc{
Key: relationKey(endpoints),
Id: id,
Endpoints: endpoints,
Life: Alive,
}
ops = append(ops, txn.Op{
C: st.relations.Name,
Id: doc.Key,
Assert: txn.DocMissing,
Insert: doc,
})
err = st.runner.Run(ops, "", nil)
if err == txn.ErrAborted {
for _, ep := range endpoints {
svc, err := st.Service(ep.ServiceName)
if IsNotFound(err) || svc.Life() != Alive {
return nil, fmt.Errorf("service %q is not alive", ep.ServiceName)
} else if err != nil {
return nil, err
}
}
return nil, fmt.Errorf("relation already exists")
} else if err != nil {
return nil, err
}
return newRelation(st, &doc), nil
}
