func (s *FastPeriodSuite) TestMustErr(c *gc.C) {
err := watcher.MustErr(&dummyWatcher{errors.New("POW")})
c.Assert(err, gc.ErrorMatches, "POW")
stillAlive := func() { watcher.MustErr(&dummyWatcher{tomb.ErrStillAlive}) }
c.Assert(stillAlive, gc.PanicMatches, "watcher is still running")
noErr := func() { watcher.MustErr(&dummyWatcher{nil}) }
c.Assert(noErr, gc.PanicMatches, "watcher was stopped cleanly")
}
func (q *AliveHookQueue) loop(initial *State) {
defer q.tomb.Done()
defer watcher.Stop(q.w, &q.tomb)
// Consume initial event, and reconcile with initial state, by inserting
// a new RelationUnitsChange before the initial event, which schedules
// every missing unit for immediate departure before anything else happens
// (apart from a single potential required post-joined changed event).
ch1, ok := <-q.w.Changes()
if !ok {
q.tomb.Kill(watcher.MustErr(q.w))
return
}
if len(ch1.Departed) != 0 {
panic("AliveHookQueue must be started with a fresh RelationUnitsWatcher")
}
q.changedPending = initial.ChangedPending
ch0 := params.RelationUnitsChange{}
for unit, version := range initial.Members {
q.info[unit] = &unitInfo{
unit: unit,
version: version,
joined: true,
}
if _, found := ch1.Changed[unit]; !found {
ch0.Departed = append(ch0.Departed, unit)
}
}
q.update(ch0)
q.update(ch1)
var next hook.Info
var out chan<- hook.Info
for {
if q.empty() {
out = nil
} else {
out = q.out
next = q.next()
}
select {
case <-q.tomb.Dying():
return
case ch, ok := <-q.w.Changes():
if !ok {
q.tomb.Kill(watcher.MustErr(q.w))
return
}
q.update(ch)
case out <- next:
q.pop()
}
}
}
func (p *ProvisionerAPI) watchOneMachineContainers(arg params.WatchContainer) (params.StringsWatchResult, error) {
nothing := params.StringsWatchResult{}
canAccess, err := p.getAuthFunc()
if err != nil {
return nothing, err
}
if !canAccess(arg.MachineTag) {
return nothing, common.ErrPerm
}
_, id, err := names.ParseTag(arg.MachineTag, names.MachineTagKind)
if err != nil {
return nothing, err
}
machine, err := p.st.Machine(id)
if err != nil {
return nothing, err
}
var watch state.StringsWatcher
if arg.ContainerType != "" {
watch = machine.WatchContainers(instance.ContainerType(arg.ContainerType))
} else {
watch = machine.WatchAllContainers()
}
// Consume the initial event and forward it to the result.
if changes, ok := <-watch.Changes(); ok {
return params.StringsWatchResult{
StringsWatcherId: p.resources.Register(watch),
Changes: changes,
}, nil
}
return nothing, watcher.MustErr(watch)
}
// WatchForEnvironConfigChanges returns a NotifyWatcher that observes
// changes to the environment configuration.
// Note that although the NotifyWatchResult contains an Error field,
// it's not used because we are only returning a single watcher,
// so we use the regular error return.
func (e *EnvironWatcher) WatchForEnvironConfigChanges() (params.NotifyWatchResult, error) {
result := params.NotifyWatchResult{}
canWatch, err := e.getCanWatch()
if err != nil {
return result, err
}
// TODO(dimitern) If we have multiple environments in state, use a
// tag argument here and as a method argument.
if !canWatch("") {
return result, ErrPerm
}
watch := e.st.WatchForEnvironConfigChanges()
// Consume the initial event. Technically, API
// calls to Watch 'transmit' the initial event
// in the Watch response. But NotifyWatchers
// have no state to transmit.
if _, ok := <-watch.Changes(); ok {
result.NotifyWatcherId = e.resources.Register(watch)
} else {
return result, watcher.MustErr(watch)
}
return result, nil
}
// WatchAuthorisedKeys starts a watcher to track changes to the authorised ssh keys
// for the specified machines.
// The current implementation relies on global authorised keys being stored in the environment config.
// This will change as new user management and authorisation functionality is added.
func (api *KeyUpdaterAPI) WatchAuthorisedKeys(arg params.Entities) (params.NotifyWatchResults, error) {
results := make([]params.NotifyWatchResult, len(arg.Entities))
canRead, err := api.getCanRead()
if err != nil {
return params.NotifyWatchResults{}, err
}
for i, entity := range arg.Entities {
// 1. Check permissions
if !canRead(entity.Tag) {
results[i].Error = common.ServerError(common.ErrPerm)
continue
}
// 2. Check entity exists
if _, err := api.state.FindEntity(entity.Tag); err != nil {
if errors.IsNotFound(err) {
results[i].Error = common.ServerError(common.ErrPerm)
} else {
results[i].Error = common.ServerError(err)
}
continue
}
// 3. Watch fr changes
var err error
watch := api.state.WatchForEnvironConfigChanges()
// Consume the initial event.
if _, ok := <-watch.Changes(); ok {
results[i].NotifyWatcherId = api.resources.Register(watch)
} else {
err = watcher.MustErr(watch)
}
results[i].Error = common.ServerError(err)
}
return params.NotifyWatchResults{Results: results}, nil
}
// watchMachinesLoop watches for changes provided by the given
// machinesWatcher and starts machine goroutines to deal
// with them, using the provided newMachineContext
// function to create the appropriate context for each new machine id.
func watchMachinesLoop(context updaterContext, w machinesWatcher) (err error) {
p := &updater{
context: context,
machines: make(map[string]chan struct{}),
machineDead: make(chan machine),
}
defer func() {
if stopErr := w.Stop(); stopErr != nil {
if err == nil {
err = fmt.Errorf("error stopping watcher: %v", stopErr)
} else {
logger.Warningf("ignoring error when stopping watcher: %v", stopErr)
}
}
for len(p.machines) > 0 {
delete(p.machines, (<-p.machineDead).Id())
}
}()
for {
select {
case ids, ok := <-w.Changes():
if !ok {
return watcher.MustErr(w)
}
if err := p.startMachines(ids); err != nil {
return err
}
case m := <-p.machineDead:
delete(p.machines, m.Id())
case <-p.context.dying():
return nil
}
}
}
// addRelation causes the unit agent to join the supplied relation, and to
// store persistent state in the supplied dir.
func (u *Uniter) addRelation(rel *uniter.Relation, dir *relation.StateDir) error {
logger.Infof("joining relation %q", rel)
ru, err := rel.Unit(u.unit)
if err != nil {
return err
}
r := NewRelationer(ru, dir, u.relationHooks)
w, err := u.unit.Watch()
if err != nil {
return err
}
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)
}
err := r.Join()
if params.IsCodeCannotEnterScopeYet(err) {
logger.Infof("cannot enter scope for relation %q; waiting for subordinate to be removed", rel)
continue
} else if err != nil {
return err
}
logger.Infof("joined relation %q", rel)
u.relationers[rel.Id()] = r
return nil
}
}
}
func (w *EnvironConfigWatcher) loop() (err error) {
sw := w.st.watchSettings(environGlobalKey)
defer sw.Stop()
out := w.out
out = nil
cfg := &config.Config{}
for {
select {
case <-w.st.watcher.Dead():
return stateWatcherDeadError(w.st.watcher.Err())
case <-w.tomb.Dying():
return tomb.ErrDying
case settings, ok := <-sw.Changes():
if !ok {
return watcher.MustErr(sw)
}
cfg, err = config.New(config.NoDefaults, settings.Map())
if err == nil {
out = w.out
} else {
out = nil
}
case out <- cfg:
out = nil
}
}
}
func (w *relationUnitsWatcher) loop() (err error) {
sentInitial := false
changes := params.RelationUnitsChange{}
out := w.out
out = nil
for {
select {
case <-w.st.watcher.Dead():
return stateWatcherDeadError(w.st.watcher.Err())
case <-w.tomb.Dying():
return tomb.ErrDying
case c, ok := <-w.sw.Changes():
if !ok {
return watcher.MustErr(w.sw)
}
if err = w.mergeScope(&changes, c); err != nil {
return err
}
if !sentInitial || !emptyRelationUnitsChanges(&changes) {
out = w.out
} else {
out = nil
}
case c := <-w.updates:
if _, err = w.mergeSettings(&changes, c.Id.(string)); err != nil {
return err
}
out = w.out
case out <- changes:
sentInitial = true
changes = params.RelationUnitsChange{}
out = nil
}
}
}
// ModeTerminating marks the unit dead and returns ErrTerminateAgent.
func ModeTerminating(u *Uniter) (next Mode, err error) {
defer modeContext("ModeTerminating", &err)()
if err = u.unit.SetStatus(params.StatusStopped, "", nil); err != nil {
return nil, err
}
w, err := u.unit.Watch()
if err != nil {
return nil, err
}
defer watcher.Stop(w, &u.tomb)
for {
select {
case <-u.tomb.Dying():
return nil, tomb.ErrDying
case _, ok := <-w.Changes():
if !ok {
return nil, watcher.MustErr(w)
}
if err := u.unit.Refresh(); err != nil {
return nil, err
}
if hasSubs, err := u.unit.HasSubordinates(); err != nil {
return nil, err
} else if hasSubs {
continue
}
// The unit is known to be Dying; so if it didn't have subordinates
// just above, it can't acquire new ones before this call.
if err := u.unit.EnsureDead(); err != nil {
return nil, err
}
return nil, worker.ErrTerminateAgent
}
}
}
func (obs *EnvironObserver) loop() error {
for {
select {
case <-obs.tomb.Dying():
return nil
case _, ok := <-obs.environWatcher.Changes():
if !ok {
return watcher.MustErr(obs.environWatcher)
}
}
config, err := obs.st.EnvironConfig()
if err != nil {
logger.Warningf("error reading environment config: %v", err)
continue
}
environ, err := environs.New(config)
if err != nil {
logger.Warningf("error creating Environ: %v", err)
continue
}
obs.mu.Lock()
obs.environ = environ
obs.mu.Unlock()
}
}
// WatchAPIHostPorts watches the API server addresses.
func (api *APIAddresser) WatchAPIHostPorts() (params.NotifyWatchResult, error) {
watch := api.getter.WatchAPIHostPorts()
if _, ok := <-watch.Changes(); ok {
return params.NotifyWatchResult{
NotifyWatcherId: api.resources.Register(watch),
}, nil
}
return params.NotifyWatchResult{}, watcher.MustErr(watch)
}
func (u *UniterAPI) watchOneRelationUnit(relUnit *state.RelationUnit) (params.RelationUnitsWatchResult, error) {
watch := relUnit.Watch()
// Consume the initial event and forward it to the result.
if changes, ok := <-watch.Changes(); ok {
return params.RelationUnitsWatchResult{
RelationUnitsWatcherId: u.resources.Register(watch),
Changes: changes,
}, nil
}
return params.RelationUnitsWatchResult{}, watcher.MustErr(watch)
}
func (task *provisionerTask) loop() error {
logger.Infof("Starting up provisioner task %s", task.machineTag)
defer watcher.Stop(task.machineWatcher, &task.tomb)
// Don't allow the safe mode to change until we have
// read at least one set of changes, which will populate
// the task.machines map. Otherwise we will potentially
// see all legitimate instances as unknown.
var safeModeChan chan bool
// Not all provisioners have a retry channel.
var retryChan <-chan struct{}
if task.retryWatcher != nil {
retryChan = task.retryWatcher.Changes()
}
// When the watcher is started, it will have the initial changes be all
// the machines that are relevant. Also, since this is available straight
// away, we know there will be some changes right off the bat.
for {
select {
case <-task.tomb.Dying():
logger.Infof("Shutting down provisioner task %s", task.machineTag)
return tomb.ErrDying
case ids, ok := <-task.machineWatcher.Changes():
if !ok {
return watcher.MustErr(task.machineWatcher)
}
if err := task.processMachines(ids); err != nil {
return fmt.Errorf("failed to process updated machines: %v", err)
}
// We've seen a set of changes. Enable safe mode change.
safeModeChan = task.safeModeChan
case safeMode := <-safeModeChan:
if safeMode == task.safeMode {
break
}
logger.Infof("safe mode changed to %v", safeMode)
task.safeMode = safeMode
if !safeMode {
// Safe mode has been disabled, so process current machines
// so that unknown machines will be immediately dealt with.
if err := task.processMachines(nil); err != nil {
return fmt.Errorf("failed to process machines after safe mode disabled: %v", err)
}
}
case <-retryChan:
if err := task.processMachinesWithTransientErrors(); err != nil {
return fmt.Errorf("failed to process machines with transient errors: %v", err)
}
}
}
}
func (u *UnitUpgraderAPI) watchAssignedMachine(unitTag string) (string, error) {
machine, err := u.getAssignedMachine(unitTag)
if err != nil {
return "", err
}
watch := machine.Watch()
// Consume the initial event. Technically, API
// calls to Watch 'transmit' the initial event
// in the Watch response. But NotifyWatchers
// have no state to transmit.
if _, ok := <-watch.Changes(); ok {
return u.resources.Register(watch), nil
}
return "", watcher.MustErr(watch)
}
func (u *UniterAPI) watchOneServiceRelations(tag string) (params.StringsWatchResult, error) {
nothing := params.StringsWatchResult{}
service, err := u.getService(tag)
if err != nil {
return nothing, err
}
watch := service.WatchRelations()
// Consume the initial event and forward it to the result.
if changes, ok := <-watch.Changes(); ok {
return params.StringsWatchResult{
StringsWatcherId: u.resources.Register(watch),
Changes: changes,
}, nil
}
return nothing, watcher.MustErr(watch)
}
func (p *environProvisioner) loop() error {
var environConfigChanges <-chan struct{}
environWatcher, err := p.st.WatchForEnvironConfigChanges()
if err != nil {
return err
}
environConfigChanges = environWatcher.Changes()
defer watcher.Stop(environWatcher, &p.tomb)
p.environ, err = worker.WaitForEnviron(environWatcher, p.st, p.tomb.Dying())
if err != nil {
return err
}
p.broker = p.environ
safeMode := p.environ.Config().ProvisionerSafeMode()
task, err := p.getStartTask(safeMode)
if err != nil {
return err
}
defer watcher.Stop(task, &p.tomb)
for {
select {
case <-p.tomb.Dying():
return tomb.ErrDying
case <-task.Dying():
err := task.Err()
logger.Errorf("environ provisioner died: %v", err)
return err
case _, ok := <-environConfigChanges:
if !ok {
return watcher.MustErr(environWatcher)
}
environConfig, err := p.st.EnvironConfig()
if err != nil {
logger.Errorf("cannot load environment configuration: %v", err)
return err
}
if err := p.setConfig(environConfig); err != nil {
logger.Errorf("loaded invalid environment configuration: %v", err)
}
task.SetSafeMode(environConfig.ProvisionerSafeMode())
}
}
}
// WatchMachineErrorRetry returns a NotifyWatcher that notifies when
// the provisioner should retry provisioning machines with transient errors.
func (p *ProvisionerAPI) WatchMachineErrorRetry() (params.NotifyWatchResult, error) {
result := params.NotifyWatchResult{}
canWatch, err := p.getCanWatchMachines()
if err != nil {
return params.NotifyWatchResult{}, err
}
if !canWatch("") {
return result, common.ErrPerm
}
watch := newWatchMachineErrorRetry()
// Consume any initial event and forward it to the result.
if _, ok := <-watch.Changes(); ok {
result.NotifyWatcherId = p.resources.Register(watch)
} else {
return result, watcher.MustErr(watch)
}
return result, nil
}
func (u *UniterAPI) watchOneUnitConfigSettings(tag string) (string, error) {
unit, err := u.getUnit(tag)
if err != nil {
return "", err
}
watch, err := unit.WatchConfigSettings()
if err != nil {
return "", err
}
// Consume the initial event. Technically, API
// calls to Watch 'transmit' the initial event
// in the Watch response. But NotifyWatchers
// have no state to transmit.
if _, ok := <-watch.Changes(); ok {
return u.resources.Register(watch), nil
}
return "", watcher.MustErr(watch)
}
func (a *AgentEntityWatcher) watchEntity(tag string) (string, error) {
entity0, err := a.st.FindEntity(tag)
if err != nil {
return "", err
}
entity, ok := entity0.(state.NotifyWatcherFactory)
if !ok {
return "", NotSupportedError(tag, "watching")
}
watch := entity.Watch()
// Consume the initial event. Technically, API
// calls to Watch 'transmit' the initial event
// in the Watch response. But NotifyWatchers
// have no state to transmit.
if _, ok := <-watch.Changes(); ok {
return a.resources.Register(watch), nil
}
return "", watcher.MustErr(watch)
}
// WatchEnvironMachines returns a StringsWatcher that notifies of
// changes to the life cycles of the top level machines in the current
// environment.
func (e *EnvironMachinesWatcher) WatchEnvironMachines() (params.StringsWatchResult, error) {
result := params.StringsWatchResult{}
canWatch, err := e.getCanWatch()
if err != nil {
return params.StringsWatchResult{}, err
}
if !canWatch("") {
return result, ErrPerm
}
watch := e.st.WatchEnvironMachines()
// Consume the initial event and forward it to the result.
if changes, ok := <-watch.Changes(); ok {
result.StringsWatcherId = e.resources.Register(watch)
result.Changes = changes
} else {
err := watcher.MustErr(watch)
return result, fmt.Errorf("cannot obtain initial environment machines: %v", err)
}
return result, nil
}
// WatchLoggingConfig starts a watcher to track changes to the logging config
// for the agents specified.. Unfortunately the current infrastruture makes
// watching parts of the config non-trivial, so currently any change to the
// config will cause the watcher to notify the client.
func (api *LoggerAPI) WatchLoggingConfig(arg params.Entities) params.NotifyWatchResults {
result := make([]params.NotifyWatchResult, len(arg.Entities))
for i, entity := range arg.Entities {
err := common.ErrPerm
if api.authorizer.AuthOwner(entity.Tag) {
watch := api.state.WatchForEnvironConfigChanges()
// Consume the initial event. Technically, API calls to Watch
// 'transmit' the initial event in the Watch response. But
// NotifyWatchers have no state to transmit.
if _, ok := <-watch.Changes(); ok {
result[i].NotifyWatcherId = api.resources.Register(watch)
err = nil
} else {
err = watcher.MustErr(watch)
}
}
result[i].Error = common.ServerError(err)
}
return params.NotifyWatchResults{Results: result}
}
// watchLoop watches the unit for port changes.
func (ud *unitData) watchLoop(latestPorts []instance.Port) {
defer ud.tomb.Done()
w, err := ud.unit.Watch()
if err != nil {
ud.fw.tomb.Kill(err)
return
}
defer watcher.Stop(w, &ud.tomb)
for {
select {
case <-ud.tomb.Dying():
return
case _, ok := <-w.Changes():
if !ok {
ud.fw.tomb.Kill(watcher.MustErr(w))
return
}
if err := ud.unit.Refresh(); err != nil {
if !params.IsCodeNotFound(err) {
ud.fw.tomb.Kill(err)
}
return
}
change, err := ud.unit.OpenedPorts()
if err != nil {
ud.fw.tomb.Kill(err)
return
}
if samePorts(change, latestPorts) {
continue
}
latestPorts = append(latestPorts[:0], change...)
select {
case ud.fw.portsChange <- &portsChange{ud, change}:
case <-ud.tomb.Dying():
return
}
}
}
}
// watchLoop watches the service's exposed flag for changes.
func (sd *serviceData) watchLoop(exposed bool) {
defer sd.tomb.Done()
w, err := sd.service.Watch()
if err != nil {
sd.fw.tomb.Kill(err)
return
}
defer watcher.Stop(w, &sd.tomb)
for {
select {
case <-sd.tomb.Dying():
return
case _, ok := <-w.Changes():
if !ok {
sd.fw.tomb.Kill(watcher.MustErr(w))
return
}
if err := sd.service.Refresh(); err != nil {
if !params.IsCodeNotFound(err) {
sd.fw.tomb.Kill(err)
}
return
}
change, err := sd.service.IsExposed()
if err != nil {
sd.fw.tomb.Kill(err)
return
}
if change == exposed {
continue
}
exposed = change
select {
case sd.fw.exposedChange <- &exposedChange{sd, change}:
case <-sd.tomb.Dying():
return
}
}
}
}
// WaitForEnviron waits for an valid environment to arrive from
// the given watcher. It terminates with tomb.ErrDying if
// it receives a value on dying.
func WaitForEnviron(w apiwatcher.NotifyWatcher, st EnvironConfigGetter, dying <-chan struct{}) (environs.Environ, error) {
for {
select {
case <-dying:
return nil, tomb.ErrDying
case _, ok := <-w.Changes():
if !ok {
return nil, watcher.MustErr(w)
}
config, err := st.EnvironConfig()
if err != nil {
return nil, err
}
environ, err := environs.New(config)
if err == nil {
return environ, nil
}
logger.Errorf("loaded invalid environment configuration: %v", err)
loadedInvalid()
}
}
}
// watchLoop watches the machine for units added or removed.
func (md *machineData) watchLoop(unitw apiwatcher.StringsWatcher) {
defer md.tomb.Done()
defer watcher.Stop(unitw, &md.tomb)
for {
select {
case <-md.tomb.Dying():
return
case change, ok := <-unitw.Changes():
if !ok {
_, err := md.machine()
if !params.IsCodeNotFound(err) {
md.fw.tomb.Kill(watcher.MustErr(unitw))
}
return
}
select {
case md.fw.unitsChange <- &unitsChange{md, change}:
case <-md.tomb.Dying():
return
}
}
}
}
func (u *UnitsWatcher) watchOneEntityUnits(canWatch AuthFunc, tag string) (params.StringsWatchResult, error) {
nothing := params.StringsWatchResult{}
if !canWatch(tag) {
return nothing, ErrPerm
}
entity0, err := u.st.FindEntity(tag)
if err != nil {
return nothing, err
}
entity, ok := entity0.(state.UnitsWatcher)
if !ok {
return nothing, NotSupportedError(tag, "watching units")
}
watch := entity.WatchUnits()
// Consume the initial event and forward it to the result.
if changes, ok := <-watch.Changes(); ok {
return params.StringsWatchResult{
StringsWatcherId: u.resources.Register(watch),
Changes: changes,
}, nil
}
return nothing, watcher.MustErr(watch)
}
// WatchAPIVersion starts a watcher to track if there is a new version
// of the API that we want to upgrade to
func (u *UpgraderAPI) WatchAPIVersion(args params.Entities) (params.NotifyWatchResults, error) {
result := params.NotifyWatchResults{
Results: make([]params.NotifyWatchResult, len(args.Entities)),
}
for i, agent := range args.Entities {
err := common.ErrPerm
if u.authorizer.AuthOwner(agent.Tag) {
watch := u.st.WatchForEnvironConfigChanges()
// Consume the initial event. Technically, API
// calls to Watch 'transmit' the initial event
// in the Watch response. But NotifyWatchers
// have no state to transmit.
if _, ok := <-watch.Changes(); ok {
result.Results[i].NotifyWatcherId = u.resources.Register(watch)
err = nil
} else {
err = watcher.MustErr(watch)
}
}
result.Results[i].Error = common.ServerError(err)
}
return result, nil
}
// startMachine creates a new data value for tracking details of the
// machine and starts watching the machine for units added or removed.
func (fw *Firewaller) startMachine(tag string) error {
machined := &machineData{
fw: fw,
tag: tag,
unitds: make(map[string]*unitData),
ports: make([]instance.Port, 0),
}
m, err := machined.machine()
if params.IsCodeNotFound(err) {
return nil
} else if err != nil {
return errgo.Annotate(err, "cannot watch machine units")
}
unitw, err := m.WatchUnits()
if err != nil {
return err
}
select {
case <-fw.tomb.Dying():
stop("units watcher", unitw)
return tomb.ErrDying
case change, ok := <-unitw.Changes():
if !ok {
stop("units watcher", unitw)
return watcher.MustErr(unitw)
}
fw.machineds[tag] = machined
err = fw.unitsChanged(&unitsChange{machined, change})
if err != nil {
stop("units watcher", unitw)
delete(fw.machineds, tag)
return errgo.Annotatef(err, "cannot respond to units changes for %q", tag)
}
}
go machined.watchLoop(unitw)
return nil
}
func (f *filter) loop(unitTag string) (err error) {
defer func() {
if params.IsCodeNotFoundOrCodeUnauthorized(err) {
err = worker.ErrTerminateAgent
}
}()
if f.unit, err = f.st.Unit(unitTag); err != nil {
return err
}
if err = f.unitChanged(); err != nil {
return err
}
f.service, err = f.unit.Service()
if err != nil {
return err
}
if err = f.serviceChanged(); err != nil {
return err
}
unitw, err := f.unit.Watch()
if err != nil {
return err
}
defer f.maybeStopWatcher(unitw)
servicew, err := f.service.Watch()
if err != nil {
return err
}
defer f.maybeStopWatcher(servicew)
// configw and relationsw can get restarted, so we need to use
// their eventual values in the defer calls.
var configw apiwatcher.NotifyWatcher
var configChanges <-chan struct{}
curl, err := f.unit.CharmURL()
if err == nil {
configw, err = f.unit.WatchConfigSettings()
if err != nil {
return err
}
configChanges = configw.Changes()
f.upgradeFrom.url = curl
} else if err != uniter.ErrNoCharmURLSet {
filterLogger.Errorf("unit charm: %v", err)
return err
}
defer func() {
if configw != nil {
watcher.Stop(configw, &f.tomb)
}
}()
relationsw, err := f.service.WatchRelations()
if err != nil {
return err
}
defer func() {
if relationsw != nil {
watcher.Stop(relationsw, &f.tomb)
}
}()
// Config events cannot be meaningfully discarded until one is available;
// once we receive the initial change, we unblock discard requests by
// setting this channel to its namesake on f.
var discardConfig chan struct{}
for {
var ok bool
select {
case <-f.tomb.Dying():
return tomb.ErrDying
// Handle watcher changes.
case _, ok = <-unitw.Changes():
filterLogger.Debugf("got unit change")
if !ok {
return watcher.MustErr(unitw)
}
if err = f.unitChanged(); err != nil {
return err
}
case _, ok = <-servicew.Changes():
filterLogger.Debugf("got service change")
if !ok {
return watcher.MustErr(servicew)
}
if err = f.serviceChanged(); err != nil {
return err
}
case _, ok = <-configChanges:
filterLogger.Debugf("got config change")
if !ok {
return watcher.MustErr(configw)
}
filterLogger.Debugf("preparing new config event")
f.outConfig = f.outConfigOn
discardConfig = f.discardConfig
case keys, ok := <-relationsw.Changes():
filterLogger.Debugf("got relations change")
if !ok {
return watcher.MustErr(relationsw)
}
var ids []int
for _, key := range keys {
relationTag := names.RelationTag(key)
rel, err := f.st.Relation(relationTag)
if params.IsCodeNotFoundOrCodeUnauthorized(err) {
// If it's actually gone, this unit cannot have entered
// scope, and therefore never needs to know about it.
} else if err != nil {
return err
} else {
ids = append(ids, rel.Id())
}
}
f.relationsChanged(ids)
// Send events on active out chans.
case f.outUpgrade <- f.upgrade:
filterLogger.Debugf("sent upgrade event")
f.outUpgrade = nil
case f.outResolved <- f.resolved:
filterLogger.Debugf("sent resolved event")
f.outResolved = nil
case f.outConfig <- nothing:
filterLogger.Debugf("sent config event")
f.outConfig = nil
case f.outRelations <- f.relations:
filterLogger.Debugf("sent relations event")
f.outRelations = nil
f.relations = nil
// Handle explicit requests.
case curl := <-f.setCharm:
filterLogger.Debugf("changing charm to %q", curl)
// We need to restart the config watcher after setting the
// charm, because service config settings are distinct for
// different service charms.
if configw != nil {
if err := configw.Stop(); err != nil {
return err
}
}
if err := f.unit.SetCharmURL(curl); err != nil {
filterLogger.Debugf("failed setting charm url %q: %v", curl, err)
return err
}
select {
case <-f.tomb.Dying():
return tomb.ErrDying
case f.didSetCharm <- nothing:
}
configw, err = f.unit.WatchConfigSettings()
if err != nil {
return err
}
configChanges = configw.Changes()
// Restart the relations watcher.
if err := relationsw.Stop(); err != nil {
return err
}
relationsw, err = f.service.WatchRelations()
if err != nil {
return err
}
f.upgradeFrom.url = curl
if err = f.upgradeChanged(); err != nil {
return err
}
case force := <-f.wantForcedUpgrade:
filterLogger.Debugf("want forced upgrade %v", force)
f.upgradeFrom.force = force
if err = f.upgradeChanged(); err != nil {
return err
}
case <-f.wantResolved:
filterLogger.Debugf("want resolved event")
if f.resolved != params.ResolvedNone {
f.outResolved = f.outResolvedOn
}
case <-f.clearResolved:
filterLogger.Debugf("resolved event handled")
f.outResolved = nil
if err := f.unit.ClearResolved(); err != nil {
return err
}
if err := f.unitChanged(); err != nil {
return err
}
select {
case <-f.tomb.Dying():
return tomb.ErrDying
case f.didClearResolved <- nothing:
}
case <-discardConfig:
filterLogger.Debugf("discarded config event")
f.outConfig = nil
}
}
}