// watchForProxyChanges kicks off a go routine to listen to the watcher and
// update the proxy settings.
func (u *Uniter) watchForProxyChanges(environWatcher apiwatcher.NotifyWatcher) {
go func() {
for {
select {
case <-u.tomb.Dying():
return
case _, ok := <-environWatcher.Changes():
logger.Debugf("new environment change")
if !ok {
return
}
environConfig, err := u.st.EnvironConfig()
if err != nil {
logger.Errorf("cannot load environment configuration: %v", err)
} else {
u.updatePackageProxy(environConfig)
}
}
}
}()
}
// 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()
}
}
}
func (f *filter) loop(unitTag string) (err error) {
// TODO(dfc) named return value is a time bomb
defer func() {
if params.IsCodeNotFoundOrCodeUnauthorized(err) {
err = worker.ErrTerminateAgent
}
}()
tag, err := names.ParseUnitTag(unitTag)
if err != nil {
return err
}
if f.unit, err = f.st.Unit(tag); 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)
}
}()
actionsw, err := f.unit.WatchActions()
if err != nil {
return err
}
f.actionsPending = make([]string, 0)
defer func() {
if actionsw != nil {
watcher.Stop(actionsw, &f.tomb)
}
}()
relationsw, err := f.service.WatchRelations()
if err != nil {
return err
}
defer func() {
if relationsw != nil {
watcher.Stop(relationsw, &f.tomb)
}
}()
var addressChanges <-chan struct{}
addressesw, err := f.unit.WatchAddresses()
if err != nil {
return err
}
defer watcher.Stop(addressesw, &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)
}
if addressChanges == nil {
// We start reacting to address changes after the
// first config-changed is processed, ignoring the
// initial address changed event.
addressChanges = addressesw.Changes()
if _, ok := <-addressChanges; !ok {
return watcher.MustErr(addressesw)
}
}
filterLogger.Debugf("preparing new config event")
f.outConfig = f.outConfigOn
discardConfig = f.discardConfig
case _, ok = <-addressChanges:
filterLogger.Debugf("got address change")
if !ok {
return watcher.MustErr(addressesw)
}
// address change causes config-changed event
filterLogger.Debugf("preparing new config event")
f.outConfig = f.outConfigOn
case ids, ok := <-actionsw.Changes():
filterLogger.Debugf("got %d actions", len(ids))
if !ok {
return watcher.MustErr(actionsw)
}
f.actionsPending = append(f.actionsPending, ids...)
f.nextAction = f.getNextAction()
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.NewRelationTag(key).String()
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.outAction <- f.nextAction:
f.nextAction = f.getNextAction()
filterLogger.Debugf("sent action event")
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
}
}
}