Exemple #1
0
// 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)
				}
			}
		}
	}()
}
Exemple #2
0
// 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()
		}
	}
}
Exemple #3
0
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
		}
	}
}