// changed ensures that the named unit is deployed, recalled, or removed, as
// indicated by its state.
func (d *Deployer) changed(unitName string) error {
unitTag := names.UnitTag(unitName)
// Determine unit life state, and whether we're responsible for it.
logger.Infof("checking unit %q", unitName)
var life params.Life
unit, err := d.st.Unit(unitTag)
if params.IsCodeNotFoundOrCodeUnauthorized(err) {
life = params.Dead
} else if err != nil {
return err
} else {
life = unit.Life()
}
// Deployed units must be removed if they're Dead, or if the deployer
// is no longer responsible for them.
if d.deployed.Contains(unitName) {
if life == params.Dead {
if err := d.recall(unitName); err != nil {
return err
}
}
}
// The only units that should be deployed are those that (1) we are responsible
// for and (2) are Alive -- if we're responsible for a Dying unit that is not
// yet deployed, we should remove it immediately rather than undergo the hassle
// of deploying a unit agent purely so it can set itself to Dead.
if !d.deployed.Contains(unitName) {
if life == params.Alive {
return d.deploy(unit)
} else if unit != nil {
return d.remove(unit)
}
}
return nil
}
func (mr *Machiner) Handle() error {
if err := mr.machine.Refresh(); params.IsCodeNotFoundOrCodeUnauthorized(err) {
return worker.ErrTerminateAgent
} else if err != nil {
return err
}
if mr.machine.Life() == params.Alive {
return nil
}
logger.Debugf("%q is now %s", mr.tag, mr.machine.Life())
if err := mr.machine.SetStatus(params.StatusStopped, "", nil); err != nil {
return fmt.Errorf("%s failed to set status stopped: %v", mr.tag, err)
}
// If the machine is Dying, it has no units,
// and can be safely set to Dead.
if err := mr.machine.EnsureDead(); err != nil {
return fmt.Errorf("%s failed to set machine to dead: %v", mr.tag, err)
}
return worker.ErrTerminateAgent
}
func (mr *Machiner) SetUp() (watcher.NotifyWatcher, error) {
// Find which machine we're responsible for.
m, err := mr.st.Machine(mr.tag)
if params.IsCodeNotFoundOrCodeUnauthorized(err) {
return nil, worker.ErrTerminateAgent
} else if err != nil {
return nil, err
}
mr.machine = m
// Set the addresses in state to the host's addresses.
if err := setMachineAddresses(m); err != nil {
return nil, err
}
// Mark the machine as started and log it.
if err := m.SetStatus(params.StatusStarted, "", nil); err != nil {
return nil, fmt.Errorf("%s failed to set status started: %v", mr.tag, err)
}
logger.Infof("%q started", mr.tag)
return m.Watch()
}
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
}
}
}