// WatchPodCluster implements a watch for the Pod cluster at _id_
// It will return a blocking channel on which the client can read
// WatchedPodCluster objects. The goroutine maintaining the watch will block on
// writing to this channel so it's up to the caller to read it with haste.
// This function will return ErrNoPodCluster if the podCluster goes away. In
// this case, the caller should close the quit chan.
// The caller may shutdown this watch by sending a sentinel on the quitChan.
func (s *consulStore) WatchPodCluster(id fields.ID, quit <-chan struct{}) <-chan WatchedPodCluster {
inCh := make(chan *api.KVPair)
outCh := make(chan WatchedPodCluster)
errChan := make(chan error, 1)
quitWatch := make(chan struct{})
key := path.Join(podClusterTree, string(id))
go consulutil.WatchSingle(key, s.kv, inCh, quitWatch, errChan)
go func() {
var kvp *api.KVPair
for {
select {
case <-quit:
return
case err := <-errChan:
s.logger.WithError(err).Errorf("WatchSingle returned error, recovered.")
case kvp = <-inCh:
if kvp == nil { // PodCluster at _id_ has been deleted
select {
case <-quit:
return
case outCh <- WatchedPodCluster{PodCluster: nil, Err: NoPodCluster}:
}
return
}
}
pc, err := kvpToPC(kvp)
var wpc WatchedPodCluster
if err != nil {
wpc.Err = err
} else {
wpc.PodCluster = &pc
}
select {
case <-quit:
return
case outCh <- wpc:
}
}
}()
return outCh
}
func (s *consulStore) Watch(rc *fields.RC, quit <-chan struct{}) (<-chan struct{}, <-chan error) {
updated := make(chan struct{})
rcp, err := s.rcPath(rc.ID)
if err != nil {
errors := make(chan error, 1)
errors <- err
close(errors)
close(updated)
return updated, errors
}
errors := make(chan error)
input := make(chan *api.KVPair)
go consulutil.WatchSingle(rcp, s.kv, input, quit, errors)
go func() {
defer close(updated)
defer close(errors)
for kvp := range input {
if kvp == nil {
// seems this RC got deleted from under us. quitting
// would be unexpected, so we'll just wait for it to
// reappear in consul
continue
}
newRC, err := kvpToRC(kvp)
if err != nil {
select {
case errors <- err:
case <-quit:
}
} else {
*rc = newRC
select {
case updated <- struct{}{}:
case <-quit:
}
}
}
}()
return updated, errors
}
// WatchPod is like WatchPods, but for a single key only. The output channel
// may contain nil manifests, if the target key does not exist.
func (c consulStore) WatchPod(
podPrefix PodPrefix,
nodename types.NodeName,
podId types.PodID,
quitChan <-chan struct{},
errChan chan<- error,
podChan chan<- ManifestResult,
) {
defer close(podChan)
key, err := podPath(podPrefix, nodename, podId)
if err != nil {
select {
case <-quitChan:
case errChan <- err:
}
return
}
kvpChan := make(chan *api.KVPair)
go consulutil.WatchSingle(key, c.client.KV(), kvpChan, quitChan, errChan)
for pair := range kvpChan {
out := ManifestResult{}
if pair != nil {
out, err = c.manifestResultFromPair(pair)
if err != nil {
select {
case <-quitChan:
return
case errChan <- util.Errorf("Could not parse pod manifest at %s: %s. Content follows: \n%s", pair.Key, err, pair.Value):
continue
}
}
}
select {
case <-quitChan:
return
case podChan <- out:
}
}
}