func StartBalancerAgent(args []string, errorSink daemon.ErrorSink) *BalancerAgent {
a := &BalancerAgent{errorSink: errorSink}
if err := a.parseArgs(args); err != nil {
errorSink.Post(err)
return a
}
if err := a.start(); err != nil {
errorSink.Post(err)
}
return a
}
func (es *etcdStore) WatchServices(ctx context.Context, resCh chan<- data.ServiceChange, errorSink daemon.ErrorSink, opts store.QueryServiceOptions) {
if ctx == nil {
ctx = es.ctx
}
svcs := make(map[string]struct{})
handleResponse := func(r *etcd.Response) {
switch r.Action {
case "delete":
switch key := parseKey(r.Node.Key).(type) {
case parsedRootKey:
for name := range svcs {
resCh <- data.ServiceChange{name, true}
}
svcs = make(map[string]struct{})
case parsedServiceRootKey:
delete(svcs, key.serviceName)
resCh <- data.ServiceChange{key.serviceName, true}
case interface {
relevantTo(opts store.QueryServiceOptions) (bool, string)
}:
if relevant, service := key.relevantTo(opts); relevant {
resCh <- data.ServiceChange{service, false}
}
}
case "set":
switch key := parseKey(r.Node.Key).(type) {
case parsedServiceKey:
svcs[key.serviceName] = struct{}{}
resCh <- data.ServiceChange{key.serviceName, false}
case interface {
relevantTo(opts store.QueryServiceOptions) (bool, string)
}:
if relevant, service := key.relevantTo(opts); relevant {
resCh <- data.ServiceChange{service, false}
}
}
}
}
// Get the initial service list, so that we can report them as
// deleted if the root node is deleted. This also gets the
// initial index for the watch. (Though perhaps that should
// really be based on the ModifieedIndex of the nodes
// themselves?)
node, startIndex, err := es.getDirNode(ROOT, true, false)
if err != nil {
errorSink.Post(err)
return
}
for name := range indexDir(node) {
svcs[name] = struct{}{}
}
go func() {
watcher := es.Watcher(ROOT,
&etcd.WatcherOptions{
AfterIndex: startIndex,
Recursive: true,
})
for {
next, err := watcher.Next(ctx)
if err != nil {
errorSink.Post(err)
break
}
handleResponse(next)
}
}()
}