// Add adds the given dependency to the list of monitored depedencies
// and start the associated view. If the dependency already exists, no action is
// taken.
//
// If the Dependency already existed, it this function will return false. If the
// view was successfully created, it will return true. If an error occurs while
// creating the view, it will be returned here (but future errors returned by
// the view will happen on the channel).
func (w *Watcher) Add(d dep.Dependency) (bool, error) {
w.Lock()
defer w.Unlock()
log.Printf("[DEBUG] (watcher) adding %s", d)
if _, ok := w.depViewMap[d.String()]; ok {
log.Printf("[TRACE] (watcher) %s already exists, skipping", d)
return false, nil
}
// Choose the correct retry function based off of the dependency's type.
var retryFunc RetryFunc
switch d.Type() {
case dep.TypeConsul:
retryFunc = w.retryFuncConsul
case dep.TypeVault:
retryFunc = w.retryFuncVault
default:
retryFunc = w.retryFuncDefault
}
v, err := NewView(&NewViewInput{
Dependency: d,
Clients: w.clients,
MaxStale: w.maxStale,
Once: w.once,
RetryFunc: retryFunc,
})
if err != nil {
return false, errors.Wrap(err, "watcher")
}
log.Printf("[TRACE] (watcher) %s starting", d)
w.depViewMap[d.String()] = v
go v.poll(w.dataCh, w.errCh)
return true, nil
}
