// Watch attempts to begin watching the requested location.
// Returns a watch.Interface, or an error.
func (r *Request) Watch() (watch.Interface, error) {
if r.err != nil {
return nil, r.err
}
url := r.URL().String()
req, err := http.NewRequest(r.verb, url, r.body)
if err != nil {
return nil, err
}
client := r.client
if client == nil {
client = http.DefaultClient
}
resp, err := client.Do(req)
if err != nil {
// The watch stream mechanism handles many common partial data errors, so closed
// connections can be retried in many cases.
if util.IsProbableEOF(err) {
return watch.NewEmptyWatch(), nil
}
return nil, err
}
if resp.StatusCode != http.StatusOK {
if result := r.transformResponse(resp, req); result.err != nil {
return nil, result.err
}
return nil, fmt.Errorf("for request '%+v', got status: %v", url, resp.StatusCode)
}
return watch.NewStreamWatcher(watchjson.NewDecoder(resp.Body, r.codec)), nil
}
// receive reads result from the decoder in a loop and sends down the result channel.
func (sw *StreamWatcher) receive() {
defer close(sw.result)
defer sw.Stop()
defer util.HandleCrash()
for {
action, obj, err := sw.source.Decode()
if err != nil {
// Ignore expected error.
if sw.stopping() {
return
}
switch err {
case io.EOF:
// watch closed normally
case io.ErrUnexpectedEOF:
glog.V(1).Infof("Unexpected EOF during watch stream event decoding: %v", err)
default:
msg := "Unable to decode an event from the watch stream: %v"
if util.IsProbableEOF(err) {
glog.V(5).Infof(msg, err)
} else {
glog.Errorf(msg, err)
}
}
return
}
sw.result <- Event{
Type: action,
Object: obj,
}
}
}