Golang errors.FromObject函数代码示例

// finishRequest makes a given resultFunc asynchronous and handles errors returned by the response.
// Any api.Status object returned is considered an "error", which interrupts the normal response flow.
func finishRequest(timeout time.Duration, fn resultFunc) (result runtime.Object, err error) {
	// these channels need to be buffered to prevent the goroutine below from hanging indefinitely
	// when the select statement reads something other than the one the goroutine sends on.
	ch := make(chan runtime.Object, 1)
	errCh := make(chan error, 1)
	go func() {
		if result, err := fn(); err != nil {
			errCh <- err
		} else {
			ch <- result
		}
	}()

	select {
	case result = <-ch:
		if status, ok := result.(*api.Status); ok {
			return nil, errors.FromObject(status)
		}
		return result, nil
	case err = <-errCh:
		return nil, err
	case <-time.After(timeout):
		return nil, errors.NewTimeoutError("request did not complete within allowed duration", 0)
	}
}

// finishRequest makes a given resultFunc asynchronous and handles errors returned by the response.
// Any api.Status object returned is considered an "error", which interrupts the normal response flow.
func finishRequest(timeout time.Duration, fn resultFunc) (result runtime.Object, err error) {
	// these channels need to be buffered to prevent the goroutine below from hanging indefinitely
	// when the select statement reads something other than the one the goroutine sends on.
	ch := make(chan runtime.Object, 1)
	errCh := make(chan error, 1)
	panicCh := make(chan interface{}, 1)
	go func() {
		// panics don't cross goroutine boundaries, so we have to handle ourselves
		defer util.HandleCrash(func(panicReason interface{}) {
			// Propagate to parent goroutine
			panicCh <- panicReason
		})

		if result, err := fn(); err != nil {
			errCh <- err
		} else {
			ch <- result
		}
	}()

	select {
	case result = <-ch:
		if status, ok := result.(*unversioned.Status); ok {
			return nil, errors.FromObject(status)
		}
		return result, nil
	case err = <-errCh:
		return nil, err
	case p := <-panicCh:
		panic(p)
	case <-time.After(timeout):
		return nil, errors.NewTimeoutError("request did not complete within allowed duration", 0)
	}
}

// watchHandler watches w and keeps *resourceVersion up to date.
func (r *Reflector) watchHandler(w watch.Interface, resourceVersion *string, resyncCh <-chan time.Time, stopCh <-chan struct{}) error {
	start := time.Now()
	eventCount := 0

	// Stopping the watcher should be idempotent and if we return from this function there's no way
	// we're coming back in with the same watch interface.
	defer w.Stop()

loop:
	for {
		select {
		case <-stopCh:
			return errorStopRequested
		case <-resyncCh:
			return errorResyncRequested
		case event, ok := <-w.ResultChan():
			if !ok {
				break loop
			}
			if event.Type == watch.Error {
				return apierrs.FromObject(event.Object)
			}
			if e, a := r.expectedType, reflect.TypeOf(event.Object); e != nil && e != a {
				utilruntime.HandleError(fmt.Errorf("%s: expected type %v, but watch event object had type %v", r.name, e, a))
				continue
			}
			meta, err := meta.Accessor(event.Object)
			if err != nil {
				utilruntime.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", r.name, event))
				continue
			}
			newResourceVersion := meta.GetResourceVersion()
			switch event.Type {
			case watch.Added:
				r.store.Add(event.Object)
			case watch.Modified:
				r.store.Update(event.Object)
			case watch.Deleted:
				// TODO: Will any consumers need access to the "last known
				// state", which is passed in event.Object? If so, may need
				// to change this.
				r.store.Delete(event.Object)
			default:
				utilruntime.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", r.name, event))
			}
			*resourceVersion = newResourceVersion
			r.setLastSyncResourceVersion(newResourceVersion)
			eventCount++
		}
	}

	watchDuration := time.Now().Sub(start)
	if watchDuration < 1*time.Second && eventCount == 0 {
		glog.V(4).Infof("%s: Unexpected watch close - watch lasted less than a second and no items received", r.name)
		return errors.New("very short watch")
	}
	glog.V(4).Infof("%s: Watch close - %v total %v items received", r.name, r.expectedType, eventCount)
	return nil
}

// transformResponse converts an API response into a structured API object
func (r *Request) transformResponse(resp *http.Response, req *http.Request) Result {
	var body []byte
	if resp.Body != nil {
		if data, err := ioutil.ReadAll(resp.Body); err == nil {
			body = data
		}
	}
	glog.V(8).Infof("Response Body: %s", string(body))

	// Did the server give us a status response?
	isStatusResponse := false
	// Because release-1.1 server returns Status with empty APIVersion at paths
	// to the Extensions resources, we need to use DecodeInto here to provide
	// default groupVersion, otherwise a status response won't be correctly
	// decoded.
	status := &unversioned.Status{}
	err := runtime.DecodeInto(r.serializers.Decoder, body, status)
	if err == nil && len(status.Status) > 0 {
		isStatusResponse = true
	}

	switch {
	case resp.StatusCode == http.StatusSwitchingProtocols:
		// no-op, we've been upgraded
	case resp.StatusCode < http.StatusOK || resp.StatusCode > http.StatusPartialContent:
		if !isStatusResponse {
			return Result{err: r.transformUnstructuredResponseError(resp, req, body)}
		}
		return Result{err: errors.FromObject(status)}
	}

	// If the server gave us a status back, look at what it was.
	success := resp.StatusCode >= http.StatusOK && resp.StatusCode <= http.StatusPartialContent
	if isStatusResponse && (status.Status != unversioned.StatusSuccess && !success) {
		// "Failed" requests are clearly just an error and it makes sense to return them as such.
		return Result{err: errors.FromObject(status)}
	}

	// TODO: Check ContentType.
	return Result{
		body:        body,
		contentType: resp.Header.Get("Content-Type"),
		statusCode:  resp.StatusCode,
		decoder:     r.serializers.Decoder,
	}
}

// Stream formats and executes the request, and offers streaming of the response.
// Returns io.ReadCloser which could be used for streaming of the response, or an error
// Any non-2xx http status code causes an error.  If we get a non-2xx code, we try to convert the body into an APIStatus object.
// If we can, we return that as an error.  Otherwise, we create an error that lists the http status and the content of the response.
func (r *Request) Stream() (io.ReadCloser, error) {
	if r.err != nil {
		return nil, r.err
	}

	r.tryThrottle()

	url := r.URL().String()
	req, err := http.NewRequest(r.verb, url, nil)
	if err != nil {
		return nil, err
	}
	req.Header = r.headers
	client := r.client
	if client == nil {
		client = http.DefaultClient
	}
	r.backoffMgr.Sleep(r.backoffMgr.CalculateBackoff(r.URL()))
	resp, err := client.Do(req)
	updateURLMetrics(r, resp, err)
	if r.baseURL != nil {
		if err != nil {
			r.backoffMgr.UpdateBackoff(r.URL(), err, 0)
		} else {
			r.backoffMgr.UpdateBackoff(r.URL(), err, resp.StatusCode)
		}
	}
	if err != nil {
		return nil, err
	}

	switch {
	case (resp.StatusCode >= 200) && (resp.StatusCode < 300):
		return resp.Body, nil

	default:
		// ensure we close the body before returning the error
		defer resp.Body.Close()

		// we have a decent shot at taking the object returned, parsing it as a status object and returning a more normal error
		bodyBytes, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			return nil, fmt.Errorf("%v while accessing %v", resp.Status, url)
		}

		// TODO: Check ContentType.
		if runtimeObject, err := runtime.Decode(r.serializers.Decoder, bodyBytes); err == nil {
			statusError := errors.FromObject(runtimeObject)

			if _, ok := statusError.(errors.APIStatus); ok {
				return nil, statusError
			}
		}

		bodyText := string(bodyBytes)
		return nil, fmt.Errorf("%s while accessing %v: %s", resp.Status, url, bodyText)
	}
}

// transformResponse converts an API response into a structured API object
func (r *Request) transformResponse(resp *http.Response, req *http.Request) Result {
	var body []byte
	if resp.Body != nil {
		if data, err := ioutil.ReadAll(resp.Body); err == nil {
			body = data
		}
	}
	glog.V(8).Infof("Response Body: %s", string(body))

	// Did the server give us a status response?
	isStatusResponse := false
	var status *unversioned.Status
	result, err := runtime.Decode(r.content.Codec, body)
	if out, ok := result.(*unversioned.Status); err == nil && ok && len(out.Status) > 0 {
		status = out
		isStatusResponse = true
	}

	switch {
	case resp.StatusCode == http.StatusSwitchingProtocols:
		// no-op, we've been upgraded
	case resp.StatusCode < http.StatusOK || resp.StatusCode > http.StatusPartialContent:
		if !isStatusResponse {
			return Result{err: r.transformUnstructuredResponseError(resp, req, body)}
		}
		return Result{err: errors.FromObject(status)}
	}

	// If the server gave us a status back, look at what it was.
	success := resp.StatusCode >= http.StatusOK && resp.StatusCode <= http.StatusPartialContent
	if isStatusResponse && (status.Status != unversioned.StatusSuccess && !success) {
		// "Failed" requests are clearly just an error and it makes sense to return them as such.
		return Result{err: errors.FromObject(status)}
	}

	return Result{
		body:        body,
		contentType: resp.Header.Get("Content-Type"),
		statusCode:  resp.StatusCode,
		decoder:     r.content.Codec,
	}
}

// Stream formats and executes the request, and offers streaming of the response.
// Returns io.ReadCloser which could be used for streaming of the response, or an error
// Any non-2xx http status code causes an error.  If we get a non-2xx code, we try to convert the body into an APIStatus object.
// If we can, we return that as an error.  Otherwise, we create an error that lists the http status and the content of the response.
func (r *Request) Stream() (io.ReadCloser, error) {
	if r.err != nil {
		return nil, r.err
	}
	url := r.URL().String()
	req, err := http.NewRequest(r.verb, url, nil)
	if err != nil {
		return nil, err
	}
	client := r.client
	if client == nil {
		client = http.DefaultClient
	}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}

	switch {
	case (resp.StatusCode >= 200) && (resp.StatusCode < 300):
		return resp.Body, nil

	default:
		// ensure we close the body before returning the error
		defer resp.Body.Close()

		// we have a decent shot at taking the object returned, parsing it as a status object and returning a more normal error
		bodyBytes, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			return nil, fmt.Errorf("%v while accessing %v", resp.Status, url)
		}

		if runtimeObject, err := r.codec.Decode(bodyBytes); err == nil {
			statusError := errors.FromObject(runtimeObject)

			if _, ok := statusError.(APIStatus); ok {
				return nil, statusError
			}
		}

		bodyText := string(bodyBytes)
		return nil, fmt.Errorf("%s while accessing %v: %s", resp.Status, url, bodyText)
	}

	return resp.Body, nil
}

// Error returns the error executing the request, nil if no error occurred.
// If the returned object is of type Status and has Status != StatusSuccess, the
// additional information in Status will be used to enrich the error.
// See the Request.Do() comment for what errors you might get.
func (r Result) Error() error {
	// if we have received an unexpected server error, and we have a body and decoder, we can try to extract
	// a Status object.
	if r.err == nil || !errors.IsUnexpectedServerError(r.err) || len(r.body) == 0 || r.decoder == nil {
		return r.err
	}

	// attempt to convert the body into a Status object
	// to be backwards compatible with old servers that do not return a version, default to "v1"
	out, _, err := r.decoder.Decode(r.body, &unversioned.GroupVersionKind{Version: "v1"}, nil)
	if err != nil {
		glog.V(5).Infof("body was not decodable (unable to check for Status): %v", err)
		return r.err
	}
	switch t := out.(type) {
	case *unversioned.Status:
		// because we default the kind, we *must* check for StatusFailure
		if t.Status == unversioned.StatusFailure {
			return errors.FromObject(t)
		}
	}
	return r.err
}

// Get returns the result as an object, which means it passes through the decoder.
// If the returned object is of type Status and has .Status != StatusSuccess, the
// additional information in Status will be used to enrich the error.
func (r Result) Get() (runtime.Object, error) {
	if r.err != nil {
		// Check whether the result has a Status object in the body and prefer that.
		return nil, r.Error()
	}
	if r.decoder == nil {
		return nil, fmt.Errorf("serializer for %s doesn't exist", r.contentType)
	}

	// decode, but if the result is Status return that as an error instead.
	out, _, err := r.decoder.Decode(r.body, nil, nil)
	if err != nil {
		return nil, err
	}
	switch t := out.(type) {
	case *unversioned.Status:
		// any status besides StatusSuccess is considered an error.
		if t.Status != unversioned.StatusSuccess {
			return nil, errors.FromObject(t)
		}
	}
	return out, nil
}

// Into stores the result into obj, if possible. If obj is nil it is ignored.
// If the returned object is of type Status and has .Status != StatusSuccess, the
// additional information in Status will be used to enrich the error.
func (r Result) Into(obj runtime.Object) error {
	if r.err != nil {
		// Check whether the result has a Status object in the body and prefer that.
		return r.Error()
	}
	if r.decoder == nil {
		return fmt.Errorf("serializer for %s doesn't exist", r.contentType)
	}

	out, _, err := r.decoder.Decode(r.body, nil, obj)
	if err != nil || out == obj {
		return err
	}
	// if a different object is returned, see if it is Status and avoid double decoding
	// the object.
	switch t := out.(type) {
	case *unversioned.Status:
		// any status besides StatusSuccess is considered an error.
		if t.Status != unversioned.StatusSuccess {
			return errors.FromObject(t)
		}
	}
	return nil
}

// transformResponse converts an API response into a structured API object
func (r *Request) transformResponse(resp *http.Response, req *http.Request) Result {
	var body []byte
	if resp.Body != nil {
		if data, err := ioutil.ReadAll(resp.Body); err == nil {
			body = data
		}
	}

	if glog.V(8) {
		if bytes.IndexFunc(body, func(r rune) bool {
			return r < 0x0a
		}) != -1 {
			glog.Infof("Response Body:\n%s", hex.Dump(body))
		} else {
			glog.Infof("Response Body: %s", string(body))
		}
	}

	// verify the content type is accurate
	contentType := resp.Header.Get("Content-Type")
	decoder := r.serializers.Decoder
	if len(contentType) > 0 && (decoder == nil || (len(r.content.ContentType) > 0 && contentType != r.content.ContentType)) {
		mediaType, params, err := mime.ParseMediaType(contentType)
		if err != nil {
			return Result{err: errors.NewInternalError(err)}
		}
		decoder, err = r.serializers.RenegotiatedDecoder(mediaType, params)
		if err != nil {
			// if we fail to negotiate a decoder, treat this as an unstructured error
			switch {
			case resp.StatusCode == http.StatusSwitchingProtocols:
				// no-op, we've been upgraded
			case resp.StatusCode < http.StatusOK || resp.StatusCode > http.StatusPartialContent:
				return Result{err: r.transformUnstructuredResponseError(resp, req, body)}
			}
			return Result{
				body:        body,
				contentType: contentType,
				statusCode:  resp.StatusCode,
			}
		}
	}

	// Did the server give us a status response?
	isStatusResponse := false
	status := &unversioned.Status{}
	// Because release-1.1 server returns Status with empty APIVersion at paths
	// to the Extensions resources, we need to use DecodeInto here to provide
	// default groupVersion, otherwise a status response won't be correctly
	// decoded.
	err := runtime.DecodeInto(decoder, body, status)
	if err == nil && len(status.Status) > 0 {
		isStatusResponse = true
	}

	switch {
	case resp.StatusCode == http.StatusSwitchingProtocols:
		// no-op, we've been upgraded
	case resp.StatusCode < http.StatusOK || resp.StatusCode > http.StatusPartialContent:
		if !isStatusResponse {
			return Result{err: r.transformUnstructuredResponseError(resp, req, body)}
		}
		return Result{err: errors.FromObject(status)}
	}

	// If the server gave us a status back, look at what it was.
	success := resp.StatusCode >= http.StatusOK && resp.StatusCode <= http.StatusPartialContent
	if isStatusResponse && (status.Status != unversioned.StatusSuccess && !success) {
		// "Failed" requests are clearly just an error and it makes sense to return them as such.
		return Result{err: errors.FromObject(status)}
	}

	return Result{
		body:        body,
		contentType: contentType,
		statusCode:  resp.StatusCode,
		decoder:     decoder,
	}
}