mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-12-19 11:30:24 +00:00
358 lines
12 KiB
Go
358 lines
12 KiB
Go
/*
|
|
Copyright 2014 The Kubernetes Authors.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
package handlers
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"net/http"
|
|
"time"
|
|
|
|
"golang.org/x/net/websocket"
|
|
|
|
"k8s.io/apimachinery/pkg/api/errors"
|
|
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
|
|
"k8s.io/apimachinery/pkg/runtime"
|
|
"k8s.io/apimachinery/pkg/util/httpstream/wsstream"
|
|
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
|
|
"k8s.io/apimachinery/pkg/watch"
|
|
"k8s.io/apiserver/pkg/endpoints/handlers/negotiation"
|
|
"k8s.io/apiserver/pkg/endpoints/metrics"
|
|
apirequest "k8s.io/apiserver/pkg/endpoints/request"
|
|
"k8s.io/apiserver/pkg/features"
|
|
"k8s.io/apiserver/pkg/storage"
|
|
utilfeature "k8s.io/apiserver/pkg/util/feature"
|
|
)
|
|
|
|
// nothing will ever be sent down this channel
|
|
var neverExitWatch <-chan time.Time = make(chan time.Time)
|
|
|
|
// timeoutFactory abstracts watch timeout logic for testing
|
|
type TimeoutFactory interface {
|
|
TimeoutCh() (<-chan time.Time, func() bool)
|
|
}
|
|
|
|
// realTimeoutFactory implements timeoutFactory
|
|
type realTimeoutFactory struct {
|
|
timeout time.Duration
|
|
}
|
|
|
|
// TimeoutCh returns a channel which will receive something when the watch times out,
|
|
// and a cleanup function to call when this happens.
|
|
func (w *realTimeoutFactory) TimeoutCh() (<-chan time.Time, func() bool) {
|
|
if w.timeout == 0 {
|
|
return neverExitWatch, func() bool { return false }
|
|
}
|
|
t := time.NewTimer(w.timeout)
|
|
return t.C, t.Stop
|
|
}
|
|
|
|
// serveWatch will serve a watch response.
|
|
// TODO: the functionality in this method and in WatchServer.Serve is not cleanly decoupled.
|
|
func serveWatch(watcher watch.Interface, scope *RequestScope, mediaTypeOptions negotiation.MediaTypeOptions, req *http.Request, w http.ResponseWriter, timeout time.Duration, metricsScope string) {
|
|
defer watcher.Stop()
|
|
|
|
options, err := optionsForTransform(mediaTypeOptions, req)
|
|
if err != nil {
|
|
scope.err(err, w, req)
|
|
return
|
|
}
|
|
|
|
// negotiate for the stream serializer from the scope's serializer
|
|
serializer, err := negotiation.NegotiateOutputMediaTypeStream(req, scope.Serializer, scope)
|
|
if err != nil {
|
|
scope.err(err, w, req)
|
|
return
|
|
}
|
|
framer := serializer.StreamSerializer.Framer
|
|
streamSerializer := serializer.StreamSerializer.Serializer
|
|
encoder := scope.Serializer.EncoderForVersion(streamSerializer, scope.Kind.GroupVersion())
|
|
useTextFraming := serializer.EncodesAsText
|
|
if framer == nil {
|
|
scope.err(fmt.Errorf("no framer defined for %q available for embedded encoding", serializer.MediaType), w, req)
|
|
return
|
|
}
|
|
// TODO: next step, get back mediaTypeOptions from negotiate and return the exact value here
|
|
mediaType := serializer.MediaType
|
|
if mediaType != runtime.ContentTypeJSON {
|
|
mediaType += ";stream=watch"
|
|
}
|
|
|
|
ctx := req.Context()
|
|
|
|
// locate the appropriate embedded encoder based on the transform
|
|
var embeddedEncoder runtime.Encoder
|
|
contentKind, contentSerializer, transform := targetEncodingForTransform(scope, mediaTypeOptions, req)
|
|
if transform {
|
|
info, ok := runtime.SerializerInfoForMediaType(contentSerializer.SupportedMediaTypes(), serializer.MediaType)
|
|
if !ok {
|
|
scope.err(fmt.Errorf("no encoder for %q exists in the requested target %#v", serializer.MediaType, contentSerializer), w, req)
|
|
return
|
|
}
|
|
embeddedEncoder = contentSerializer.EncoderForVersion(info.Serializer, contentKind.GroupVersion())
|
|
} else {
|
|
embeddedEncoder = scope.Serializer.EncoderForVersion(serializer.Serializer, contentKind.GroupVersion())
|
|
}
|
|
|
|
var memoryAllocator runtime.MemoryAllocator
|
|
|
|
if encoderWithAllocator, supportsAllocator := embeddedEncoder.(runtime.EncoderWithAllocator); supportsAllocator {
|
|
// don't put the allocator inside the embeddedEncodeFn as that would allocate memory on every call.
|
|
// instead, we allocate the buffer for the entire watch session and release it when we close the connection.
|
|
memoryAllocator = runtime.AllocatorPool.Get().(*runtime.Allocator)
|
|
defer runtime.AllocatorPool.Put(memoryAllocator)
|
|
embeddedEncoder = runtime.NewEncoderWithAllocator(encoderWithAllocator, memoryAllocator)
|
|
}
|
|
var tableOptions *metav1.TableOptions
|
|
if options != nil {
|
|
if passedOptions, ok := options.(*metav1.TableOptions); ok {
|
|
tableOptions = passedOptions
|
|
} else {
|
|
scope.err(fmt.Errorf("unexpected options type: %T", options), w, req)
|
|
return
|
|
}
|
|
}
|
|
embeddedEncoder = newWatchEmbeddedEncoder(ctx, embeddedEncoder, mediaTypeOptions.Convert, tableOptions, scope)
|
|
|
|
if encoderWithAllocator, supportsAllocator := encoder.(runtime.EncoderWithAllocator); supportsAllocator {
|
|
if memoryAllocator == nil {
|
|
// don't put the allocator inside the embeddedEncodeFn as that would allocate memory on every call.
|
|
// instead, we allocate the buffer for the entire watch session and release it when we close the connection.
|
|
memoryAllocator = runtime.AllocatorPool.Get().(*runtime.Allocator)
|
|
defer runtime.AllocatorPool.Put(memoryAllocator)
|
|
}
|
|
encoder = runtime.NewEncoderWithAllocator(encoderWithAllocator, memoryAllocator)
|
|
}
|
|
|
|
var serverShuttingDownCh <-chan struct{}
|
|
if signals := apirequest.ServerShutdownSignalFrom(req.Context()); signals != nil {
|
|
serverShuttingDownCh = signals.ShuttingDown()
|
|
}
|
|
|
|
server := &WatchServer{
|
|
Watching: watcher,
|
|
Scope: scope,
|
|
|
|
UseTextFraming: useTextFraming,
|
|
MediaType: mediaType,
|
|
Framer: framer,
|
|
Encoder: encoder,
|
|
EmbeddedEncoder: embeddedEncoder,
|
|
|
|
TimeoutFactory: &realTimeoutFactory{timeout},
|
|
ServerShuttingDownCh: serverShuttingDownCh,
|
|
|
|
metricsScope: metricsScope,
|
|
}
|
|
|
|
server.ServeHTTP(w, req)
|
|
}
|
|
|
|
// WatchServer serves a watch.Interface over a websocket or vanilla HTTP.
|
|
type WatchServer struct {
|
|
Watching watch.Interface
|
|
Scope *RequestScope
|
|
|
|
// true if websocket messages should use text framing (as opposed to binary framing)
|
|
UseTextFraming bool
|
|
// the media type this watch is being served with
|
|
MediaType string
|
|
// used to frame the watch stream
|
|
Framer runtime.Framer
|
|
// used to encode the watch stream event itself
|
|
Encoder runtime.Encoder
|
|
// used to encode the nested object in the watch stream
|
|
EmbeddedEncoder runtime.Encoder
|
|
|
|
TimeoutFactory TimeoutFactory
|
|
ServerShuttingDownCh <-chan struct{}
|
|
|
|
metricsScope string
|
|
}
|
|
|
|
// ServeHTTP serves a series of encoded events via HTTP with Transfer-Encoding: chunked
|
|
// or over a websocket connection.
|
|
func (s *WatchServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
|
|
kind := s.Scope.Kind
|
|
|
|
if wsstream.IsWebSocketRequest(req) {
|
|
w.Header().Set("Content-Type", s.MediaType)
|
|
websocket.Handler(s.HandleWS).ServeHTTP(w, req)
|
|
return
|
|
}
|
|
|
|
flusher, ok := w.(http.Flusher)
|
|
if !ok {
|
|
err := fmt.Errorf("unable to start watch - can't get http.Flusher: %#v", w)
|
|
utilruntime.HandleError(err)
|
|
s.Scope.err(errors.NewInternalError(err), w, req)
|
|
return
|
|
}
|
|
|
|
framer := s.Framer.NewFrameWriter(w)
|
|
if framer == nil {
|
|
// programmer error
|
|
err := fmt.Errorf("no stream framing support is available for media type %q", s.MediaType)
|
|
utilruntime.HandleError(err)
|
|
s.Scope.err(errors.NewBadRequest(err.Error()), w, req)
|
|
return
|
|
}
|
|
|
|
// ensure the connection times out
|
|
timeoutCh, cleanup := s.TimeoutFactory.TimeoutCh()
|
|
defer cleanup()
|
|
|
|
// begin the stream
|
|
w.Header().Set("Content-Type", s.MediaType)
|
|
w.Header().Set("Transfer-Encoding", "chunked")
|
|
w.WriteHeader(http.StatusOK)
|
|
flusher.Flush()
|
|
|
|
watchEncoder := newWatchEncoder(req.Context(), kind, s.EmbeddedEncoder, s.Encoder, framer)
|
|
ch := s.Watching.ResultChan()
|
|
done := req.Context().Done()
|
|
|
|
for {
|
|
select {
|
|
case <-s.ServerShuttingDownCh:
|
|
// the server has signaled that it is shutting down (not accepting
|
|
// any new request), all active watch request(s) should return
|
|
// immediately here. The WithWatchTerminationDuringShutdown server
|
|
// filter will ensure that the response to the client is rate
|
|
// limited in order to avoid any thundering herd issue when the
|
|
// client(s) try to reestablish the WATCH on the other
|
|
// available apiserver instance(s).
|
|
return
|
|
case <-done:
|
|
return
|
|
case <-timeoutCh:
|
|
return
|
|
case event, ok := <-ch:
|
|
if !ok {
|
|
// End of results.
|
|
return
|
|
}
|
|
metrics.WatchEvents.WithContext(req.Context()).WithLabelValues(kind.Group, kind.Version, kind.Kind).Inc()
|
|
isWatchListLatencyRecordingRequired := shouldRecordWatchListLatency(event)
|
|
|
|
if err := watchEncoder.Encode(event); err != nil {
|
|
utilruntime.HandleError(err)
|
|
// client disconnect.
|
|
return
|
|
}
|
|
|
|
if len(ch) == 0 {
|
|
flusher.Flush()
|
|
}
|
|
if isWatchListLatencyRecordingRequired {
|
|
metrics.RecordWatchListLatency(req.Context(), s.Scope.Resource, s.metricsScope)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// HandleWS implements a websocket handler.
|
|
func (s *WatchServer) HandleWS(ws *websocket.Conn) {
|
|
defer ws.Close()
|
|
done := make(chan struct{})
|
|
|
|
go func() {
|
|
defer utilruntime.HandleCrash()
|
|
// This blocks until the connection is closed.
|
|
// Client should not send anything.
|
|
wsstream.IgnoreReceives(ws, 0)
|
|
// Once the client closes, we should also close
|
|
close(done)
|
|
}()
|
|
|
|
var unknown runtime.Unknown
|
|
internalEvent := &metav1.InternalEvent{}
|
|
buf := &bytes.Buffer{}
|
|
streamBuf := &bytes.Buffer{}
|
|
ch := s.Watching.ResultChan()
|
|
|
|
for {
|
|
select {
|
|
case <-done:
|
|
return
|
|
case event, ok := <-ch:
|
|
if !ok {
|
|
// End of results.
|
|
return
|
|
}
|
|
|
|
if err := s.EmbeddedEncoder.Encode(event.Object, buf); err != nil {
|
|
// unexpected error
|
|
utilruntime.HandleError(fmt.Errorf("unable to encode watch object %T: %v", event.Object, err))
|
|
return
|
|
}
|
|
|
|
// ContentType is not required here because we are defaulting to the serializer
|
|
// type
|
|
unknown.Raw = buf.Bytes()
|
|
event.Object = &unknown
|
|
|
|
// the internal event will be versioned by the encoder
|
|
// create the external type directly and encode it. Clients will only recognize the serialization we provide.
|
|
// The internal event is being reused, not reallocated so its just a few extra assignments to do it this way
|
|
// and we get the benefit of using conversion functions which already have to stay in sync
|
|
outEvent := &metav1.WatchEvent{}
|
|
*internalEvent = metav1.InternalEvent(event)
|
|
err := metav1.Convert_v1_InternalEvent_To_v1_WatchEvent(internalEvent, outEvent, nil)
|
|
if err != nil {
|
|
utilruntime.HandleError(fmt.Errorf("unable to convert watch object: %v", err))
|
|
// client disconnect.
|
|
return
|
|
}
|
|
if err := s.Encoder.Encode(outEvent, streamBuf); err != nil {
|
|
// encoding error
|
|
utilruntime.HandleError(fmt.Errorf("unable to encode event: %v", err))
|
|
return
|
|
}
|
|
if s.UseTextFraming {
|
|
if err := websocket.Message.Send(ws, streamBuf.String()); err != nil {
|
|
// Client disconnect.
|
|
return
|
|
}
|
|
} else {
|
|
if err := websocket.Message.Send(ws, streamBuf.Bytes()); err != nil {
|
|
// Client disconnect.
|
|
return
|
|
}
|
|
}
|
|
buf.Reset()
|
|
streamBuf.Reset()
|
|
}
|
|
}
|
|
}
|
|
|
|
func shouldRecordWatchListLatency(event watch.Event) bool {
|
|
if event.Type != watch.Bookmark || !utilfeature.DefaultFeatureGate.Enabled(features.WatchList) {
|
|
return false
|
|
}
|
|
// as of today the initial-events-end annotation is added only to a single event
|
|
// by the watch cache and only when certain conditions are met
|
|
//
|
|
// for more please read https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/3157-watch-list
|
|
hasAnnotation, err := storage.HasInitialEventsEndBookmarkAnnotation(event.Object)
|
|
if err != nil {
|
|
utilruntime.HandleError(fmt.Errorf("unable to determine if the obj has the required annotation for measuring watchlist latency, obj %T: %v", event.Object, err))
|
|
return false
|
|
}
|
|
return hasAnnotation
|
|
}
|