/
xds_proxy_delta.go
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/
xds_proxy_delta.go
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// Copyright Istio 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 istioagent
import (
"context"
"fmt"
"strings"
"time"
discovery "github.com/envoyproxy/go-control-plane/envoy/service/discovery/v3"
"go.uber.org/atomic"
google_rpc "google.golang.org/genproto/googleapis/rpc/status"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/metadata"
anypb "google.golang.org/protobuf/types/known/anypb"
"istio.io/istio/pilot/pkg/features"
"istio.io/istio/pkg/channels"
"istio.io/istio/pkg/istio-agent/metrics"
"istio.io/istio/pkg/log"
"istio.io/istio/pkg/model"
"istio.io/istio/pkg/slices"
"istio.io/istio/pkg/wasm"
)
// sendDeltaRequest is a small wrapper around sending to con.requestsChan. This ensures that we do not
// block forever on
func (con *ProxyConnection) sendDeltaRequest(req *discovery.DeltaDiscoveryRequest) {
con.deltaRequestsChan.Put(req)
}
// DeltaAggregatedResources is an implementation of Delta XDS API used for proxying between Istiod and Envoy.
// Every time envoy makes a fresh connection to the agent, we reestablish a new connection to the upstream xds
// This ensures that a new connection between istiod and agent doesn't end up consuming pending messages from envoy
// as the new connection may not go to the same istiod. Vice versa case also applies.
func (p *XdsProxy) DeltaAggregatedResources(downstream DeltaDiscoveryStream) error {
proxyLog.Debugf("accepted delta xds connection from envoy, forwarding to upstream")
con := &ProxyConnection{
conID: connectionNumber.Inc(),
upstreamError: make(chan error), // can be produced by recv and send
downstreamError: make(chan error), // can be produced by recv and send
deltaRequestsChan: channels.NewUnbounded[*discovery.DeltaDiscoveryRequest](),
// Allow a buffer of 1. This ensures we queue up at most 2 (one in process, 1 pending) responses before forwarding.
deltaResponsesChan: make(chan *discovery.DeltaDiscoveryResponse, 1),
stopChan: make(chan struct{}),
downstreamDeltas: downstream,
}
p.registerStream(con)
defer p.unregisterStream(con)
ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
defer cancel()
upstreamConn, err := p.buildUpstreamConn(ctx)
if err != nil {
proxyLog.Errorf("failed to connect to upstream %s: %v", p.istiodAddress, err)
metrics.IstiodConnectionFailures.Increment()
return err
}
defer upstreamConn.Close()
xds := discovery.NewAggregatedDiscoveryServiceClient(upstreamConn)
ctx = metadata.AppendToOutgoingContext(context.Background(), "ClusterID", p.clusterID)
for k, v := range p.xdsHeaders {
ctx = metadata.AppendToOutgoingContext(ctx, k, v)
}
// We must propagate upstream termination to Envoy. This ensures that we resume the full XDS sequence on new connection
return p.handleDeltaUpstream(ctx, con, xds)
}
func (p *XdsProxy) handleDeltaUpstream(ctx context.Context, con *ProxyConnection, xds discovery.AggregatedDiscoveryServiceClient) error {
log := proxyLog.WithLabels("id", con.conID)
deltaUpstream, err := xds.DeltaAggregatedResources(ctx,
grpc.MaxCallRecvMsgSize(defaultClientMaxReceiveMessageSize))
if err != nil {
// Envoy logs errors again, so no need to log beyond debug level
log.Debugf("failed to create delta upstream grpc client: %v", err)
// Increase metric when xds connection error, for example: forgot to restart ingressgateway or sidecar after changing root CA.
metrics.IstiodConnectionErrors.Increment()
return err
}
log.Infof("connected to delta upstream XDS server: %s", p.istiodAddress)
defer log.Debugf("disconnected from delta XDS server: %s", p.istiodAddress)
con.upstreamDeltas = deltaUpstream
// handle responses from istiod
go func() {
for {
resp, err := con.upstreamDeltas.Recv()
if err != nil {
upstreamErr(con, err)
return
}
select {
case con.deltaResponsesChan <- resp:
case <-con.stopChan:
}
}
}()
go p.handleUpstreamDeltaRequest(con)
go p.handleUpstreamDeltaResponse(con)
for {
select {
case err := <-con.upstreamError:
return err
case err := <-con.downstreamError:
// On downstream error, we will return. This propagates the error to downstream envoy which will trigger reconnect
return err
case <-con.stopChan:
log.Debugf("upstream stopped")
return nil
}
}
}
func (p *XdsProxy) handleUpstreamDeltaRequest(con *ProxyConnection) {
log := proxyLog.WithLabels("id", con.conID)
initialRequestsSent := atomic.NewBool(false)
go func() {
for {
// recv delta xds requests from envoy
req, err := con.downstreamDeltas.Recv()
if err != nil {
downstreamErr(con, err)
return
}
// forward to istiod
con.sendDeltaRequest(req)
if !initialRequestsSent.Load() && req.TypeUrl == model.ListenerType {
// fire off an initial NDS request
if _, f := p.handlers[model.NameTableType]; f {
con.sendDeltaRequest(&discovery.DeltaDiscoveryRequest{
TypeUrl: model.NameTableType,
})
}
// fire off an initial PCDS request
if _, f := p.handlers[model.ProxyConfigType]; f {
con.sendDeltaRequest(&discovery.DeltaDiscoveryRequest{
TypeUrl: model.ProxyConfigType,
})
}
// set flag before sending the initial request to prevent race.
initialRequestsSent.Store(true)
// Fire of a configured initial request, if there is one
p.connectedMutex.RLock()
initialRequest := p.initialDeltaHealthRequest
if initialRequest != nil {
con.sendDeltaRequest(initialRequest)
}
p.connectedMutex.RUnlock()
}
}
}()
defer func() {
_ = con.upstreamDeltas.CloseSend()
}()
for {
select {
case req := <-con.deltaRequestsChan.Get():
con.deltaRequestsChan.Load()
if req.TypeUrl == model.HealthInfoType && !initialRequestsSent.Load() {
// only send healthcheck probe after LDS request has been sent
continue
}
log.WithLabels(
"type", model.GetShortType(req.TypeUrl),
"sub", len(req.ResourceNamesSubscribe),
"unsub", len(req.ResourceNamesUnsubscribe),
"nonce", req.ResponseNonce,
"initial", len(req.InitialResourceVersions),
).Debugf("delta request")
metrics.XdsProxyRequests.Increment()
if req.TypeUrl == model.ExtensionConfigurationType {
p.ecdsLastNonce.Store(req.ResponseNonce)
}
if err := con.upstreamDeltas.Send(req); err != nil {
err = fmt.Errorf("send error for type url %s: %v", req.TypeUrl, err)
upstreamErr(con, err)
return
}
case <-con.stopChan:
return
}
}
}
func (p *XdsProxy) handleUpstreamDeltaResponse(con *ProxyConnection) {
forwardEnvoyCh := make(chan *discovery.DeltaDiscoveryResponse, 1)
for {
select {
case resp := <-con.deltaResponsesChan:
// TODO: separate upstream response handling from requests sending, which are both time costly
proxyLog.WithLabels(
"id", con.conID,
"type", model.GetShortType(resp.TypeUrl),
"nonce", resp.Nonce,
"resources", len(resp.Resources),
"removes", len(resp.RemovedResources),
).Debugf("upstream response")
metrics.XdsProxyResponses.Increment()
if h, f := p.handlers[resp.TypeUrl]; f {
if len(resp.Resources) == 0 {
// Empty response, nothing to do
// This assumes internal types are always singleton
break
}
err := h(resp.Resources[0].Resource)
var errorResp *google_rpc.Status
if err != nil {
errorResp = &google_rpc.Status{
Code: int32(codes.Internal),
Message: err.Error(),
}
}
// Send ACK/NACK
con.sendDeltaRequest(&discovery.DeltaDiscoveryRequest{
TypeUrl: resp.TypeUrl,
ResponseNonce: resp.Nonce,
ErrorDetail: errorResp,
})
continue
}
switch resp.TypeUrl {
case model.ExtensionConfigurationType:
if features.WasmRemoteLoadConversion {
// If Wasm remote load conversion feature is enabled, rewrite and send.
go p.deltaRewriteAndForward(con, resp, func(resp *discovery.DeltaDiscoveryResponse) {
// Forward the response using the thread of `handleUpstreamResponse`
// to prevent concurrent access to forwardToEnvoy
select {
case forwardEnvoyCh <- resp:
case <-con.stopChan:
}
})
} else {
// Otherwise, forward ECDS resource update directly to Envoy.
forwardDeltaToEnvoy(con, resp)
}
default:
if strings.HasPrefix(resp.TypeUrl, model.DebugType) {
p.forwardDeltaToTap(resp)
} else {
forwardDeltaToEnvoy(con, resp)
}
}
case resp := <-forwardEnvoyCh:
forwardDeltaToEnvoy(con, resp)
case <-con.stopChan:
return
}
}
}
func (p *XdsProxy) deltaRewriteAndForward(con *ProxyConnection, resp *discovery.DeltaDiscoveryResponse, forward func(resp *discovery.DeltaDiscoveryResponse)) {
resources := make([]*anypb.Any, 0, len(resp.Resources))
for i := range resp.Resources {
resources = append(resources, resp.Resources[i].Resource)
}
if err := wasm.MaybeConvertWasmExtensionConfig(resources, p.wasmCache); err != nil {
proxyLog.Debugf("sending NACK for ECDS resources %+v, err: %+v", resp.Resources, err)
con.sendDeltaRequest(&discovery.DeltaDiscoveryRequest{
TypeUrl: resp.TypeUrl,
ResponseNonce: resp.Nonce,
ErrorDetail: &google_rpc.Status{
Code: int32(codes.Internal),
Message: err.Error(),
},
})
return
}
for i := range resources {
resp.Resources[i].Resource = resources[i]
}
proxyLog.WithLabels("resources", slices.Map(resp.Resources, (*discovery.Resource).GetName), "removes", resp.RemovedResources).Debugf("forward ECDS")
forward(resp)
}
func forwardDeltaToEnvoy(con *ProxyConnection, resp *discovery.DeltaDiscoveryResponse) {
if !model.IsEnvoyType(resp.TypeUrl) && resp.TypeUrl != model.WorkloadType {
proxyLog.Errorf("Skipping forwarding type url %s to Envoy as is not a valid Envoy type", resp.TypeUrl)
return
}
if con.isClosed() {
proxyLog.WithLabels("id", con.conID).Errorf("downstream dropped delta xds push to Envoy, connection already closed")
return
}
if err := sendDownstreamDelta(con.downstreamDeltas, resp); err != nil {
err = fmt.Errorf("send error for type url %s: %v", resp.TypeUrl, err)
downstreamErr(con, err)
return
}
}
func sendDownstreamDelta(deltaDownstream DeltaDiscoveryStream, res *discovery.DeltaDiscoveryResponse) error {
tStart := time.Now()
defer func() {
// This is a hint to help debug slow responses.
if time.Since(tStart) > 10*time.Second {
proxyLog.Warnf("sendDownstreamDelta took %v", time.Since(tStart))
}
}()
return deltaDownstream.Send(res)
}
func (p *XdsProxy) sendDeltaHealthRequest(req *discovery.DeltaDiscoveryRequest) {
p.connectedMutex.Lock()
// Immediately send if we are currently connected.
if p.connected != nil && p.connected.deltaRequestsChan != nil {
p.connected.deltaRequestsChan.Put(req)
}
// Otherwise place it as our initial request for new connections
p.initialDeltaHealthRequest = req
p.connectedMutex.Unlock()
}
func (p *XdsProxy) forwardDeltaToTap(resp *discovery.DeltaDiscoveryResponse) {
select {
// Convert back to a SotW response
case p.tapResponseChannel <- &discovery.DiscoveryResponse{
VersionInfo: resp.SystemVersionInfo,
Resources: slices.Map(resp.Resources, (*discovery.Resource).GetResource),
Canary: false,
TypeUrl: resp.TypeUrl,
Nonce: resp.Nonce,
ControlPlane: resp.ControlPlane,
}:
default:
log.Infof("tap response %q arrived too late; discarding", resp.TypeUrl)
}
}