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AbstractXdsClient.java
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AbstractXdsClient.java
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/*
* Copyright 2020 The gRPC 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 io.grpc.xds;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Stopwatch;
import com.google.common.base.Supplier;
import com.google.protobuf.Any;
import com.google.rpc.Code;
import io.envoyproxy.envoy.service.discovery.v3.AggregatedDiscoveryServiceGrpc;
import io.envoyproxy.envoy.service.discovery.v3.DiscoveryRequest;
import io.envoyproxy.envoy.service.discovery.v3.DiscoveryResponse;
import io.grpc.Context;
import io.grpc.InternalLogId;
import io.grpc.ManagedChannel;
import io.grpc.Status;
import io.grpc.SynchronizationContext;
import io.grpc.SynchronizationContext.ScheduledHandle;
import io.grpc.internal.BackoffPolicy;
import io.grpc.stub.StreamObserver;
import io.grpc.xds.XdsLogger.XdsLogLevel;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import javax.annotation.Nullable;
/**
* Common base type for XdsClient implementations, which encapsulates the layer abstraction of
* the xDS RPC stream.
*/
abstract class AbstractXdsClient extends XdsClient {
private static final String ADS_TYPE_URL_LDS_V2 = "type.googleapis.com/envoy.api.v2.Listener";
private static final String ADS_TYPE_URL_LDS =
"type.googleapis.com/envoy.config.listener.v3.Listener";
private static final String ADS_TYPE_URL_RDS_V2 =
"type.googleapis.com/envoy.api.v2.RouteConfiguration";
private static final String ADS_TYPE_URL_RDS =
"type.googleapis.com/envoy.config.route.v3.RouteConfiguration";
@VisibleForTesting
static final String ADS_TYPE_URL_CDS_V2 = "type.googleapis.com/envoy.api.v2.Cluster";
private static final String ADS_TYPE_URL_CDS =
"type.googleapis.com/envoy.config.cluster.v3.Cluster";
private static final String ADS_TYPE_URL_EDS_V2 =
"type.googleapis.com/envoy.api.v2.ClusterLoadAssignment";
private static final String ADS_TYPE_URL_EDS =
"type.googleapis.com/envoy.config.endpoint.v3.ClusterLoadAssignment";
private final SynchronizationContext syncContext = new SynchronizationContext(
new Thread.UncaughtExceptionHandler() {
@Override
public void uncaughtException(Thread t, Throwable e) {
getLogger().log(
XdsLogLevel.ERROR,
"Uncaught exception in XdsClient SynchronizationContext. Panic!",
e);
// TODO(chengyuanzhang): better error handling.
throw new AssertionError(e);
}
});
private final InternalLogId logId;
private final XdsLogger logger;
private final ManagedChannel channel;
private final Context context;
private final ScheduledExecutorService timeService;
private final BackoffPolicy.Provider backoffPolicyProvider;
private final Stopwatch stopwatch;
private final Bootstrapper.BootstrapInfo bootstrapInfo;
// Last successfully applied version_info for each resource type. Starts with empty string.
// A version_info is used to update management server with client's most recent knowledge of
// resources.
private String ldsVersion = "";
private String rdsVersion = "";
private String cdsVersion = "";
private String edsVersion = "";
private boolean shutdown;
@Nullable
private AbstractAdsStream adsStream;
@Nullable
private BackoffPolicy retryBackoffPolicy;
@Nullable
private ScheduledHandle rpcRetryTimer;
AbstractXdsClient(ManagedChannel channel, Bootstrapper.BootstrapInfo bootstrapInfo,
Context context, ScheduledExecutorService timeService,
BackoffPolicy.Provider backoffPolicyProvider, Supplier<Stopwatch> stopwatchSupplier) {
this.channel = checkNotNull(channel, "channel");
this.bootstrapInfo = checkNotNull(bootstrapInfo, "bootstrapInfo");
this.context = checkNotNull(context, "context");
this.timeService = checkNotNull(timeService, "timeService");
this.backoffPolicyProvider = checkNotNull(backoffPolicyProvider, "backoffPolicyProvider");
stopwatch = checkNotNull(stopwatchSupplier, "stopwatchSupplier").get();
logId = InternalLogId.allocate("xds-client", null);
logger = XdsLogger.withLogId(logId);
logger.log(XdsLogLevel.INFO, "Created");
}
/**
* Called when an LDS response is received.
*/
// Must be synchronized.
protected void handleLdsResponse(String versionInfo, List<Any> resources, String nonce) {
}
/**
* Called when a RDS response is received.
*/
// Must be synchronized.
protected void handleRdsResponse(String versionInfo, List<Any> resources, String nonce) {
}
/**
* Called when a CDS response is received.
*/
// Must be synchronized.
protected void handleCdsResponse(String versionInfo, List<Any> resources, String nonce) {
}
/**
* Called when an EDS response is received.
*/
// Must be synchronized.
protected void handleEdsResponse(String versionInfo, List<Any> resources, String nonce) {
}
/**
* Called when the ADS stream is closed passively.
*/
// Must be synchronized.
protected void handleStreamClosed(Status error) {
}
/**
* Called when the ADS stream has been recreated.
*/
// Must be synchronized.
protected void handleStreamRestarted() {
}
/**
* Called when being shut down.
*/
// Must be synchronized.
protected void handleShutdown() {
}
@Override
final void shutdown() {
syncContext.execute(new Runnable() {
@Override
public void run() {
shutdown = true;
logger.log(XdsLogLevel.INFO, "Shutting down");
if (adsStream != null) {
adsStream.close(Status.CANCELLED.withDescription("shutdown").asException());
}
if (rpcRetryTimer != null && rpcRetryTimer.isPending()) {
rpcRetryTimer.cancel();
}
handleShutdown();
}
});
}
@Override
boolean isShutDown() {
return shutdown;
}
@Override
Bootstrapper.BootstrapInfo getBootstrapInfo() {
return bootstrapInfo;
}
@Override
public String toString() {
return logId.toString();
}
/**
* Returns the collection of resources currently subscribing to or {@code null} if not
* subscribing to any resources for the given type.
*
* <p>Note an empty collection indicates subscribing to resources of the given type with
* wildcard mode.
*/
// Must be synchronized.
@Nullable
abstract Collection<String> getSubscribedResources(ResourceType type);
/**
* Updates the resource subscription for the given resource type.
*/
// Must be synchronized.
protected final void adjustResourceSubscription(ResourceType type) {
if (isInBackoff()) {
return;
}
if (adsStream == null) {
startRpcStream();
}
Collection<String> resources = getSubscribedResources(type);
if (resources != null) {
adsStream.sendDiscoveryRequest(type, resources);
}
}
/**
* Accepts the update for the given resource type by updating the latest resource version
* and sends an ACK request to the management server.
*/
// Must be synchronized.
protected final void ackResponse(ResourceType type, String versionInfo, String nonce) {
switch (type) {
case LDS:
ldsVersion = versionInfo;
break;
case RDS:
rdsVersion = versionInfo;
break;
case CDS:
cdsVersion = versionInfo;
break;
case EDS:
edsVersion = versionInfo;
break;
case UNKNOWN:
default:
throw new AssertionError("Unknown resource type: " + type);
}
logger.log(XdsLogLevel.INFO, "Sending ACK for {0} update, nonce: {1}, current version: {2}",
type, nonce, versionInfo);
Collection<String> resources = getSubscribedResources(type);
if (resources == null) {
resources = Collections.emptyList();
}
adsStream.sendDiscoveryRequest(type, versionInfo, resources, nonce, null);
}
/**
* Rejects the update for the given resource type and sends an NACK request (request with last
* accepted version) to the management server.
*/
// Must be synchronized.
protected final void nackResponse(ResourceType type, String nonce, String errorDetail) {
String versionInfo = getCurrentVersion(type);
logger.log(XdsLogLevel.INFO, "Sending NACK for {0} update, nonce: {1}, current version: {2}",
type, nonce, versionInfo);
Collection<String> resources = getSubscribedResources(type);
if (resources == null) {
resources = Collections.emptyList();
}
adsStream.sendDiscoveryRequest(type, versionInfo, resources, nonce, errorDetail);
}
protected final SynchronizationContext getSyncContext() {
return syncContext;
}
protected final ScheduledExecutorService getTimeService() {
return timeService;
}
protected final XdsLogger getLogger() {
return logger;
}
/**
* Returns {@code true} if the resource discovery is currently in backoff.
*/
// Must be synchronized.
protected final boolean isInBackoff() {
return rpcRetryTimer != null && rpcRetryTimer.isPending();
}
/**
* Establishes the RPC connection by creating a new RPC stream on the given channel for
* xDS protocol communication.
*/
// Must be synchronized.
private void startRpcStream() {
checkState(adsStream == null, "Previous adsStream has not been cleared yet");
if (bootstrapInfo.servers().get(0).useProtocolV3()) {
adsStream = new AdsStreamV3();
} else {
adsStream = new AdsStreamV2();
}
Context prevContext = context.attach();
try {
adsStream.start();
} finally {
context.detach(prevContext);
}
logger.log(XdsLogLevel.INFO, "ADS stream started");
stopwatch.reset().start();
}
// Must be synchronized.
@Override
String getCurrentVersion(ResourceType type) {
String version;
switch (type) {
case LDS:
version = ldsVersion;
break;
case RDS:
version = rdsVersion;
break;
case CDS:
version = cdsVersion;
break;
case EDS:
version = edsVersion;
break;
case UNKNOWN:
default:
throw new AssertionError("Unknown resource type: " + type);
}
return version;
}
@VisibleForTesting
final class RpcRetryTask implements Runnable {
@Override
public void run() {
if (shutdown) {
return;
}
startRpcStream();
for (ResourceType type : ResourceType.values()) {
if (type == ResourceType.UNKNOWN) {
continue;
}
Collection<String> resources = getSubscribedResources(type);
if (resources != null) {
adsStream.sendDiscoveryRequest(type, resources);
}
}
handleStreamRestarted();
}
}
protected enum ResourceType {
UNKNOWN, LDS, RDS, CDS, EDS;
String typeUrl() {
switch (this) {
case LDS:
return ADS_TYPE_URL_LDS;
case RDS:
return ADS_TYPE_URL_RDS;
case CDS:
return ADS_TYPE_URL_CDS;
case EDS:
return ADS_TYPE_URL_EDS;
case UNKNOWN:
default:
throw new AssertionError("Unknown or missing case in enum switch: " + this);
}
}
String typeUrlV2() {
switch (this) {
case LDS:
return ADS_TYPE_URL_LDS_V2;
case RDS:
return ADS_TYPE_URL_RDS_V2;
case CDS:
return ADS_TYPE_URL_CDS_V2;
case EDS:
return ADS_TYPE_URL_EDS_V2;
case UNKNOWN:
default:
throw new AssertionError("Unknown or missing case in enum switch: " + this);
}
}
private static ResourceType fromTypeUrl(String typeUrl) {
switch (typeUrl) {
case ADS_TYPE_URL_LDS:
// fall trough
case ADS_TYPE_URL_LDS_V2:
return LDS;
case ADS_TYPE_URL_RDS:
// fall through
case ADS_TYPE_URL_RDS_V2:
return RDS;
case ADS_TYPE_URL_CDS:
// fall through
case ADS_TYPE_URL_CDS_V2:
return CDS;
case ADS_TYPE_URL_EDS:
// fall through
case ADS_TYPE_URL_EDS_V2:
return EDS;
default:
return UNKNOWN;
}
}
}
private abstract class AbstractAdsStream {
private boolean responseReceived;
private boolean closed;
// Response nonce for the most recently received discovery responses of each resource type.
// Client initiated requests start response nonce with empty string.
// A nonce is used to indicate the specific DiscoveryResponse each DiscoveryRequest
// corresponds to.
// A nonce becomes stale following a newer nonce being presented to the client in a
// DiscoveryResponse.
private String ldsRespNonce = "";
private String rdsRespNonce = "";
private String cdsRespNonce = "";
private String edsRespNonce = "";
abstract void start();
abstract void sendError(Exception error);
/**
* Sends a discovery request with the given {@code versionInfo}, {@code nonce} and
* {@code errorDetail}. Used for reacting to a specific discovery response. For
* client-initiated discovery requests, use {@link
* #sendDiscoveryRequest(ResourceType, Collection)}.
*/
abstract void sendDiscoveryRequest(ResourceType type, String versionInfo,
Collection<String> resources, String nonce, @Nullable String errorDetail);
/**
* Sends a client-initiated discovery request.
*/
final void sendDiscoveryRequest(ResourceType type, Collection<String> resources) {
String nonce;
switch (type) {
case LDS:
nonce = ldsRespNonce;
break;
case RDS:
nonce = rdsRespNonce;
break;
case CDS:
nonce = cdsRespNonce;
break;
case EDS:
nonce = edsRespNonce;
break;
case UNKNOWN:
default:
throw new AssertionError("Unknown resource type: " + type);
}
logger.log(XdsLogLevel.INFO, "Sending {0} request for resources: {1}", type, resources);
sendDiscoveryRequest(type, getCurrentVersion(type), resources, nonce, null);
}
final void handleRpcResponse(
ResourceType type, String versionInfo, List<Any> resources, String nonce) {
if (closed) {
return;
}
responseReceived = true;
// Nonce in each response is echoed back in the following ACK/NACK request. It is
// used for management server to identify which response the client is ACKing/NACking.
// To avoid confusion, client-initiated requests will always use the nonce in
// most recently received responses of each resource type.
switch (type) {
case LDS:
ldsRespNonce = nonce;
handleLdsResponse(versionInfo, resources, nonce);
break;
case RDS:
rdsRespNonce = nonce;
handleRdsResponse(versionInfo, resources, nonce);
break;
case CDS:
cdsRespNonce = nonce;
handleCdsResponse(versionInfo, resources, nonce);
break;
case EDS:
edsRespNonce = nonce;
handleEdsResponse(versionInfo, resources, nonce);
break;
case UNKNOWN:
default:
logger.log(XdsLogLevel.WARNING, "Ignore an unknown type of DiscoveryResponse");
}
}
final void handleRpcError(Throwable t) {
handleRpcStreamClosed(Status.fromThrowable(t));
}
final void handleRpcCompleted() {
handleRpcStreamClosed(Status.UNAVAILABLE.withDescription("Closed by server"));
}
private void handleRpcStreamClosed(Status error) {
checkArgument(!error.isOk(), "unexpected OK status");
if (closed) {
return;
}
logger.log(
XdsLogLevel.ERROR,
"ADS stream closed with status {0}: {1}. Cause: {2}",
error.getCode(), error.getDescription(), error.getCause());
closed = true;
handleStreamClosed(error);
cleanUp();
if (responseReceived || retryBackoffPolicy == null) {
// Reset the backoff sequence if had received a response, or backoff sequence
// has never been initialized.
retryBackoffPolicy = backoffPolicyProvider.get();
}
long delayNanos = 0;
if (!responseReceived) {
delayNanos =
Math.max(
0,
retryBackoffPolicy.nextBackoffNanos()
- stopwatch.elapsed(TimeUnit.NANOSECONDS));
}
logger.log(XdsLogLevel.INFO, "Retry ADS stream in {0} ns", delayNanos);
rpcRetryTimer = syncContext.schedule(
new RpcRetryTask(), delayNanos, TimeUnit.NANOSECONDS, timeService);
}
private void close(Exception error) {
if (closed) {
return;
}
closed = true;
cleanUp();
sendError(error);
}
private void cleanUp() {
if (adsStream == this) {
adsStream = null;
}
}
}
private final class AdsStreamV2 extends AbstractAdsStream {
private StreamObserver<io.envoyproxy.envoy.api.v2.DiscoveryRequest> requestWriter;
@Override
void start() {
io.envoyproxy.envoy.service.discovery.v2.AggregatedDiscoveryServiceGrpc
.AggregatedDiscoveryServiceStub stub =
io.envoyproxy.envoy.service.discovery.v2.AggregatedDiscoveryServiceGrpc.newStub(channel);
StreamObserver<io.envoyproxy.envoy.api.v2.DiscoveryResponse> responseReaderV2 =
new StreamObserver<io.envoyproxy.envoy.api.v2.DiscoveryResponse>() {
@Override
public void onNext(final io.envoyproxy.envoy.api.v2.DiscoveryResponse response) {
syncContext.execute(new Runnable() {
@Override
public void run() {
ResourceType type = ResourceType.fromTypeUrl(response.getTypeUrl());
if (logger.isLoggable(XdsLogLevel.DEBUG)) {
logger.log(
XdsLogLevel.DEBUG, "Received {0} response:\n{1}", type,
MessagePrinter.print(response));
}
handleRpcResponse(type, response.getVersionInfo(), response.getResourcesList(),
response.getNonce());
}
});
}
@Override
public void onError(final Throwable t) {
syncContext.execute(new Runnable() {
@Override
public void run() {
handleRpcError(t);
}
});
}
@Override
public void onCompleted() {
syncContext.execute(new Runnable() {
@Override
public void run() {
handleRpcCompleted();
}
});
}
};
requestWriter = stub.withWaitForReady().streamAggregatedResources(responseReaderV2);
}
@Override
void sendDiscoveryRequest(ResourceType type, String versionInfo, Collection<String> resources,
String nonce, @Nullable String errorDetail) {
checkState(requestWriter != null, "ADS stream has not been started");
io.envoyproxy.envoy.api.v2.DiscoveryRequest.Builder builder =
io.envoyproxy.envoy.api.v2.DiscoveryRequest.newBuilder()
.setVersionInfo(versionInfo)
.setNode(bootstrapInfo.node().toEnvoyProtoNodeV2())
.addAllResourceNames(resources)
.setTypeUrl(type.typeUrlV2())
.setResponseNonce(nonce);
if (errorDetail != null) {
com.google.rpc.Status error =
com.google.rpc.Status.newBuilder()
.setCode(Code.INVALID_ARGUMENT_VALUE) // FIXME(chengyuanzhang): use correct code
.setMessage(errorDetail)
.build();
builder.setErrorDetail(error);
}
io.envoyproxy.envoy.api.v2.DiscoveryRequest request = builder.build();
requestWriter.onNext(request);
if (logger.isLoggable(XdsLogLevel.DEBUG)) {
logger.log(XdsLogLevel.DEBUG, "Sent DiscoveryRequest\n{0}", MessagePrinter.print(request));
}
}
@Override
void sendError(Exception error) {
requestWriter.onError(error);
}
}
private final class AdsStreamV3 extends AbstractAdsStream {
private StreamObserver<DiscoveryRequest> requestWriter;
@Override
void start() {
AggregatedDiscoveryServiceGrpc.AggregatedDiscoveryServiceStub stub =
AggregatedDiscoveryServiceGrpc.newStub(channel);
StreamObserver<DiscoveryResponse> responseReader = new StreamObserver<DiscoveryResponse>() {
@Override
public void onNext(final DiscoveryResponse response) {
syncContext.execute(new Runnable() {
@Override
public void run() {
ResourceType type = ResourceType.fromTypeUrl(response.getTypeUrl());
if (logger.isLoggable(XdsLogLevel.DEBUG)) {
logger.log(
XdsLogLevel.DEBUG, "Received {0} response:\n{1}", type,
MessagePrinter.print(response));
}
handleRpcResponse(type, response.getVersionInfo(), response.getResourcesList(),
response.getNonce());
}
});
}
@Override
public void onError(final Throwable t) {
syncContext.execute(new Runnable() {
@Override
public void run() {
handleRpcError(t);
}
});
}
@Override
public void onCompleted() {
syncContext.execute(new Runnable() {
@Override
public void run() {
handleRpcCompleted();
}
});
}
};
requestWriter = stub.withWaitForReady().streamAggregatedResources(responseReader);
}
@Override
void sendDiscoveryRequest(ResourceType type, String versionInfo, Collection<String> resources,
String nonce, @Nullable String errorDetail) {
checkState(requestWriter != null, "ADS stream has not been started");
DiscoveryRequest.Builder builder =
DiscoveryRequest.newBuilder()
.setVersionInfo(versionInfo)
.setNode(bootstrapInfo.node().toEnvoyProtoNode())
.addAllResourceNames(resources)
.setTypeUrl(type.typeUrl())
.setResponseNonce(nonce);
if (errorDetail != null) {
com.google.rpc.Status error =
com.google.rpc.Status.newBuilder()
.setCode(Code.INVALID_ARGUMENT_VALUE) // FIXME(chengyuanzhang): use correct code
.setMessage(errorDetail)
.build();
builder.setErrorDetail(error);
}
DiscoveryRequest request = builder.build();
requestWriter.onNext(request);
if (logger.isLoggable(XdsLogLevel.DEBUG)) {
logger.log(XdsLogLevel.DEBUG, "Sent DiscoveryRequest\n{0}", MessagePrinter.print(request));
}
}
@Override
void sendError(Exception error) {
requestWriter.onError(error);
}
}
}