io.grpc.netty.NettyClientTransport Maven / Gradle / Ivy
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package io.grpc.netty;
import static io.netty.channel.ChannelOption.SO_KEEPALIVE;
import com.google.common.base.Preconditions;
import com.google.common.base.Ticker;
import io.grpc.Attributes;
import io.grpc.CallOptions;
import io.grpc.Metadata;
import io.grpc.MethodDescriptor;
import io.grpc.Status;
import io.grpc.internal.ClientStream;
import io.grpc.internal.ConnectionClientTransport;
import io.grpc.internal.GrpcUtil;
import io.grpc.internal.Http2Ping;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.util.AsciiString;
import java.net.SocketAddress;
import java.nio.channels.ClosedChannelException;
import java.util.concurrent.Executor;
import javax.annotation.Nullable;
/**
* A Netty-based {@link ConnectionClientTransport} implementation.
*/
class NettyClientTransport implements ConnectionClientTransport {
private final SocketAddress address;
private final Class channelType;
private final EventLoopGroup group;
private final ProtocolNegotiator negotiator;
private final AsciiString authority;
private final AsciiString userAgent;
private final int flowControlWindow;
private final int maxMessageSize;
private final int maxHeaderListSize;
private ProtocolNegotiator.Handler negotiationHandler;
private NettyClientHandler handler;
// We should not send on the channel until negotiation completes. This is a hard requirement
// by SslHandler but is appropriate for HTTP/1.1 Upgrade as well.
private Channel channel;
/** Since not thread-safe, may only be used from event loop. */
private ClientTransportLifecycleManager lifecycleManager;
NettyClientTransport(SocketAddress address, Class channelType,
EventLoopGroup group, ProtocolNegotiator negotiator,
int flowControlWindow, int maxMessageSize, int maxHeaderListSize,
String authority, @Nullable String userAgent) {
this.negotiator = Preconditions.checkNotNull(negotiator, "negotiator");
this.address = Preconditions.checkNotNull(address, "address");
this.group = Preconditions.checkNotNull(group, "group");
this.channelType = Preconditions.checkNotNull(channelType, "channelType");
this.flowControlWindow = flowControlWindow;
this.maxMessageSize = maxMessageSize;
this.maxHeaderListSize = maxHeaderListSize;
this.authority = new AsciiString(authority);
this.userAgent = new AsciiString(GrpcUtil.getGrpcUserAgent("netty", userAgent));
}
@Override
public void ping(final PingCallback callback, final Executor executor) {
ChannelFutureListener failureListener = new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (!future.isSuccess()) {
Status s = statusFromFailedFuture(future);
Http2Ping.notifyFailed(callback, executor, s.asException());
}
}
};
// Write the command requesting the ping
handler.getWriteQueue().enqueue(new SendPingCommand(callback, executor), true)
.addListener(failureListener);
}
@Override
public ClientStream newStream(MethodDescriptor method, Metadata headers, CallOptions
callOptions) {
Preconditions.checkNotNull(method, "method");
Preconditions.checkNotNull(headers, "headers");
return new NettyClientStream(method, headers, channel, handler, maxMessageSize, authority,
negotiationHandler.scheme(), userAgent) {
@Override
protected Status statusFromFailedFuture(ChannelFuture f) {
return NettyClientTransport.this.statusFromFailedFuture(f);
}
};
}
@Override
public ClientStream newStream(MethodDescriptor method, Metadata headers) {
return newStream(method, headers, CallOptions.DEFAULT);
}
@Override
public void start(Listener transportListener) {
lifecycleManager = new ClientTransportLifecycleManager(
Preconditions.checkNotNull(transportListener, "listener"));
handler = newHandler();
negotiationHandler = negotiator.newHandler(handler);
Bootstrap b = new Bootstrap();
b.group(group);
b.channel(channelType);
if (NioSocketChannel.class.isAssignableFrom(channelType)) {
b.option(SO_KEEPALIVE, true);
}
/**
* We don't use a ChannelInitializer in the client bootstrap because its "initChannel" method
* is executed in the event loop and we need this handler to be in the pipeline immediately so
* that it may begin buffering writes.
*/
b.handler(negotiationHandler);
// Start the connection operation to the server.
channel = b.connect(address).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (!future.isSuccess()) {
ChannelHandlerContext ctx = future.channel().pipeline().context(handler);
if (ctx != null) {
// NettyClientHandler doesn't propagate exceptions, but the negotiator will need the
// exception to fail any writes. Note that this fires after handler, because it is as if
// handler was propagating the notification.
ctx.fireExceptionCaught(future.cause());
}
future.channel().pipeline().fireExceptionCaught(future.cause());
}
}
}).channel();
// Start the write queue as soon as the channel is constructed
handler.startWriteQueue(channel);
// This write will have no effect, yet it will only complete once the negotiationHandler
// flushes any pending writes.
channel.write(NettyClientHandler.NOOP_MESSAGE).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (!future.isSuccess()) {
// Need to notify of this failure, because NettyClientHandler may not have been added to
// the pipeline before the error occurred.
lifecycleManager.notifyTerminated(Utils.statusFromThrowable(future.cause()));
}
}
});
// Handle transport shutdown when the channel is closed.
channel.closeFuture().addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
// Typically we should have noticed shutdown before this point.
lifecycleManager.notifyTerminated(
Status.INTERNAL.withDescription("Connection closed with unknown cause"));
}
});
}
@Override
public void shutdown() {
// Notifying of termination is automatically done when the channel closes.
if (channel.isOpen()) {
Status status
= Status.UNAVAILABLE.withDescription("Channel requested transport to shut down");
handler.getWriteQueue().enqueue(new GracefulCloseCommand(status), true);
}
}
@Override
public void shutdownNow(Status reason) {
// Notifying of termination is automatically done when the channel closes.
if (channel != null && channel.isOpen()) {
handler.getWriteQueue().enqueue(new ForcefulCloseCommand(reason), true);
}
}
@Override
public String toString() {
return getLogId() + "(" + address + ")";
}
@Override
public String getLogId() {
return GrpcUtil.getLogId(this);
}
@Override
public Attributes getAttrs() {
// TODO(zhangkun83): fill channel security attributes
return Attributes.EMPTY;
}
/**
* Convert ChannelFuture.cause() to a Status, taking into account that all handlers are removed
* from the pipeline when the channel is closed. Since handlers are removed, you may get an
* unhelpful exception like ClosedChannelException.
*/
private Status statusFromFailedFuture(ChannelFuture f) {
Throwable t = f.cause();
if (t instanceof ClosedChannelException) {
synchronized (this) {
Status shutdownStatus = lifecycleManager.getShutdownStatus();
if (shutdownStatus == null) {
return Status.UNKNOWN.withDescription("Channel closed but for unknown reason");
}
return shutdownStatus;
}
}
return Utils.statusFromThrowable(t);
}
private NettyClientHandler newHandler() {
return NettyClientHandler.newHandler(lifecycleManager, flowControlWindow, maxHeaderListSize,
Ticker.systemTicker());
}
}
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