Examples with PingCallback io.grpc.internal.ClientTransport.PingCallback used on opensource projects

Example 1 with PingCallback

use of io.grpc.internal.ClientTransport.PingCallback in project grpc-java by grpc.

the class NettyClientHandler method sendPingFrame.

/**
   * Sends a PING frame. If a ping operation is already outstanding, the callback in the message is
   * registered to be called when the existing operation completes, and no new frame is sent.
   */
private void sendPingFrame(ChannelHandlerContext ctx, SendPingCommand msg, ChannelPromise promise) {
    // Don't check lifecycleManager.getShutdownStatus() since we want to allow pings after shutdown
    // but before termination. After termination, messages will no longer arrive because the
    // pipeline clears all handlers on channel close.
    PingCallback callback = msg.callback();
    Executor executor = msg.executor();
    // any outstanding operation
    if (ping != null) {
        promise.setSuccess();
        ping.addCallback(callback, executor);
        return;
    }
    // Use a new promise to prevent calling the callback twice on write failure: here and in
    // NettyClientTransport.ping(). It may appear strange, but it will behave the same as if
    // ping != null above.
    promise.setSuccess();
    promise = ctx().newPromise();
    // set outstanding operation
    long data = USER_PING_PAYLOAD;
    ByteBuf buffer = ctx.alloc().buffer(8);
    buffer.writeLong(data);
    Stopwatch stopwatch = Stopwatch.createStarted(ticker);
    ping = new Http2Ping(data, stopwatch);
    ping.addCallback(callback, executor);
    // and then write the ping
    encoder().writePing(ctx, false, buffer, promise);
    ctx.flush();
    final Http2Ping finalPing = ping;
    promise.addListener(new ChannelFutureListener() {

        @Override
        public void operationComplete(ChannelFuture future) throws Exception {
            if (!future.isSuccess()) {
                Throwable cause = future.cause();
                if (cause instanceof ClosedChannelException) {
                    cause = lifecycleManager.getShutdownThrowable();
                    if (cause == null) {
                        cause = Status.UNKNOWN.withDescription("Ping failed but for unknown reason.").withCause(future.cause()).asException();
                    }
                }
                finalPing.failed(cause);
                if (ping == finalPing) {
                    ping = null;
                }
            }
        }
    });
}