replicate/mdsal-replicate-netty/src/main/java/org/opendaylight/mdsal/replicate/netty/SourceRequestHandler.java

   1 /*
   2  * Copyright (c) 2020 PANTHEON.tech, s.r.o. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.mdsal.replicate.netty;
   9
  10 import static com.google.common.base.Verify.verify;
  11 import static java.util.Objects.requireNonNull;
  12
  13 import io.netty.buffer.ByteBuf;
  14 import io.netty.buffer.ByteBufInputStream;
  15 import io.netty.channel.Channel;
  16 import io.netty.channel.ChannelHandlerContext;
  17 import io.netty.channel.SimpleChannelInboundHandler;
  18 import java.io.IOException;
  19 import java.util.List;
  20 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  21 import org.opendaylight.mdsal.dom.api.ClusteredDOMDataTreeChangeListener;
  22 import org.opendaylight.mdsal.dom.api.DOMDataBroker.DataTreeChangeExtension;
  23 import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier;
  24 import org.opendaylight.yangtools.concepts.Registration;
  25 import org.opendaylight.yangtools.yang.data.codec.binfmt.NormalizedNodeDataInput;
  26 import org.opendaylight.yangtools.yang.data.tree.api.DataTreeCandidate;
  27 import org.slf4j.Logger;
  28 import org.slf4j.LoggerFactory;
  29
  30 /**
  31  * Final inbound handler on source side. Handles requests coming from sink and reacts to them.
  32  */
  33 final class SourceRequestHandler extends SimpleChannelInboundHandler<ByteBuf> {
  34     private static final Logger LOG = LoggerFactory.getLogger(SourceRequestHandler.class);
  35
  36     private final DataTreeChangeExtension dtcs;
  37
  38     private Registration reg;
  39
  40     SourceRequestHandler(final DataTreeChangeExtension dtcs) {
  41         this.dtcs = requireNonNull(dtcs);
  42     }
  43
  44     @Override
  45     public void channelInactive(final ChannelHandlerContext ctx) {
  46         LOG.info("Channel {} going inactive", ctx.channel());
  47         if (reg != null) {
  48             reg.close();
  49             reg = null;
  50         }
  51         ctx.fireChannelInactive();
  52     }
  53
  54     @Override
  55     protected void channelRead0(final ChannelHandlerContext ctx, final ByteBuf msg) throws IOException {
  56         verify(msg.isReadable(), "Empty message received");
  57
  58         final short msgType = msg.readUnsignedByte();
  59         final Channel channel = ctx.channel();
  60         LOG.trace("Channel {} received message type {}", channel, msgType);
  61         switch (msgType) {
  62             case Constants.MSG_SUBSCRIBE_REQ -> subscribe(channel, msg);
  63             case Constants.MSG_PONG -> {
  64                 // No-op
  65             }
  66             default -> throw new IllegalStateException("Unexpected message type " + msgType);
  67         }
  68     }
  69
  70     @Override
  71     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
  72         LOG.warn("Closing channel {} due to an error", ctx.channel(), cause);
  73         ctx.close();
  74     }
  75
  76     private void subscribe(final Channel channel, final ByteBuf msg) throws IOException {
  77         verify(reg == null, "Unexpected subscription when already subscribed");
  78
  79         final DOMDataTreeIdentifier dataTree;
  80         try (var input = new ByteBufInputStream(msg)) {
  81             final var normalizedInput = NormalizedNodeDataInput.newDataInput(input);
  82
  83             dataTree = DOMDataTreeIdentifier.of(LogicalDatastoreType.readFrom(normalizedInput),
  84                 normalizedInput.readYangInstanceIdentifier());
  85         }
  86
  87         LOG.info("Channel {} subscribing to {}", channel, dataTree);
  88         reg = dtcs.registerDataTreeChangeListener(dataTree, new ClusteredDOMDataTreeChangeListener() {
  89             @Override
  90             public void onInitialData() {
  91                 LOG.debug("Channel {} tree {} has empty data", channel, dataTree);
  92                 channel.writeAndFlush(AbstractSourceMessage.empty());
  93             }
  94
  95             @Override
  96             public void onDataTreeChanged(final List<DataTreeCandidate> changes) {
  97                 LOG.debug("Channel {} tree {} has {} changes", channel, dataTree, changes.size());
  98                 channel.writeAndFlush(AbstractSourceMessage.of(changes));
  99             }
 100         });
 101     }
 102 }