Fix NullPointerException in transport trace logger

[howardhuanghua]

When trace-level logging is enabled, a node might disconnect from
cluster due to an NPE that causes the transport connection closed
between the data node and the master node.

InboundMessages printed by TransportLogger might throw an NPE in the
format function because content might be NULL if another node sends an
abnormal exception response.

Also there's no good reason to close the connection because of a logging
exception, so with this commit we catch all exceptions (rather than just
IOException)

[DaveCTurner]

I think we should also fix the NPE you found. I see no reason to even call openOrGetStreamInput() within this format method.

[elasticsearchmachine]

Pinging @elastic/es-distributed-coordination (Team:Distributed Coordination)

[howardhuanghua]

I think we should also fix the NPE you found. I see no reason to even call openOrGetStreamInput() within this format method.

Yes, I also removed unused openOrGetStreamInput() and CompressorFactory function.

[DaveCTurner]

Looks good, could we also have a test covering this case in org.elasticsearch.transport.TransportLoggerTests?

[howardhuanghua]

TransportLoggerTests

Sure, I am going to add a test case.

[DaveCTurner]

LGTM

[DaveCTurner]

Original report:

Issue

When trace-level logging is enabled, a node might disconnect from cluster due to an NPE that causes the transport connection closed between the data node and the master node.

InboundMessages printed by TransportLogger might throw an NPE in the format function because content might be NULL if another node sends an abnormal exception response.

https://github.com/elastic/elasticsearch/blob/fe4a5237edd7503029390f0cb81c9b40ee44fea3/server/src/main/java/org/elasticsearch/transport/InboundMessage.java#L103C27-L103C34

[2025-07-28T16:40:17,554] [WARN ] [o.e.t.TcpTransport]  [node] exception caught on transport layer [Netty4TcpChannel{localAddress=/10.0.0.1:9300, remoteAddress=/10.0.0.2:36424}], closing connection
java. lang.NullPointerException: null
at org.elasticsearch.transport.InboundMessage.open0rGetStreamInput(InboundMessage.java:100) ~[elasticsearch-7.10.1.jar:7.10.1]
at org.elasticsearch.transport.TransportLogger.format(TransportLogger.java:140) ~[elasticsearch-7.10.1.jar:7.10.1]
at org.elasticsearch.transport.TransportLogger.logInboundMessage(TransportLogger.java:52) ~[elasticsearch-7.10.1.jar:7.10.11
at org.elasticsearch.transport.InboundHandler.inboundMessage(InboundHandler.java:90) ~[elasticsearch-7.10.1.jar:7.10.11
at org.elasticsearch. transport.TcpTransport.inboundMessage(TcpTransport.java:700) ~[elasticsearch-7.10.1.jar:7.10.1]
at org.elasticsearch.transport.InboundPipeline.forwardFragments(InboundPipeline.java:142) ~[elasticsearch-7.10.1.jar:7.10.11
at org.elasticsearch.transport.InboundPipeline.doHandleBytes(InboundPipeline.java:117) ~[elasticsearch-7.10.1.jar:7.10.1]
at org.elasticsearch.transport.InboundPipeline.handleBytes(InboundPipeline.java:82) ~[elasticsearch-7.10.1.jar:7.10.11
at org.elasticsearch.transport.netty4.Netty4MessageChannelHandler.channelRead(Netty4MessageChannelHandler.java:74) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext. invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext. invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[?:?]
at io.netty.handler.logging.LoggingHandler.channelRead(LoggingHandler.java:271) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext. invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext. invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead (AbstractChannelHandlerContext.java:357) ~[?:?]
at io.netty.handler. codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext. invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext. invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext. fireChannelRead(AbstractChannelHandlerContext.java:357) ~[?:?]
at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1518) ~[?:?]
at io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1267) ~[?:?]
at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1314) ~[?:?]
at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:501) ~[?:?]
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:440) ~[?:?]
at io.netty.handler. codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext. invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[?:?]
at io.netty. channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~|?:?1
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[?:?]
at io.netty.channel.AbstractChannelHandlerContext. invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[?:?]

Resolve

We should only print warn logs instead of throwing NPE to caused connection closed between nodes. So try to catch all the exceptions instead of IOException.