Carapace 1.8 > java.lang.NullPointerException

[hamadodene]

In our production setup I have noticed several NPE.
I have no way to reproduce it.

eb 20, 2023 1:30:48 PM reactor.util.Loggers$Slf4JLogger error
SEVERE: [2e92224d-1, L:/xxxxxxxxxx:8089 - R:/xxxxxxxxxxx:43834]
java.lang.NullPointerException: Cannot invoke "java.lang.CharSequence.length()" because "this.text" is null
        at java.base/java.util.regex.Matcher.getTextLength(Matcher.java:1769)
        at java.base/java.util.regex.Matcher.reset(Matcher.java:415)
        at java.base/java.util.regex.Matcher.<init>(Matcher.java:252)
        at java.base/java.util.regex.Pattern.matcher(Pattern.java:1134)
        at java.base/java.util.regex.Pattern.matches(Pattern.java:1175)
        at org.carapaceproxy.core.ProxyRequestsManager$ConnectionsManager.lambda$apply$4(ProxyRequestsManager.java:598)
        at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:178)
        at java.base/java.util.concurrent.ConcurrentHashMap$EntrySpliterator.tryAdvance(ConcurrentHashMap.java:3660)
        at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:129)
        at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:527)
        at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:513)
        at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
        at java.base/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)
        at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.base/java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:647)
        at org.carapaceproxy.core.ProxyRequestsManager$ConnectionsManager.apply(ProxyRequestsManager.java:599)
        at org.carapaceproxy.core.ProxyRequestsManager.forward(ProxyRequestsManager.java:343)
        at org.carapaceproxy.core.ProxyRequestsManager.processRequest(ProxyRequestsManager.java:161)
        at org.carapaceproxy.core.Listeners.lambda$bootListener$4(Listeners.java:270)
        at reactor.netty.http.server.HttpServer$HttpServerHandle.onStateChange(HttpServer.java:959)
        at reactor.netty.ReactorNetty$CompositeConnectionObserver.onStateChange(ReactorNetty.java:677)
        at reactor.netty.transport.ServerTransport$ChildObserver.onStateChange(ServerTransport.java:475)
        at reactor.netty.http.server.HttpServerOperations.onInboundNext(HttpServerOperations.java:570)
        at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:93)
        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 reactor.netty.http.server.AbstractHttpServerMetricsHandler.channelRead(AbstractHttpServerMetricsHandler.java:190)
        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 reactor.netty.http.server.HttpTrafficHandler.channelRead(HttpTrafficHandler.java:214)
        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.handler.codec.MessageToMessageCodec.channelRead(MessageToMessageCodec.java:111)
        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 org.carapaceproxy.core.Listeners$2.channelRead(Listeners.java:249)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
        at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436)
        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:336)
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:308)
        at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251)
        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.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286)
        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.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
        at io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:800)
        at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:499)
        at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:397)
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Thread.java:833)

[hamadodene]

   Map.Entry<ConnectionPoolConfiguration, ConnectionProvider> selectedPool = connectionPools.entrySet().stream()
                    .filter(e -> Pattern.matches(e.getKey().getDomain(), hostName))
                    .findFirst()
                    .orElse(defaultConnectionPool);

This exception is about the Filter and it seems that e.getKey().getDomain() returns null.
Can this be possible? @pv3nturi ?

[pv3ntur1]

According to the stacktrace, the NPE is because hostName (the hostname in the request header HOST) is null

[hamadodene]

Yes I agree with you.
I reproduced it with a unit test.
Host header in a valid http1.1 request should never be null. So it should always be valued.

Probably these requests are http1.0 requests. or simply an incomplete request.

In my opinion, in this case we should respond with a "400 Bad request" or in any case the request shouldn't be handled completely.

@aluccaroni what do you think about it?

[hamadodene]

I was able to reproduce the problem also manually directly from the browser.
The problem can be reproduced if these conditions are met:

1. You have more than 1 connection pool (If you only have the default connection pool you have an error elsewhere in the code)

2. We have a route that accepts all requests without a particular filter on the HOST header. Otherwise the request returns 404 (since in our specific case we match using Header Host in the route) because if Header host is null it is set as default "". This causes a 404 to be returned as there are no other routes.

3. You have an empty HOST header

As a workaround you can simply create a route that returns 404 or other in case of null Host Header. Something like:

route.1.action=404notfound
route.1.enabled=true
route.1.id=missingHeaderHostRoute
route.1.match=request.headers.host ~ "^.{0}$"

the 404notfound action is an action that returns an html error page with a 404 code.

But in my opinion the Fix should be done directly from code. A NullPointerException is not acceptable in this specific case.

We can create an specific action BadRequest with errore code 400 and if Header host is not present we can redirect

We can handle it as for 404 NotFound. We can create a 400 BadRequest action and if Header host is not present in the request we return a BadRequest error page (https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Host)