Connection keepAlive equivalent config for Micronaut http client.

[subash89]

I am getting following error when load testing against a certain backend. When tested same backend with an apache http client within micronaut, this error does not come. Because we can set connection keepAlive to a higher value for apache client.

But what's the similar configuration for micronaut http client(Netty) ?

io.micronaut.http.client.exceptions.ResponseClosedException: Connection closed before response was received
	at io.micronaut.http.client.netty.DefaultHttpClient$BaseHttpResponseHandler.channelInactive(DefaultHttpClient.java:2073)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:305)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:274)
	at io.netty.channel.ChannelInboundHandlerAdapter.channelInactive(ChannelInboundHandlerAdapter.java:81)
	at io.netty.handler.codec.MessageAggregator.channelInactive(MessageAggregator.java:441)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:305)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:274)
	at io.netty.channel.ChannelInboundHandlerAdapter.channelInactive(ChannelInboundHandlerAdapter.java:81)
	at io.netty.handler.codec.http.HttpContentDecoder.channelInactive(HttpContentDecoder.java:235)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:305)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:274)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelInactive(DefaultChannelPipeline.java:1405)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:301)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
	at io.netty.channel.DefaultChannelPipeline.fireChannelInactive(DefaultChannelPipeline.java:901)
	at io.netty.handler.codec.http2.AbstractHttp2StreamChannel$Http2ChannelUnsafe$2.run(AbstractHttp2StreamChannel.java:775)
	at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:166)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470)
	at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:413)
	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:1583)

[subash89]

@yawkat I saw similar post here as well. #9995
Any idea we can set a keep alive ?

[sdelamo]

Maybe, the Micronaut HTTP Client configuration helps: https://docs.micronaut.io/latest/guide/configurationreference.html#io.micronaut.http.client.DefaultHttpClientConfiguration

[subash89]

I looked at it, but could not find anything related to http keep alive.

[yawkat]

Not sure what you mean by keepalive. We set the Connection: keep-alive header. Or do you mean the Keep-Alive header?

[subash89]

@yawkat here what I meant was apache http client, ConnectionReuseStrategy. So it sends Connection: Keep-Alive for persistent connections. the keepAlive parameter in apache client used as a timeout to close the connections on client side.

What other scenarios that can possibly trigger a "io.micronaut.http.client.exceptions.ResponseClosedException: Connection closed before response was received". error ?

[yawkat]

we use keep-alive connections by default already. The error means that the server is closing the connection, can't tell from the error what the reason is.

[sgammon]

@yawkat I don't know if our issue is identical to OP's, but we have been experiencing this same exception with some frequency when using the Micronaut client, particularly when proxying with HttpProxyClient. I can file a new issue and potentially try and help track it down.

[yawkat]

feel free to make an issue, but im not sure it's a bug. this exception is exactly what i would expect if the client and server keepalive timeout settings are close or identical.

[yawkat]

oh there is an issue #9995

[subash89]

@sgammon can you share link to your code for this reproducible issue. Like to know how you use it.
If you don't use proxy client, you don't see the error ?