Sandbox: Unexpected HTTP/1.x request: GET /

Questions
1

Hi,

I took the create app template, adding some of my own DAML code, and launched the Sandbox. It starts just fine, the Navigator connects, I can play around, all good. But then, without a clear trigger, every now and then this appears in the logs

INFO: Initialized sandbox version 1.9.0 with ledger-id = b9eec514-4027-4b54-8247-dac9410b1438, port = 6865, dar file = List(.daml/dist/daml-app-0.1.0.dar, ./lib/cdm.dar), time mode = wall-clock time, ledger = in-memory, auth-service = AuthServiceWildcard$, contract ids seeding = strong
Feb 09, 2021 6:10:34 PM io.grpc.netty.NettyServerTransport notifyTerminated
INFO: Transport failed
io.netty.handler.codec.http2.Http2Exception: Unexpected HTTP/1.x request: GET / 
        at io.netty.handler.codec.http2.Http2Exception.connectionError(Http2Exception.java:103)
        at io.netty.handler.codec.http2.Http2ConnectionHandler$PrefaceDecoder.readClientPrefaceString(Http2ConnectionHandler.java:302)
        at io.netty.handler.codec.http2.Http2ConnectionHandler$PrefaceDecoder.decode(Http2ConnectionHandler.java:239)
        at io.netty.handler.codec.http2.Http2ConnectionHandler.decode(Http2ConnectionHandler.java:438)
        at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:498)
        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:437)
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
        at io.netty.channel.DefaultChannelPipeline$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.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:714)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:650)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:576)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
        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:832)

It seems, the Sandbox continues to operate just fine after this.

Is this something known? Is this something to worry about?

Regards,
Alex

1 Like
2

That’s the error message you’d get if you point a browser or any other HTTP client at http://localhost:6865/. It’s not going to cause a problem for your Daml App, but if you don’t know where those requests are coming from it might be worth investigating. A first step would be running a tool like Wireshark with a filter like http.host matches "6865$" to confirm that something is indeed sending HTTP requests to port 6865.

1 Like
3

Thank you, @bernhard.

My best guess is that this is caused by VS Code and the remote container plugin. It must be probing this port so that it can forward it to the host system.

Regards,
Alex

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