[undertow-dev] occasional 502 from Apache HTTP Proxy
Edgar Espina
espina.edgar at gmail.com
Mon Jan 19 07:15:48 EST 2015
The source code can be found here: https://github.com/jooby-project/jooby
Undertow related classes are here:
https://github.com/jooby-project/jooby/tree/master/jooby/src/main/java/org/jooby/internal/undertow
.
Server is built here:
https://github.com/jooby-project/jooby/blob/master/jooby/src/main/java/org/jooby/internal/undertow/UndertowServer.java
Response is sent here:
https://github.com/jooby-project/jooby/blob/master/jooby/src/main/java/org/jooby/internal/undertow/UndertowResponse.java#L336-382
My microweb-framework was built on top of Jetty, so for now I used the
blocking API and follow more or less what we usually do with Servlets
(acquire an outstream).
I will review what I'm doing and try to figure it out what is going on too.
Thanks for your help, Stuart.
On Mon, Jan 19, 2015 at 2:12 AM, Stuart Douglas <sdouglas at redhat.com> wrote:
> My best guess as to what is happening is that Undertow closing a
> connection after a request is done for some reason, and the apache attempts
> to re-use this connection without realising that it is dead.
>
> In general this should not happen, Undertow should only forcibly close a
> connection if it knows that it is broken (e.g. a content length is set and
> the full amount of content is not written). For a normal graceful close
> Undertow should be sending Connection:close headers.
>
> I am going to investigate some more, and see if I can figure out what is
> going on. It seems unlikely but is there any chance your code forcibly
> closes the ServerConnection (HttpServerExchange.getConnection()) because
> that could potentially cause this issue. Setting the exchange to
> non-persistent after headers have been sent could also cause it.
>
> Stuart
>
> ----- Original Message -----
> > From: "Edgar Espina" <espina.edgar at gmail.com>
> > To: "Stuart Douglas" <sdouglas at redhat.com>
> > Cc: undertow-dev at lists.jboss.org
> > Sent: Monday, 19 January, 2015 2:53:06 PM
> > Subject: Re: [undertow-dev] occasional 502 from Apache HTTP Proxy
> >
> > Done, but makes no difference. Still got the 502 random errors :S
> >
> > On Sun, Jan 18, 2015 at 11:13 PM, Stuart Douglas <sdouglas at redhat.com>
> > wrote:
> >
> > > I had a play around with apache locally, and I could reproduce this in
> > > some circumstances, and it looks like we are not setting a high enough
> > > backlog by default.
> > >
> > > Can you try adding:
> > >
> > > undertow.setSocketOption(Options.BACKLOG, 1000)
> > >
> > > To your Undertow builder? I am going to increase this in our default
> > > config upstream.
> > >
> > > Hopefully this is the issue that you are running into.
> > >
> > > Stuart
> > >
> > >
> > > ----- Original Message -----
> > > > From: "Edgar Espina" <espina.edgar at gmail.com>
> > > > To: "Stuart Douglas" <sdouglas at redhat.com>
> > > > Cc: undertow-dev at lists.jboss.org
> > > > Sent: Monday, 19 January, 2015 12:10:16 PM
> > > > Subject: Re: [undertow-dev] occasional 502 from Apache HTTP Proxy
> > > >
> > > > It is a default undertow instance with a HTTP listener, just set work
> > > > threads to 200. Is there a default idle timeout? I can' tell from
> javadoc
> > > > and looking at the code.
> > > >
> > > >
> > > > On Sun, Jan 18, 2015 at 9:59 PM, Stuart Douglas <sdouglas at redhat.com
> >
> > > wrote:
> > > >
> > > > >
> > > > >
> > > > > Edgar Espina wrote:
> > > > >
> > > > >> I'm not, channel does it.
> > > > >>
> > > > >> Problem is present on both. For example, home page has a
> > > content-length
> > > > >> header but jquery.js use chunked.
> > > > >>
> > > > >
> > > > > In general if you are serving static resources you are better off
> > > setting
> > > > > the content length (slightly more efficient, and the browser can
> > > display
> > > > > progress on downloads).
> > > > >
> > > > >
> > > > >> Do I have to call .endExchange? or closing the output stream is
> > > enough?
> > > > >>
> > > > >
> > > > > Closing the output stream is enough. endExchange is automatically
> > > called
> > > > > once the call stack returns anyway, unless you have dispatched the
> > > exchange
> > > > > or started async IO.
> > > > >
> > > > > The 'connection reset by peer' error in the apache log while
> reading
> > > the
> > > > > status like kinda indicates that the request does not even get to
> this
> > > > > point anyway, and the underlying TCP connection is probably being
> torn
> > > down
> > > > > somehow.
> > > > >
> > > > > Do you have any kind of timeouts set? If you have an idle timeout
> set
> > > on
> > > > > the listener there is a race where Undertow can close the channel
> due
> > > to
> > > > > inactivity just as the front end starts to send a request.
> > > > >
> > > > > Stuart
> > > > >
> > > > >
> > > > >> Thanks
> > > > >>
> > > > >> On Sun, Jan 18, 2015 at 9:48 PM, Stuart Douglas <
> sdouglas at redhat.com
> > > > >> <mailto:sdouglas at redhat.com>> wrote:
> > > > >>
> > > > >> Another question, are you setting a content length on the
> > > responses?
> > > > >> If not the channel will automatically set one if the response
> fits
> > > > >> inside a buffer, otherwise chunked encoding will be used.
> > > > >>
> > > > >> It might be helpful to know if this only happens on chunked,
> fixed
> > > > >> length or both.
> > > > >>
> > > > >> Stuart
> > > > >>
> > > > >> Edgar Espina wrote:
> > > > >>
> > > > >> latest: 1.2.0.Beta8
> > > > >>
> > > > >> On Sun, Jan 18, 2015 at 9:42 PM, Stuart Douglas
> > > > >> <sdouglas at redhat.com <mailto:sdouglas at redhat.com>
> > > > >> <mailto:sdouglas at redhat.com <mailto:sdouglas at redhat.com
> >>>
> > > wrote:
> > > > >>
> > > > >> Also what version of Undertow are you using?
> > > > >>
> > > > >> Stuart
> > > > >>
> > > > >> ----- Original Message -----
> > > > >> > From: "Edgar Espina" <espina.edgar at gmail.com
> > > > >> <mailto:espina.edgar at gmail.com>
> > > > >> <mailto:espina.edgar at gmail.com <mailto:
> espina.edgar at gmail.com
> > > > >> >__>>
> > > > >> > To: "Stuart Douglas" <sdouglas at redhat.com
> > > > >> <mailto:sdouglas at redhat.com>
> > > > >> <mailto:sdouglas at redhat.com <mailto:sdouglas at redhat.com
> >>>
> > > > >> > Cc: undertow-dev at lists.jboss.org
> > > > >> <mailto:undertow-dev at lists.jboss.org>
> > > > >> <mailto:undertow-dev at lists.__jboss.org
> > > > >> <mailto:undertow-dev at lists.jboss.org>>
> > > > >> > Sent: Monday, 19 January, 2015 11:13:21 AM
> > > > >> > Subject: Re: [undertow-dev] occasional 502 from Apache
> HTTP
> > > > >> Proxy
> > > > >> >
> > > > >> > found this in apache:
> > > > >> >
> > > > >> > (104) Connection reset by peer: proxy: error reading
> status
> > > > >> line from
> > > > >> > remote server
> > > > >> >
> > > > >> > but nothing in undertow.
> > > > >> >
> > > > >> > got 502 on HTTP GET. Sometimes while calling the home
> page
> > > / or
> > > > >> when page
> > > > >> > loads OK, got 502 on page resources (js, css, images).
> > > > >> >
> > > > >> > I call startBlocking and use the outputstream to write
> the
> > > > >> response, when
> > > > >> > everything has been written I call the
> "outputstream.close"
> > > > >> method. Do I
> > > > >> > need to call exchange.endExchange too?
> > > > >> >
> > > > >> > Thanks
> > > > >> >
> > > > >> > On Sun, Jan 18, 2015 at 8:52 PM, Stuart Douglas
> > > > >> <sdouglas at redhat.com <mailto:sdouglas at redhat.com>
> > > > >> <mailto:sdouglas at redhat.com <mailto:sdouglas at redhat.com
> >>>
> > > wrote:
> > > > >> >
> > > > >> > > Is there any info in the log? Or is there any
> specific
> > > type
> > > > >> of
> > > > >> request
> > > > >> > > that causes this?
> > > > >> > >
> > > > >> > > Stuart
> > > > >> > >
> > > > >> > >
> > > > >> > > ----- Original Message -----
> > > > >> > > > From: "Edgar Espina" <espina.edgar at gmail.com
> > > > >> <mailto:espina.edgar at gmail.com>
> > > > >> <mailto:espina.edgar at gmail.com <mailto:
> espina.edgar at gmail.com
> > > > >> >__>>
> > > > >> > > > To: undertow-dev at lists.jboss.org
> > > > >> <mailto:undertow-dev at lists.jboss.org>
> > > > >> <mailto:undertow-dev at lists.__jboss.org
> > > > >> <mailto:undertow-dev at lists.jboss.org>>
> > > > >> > > > Sent: Monday, 19 January, 2015 9:42:19 AM
> > > > >> > > > Subject: [undertow-dev] occasional 502 from Apache
> HTTP
> > > > >> Proxy
> > > > >> > > >
> > > > >> > > > Hi,
> > > > >> > > >
> > > > >> > > > I've an Undertow application behind apache reverse
> > > proxy,
> > > > >> trying to load
> > > > >> > > a
> > > > >> > > > page displays error 502 proxy error.
> > > > >> > > >
> > > > >> > > > Still couldn't find why so I wonder if any of you
> find
> > > a
> > > > >> similar problem
> > > > >> > > with
> > > > >> > > > Undertow and Apache.
> > > > >> > > >
> > > > >> > > > Please note this is our first app on top of
> Undertow,
> > > > >> existing apps
> > > > >> > > running
> > > > >> > > > on Tomcat/Jetty are OK.
> > > > >> > > >
> > > > >> > > > Appreciate any help.
> > > > >> > > >
> > > > >> > > > Thanks
> > > > >> > > >
> > > > >> > > > --
> > > > >> > > > edgar
> > > > >> > > >
> > > > >> > > > _________________________________________________
> > > > >> > > > undertow-dev mailing list
> > > > >> > > > undertow-dev at lists.jboss.org
> > > > >> <mailto:undertow-dev at lists.jboss.org>
> > > > >> <mailto:undertow-dev at lists.__jboss.org
> > > > >> <mailto:undertow-dev at lists.jboss.org>>
> > > > >> > > >
> > > https://lists.jboss.org/__mailman/listinfo/undertow-dev
> > > > >> <https://lists.jboss.org/mailman/listinfo/undertow-dev>
> > > > >> > >
> > > > >> >
> > > > >> >
> > > > >> >
> > > > >> > --
> > > > >> > edgar
> > > > >> >
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> --
> > > > >> edgar
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> --
> > > > >> edgar
> > > > >>
> > > > >
> > > >
> > > >
> > > > --
> > > > edgar
> > > >
> > >
> >
> >
> >
> > --
> > edgar
> >
>
--
edgar
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