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https://issues.apache.org/jira/browse/KNOX-961?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Larry McCay resolved KNOX-961.
------------------------------
Resolution: Fixed
As verified in the comments KNOX-964 fixes this issue - since this has been
recently committed, I am resolving this as fixed.
Please feel free to reopen if you can reproduce with a build of master.
> Knox HTTP connection pool does not honor "Connection: close" in the client
> request
> ----------------------------------------------------------------------------------
>
> Key: KNOX-961
> URL: https://issues.apache.org/jira/browse/KNOX-961
> Project: Apache Knox
> Issue Type: Bug
> Components: Server
> Affects Versions: 0.11.0
> Reporter: Vinayak Joshi
> Fix For: 0.13.0
>
> Attachments: knox_http.txt
>
>
> Client makes a HTTP request for a service with "Connection: close" in the
> HTTP header. When Knox proxies this request as is to the backend service i.e.
> passing all headers through to the backend service, the backend service
> honors the "Connection: close" and closes the connection from it's end. In
> case the backend service does not return "Connection: close" in it's
> response, Knox HTTP library assumes the connection can be kept alive
> indefinitely and places it into a pool. Immediate next request for the same
> resource causes Knox's HTTP library to allocate the pooled connection to it.
> Since the backend service has closed the connection, this reuse fails and
> Knox returns a Service connectivity error. The stale connection check by
> default will not run on every connection request, so requests coming in
> quickly exacerbate the problem.
> In addition I have observed, in some instances the stale connection check
> will also not help, and so the request fails every alternate time - the first
> call is where a connection is leased and pooled (though closed already by
> backend service). The second time the pooled connection is reused and the
> request fails.
> Per https://tools.ietf.org/html/rfc7230#section-6.3 the HTTP library should
> recognise that a request with "Connection: close" can not possibly leave the
> connection open so this connection should never be reused/pooled. The latest
> versions of Knox uses httpcore-4.4.3. From testing and looking at the code, I
> believe this issue is fixed in httpcore-4.4.6
> (`org.apache.http.impl.DefaultConnectionReuseStrategy`).
> To fix this issue Knox should move to having httpcore-4.4.6 or higher in it's
> dependencies. Will attach knox gateway logs that show this problem. The logs
> are with knox-0.11 but I believe the same problem must exist in knox-0.12 as
> the same HTTP libraries are used.
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