[jira] [Created] (KNOX-961) Knox HTTP may not honour "Connection: close" header in the client request

["Vinayak Joshi (JIRA)" <ji...@apache.org>]

Vinayak Joshi created KNOX-961:
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             Summary: Knox HTTP may not honour "Connection: close" header 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


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 time a connection is leased and pooled (though closed already by backend service). And the second time the connection is reused and it 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. The latest versions of Knox uses httpcore-4.4.3. From testing and looking at the code, I believe this is fixed in httpcore-4.4.6. 

To fix this issue Knox should move to having httpcore-4.4.6 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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