Cannot access file on server (HTTP 403: Forbidden)

#1

When accessing a file using a Table Reader on the KNIME server (using a relative path), the workflow in some cases returns a HTTP 403 error (Forbidden). The Table Reader seems to be fetching the file using the REST API:

Response in workflow message overview:
Table Reader (…) - WARNING: Server returned HTTP response code: 403 for URL: http://(…):8080/knime/rest/v4/repository/(…)/filename.table:data

Since this happens in an automated workflow and in most cases accessing the file works like expected, there does not seem to be a problem with the permissions. It seems to be happening randomly but it could block the automated workflow if the file is required for processing. What could be causing this issue?

We are using the Knime Server Medium version 4.8.2 with Executor version 3.7.2

#2

Hi @JacobW,

Welcome to our forum.

Is it possible, that the file is accessed by an other user, process or other parallel write access so that the knime server has no read access to it temporarily?

If that is not the case I will have a look at the server logs to provide you further support.

Cheers,
Michael

#3

Hi @MichaelRespondek,
This file could have been opened by another process (job), but not in parallel. These other jobs were in an executed or idle state. Could it be that the file is still locked or otherwise not yet released if a previous job has finished executing? The server logging mentions the same error (HTTP 403). Which specific logging file could give more information these IO issues? Thanks in advance!

#4

The server’s access log file shows every request including username and response code. If you encounter that problem again, have a look into that file and check whether the request comes from the expected user and what the response code was - and if the request shows up at all. We had cases where the requests were routed through a proxy and the proxy denied the request so that it never reached the server.
It’s not a problem with concurrency. The server parks read access while a file is being written and vice versa. You won’t get a 403 only a 504 may be possible if the file is locked for too long (>>30s).

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