How to set the request life time for a srmBringOnLine call , using the GFAL API?

It would be useful to set a lifetime for the request in order to implement an efficient polling in the client script, and eventually a timeout for the request. The GFAL API has some initialization arguments, listed here in the man page of gfal.gfal_init function. Just to clarify, there are 2 arguments concerning the time:

  • The srmv2_desiredpintime which corresponds to the srmBringOnLine argument desiredLifeTime, so it refers to the copy pin life time, and has nothing to do with the life time of the request
  • the timeout argument.

Does the timeout argument correspond to the desiredTotalRequestTime argument of the srmBringOnLine function? After asking to Remi the answer is no. He says: The timeout is used as desiredTotalRequestTime for srmPrepareToGet, but unfortunately it isn't used for srmBringOnLine with current production versions. But note that it will be used for srmBringOnLine as well in the next version of GFAL which is in the certification process.

And a second question to Remi was: does the gfal API returns the output argument corresponding to the output argument remainingTotalRequestTime of the srmBringOnLine ? His answer: No, it doesn't. There is no such output argument. You can open a Savannah bug for that, but note that required changes will generate binary incompatibilities with older versions, so the fix will be delayed, waiting for a bigger release, except if it is a major requirement for you.

Remark it would be very important to have the output argument remainingTotalRequestTime because the value of the timeout is negotiated between server and client, and the server can return a time which is different from what the client had asked as input. This gives somehow an indication on how busy the server is. Actually, it is useless to pass the desired request life time if then we cannot retrieve the output of the actual timeout set by the server.

-- ElisaLanciotti - 09 Feb 2009

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Topic revision: r1 - 2009-06-05 - AndreaSciaba
 
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