[Engine-devel] Question about Engine user session timeout

[Vojtech Szocs]

Thanks, Juan! Please see my comments inline.


----- Original Message -----
> From: "Juan Hernandez" <jhernand at redhat.com>
> To: "Vojtech Szocs" <vszocs at redhat.com>, "Itamar Heim" <iheim at redhat.com>
> Cc: "engine-devel" <engine-devel at ovirt.org>
> Sent: Wednesday, November 13, 2013 11:27:11 AM
> Subject: Re: [Engine-devel] Question about Engine user session timeout
> 
> On 10/22/2013 01:44 PM, Vojtech Szocs wrote:
> > 
> > ----- Original Message -----
> >> From: "Itamar Heim" <iheim at redhat.com>
> >> To: "Vojtech Szocs" <vszocs at redhat.com>
> >> Cc: "engine-devel" <engine-devel at ovirt.org>
> >> Sent: Tuesday, October 22, 2013 12:22:14 PM
> >> Subject: Re: [Engine-devel] Question about Engine user session timeout
> >>
> >> On 10/22/2013 10:12 AM, Vojtech Szocs wrote:
> >>> However, as we have two distinct values for Engine session timeout, I
> >>> guess
> >>> my best shot is to do
> >>> "min(UserSessionTimeOutInterval,UserSessionTimeOutInvalidationInterval)"
> >>> and expose both via admin-only GetConfigurationValue query, but I'm not
> >>> sure this is the best approach..
> >>
> >> shouldn't that be sum() rather than min?
> > 
> > IIUC, the first config value (UserSessionTimeOutInterval) represents the
> > delay between Engine startup and first "cleanExpiredUsersSessions" job
> > execution. The second config value
> > (UserSessionTimeOutInvalidationInterval) is the delay between subsequent
> > executions of this job. This is why I thought it should be min() out of
> > these two; user could open WebAdmin right after Engine startup or anytime
> > after that.
> > 
> > Both config values have validValues=-1,1..100000 so -1 could disable first
> > (UserSessionTimeOutInterval) or subsequent
> > (UserSessionTimeOutInvalidationInterval) job execution. I'm still confused
> > why we have two values, though..
> > 
> >>
> 
> I may be wrong, but I would bet that the reason for having two
> configuration options is that the method of the scheduler that we use
> requires those two parameters.

Yes, this makes sense, feels like some general pattern to have scheduled jobs (of whatever kind) parametrized via two parameters, which are just delegated to actual scheduler method.

> 
> As far as I can tell the only real value of the first parameter
> (UserSessionTimeOutInterval) is to disable completely session cleanup if
> the value is negative, and that seems mostly useless, as doing so would
> generate a memory leak.

Agreed, "UserSessionTimeOutInterval=-1" is rather meaningless.

> 
> I would suggest to completely remove the first parameter. I will then be
> clear that for your purpose the only relevant one is the second.

Sounds good to me, I'll make a separate patch to consolidate Engine user session timeout into single parameter.

> 
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