Do we need to cluster activemq? Can't each app server service its own queues? Erik
On Tue, Jul 17, 2012 at 11:23 AM, Carl Hall <c...@hallwaytech.com> wrote: > What Erik describes has been on the dev wish list for a little while now. > Moving to an event-driven model would allow us to build out concurrency but > there also comes the question of clustering ActiveMQ. > > > On Thu, Jul 12, 2012 at 6:27 AM, Erik Froese <erik.fro...@gmail.com> wrote: >> >> Hey David, >> >> The code is not clustered. >> >> You'd need to write an event listener that would fire when new content >> is uploaded. It would put the content ids on a JMS queue. Then >> implement a ContentFetcher that grabs a message off of the queue and >> wire that into the PPI. Events and Messages are not clustered in OAE >> (AFAIK) so this would have to be run on each app server. >> >> While we're in event-land it'd be nice to be able to regenerate a >> preview when a content body is updated. I'm not sure if this is >> possible yet. >> >> I'm not sure how we'd limit the CPU usage yet either. You could manage >> the quartz schedule that runs the PPI. >> >> We can also disable concurrent executions of the job. >> >> Erik >> >> On Wed, Jul 11, 2012 at 8:44 PM, Roma, David <dr...@csu.edu.au> wrote: >> > Awesome news Erik! >> > >> > Our Ops guys will be stoked when we can get this in.. A couple of >> > questions from someone who hasn't looked at the code or read too deeply.... >> > - Does it support clustering >> > -e.g. can we just run it side by side on each of our app servers >> > and they will play nice sharing out processing jobs? >> > -will it affect performance of the app servers much? Can we >> > limit the preview processor to say 10%cpu and 500mb ram or low priority >> > threads or limit the number of items to process or something? This would >> > make for a nice simple deployment that wouldn't threaten the app server >> > stability. >> > >> > Cheers, >> > Dave. >> > >> > >> > >> > >> > >> > -----Original Message----- >> > From: oae-dev-boun...@collab.sakaiproject.org >> > [mailto:oae-dev-boun...@collab.sakaiproject.org] On Behalf Of Erik Froese >> > Sent: Thursday, 12 July 2012 2:37 AM >> > To: Carl Hall >> > Cc: oae-dev@collab.sakaiproject.org; Clay Fenlason >> > Subject: Re: [oae-dev] Moving the preview processor to java >> > >> > Hey everyone, >> > >> > Its been a few months but I actually implemented the Java preview >> > processor as an OSGi bundle. I filed a ticket for it [1] >> > >> > I'm not sure where to go from here. Is this something that could be >> > included POST 1.4.0? >> > Should I open a PR so we can review the code? If so, PR against which >> > branch? >> > >> > Either way, have a look, give it a go. We'll probably wind up using it >> > at rSmart. >> > >> > Erik >> > >> > [1] https://jira.sakaiproject.org/browse/KERN-3021 >> > >> > >> > >> > On Tue, Apr 17, 2012 at 9:09 AM, Carl Hall <c...@hallwaytech.com> wrote: >> >> I totally agree that we should ally ourselves with other communities. I >> >> see >> >> where we get docsplit from DocumentCloud[1] and we use several other >> >> libraries for processing that they've most likely contributed to. >> >> The Java approach is very little custom code compared to the libraries >> >> we're >> >> getting from Apache (tika, sanselan, commons, pdfbox), so we would >> >> still >> >> building on the shoulders of our friendly community giants. >> >> >> >> 1 https://github.com/documentcloud/docsplit >> >> >> >> >> >> >> >> On Sat, Apr 14, 2012 at 5:43 AM, John Norman <j...@caret.cam.ac.uk> >> >> wrote: >> >>> >> >>> My recollection (perhaps wrong) is that we got this from Document >> >>> Cloud >> >>> and I /think/ Chris Roby found it. Document Cloud seems a very >> >>> relevant and >> >>> valuable project. If we were able to help them while helping >> >>> ourselves, >> >>> other good things could come from the relationship. My general point >> >>> is that >> >>> we are thin on resources and so, in principle, symbiotic relationships >> >>> are >> >>> helpful. >> >>> >> >>> http://www.documentcloud.org/home >> >>> >> >>> John >> >>> >> >>> Sent from my iPad >> >>> >> >>> On 13 Apr 2012, at 17:03, Carl Hall <c...@hallwaytech.com> wrote: >> >>> >> >>> I agree with Daniel that our modifications to the preview processor >> >>> have >> >>> put its ownership square on us. Was there a community that this script >> >>> was >> >>> borrowed from? I thought it was original development that uses various >> >>> external libraries to do the actual work. This is the approach that >> >>> Erik is >> >>> taking with the rewrite using things like Tika (text extraction), >> >>> Sanselan >> >>> (images) and a Java port of the python topia.termextract library. >> >>> >> >>> I certainly don't deny the speed of development that was realized in >> >>> creating the PP but the current state of the code is a mess at best. >> >>> Reuse >> >>> of libraries in Java is showing a fast rewrite with very little >> >>> managed code >> >>> on our part. >> >>> >> >>> >> >>> On Fri, Apr 13, 2012 at 12:50 AM, Daniel Parry >> >>> <dan...@caret.cam.ac.uk> >> >>> wrote: >> >>>> >> >>>> On Thu, Apr 12, 2012 at 04:21:36PM -0400, Clay Fenlason wrote: >> >>>> > I think this response is at best orthogonal to the point John's >> >>>> > trying >> >>>> > to raise, though I gather this kind of reaction must come from a >> >>>> > buildup of some real frustration around the PP, which I don't mean >> >>>> > to >> >>>> > discount. I also think John was pretty clear about what he was >> >>>> > suggesting: that there be a conversation with the community we got >> >>>> > the >> >>>> > PP from, if the conversation hasn't happened already, to see if >> >>>> > there >> >>>> > might still be a way to work together before we decide to just own >> >>>> > it >> >>>> > ourselves. >> >>>> >> >>>> I'd suggest the way that the preview processor was being extended >> >>>> (initially a >> >>>> python server add on, followed by a ruby rewrite for tag extraction) >> >>>> and >> >>>> the >> >>>> variety of ruby versions that deployers were using and the methods >> >>>> used >> >>>> to >> >>>> deploy it were indicative of a) the OAE community already 'owning' >> >>>> the PP >> >>>> and b) >> >>>> as has already been pointed out some standardization needed restoring >> >>>> and >> >>>> additional functionality added for deployers. Hence, the list was >> >>>> pinged[0] a >> >>>> while back to ask about standardizing and extending in java. I'm not >> >>>> sure >> >>>> of any >> >>>> other way to contact the original PP community or if such a community >> >>>> separate >> >>>> to OAE even still exists? >> >>>> >> >>>> Best wishes, >> >>>> >> >>>> Daniel >> >>>> >> >>>> [0] >> >>>> >> >>>> http://collab.sakaiproject.org/pipermail/oae-dev/2012-April/001677.html >> >>>> >> >>>> -- >> >>>> --| Daniel Parry: dan...@caret.cam.ac.uk. www.caret.cam.ac.uk/ |-- >> >>>> "Of all the things a leader should fear, complacency should >> >>>> head the list." [John C. 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