On Mon, 2020-11-23 at 19:29 +0100, Clement Verna wrote: > > > On Wed, 18 Nov 2020 at 18:30, Fabio Valentini <decatho...@gmail.com> > wrote: > > On Mon, Nov 9, 2020 at 3:05 PM Aoife Moloney <amolo...@redhat.com> > > wrote: > > > > > > Hi everyone, > > > > > > I hope you enjoyed the F33 release party this weekend! Getting > > back to > > > the GitLab topic mail threads, this weeks topic from the GitLab > > AMA > > > session on September 10th is on Message Bus. As always, here are > > some > > > links to the resources I have been pulling content from as well: > > > * Questions and Answers hackmd link > > https://hackmd.io/RW8HahOeR7OJPON1dwuo3w > > > * Chat log from session > > > > > https://meetbot.fedoraproject.org/fedora-meeting-1/2020-09-10/ama_session_with_gitlab.2020-09-10-13.31.log.html > > > * AMA Blog post > > > > > https://communityblog.fedoraproject.org/gitlab-ama-follow-up/#more-9346 > > > * Here is this email in hackmd if you wish to view it there: > > > https://hackmd.io/tfOqCXNEQtqsGNLAEfZ2zg?view > > > > Sorry for taking so long to respond, the past weeks have been quite > > busy. > > > > Sorry for taking even longer to answer, you know the feeling :P > > > > > (snip) > > > > > ## Topic: Message Bus > > > - Question: Fedora uses a message bus to integrate different > > parts of > > > its infrastructure. How should we onboard GitLab into this > > message > > > bus? > > > - Answer: Currently we would need to have a service that > > proxies > > > GitLab’s events to fedora-messaging something similar to > > > github2fedmsg. > > > There were some concerns raised about the order of events sent by > > > GitLab’s webhooks, these will need to be looked after during a > > Proof > > > of Concept stage. > > > > Do we know if such a proxy would even be theoretically possible for > > GitLab? > > IIRC, some doubts were raised during the AMA that getting a > > chronologically consistent stream of events out of GitLab would be > > ∈ > > [hard, impossible[. > > What would that mean for fedora? Do services relying on > > fedora-messaging events related to dist-git need them to be > > consistent > > / chronological? > > What would be the effect of those services not having a reliable > > stream of events from dist-git? > > > > I personally don't have a good answer to these questions, and I don't > think we will be able to > have without actually doing a Proof of Concept and see how that would > work and scale. > > Regarding the order or messages, I believe that anything related to > CI testing might need to > have the chronological order of messages consistent. > I am not sure if there are any other use cases ? >
If any service relies on chronological ordering for messaging, I've got bad news on that front. There's plenty of scenarios where messages can arrive out-of-order now, regardless of whether they were queued up sequentially (which, in a distributed system, with multiple nodes accepting messages for publication...). There's also no guarantees about messages only being delivered once. Never mind that GitLab's webhooks may well fire multiple times if a response is not received in a timely manner. I would highly recommend not creating message consumers that rely on any particular message ordering because they're not going to work properly, GitLab or not. - Jeremy _______________________________________________ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org
