Cheers, thanks again for a very quick reply Robbie! Have a nice night!
Regards, Sebastiaan la Fleur -----Original Message----- From: Robbie Gemmell <robbie.gemm...@gmail.com> Sent: donderdag 3 juni 2021 17:45 To: users <users@qpid.apache.org> Subject: Re: Question: How can I achieve the 'exactly-once' and 'at-least-once' guarantee using Python proton? It is not exposed no, as it is really only used for the exactly-once scenario which isnt supported. For at-least-once, you would simply resend all messages for which an outcome was not received before the link/connection is lost. You typically wouldnt even need to know the delivery tag to do that, just have some list of 'unconfirmed' messages to send. On Thu, 3 Jun 2021 at 16:19, La Fleur, Sebastiaan <sebastiaan.lafl...@ns.nl.invalid> wrote: > > Thank you Robbie! > > In the mean time I have been able to extend our implementation (based on > Python Proton) with the at_least_once settling mechanism. We are now caching > the unsettled messages using the delivery tag according to the AMQP 1.0 > specification and retrying all of them whenever a link is opened and there > are unsettled messages. > > Am I correct that the unsettled map in the attach frame from the AMQP 1.0 > specification is currently not exposed or implemented by the Proton client? > Source: http://docs.oasis-open.org/amqp/core/v1.0/amqp-core-complete-v1.0.pdf > Page 65, section 2.7.3 Attach: <field name="unsettled" type="map"/> > > Am I also correct that any resume link functionality currently is not > implemented? > Same document, page 49, 2.63. Establishing or Resuming A Link > > I have been unable to find these implementations in the (python) proton > client so I would like to confirm if they are indeed missing or I overlooked > a resource. > > Thanks in advance! > > > Regards, > > Sebastiaan la Fleur > > -----Original Message----- > From: Robbie Gemmell <robbie.gemm...@gmail.com> > Sent: vrijdag 23 april 2021 12:02 > To: users <users@qpid.apache.org> > Subject: Re: Question: How can I achieve the 'exactly-once' and > 'at-least-once' guarantee using Python proton? > > You can't do exactly-once, it requires complicated interactions neither the > clients or servers support. > > I dont believe the python client can ever re-send a message itself, as it > doesnt retain messages once actually sent, but the 'buffer' > question is perhaps nuanced depending on what you meant by that precisely, > and possibly also whether you are using the built in connection reconnect. > Essentially when the client has actually sent things then it no longer has > the payload and so it would be up to you to resend if required, but if for > example it has a message to send that hasnt actually been transmitted yet > (e.g send call was made before credit was given, or flow control meant it > hadnt yet gone onto the wire, socket wasnt writable etc) before a disconnect, > then that can mean it is still effectively not-sent and it can then be after > it reconnected itself. If you dont want that you would handle disconnects > yourself, recreate your sender, and begin sending again. > > On Thu, 22 Apr 2021 at 15:34, La Fleur, Sebastiaan > <sebastiaan.lafl...@ns.nl.invalid> wrote: > > > > Dear all, > > > > Thank you for this software. Currently I am investigating proton as our > > AMQP 1.0 library of choice and as such I have reached a number of questions > > I hope you can help me with. > > To maintain simplicity on the mailing list index, I will try to keep 1 > > question to a single subject (area). > > > > With AMQP you can use the accepting and settling of messages to achieve 3 > > delivery guarantees: at-least once, at-most once and exactly-once. > > For the former 2, I have found the relevant Link options: > > https://qpid.apache.org/releases/qpid-proton-0.34.0/proton/python/do > > cs /proton.reactor.html#proton.reactor.AtLeastOnce > > > > For the latter, exactly-once, I have been unable to find any pre-existing > > mechanisms in the API documentation except a small explanation of the steps > > associated with this guarantee: > > http://qpid.apache.org/releases/qpid-proton-0.34.0/proton/python/doc > > s/ > > overview.html#delivery-guarantees > > > > Can you confirm there is no mechanism for achieving the exactly-once > > guarantee? If not, how would I achieve this? > > Can you also confirm proton will NOT buffer any messages or resend them > > with the At-Least-once guarantee and these concerns are up to the user of > > the library? > > > > Thank you in advance! > > > > > > Sincere regards, > > > > Sebastiaan la Fleur > > > > > > ________________________________ > > > > Deze e-mail, inclusief eventuele bijlagen, is uitsluitend bestemd voor > > (gebruik door) de geadresseerde. De e-mail kan persoonlijke of > > vertrouwelijke informatie bevatten. Openbaarmaking, vermenigvuldiging, > > verspreiding en/of verstrekking van (de inhoud van) deze e-mail (en > > eventuele bijlagen) aan derden is uitdrukkelijk niet toegestaan. Indien u > > niet de bedoelde geadresseerde bent, wordt u vriendelijk verzocht degene > > die de e-mail verzond hiervan direct op de hoogte te brengen en de e-mail > > (en eventuele bijlagen) te vernietigen. > > > > Informatie vennootschap<http://www.ns.nl/emaildisclaimer> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@qpid.apache.org For > additional commands, e-mail: users-h...@qpid.apache.org > > > ________________________________ > > Deze e-mail, inclusief eventuele bijlagen, is uitsluitend bestemd voor > (gebruik door) de geadresseerde. De e-mail kan persoonlijke of vertrouwelijke > informatie bevatten. Openbaarmaking, vermenigvuldiging, verspreiding en/of > verstrekking van (de inhoud van) deze e-mail (en eventuele bijlagen) aan > derden is uitdrukkelijk niet toegestaan. 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