Hello, Knowing that the on_transport_error will be called only when the max_reconnect is reached, the user will have to manage one reattempt at a time. It will become too flexible, the user will have to write his own reconnect strategy with out reusing what was done already the embedded reconnect code.
We would like to reuse the native reconnect way that is implemented in proton and be flexible in the URLs like Qpid JMS and Qpid Python. Best regards, Rabih On Fri, Jan 18, 2019 at 4:58 PM Alan Conway <[email protected]> wrote: > On Fri, Jan 18, 2019 at 10:35 AM Alan Conway <[email protected]> wrote: > > > > > > > On Thu, Jan 17, 2019 at 6:56 AM Rabih M <[email protected]> wrote: > > > >> Hello, > >> > >> What Olivier was proposing is more at the level of the C++ proton > binding. > >> What we would like to do is: > >> Instead of taking a vector of fixed fail-over urls in the > >> reconnect_options, we would like the reconnect_options to take an > >> std::function that returns a URL. This function will be called by proton > >> to > >> get the next URL when there is failure. This will allow the clients to > >> write there own logic to fetch the new URLs dynamically... > >> On the qpid-jms side we have already this possibility. > >> > > > > That sounds reasonable but I'd suggest an alternative that is a bit more > > flexible, add this to proton::connection: > > > > // Over-ride connection options to be used the next time the connection > > re-connects. > > // Takes effect only if/when the connection does re-connect. > > // Typically called in on_transport_error() to influence automatic > > re-connect. > > connection::reconnect_options(connection::options& overrides) > > > > > BROKEN sorry - that would *replace* all your connection options, not > override the ones you want which is not what I meant. > This is better: > > // Allow updates to the connection_options used by this connection. > // These updates only take effect if/when the connection is re-connected. > // Typically used in on_transport_error() to change the options used for > automatic re-connect. > connection_options& connection::options(); > > So now your case becomes: > > myhandler { > connection_options::reconnect_opts_; // Save initial reconnect opts > > void on_transport_error(transport& t) { > reconnect_opts_.failover_urls(pick_my_urls()); // Update the URLs > t .connection().options().reconnect(reconnect_opts_)); // Update the > connection's options > } > } > > > > > > >> We would like to know if it sounds reasonable to you before proposing a > >> patch. WDYT? > >> > >> Best regards, > >> Rabih > >> > >> On Thu, Jan 3, 2019 at 9:15 PM Alan Conway <[email protected]> wrote: > >> > >> > On Thu, Jan 3, 2019 at 7:12 AM Gordon Sim <[email protected]> wrote: > >> > > >> > > Are you talking specifically about something at the c level rather > >> than > >> > > e.g. c++? > >> > > > >> > > As far as I recall, the c layer has no built in support for > >> > > reconnection, that is added by the c++ (or other) wrappers. > >> > > > >> > > In the c++ api, perhaps the reconnect options in use could be > exposed > >> > > (such that they can then be altered), or else there could be a way > to > >> > > provide a function that returns the next url to use rather than a > >> static > >> > > list (this is sort of what the python wrapper allows). That may be > >> what > >> > > you mean by the onReconnect callback? If so, it sounds reasonable to > >> me, > >> > > though it would be better to get the thoughts of those more involved > >> > > with that component. (Alan, Cliff, Andrew?) > >> > > > >> > > > >> > Just to add some detail to what Gordon said - in C there is no > reconnect > >> > support out-of-the-box but you have the tools to implement any > strategy > >> > you like. Use the PN_TRANSPORT_CLOSED event (with pn_transport_error() > >> set) > >> > to react to an unexpected disconnect. You can modify the parameters > used > >> > for re-connect any way you like. If you re-use the existing > >> pn_connection_t > >> > your sessions and links will be automatically re-opened. If you don't > >> want > >> > that, you can throw away the old pn_connection_t and re-connect with > a > >> new > >> > one. > >> > > >> > The C++ binding provides automatic reconnect with some built-in > options, > >> > including a list of URLs. You can be notified of a disconnect by > >> > on_transport_error(), but I don't think the current API allows you to > >> > change the reconnect URL list at that point. If the built-in options > >> > don't do what you need, you can turn off the built-in automatic > >> reconnect > >> > and implement your own custom reconnect strategy in > >> on_transport_error(), > >> > similar to what I described for C above. > >> > > >> > > >> > > On 03/01/19 10:30, VERMEULEN Olivier wrote: > >> > > > Hello, > >> > > > > >> > > > Any feedback on the below proposition? > >> > > > > >> > > > Thanks, > >> > > > Olivier > >> > > > > >> > > > From: VERMEULEN Olivier > >> > > > Sent: mardi 18 décembre 2018 15:01 > >> > > > To: '[email protected]' <[email protected]> > >> > > > Subject: RE: [Proton-C] Discovery > >> > > > > >> > > > Hello, > >> > > > > >> > > > We looked into the proton-c implementation and didn't find > anything > >> > that > >> > > would allow us to implement a qpid-jms like discovery. > >> > > > So I was wondering if we could add, directly in proton-c, an > >> > onReconnect > >> > > callback (or something similar) that would allow us to modify the > >> list of > >> > > URLs the client tries to connect to. > >> > > > We need this to answer the following use case: > >> > > > the dispatch-router (host1:1234) on which the client was connected > >> goes > >> > > down > >> > > > the client enters the reconnect loop (on host1:1234) > >> > > > we restart the dispatch-router but on another machine (host2:5678) > >> > > > the client reconnects -> this is currently not happening > >> > > > Note that we can do the pull-request but I wanted to run the > >> > proposition > >> > > by you first. > >> > > > > >> > > > Thanks, > >> > > > Olivier > >> > > > > >> > > > From: VERMEULEN Olivier > >> > > > Sent: mardi 11 décembre 2018 12:34 > >> > > > To: [email protected]<mailto:[email protected]> > >> > > > Subject: [Proton-C] Discovery > >> > > > > >> > > > Hello, > >> > > > > >> > > > I was looking into the qpid-jms-discovery project which seems very > >> nice > >> > > for what I'm trying to do: update the list of dispatch-routers the > >> client > >> > > can connect to during failover (with a custom discovery logic). > >> > > > I wanted to know if there is something similar with proton-c or at > >> > least > >> > > a way for me to implement it? > >> > > > > >> > > > Thanks, > >> > > > Olivier > >> > > > > >> > > > ******************************* > >> > > > This e-mail contains information for the intended recipient only. > It > >> > may > >> > > contain proprietary material or confidential information. 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