Taras, I believe we should have the same mechanism but different set of flags.
Alexey, The idea is to add new flag when you make changes instead of increment protocol version. This way client maintainer can introduce the same change (probably fix) in they client without the necessity to implement all other features that were introduced in between. Probably the "feature" word is confusing here. Maybe we should use term "Changes Mask" or something like that. Best Regards, Igor On Thu, Jan 23, 2020 at 5:27 PM Pavel Tupitsyn <ptupit...@apache.org> wrote: > Igor, great idea, I think this should be our priority for all thin clients. > > Alexei, protocol version bump can be still required for major changes (e.g. > if we want to change handshake format). > But for simpler things like new features that don't affect existing ones, > feature masks allow us to keep current protocol version. > > On Thu, Jan 23, 2020 at 3:55 PM Taras Ledkov <tled...@gridgain.com> wrote: > > > Alexei, > > > > After the flags is introduced we can change the flag set instead of > > change protocol version. > > Of course, we will need to up the protocol version for introducing > flags. > > > > On 23.01.2020 15:47, Alexei Scherbakov wrote: > > > Igor Sapego, > > > > > > I do not understand how feature masks can remove the necessity of > having > > > protocol versioning. > > > A protocol for one feature can change from release to release. > > > > > > чт, 23 янв. 2020 г. в 15:36, Igor Sapego <isap...@apache.org>: > > > > > >> Hi Igniters, > > >> > > >> As we have a lot of different thin clients now, maintained by > different > > >> people, the issues with our backward compatibility mechanism becomes > > >> more and more prominent. > > >> > > >> Currently, we use protocol versioning as the only approach to provide > > >> backward compatibility. The main issue of this approach is that we can > > >> not skip some change in protocol and implement i.e. protocol of > version > > >> 1.5 without implementation of 1.4. There are many cases when one may > > >> want to do so: e.g. when feature provided in 1.4 is not relevant for a > > >> specific client, or when protocol version 1.5 contains urgent fix or > > >> feature > > >> which is easy to implement, but its blocked by not-so-urgent and > > >> hard-to-implement feature introduced in 1.4. > > >> > > >> So to fix this issue I propose to introduce another backward > > compatibility > > >> mechanism. The idea is to send "supported features" mask by a client > to > > >> a server, which should be answered with the same mask by the server. > > >> The resulting set of enabled features is acquired with a simple > logical > > >> "AND" > > >> operation on these two masks. > > >> > > >> This change has many other positive effects: > > >> 1. It improves readability and also potentially simplifies debugging. > > >> 2. It gives users the ability to enable or disable features of thin > > clients > > >> on both > > >> server and client as they desire. > > >> > > >> What are your thoughts guys? > > >> > > >> Best Regards, > > >> Igor > > >> > > > > > -- > > Taras Ledkov > > Mail-To: tled...@gridgain.com > > > > >
