Infrastructure ticket opened: https://issues.apache.org/jira/browse/INFRA-7203
On Thu, Jan 16, 2014 at 1:42 PM, Jan Lehnardt <[email protected]> wrote: > > On 16 Jan 2014, at 20:42 , Paul Davis <[email protected]> wrote: > >> It doesn't appear that this is objectionable to anyone. Does anyone >> have an objection to us having infra/me create these repos to use for >> the bigcouch/rcouch merge work? This won't affect master or releases >> until those merges finish. > > no objections. > > Jan > -- > >> >> On Tue, Jan 14, 2014 at 11:02 PM, Paul J Davis >> <[email protected]> wrote: >>> >>> >>>> On Jan 14, 2014, at 8:37 PM, Benoit Chesneau <[email protected]> wrote: >>>> >>>> On Wed, Jan 15, 2014 at 12:22 AM, Paul Davis >>>> <[email protected]>wrote: >>>> >>>>> I've recently been having discussions about how to handle the >>>>> repository configuration for various bits of CouchDB post-merge. The >>>>> work that Benoit has been doing on the rcouch merge branch have also >>>>> touched on this topic as well. >>>>> >>>>> The background for those unfamiliar is that the standard operating >>>>> procedure for Erlang is to have a single Erlang application per >>>>> repository and then rely on rebar to fetch each dependency. >>>>> Traditionally in CouchDB land we've always just included the source to >>>>> all applications in a single monolithic repository and periodically >>>>> reimport changes from upstream dependencies. >>>>> >>>>> Recently rcouch changed from the monolithic repository to use external >>>>> repositories for some dependencies. Originally the BigCouch used an >>>>> even more federated scheme that had each Erlang application in an >>>>> external repository (and the core couch Erlang application was in the >>>>> root repository). When Bob Newson and I did the initial hacking on the >>>>> BigCouch merge we pulled those external dependencies into the root >>>>> repository reverting back to the large monolithic approach. >>>>> >>>>> After trying to deal with the merge and contemplating how various >>>>> Erlang release things might work it's become fairly apparent that the >>>>> monolithic approach is a bit constrictive. For instance, part of >>>>> rebar's versioning abilities lets you tag repositories to generate >>>>> versions rather than manually updating versions in source files. >>>>> Another thing I've found on other projects is that having each >>>>> application in a separate repository requires developers to think a >>>>> bit more detailed about the public internal interfaces used through >>>>> out the system. We've done some work to this extent already with >>>>> separating source directories but forcing commits to multiple >>>>> repositories shoots up a big red flag that maybe there's a high level >>>>> of coupling between two bits of code. >>>>> >>>>> Other benefits of having the multiple repository setup is that its >>>>> possible that this lends itself to being integrated with the proposed >>>>> plugin system. It'd be fairly trivial to have a script that went and >>>>> fetched plugins that aren't developed at Apache (as a ./configure time >>>>> switch type of thing). Having a system like this would also allow us >>>>> to have groups focused on particular bits of development not have to >>>>> concern themselves with the unrelated parts of the system. >>>>> >>>>> Given all that, I'd like to propose that we move to having a >>>>> repository for each application/dependency that we use to build >>>>> CouchDB. Each repository would be hosted on ASF infra and mirrored to >>>>> GitHub as expected. This means that we could have the root repository >>>>> be a simple repo that contains packaging/release/build stuff that >>>>> would enable lots of the ideas offered on configurable types of >>>>> release generation. I've included an initial list of repositories at >>>>> the end of this email. Its basically just the apps that have been >>>>> split out in either rcouch or bigcouch plus a few other bits from >>>>> CouchDB master. >>>>> >>>>> I would also point out that even though our main repo would need to >>>>> fetch other dependencies from the internet to build the final output, >>>>> we fully intend that our release tarballs would *not* have this >>>>> requirement. Ie, when we go to cut a release part of the process the >>>>> RM would run would be to pull all of those dependencies before >>>>> creating a tarball that would be wholly self contained. Given an >>>>> apache-couchdb-x.y.z.tar.gz release file, there won't be a requirement >>>>> to have access to the ASF git repos. >>>>> >>>>> I'm not entirely sure how controversial this is for anyone. For the >>>>> most part the reactions I remember hearing were more concerned on >>>>> whether the infrastructure team would allow us to use this sort of >>>>> configuration. I looked yesterday and asked and apparently its >>>>> something we can request but as always we'll want to verify again if >>>>> we have consensus to move in this direction. >>>>> >>>>> Anyone have comments or flames? Right now I'm just interested in >>>>> feeling out what sort of (lack of?) consensus there is on such a >>>>> change. If there's general consensus I'd think we'd do a vote in a >>>>> couple weeks and if that passes then start on down this road for the >>>>> two merge projects and then it would become part of master once those >>>>> land (as opposed to doing this to master and then attempting to merge >>>>> rcouch/bigcouch onto that somehow). >>>>> >>>>> >>>>> This is a quick pass at listing what extra repositories I'd have >>>>> created. Some of these applications only exist in the bigcouch and/or >>>>> rcouch branches so that's where the unfamiliar application names are >>>>> from. I'd also point out that the documentation and fauxton things are >>>>> just on a whim in that we could decouple that development from the >>>>> erlang development. I can see arguments for an against those. I'm much >>>>> less concerned on that aspect than the Erlang parts that are directly >>>>> affected by rebar/Erlang conventions. >>>>> >>>>> chttpd >>>>> config >>>>> couch >>>>> couch_collate >>>>> couch_dbupdates >>>>> couch_httpd >>>>> couch_index >>>>> couch_mrview >>>>> couch_plugins >>>>> couch_replicator >>>>> documentation >>>>> ddoc_cache >>>>> ets_lru >>>>> fabric >>>>> fauxton >>>>> ibrowse >>>>> jiffy >>>>> mem3 >>>>> mochiweb >>>>> oauth >>>>> rebar >>>>> rexi >>>>> snappy >>>>> twig >>>> >>>> >>>> I also contemplated this and and I am generally +1 on this. And definitely >>>> +1 to mirror them on the apache git if possible. I have a couple of >>>> comments though. >>>> >>>> Initially I also had everything separated in its own source repository. 1 >>>> year ago I merged back as one core repo the couchdb erlang applications and >>>> put all the dependencies in the refuge repository or in the refuge CDN for >>>> the spidermonkey and ICU sources. >>>> >>>> I merged back as one core repo the couchdb erlang applications because they >>>> were a little too much dependant. Especially couch_httpd, couch_index and >>>> couch_mrview. These applications are not yet enough by themselves. >>>> >>>> Imo if we split everything in their own apps, then we should make sure >>>> that couch_httpd can be used without couch_index and couch_mrview (which >>>> means that "all_docs" is available in couch_httpd). Also we should be able >>>> to just launch couch without any of the above. And probably without the >>>> need of an ini. The couch_query_server module thing is an interesting case. >>>> bigcouch is also introducing `ddoc_cache` which I am not sure why it is >>>> provided as a standalone app. Does it means it can be replaced by another >>>> application eventually? Why not having it simply in the couch application? >>>> Does it needs to be updated separately? >>>> >>>> Also all our base applications should also be named spaced correctly so >>>> they will be strictly identified as erlang modules: "config" is too >>>> generic, "ddoc_cache" too. Others are probably OK. >>>> >>>> There are probably other things that we could provide as apps: >>>> >>>> - couch_daemon, >>>> - couch_js >>>> - couch_external >>>> - couch_stats >>>> - couch_compaction_daemon >>>> - couch_httpd_proxy >>>> >>>> Anyway again i'm +1 for this move, I really think it's a good idea. >>>> >>>> - benoit >>> >>> I agree on most of this. Roughly I see three general points. >>> >>> First, deciding on whether some things are external deps is definitely up >>> for discussion. Whether couch_mrview is a different app/repo is not >>> necessarily clear cut. Personally I think I over engineered couch_index >>> which blurs the lines a bit. If I could wave a wand I'd have just >>> couch_mrview and it'd be separate. More importantly I think the separate >>> repos makes these things more apparent. The fact were discussing this sort >>> of architecture thing is suggestive that it's forcing us to think a bit >>> harder. >>> >>> Second is the aspect of composability. For instance the mrview thing to me >>> is obviously a different repo precisely so a user could import couch >>> (_core?) directly without requiring the spider monkey dependency. The >>> monolithic repo doesn't allow this without some very non-standard tooling. >>> >>> Thirdly, app naming is always a contention. The config name was actually a >>> hot code upgrade concern. We couldn't reuse couch_config directly at the >>> time. And Adam was also hopeful we could the it into a useful non-specific >>> config app. >>> >>> Fourthly, and related to secondly, we'll also want to look at splitting >>> other apps out as necessary. The ones you listed I think aren't >>> controversial it's just that no one has done it yet. My list was purely >>> what existed so far without attempting to carve things up more. I >>> definitely agree we should carve more in just wanted to cover consensus >>> that carving is the right direction. >>> >>> Fifthly, I'm done typing on my phone. I'll fill in more thoughts tomorrow. >>> >
