FYI, MNG-5899 makes shaded builds fragile, effectively limiting multi-module shaded projects to maven 3.2.x. Apparently the Apache Storm folks tripped over this earlier, and as I recall, Apache Flink used to require building with 3.2.x for the same reason.
https://issues.apache.org/jira/browse/MNG-5899 On Tue, Apr 18, 2017 at 9:20 PM, Nick Dimiduk <[email protected]> wrote: > On Wed, Apr 12, 2017 at 2:30 PM, Stack <[email protected]> wrote: > >> > >> If the above quote is true, then I think what we want is a set of >> > shaded >> > > >> Hadoop client libs that we can depend on so as to not get all the >> > > >> transitive deps. Hadoop doesn't provide it, but we could do so >> > ourselves >> > > >> with (yet another) module in our project. Assuming, that is, the >> > > upstream >> > > >> client interfaces are well defined and don't leak stuff we care >> about. >> > >> >> >> We should do this too (I think you've identified the big 'if' w/ the above >> identified assumption). As you say later, "... it's time we firm up the >> boundaries between us and Hadoop.". There is some precedent with >> hadoop-compat-* modules. Hadoop would be relocated? >> > > Ideally we'd relocate any parts of Hadoop that are not part of our public > contract. Not sure if there's an intersection between "ideal" and > "practical" though. > > Spitballing, IIUC, I think this would be a big job (once per version and >> the vagaries of hadoop/spark) with no guarantee of success on other end >> because of assumption you call out. Do I have this right? >> > > Yeah you have my meaning. My argument is not whether we should shade but > rather how we make it a maintainable deployment tool for our team of > volunteers. Hence interest in compatibility verification tools like we do > with our api compatibility tools. > > > Isolating our clients from our deps is best served by our shaded modules. >> > What do you think about turning things on their head: for 2.0 the >> > hbase-client jar is the shaded artifact by default, not the other way >> > around? We have cleanup to get our deps out of our public interfaces in >> > order to make this work. >> > >> > >> We should do this at least going forward. hbase2 is the opportunity. >> Testing and doc is all that is needed? I added it to our hbase2 >> description >> doc as a deliverable (though not a blocker). >> > > I've not tried to consume these efforts. A reasonable test-case to see if > these are ready for prime-time would be to try rebuilding one of the more > complex downstream projects (i.e, Phoenix, Trafodion, Splice) using the > shaded jars and see how bad the diff is. > > > This proposal of an external shaded dependencies module sounds like an >> > attempt to solve both concerns at once. It would isolate ourselves from >> > Hadoop's deps, and it would isolate our clients from our deps. However, >> it >> > doesn't isolate our clients from Hadoop's deps, so our users don't >> really >> > gain anything from it. I also argue that it creates an unreasonable >> release >> > engineering burden on our project. I'm also not clear on the >> implications >> > to downstreamers who extend us with coprocessors. >> > >> >> >> Other than a missing 'quick-fix' descriptor, you call what is proposed >> well >> ....except where you think the prebuild will be burdensome. Here I think >> otherwise as I think releases will be rare, there is nought 'new' in a >> release but packaged 3rd-party libs, and verification/vote by PMCers >> should >> be a simple affair. >> > > Maybe it's not such a burden? If the 2.0 and 3.0 RM's are brave and true, > it's worth a go. > > Do you agree that the fixing-what-we-leak-of-hadoop-to-downstreamers is >> distinct from the narrower task proposed here where we are trying to >> unhitch ourselves of the netty/guava hadoop uses? (Currently we break >> against hadoop3 because of netty incompat., HADOOP-13866, which we might >> be >> able to solve w/ exclusions.....but....). >> >> The two tasks can be run in parallel? >> > > Indeed, they seem distinct but quite related. > > For CPs, they should bring their own bedding and towels and not be trying >> to use ours. On the plus-side, we could upgrade core 3rd-party libs and >> the >> CP would keep working. >> > > All of this sounds like an ideal state. >
