Hi Ted, Well said. Just to be clear, I wasn't suggesting that we use Maven-the-build-tool to distribute plugins. Rather, I was simply observing that building a global repo is a bit of a project and asked, "what could we use that already exists?" The Python repo? No. The Ubuntu/RedHat/whatever Linux repos? Maybe. Maven's repo? Why not?
The idea would be that Drill might have a tool that says, "install the FooBlaster" plugin. It downloads from a repo (Maven central, say) and puts the plugin in the proper plugins directory. In a cluster, either it does that on every node, or the work is done as part of preparing a Docker container which is then pushed to every node. The key thought is just to make the problem simpler by avoiding the need to create and maintain a Drill-specific repo when we can barely have enough resources to keep Drill itself afloat. None of this can happen, however, unless we clean up the plugin APIs and ensure plugins can be built outside of the Drill repo. (That means, say, that Drill needs an API library that resides in Maven.) There are probably many ways this has been done. Anyone know of any good examples we can learn from? Thanks, - Paul On Mon, Jan 17, 2022 at 9:40 AM Ted Dunning <ted.dunn...@gmail.com> wrote: > > I don't think that Maven is a forced move just because Drill is in Java. > It may be a good move, but it isn't a forgone conclusion. For one thing, > the conventions that Maven uses are pretty hard-wired and it may be > difficult to have a reliable deny-list of known problematic plugins. > Publishing to Maven is more of a pain than simply pushing to github. > > The usability here is paramount both for the ultimate Drill user, but also > for the writer of plugins. > > > > On Mon, Jan 17, 2022 at 5:06 AM James Turton <dz...@apache.org> wrote: > >> Thank you Ted and Paul for the feedback. Since Java is compiled, Maven >> is probably better fit than GitHub for distribution? If Drillbits can >> write to their jars/3rdparty directory then I can imagine Drill gaining >> the ability to fetch and install plugins itself without too much >> trouble, at least for Drill clusters with Internet access. >> "Sideloading" by downloading from Maven and copying manually would >> always remain possible. >> >> @Paul I'll try to get a little time with you to get some ideas about >> designing a plugin API. >> >> On 2022/01/14 23:20, Paul Rogers wrote: >> > Hi All, >> > >> > James raises an important issue, I've noticed that it used to be easy to >> > build and test Drill, now it is a struggle, because of the many odd >> > external dependencies we have introduced. That acts as a big damper on >> > contributions: none of us get paid enough to spend more time fighting >> > builds than developing the code... >> > >> > Ted is right that we need a good way to install plugins. There are two >> > parts. Ted is talking about the high-level part: make it easy to point >> to >> > some repo and use the plugin. Since Drill is Java, the Maven repo could >> be >> > a good mechanism. In-house stuff is often in an internal repo that does >> > whatever Maven needs. >> > >> > The reason that plugins are in the Drill project now is that Drill's >> "API" >> > is all of Drill. Plugins can (and some do) access all of Drill though >> the >> > fragment context. The API to Calcite and other parts of Drill are wide, >> and >> > tend to be tightly coupled with Drill internals. By contrast, other >> tools, >> > such as Presto/Trino, have defined very clean APIs that extensions use. >> In >> > Druid, everything is integrated via Google Guice and an extension can >> > replace any part of Druid (though, I'm not convinced that's actually a >> good >> > idea.) I'm sure there are others we can learn from. >> > >> > So, we need to define a plugin API for Drill. I started down that route >> a >> > while back: the first step was to refactor the plugin registry so it is >> > ready for extensions. The idea was to use the same mechanism for all >> kinds >> > of extensions (security, UDFs, metastore, etc.) The next step was to >> build >> > something that roughly followed Presto, but that kind of stalled out. >> > >> > In terms of ordering, we'd first need to define the plugin API. Then, we >> > can shift plugins to use that. Once that is done, we can move plugins to >> > separate projects. (The metastore implementation can also move, if we >> > want.) Finally, figure out a solution for Ted's suggestion to make it >> easy >> > to grab new extensions. Drill is distributed, so adding a new plugin >> has to >> > happen on all nodes, which is a bit more complex than the typical >> > Julia/Python/R kind of extension. >> > >> > The reason we're where we're at is that it is the path of least >> resistance. >> > Creating a good extension mechanism is hard, but valuable, as Ted noted. >> > >> > Thanks, >> > >> > - Paul >> > >> > On Thu, Jan 13, 2022 at 10:18 PM Ted Dunning<ted.dunn...@gmail.com> >> wrote: >> > >> >> The bigger reason for a separate plug-in world is the enhancement of >> >> community. >> >> >> >> I would recommend looking at the Julia community for examples of >> >> effective ways to drive plug in structure. >> >> >> >> At the core, for any pure julia package, you can simply add a package >> by >> >> referring to the github repository where the package is stored. For >> >> packages that are "registered" (i.e. a path and a checksum is recorded >> in a >> >> well known data store), you can add a package by simply naming it >> without >> >> knowing the path. All such plugins are tested by the authors and the >> >> project records all dependencies with version constraints so that >> cascading >> >> additions are easy. The community leaders have made tooling available >> so >> >> that you can test your package against a range of versions of Julia by >> >> pretty simple (to use) Github actions. >> >> >> >> The result has been an absolute explosion in the number of pure Julia >> >> packages. >> >> >> >> For packages that include C or Fortran (or whatever) code, there is >> some >> >> amazing tooling available that lets you record a build process on any >> of >> >> the supported platforms (Linux, LinuxArm, 32 or 64 bit, windows, BSD, >> OSX >> >> and so on). WHen you register such a package, it is automagically >> built on >> >> all the platforms you indicate and the binary results are checked into >> a >> >> central repository known as Yggdrasil. >> >> >> >> All of these registration events for different packages are recorded >> in a >> >> central registry as I mentioned. That registry is recorded in Github as >> >> well which makes it easy to propagate changes. >> >> >> >> >> >> >> >> On Thu, Jan 13, 2022 at 8:45 PM James Turton<dz...@apache.org> wrote: >> >> >> >>> Hello dev community >> >>> >> >>> Discussions about reorganising the Drill source code to better >> position >> >>> the project to support plug-ins for the "long tail" of weird and >> >>> wonderful systems and data formats have been coming up here and there >> >>> for a few months, e.g. inhttps://github.com/apache/drill/pull/2359. >> >>> >> >>> A view which I personally share is that adding too large a number and >> >>> variety of plug-ins to the main tree would create a lethal maintenance >> >>> burden for developers working there and lead down a road of >> accumulating >> >>> technical debt. The Maven tricks we must employ to harmonise the >> >>> growing set of dependencies of the main tree to keep it buildable are >> >>> already enough, as is the size of our distributable and the count of >> >>> open bug reports. >> >>> >> >>> >> >>> Thus, the idea of splitting out "/contrib" into a new >> >>> apache/drill-contrib repo after selecting a subset of plugins to >> remain >> >>> in apache/drill. I'll now volunteer a set of criteria to decide >> whether >> >>> a plug-in should live in this notional apache/drill-contrib. >> >>> >> >>> 1. The plug-in queries an unstructured data format (even if it only >> >>> reads metadata fields) e.g. Image format plug-in. >> >>> 2. The plug-in queries a data format that was designed for human >> >>> consumption e.g. Excel format plug-in. >> >>> 3. The plug-in cannot be expected to run with speed and reliability >> >>> comparable to querying structured data on the local network e.g. >> >>> Dropbox storage plugin. >> >>> 4. The plug-in queries an obscure system or format e.g. we receive a >> >>> plug-in for some data format used only on old Cray >> supercomputers. >> >>> 5. The plug-in can for some reason not be well supported by the >> Drill >> >>> devs e.g. it has a JNI dependency on some difficult native libs. >> >>> >> >>> >> >>> Any one of those suggests that an apache/drill-contrib is the better >> >>> home to me, but what is your view? Would we apply significantly more >> >>> relaxed standards when reviewing PRs to apache/drill-contrib? Would >> we >> >>> tag, build and test apache/drill-contrib with every release of >> >>> apache/drill, or would it run on its own schedule, perhaps with users >> >>> downloading builds made continuously from snapshots of HEAD? >> >>> >> >>> >> >>> Regards >> >>> James >> >>> >> >>> >> >>> >> >>
