Henrik, Thanks for the suggest. Yes, definitely, I think your more nuanced test would be a big improvement. The only wrinkle is that the connection is established *not* when the package is *loaded* but rather when the connection is *first needed* (using delayedAssign when the package is loaded). That way, loading the package doesn't block the REPL for ~5 seconds while Scala and the JVM first start.
-- David On Thu, Aug 23, 2018 at 11:19 PM Henrik Bengtsson <henrik.bengts...@gmail.com> wrote: > > Does R CMD check --as-cran test for newly opened connections or any > open connections? Could the check for stray connection in > examples/vignettes be: > > 1. Record what connections are open > 2. Attach the package > 3. Record what connections are open > 4. Run the example > 5. Assert that no *new* connections in addition to what's recorded in > Step 3 are open > 6. Unload the package > 7. Assert that no *new* connections in addition to what's recorded in > Step 1 are open > > Step 5 asserts that the code in the example does not leave stray > connections behind, and Step 7 that the package itself does not leave > stray connections behind. > > /Henrik > On Thu, Aug 23, 2018 at 1:25 PM David B. Dahl <d...@stat.byu.edu> wrote: > > > > Oops, I accidentally did not "reply-all".... Here is my message: > > > > Thanks Uwe, Duncan, and Gabor for the response, advise, and flexibility. > > > > Regarding Uwe's suggestion: "... there should be a function that > > creates the connction and one that closes the connection," I should > > clarify. The rscala package does just that. There is a function > > (named "scala") that creates the connection (using delayedAssign) and > > another the closes the function (namely an S3 close method). The > > examples for the rscala package do this full open/close semantics, > > but... > > > > The problem comes when authors of another package, let's call it the > > "FooBar" package, want to implement an algorithm in Scala based on > > functionality provided by the rscala package. Let's say they write a > > function called "neatAlgorithm" based on Scala. Yes, the FooBar > > package author could require that, before the user calls the > > "neatAlgorithm" function, they first call a function to set up the > > connection (which itself would call the "rscala::scala" function) and > > then, after calling the "neatAlgorithm" function, they call a function > > to close the connection. > > > > But that is not very user friendly and exposes the user to > > implementation details of the algorithm. The user of the FooBar > > package don't really care whether the "neatAlgorithm" is implemented > > in pure R, C++, Scala, or whatever, much like the users of the 'lm' > > function don't need to know the implementation details or do any setup > > before and after calling the function. > > > > The current approach is that the connection to Scala is transparent to > > the end user of a package. Behind the scenes, the package author > > establish the connection once it is needed and the rscala package > > manages the connection and explicitly closes it when 1. the package is > > unloaded or 2. the R session ends. This approach does not leave > > dangling connections --- which I believe is the point of the new test > > --- yet my package is caught up in the test. > > > > I hope that this approach is still valid. Perhaps the test could > > result in a warning (instead of an error) and CRAN could accept > > packages with such a warning. > > > > If not, a work-around is to have a \dontshow section in the examples > > that will close the connection (but leave the Scala process running) > > and then automatically reestablish the connection as needed. This > > would not be very efficient but, as Duncan mentioned, it mostly only > > effects the package examples themselves. Plus, it would not be too > > burdensome for package developers. > > > > Again, thanks for considering my situation. > > > > Best regards, > > > > -- David > > > > On Mon, Aug 20, 2018 at 11:11 PM Uwe Ligges > > <lig...@statistik.tu-dortmund.de> wrote: > > > > > > My advise: > > > > > > Apparently you want to have communication via sockets to scala. > > > > > > So there should be a function that creates the connction and one tha > > > closes the connection. > > > Comparable to starting some parallel cluster and stopping it again. > > > > > > In the meantime, you can allow for all sorts of communication. > > > > > > So that's fine. > > > > > > Then in your examples, simply design them to be standalone, i.e. in > > > *your* examples always start the connection and stop it again at the end > > > of one examples block, i.e. the exampels defined in one Rd file. > > > > > > Best, > > > Uwe Ligges > > > > > > > > > > > > On 20.08.2018 02:11, Duncan Murdoch wrote: > > > > On 19/08/2018 12:34 PM, Gábor Csárdi wrote: > > > >> Sorry, missed that these were examples, so, yeah, that's harder. G. > > > > > > > > How about a function that checks if the connection is open before doing > > > > anything, and then at the end you close it if it wasn't already open? > > > > This will make all examples run slower on CRAN, but won't affect most > > > > users who are doing their own stuff as well as running examples. > > > > > > > > Or, how about the startup code for the package opens the connection? > > > > > > > > Or perhaps CRAN will respond to this thread with another suggestion. > > > > > > > > Duncan Murdoch > > > > > > > > > > > >> On Sun, Aug 19, 2018 at 6:32 PM Gábor Csárdi <csardi.ga...@gmail.com> > > > >> wrote: > > > >>> > > > >>> You could just create a function to close the connection and then > > > >>> people could call it at the end of their test suites. >> > > > >>> Gabor > > > >>> On Sun, Aug 19, 2018 at 6:22 PM David B. Dahl <d...@stat.byu.edu> > > > >>> wrote: > > > >>>> > > > >>>> In preparing to submit an update of my package to CRAN, I found that > > > >>>> R-devel has a new test regarding "connects left open" that my > > > >>>> packages > > > >>>> fail. The new test appears to have been committed by Uwe Ligges in > > > >>>> revisions 74959 and 74964 on 2018-07-14 and 2018-07-15, respectively. > > > >>>> The commit message says, "check after each example whether open > > > >>>> connections exist, indicating e.g. file connections were left open or > > > >>>> parallel clusters still running." > > > >>>> > > > >>>> I am hoping for advice on how to pass "R CMD check --as-cran". Or, > > > >>>> perhaps my situation will prompt a change to the test or, at least, > > > >>>> having it result in a warning instead of an error. > > > >>>> > > > >>>> Below I describe the situation. My rscala package allows developers > > > >>>> to write R packages based on Scala (much like rJava and Rcpp for Java > > > >>>> and C++, respectively). Scala runs as a separate process and > > > >>>> interprocess communication is implemented using socket connections. > > > >>>> > > > >>>> Suppose a package using rscala has functions that call Scala code. > > > >>>> (Such packages are 'bamboo', 'sdols', and 'shallot' on CRAN.) The > > > >>>> first time a user executes an R function calling down into Scala, a > > > >>>> socket connect between Scala and R is established. For the sake of > > > >>>> low latency, after the call to the function ends, the connection > > > >>>> stays > > > >>>> open until the package is unloaded or the R session ends. But, this > > > >>>> approach runs afoul of the new test mentioned above that appears to > > > >>>> be > > > >>>> designed to catch connections that are *accidentally* left open. > > > >>>> > > > >>>> I definitely do not want to users of my packages 'bamboo', 'sdols', > > > >>>> and 'shallot' to have to think about managing connection between > > > >>>> Scala > > > >>>> and R. That's an implementation detail and uing the package should > > > >>>> be > > > >>>> transparent for the user (who doesn't care about the implementation > > > >>>> details). > > > >>>> > > > >>>> On my end, I see two solutions: 1. I could try to reengineer my > > > >>>> approach --- establishing a new connection for every single call into > > > >>>> Scala --- although I am loath to do anything to increase the latency, > > > >>>> or 2. I could wrap all the examples in \donttest so that CRAN checks > > > >>>> are passed. > > > >>>> > > > >>>> Or, again, perhaps my situation will prompt a reevaluation of the > > > >>>> test. Perhaps it could result in a warning (instead of an error) and > > > >>>> the CRAN maintainers would accept packages with such a warning. > > > >>>> > > > >>>> Any advise? Thanks a lot! > > > >>>> > > > >>>> -- David > > > >>>> > > > >>>> ______________________________________________ > > > >>>> R-package-devel@r-project.org mailing list > > > >>>> https://stat.ethz.ch/mailman/listinfo/r-package-devel > > > >> > > > >> ______________________________________________ > > > >> R-package-devel@r-project.org mailing list > > > >> https://stat.ethz.ch/mailman/listinfo/r-package-devel > > > >> > > > > > > > > ______________________________________________ > > > > R-package-devel@r-project.org mailing list > > > > https://stat.ethz.ch/mailman/listinfo/r-package-devel > > > > ______________________________________________ > > R-package-devel@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-package-devel ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
