[Rd] Process to Incorporate Functions from {parallely} into base R's {parallel} package

[Henrik Bengtsson]

FWIW, there are indeed a few low hanging bug fixes in 'parallelly'
that should be easy to incorporate into 'parallel' without adding
extra maintenance.  For example, in parallel::makePSOCKcluster(), it
is not possible to disable SSH option '-l USER' so that it can be set
in ~/.ssh/config.  The remote user name will be the user name of your
local machine and if you try to set user=NULL, you'll end up with an
invalid SSH call.   The current behavior means that you are forced to
specify the remote user name in your R code.  All that it takes is to
fix this is to update:

  cmd <- paste(rshcmd, "-l", user, machine, cmd)

to something like:

  cmd <- paste(rshcmd, if (length(user) == 1L) paste("-l", user), machine, cmd)

This is one example of what I've patched in
parallelly::makeClusterPSOCK() over the years.  Another is the use of
reverse tunneling in SSH - that completely avoids the need to know and
specify your public IP and reconfiguring the firewalls from the remote
server back to your local machine so that the worker can connect back
to your local machine.  Not many users have the permission to
reconfigure firewalls and it's also extremely tedious.  Reverse SSH
tunneling is super simply; all you need to to is something like:

rshopts <- c(sprintf("-R %d:%s:%d", rscript_port, master, port), rshopts)

/Henrik

On Fri, Nov 6, 2020 at 4:37 PM Duncan Murdoch <murdoch.duncan using gmail.com> wrote:
>
> On 06/11/2020 4:47 p.m., Balamuta, James Joseph wrote:
> > Hi all,
> >
> > Henrik Bengtsson has done some fantastic work with {future} and, more importantly, greatly improved constructing and deconstructing a parallelized environment within R. It was with great joy that I saw Henrik slowly split off some functionality of {future} into {parallelly} package. Reading over the package’s README, he states:
> >
> >> The functions and features added to this package are written to be backward compatible with the parallel package, such that they may be incorporated there later.
> >> The parallelly package comes with an open invitation for the R Core Team to adopt all or parts of its code into the parallel package.
> >
> > https://github.com/HenrikBengtsson/parallelly
> >
> > I’m wondering what the appropriate process would be to slowly merge some functions from {parallelly} into the base R {parallel} package. Should this be done with targeted issues on Bugzilla for different fields Henrik has identified? Or would an omnibus patch bringing in all suggested modifications be preferred? Or is it best to discuss via the list-serv appropriate contributions?
>
> One way is to convince R Core that incorporating this into the parallel
> package would
>
>   - make less work for them, or
>   - add a lot to R that couldn't happen if it was a contributed package.
>
> The fact that it's good isn't a good reason to put it into a base
> package, which would largely mean transferring Henrik's workload to R
> Core.  There are lots of good packages, and their maintainers should
> continue to maintain them.
>
> Duncan Murdoch
>
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