How to redirect callr output while calling from future

[001ben]

I'm wondering if it's possible to pass an argument down to the underlying callr::r method when using the futures API.

Specifically, i want to make use of the callr::r(show = TRUE) argument, however i can't see any reference in the documentation to pass the parameter down.

P.S. the future-verse is amazing

[HenrikBengtsson]

Hi, sorry for the late reply.

This feature request falls under the section of a "Extended/Optional Future API" discussed in futureverse/future#172. The same wish for viewing output of parallel workers has been raised for other type of backends as well.

The key idea behind the Future API is that your future code (as a developer) should work regardless of which future backend is used (set by the user via plan().) Because of this, it is important that future backends (such as future.callr) do not provide their own extensions/back doors to whatever underlying framework they're building upon. In other words, what you're asking for needs to be defined via the Future API that the future package defines. Exactly how these type of extended/optional features will be declared/provided is still to be decided, but it is on the road map.

The capturing of standard output (stdout) produced by a future is one of the first things that will be supported (hopefully already by one of the near future 'future' releases). This will most likely not involve displaying output live, but rather displaying / making the output available when the future has resolved. So, in the near term it will still not be possible to follow future evaluation live via output or progress bars. Please feel free to continue this discussion over at futureverse/future#172 - any feedback and use cases will help identify what's needed.

[HenrikBengtsson]

... and thanks for the kind words :)

[001ben]

Thanks for the reply, looking forward to extended future options :D