Non-interactive (batch) mode

[djbios]

We are currently utilizing rpy2 in our production code and have encountered issues with the interactive mode causing the entire application to become stuck when certain libraries are awaiting input.

A solution would be to implement a way to force rpy2 to operate in non-interactive mode for R.

[lgautier]

Initializing the embedded R in non-interactive mode is more tedious and less documented than ideal, but you might be able to get away with it by setting R to non-interactive after initialization. Try:

import rpy2.rinterface as ri
ri.initr()
ri.openrlib.rlib.R_Interactive = False

[djbios]

@lgautier Thanks for the answer! Unfortunately, because it could be more than one entry point in production code (for example in the application and in the tests) this solution leads to a violation of DRY and it's easy to forget to write it in some new entry point. Could you please consider my PR #980 with an environment variable-based setting? It allows setting batch mode in a clean way in one place.

[lgautier]

I am not a big fan of having an environment variable here. The interactivity status can be set (changed) at any time in the Python code.

The embedded R is initialized only once (the public function initr is protected from accidental repeated attempts to initialize). I believe that applying DRY principles is up to the user of the library here. Having one entry point to set up the initialization is straightforward. For example, you have a module my-prod-code-setup.py that is called at top-level. That module can have the lines:

import rpy2.rinterface_lib.embedded
rpy2.rinterface_lib.embedded._initr(interactive=False)
# from now R will stay initialized and in non-interactive mode

I caught missed in the API though, and wrote an PR to fix them. With PR #986 it can be written

import rpy2.rinterface as ri
ri.initr(interactive=False)
# from now R will stay initialized and in non-interactive mode

I have also made the default initialization a module-level variable, albeit not a public one to indicate that things are less safe.
It is possible to write the following

import rpy2.rinterface.embedded
rpy2.rinterface_embedded._DEFAULT_R_INTERACTIVE = False
# from now on the default interactive-mode for R as initialization is the non-interactive mode...
# ... unless this is reverted before R is initialized, or R is initialized when a different interactive mode.

[lgautier]

Fixed with PR #986 , and included in rpy2 release 3.5.8.