[R] Mysterious R script behavior when called from webserver

[Dylan Beaudette]

Hi,

I am trying to transition a system based on dynamic image generation (via R) 
from our development system to a production environment. Our R script 
functions as expected when run by a regular user. However the script dies 
when calling the png() function, when started by the webserver user.

Here are some details

>sessionInfo()
R version 2.9.2 (2009-08-24)
i686-pc-linux-gnu
locale:
C 
attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

The script gets to this line:

png(file=filename, width=600, height=400)

and then dies. It leaves an empty PNG file where it should be, however it 
never finishes the file. If 

I replace png() with pdf() an output file is generated and closed by dev.off() 
as expected.

It seems like the environment is setup just as when started by a regular user, 
specifically the LD_LIBRARY_PATH variable.

This behavior suggests that R is encountering an error, and stopping. However 
there is no reporting of the error. Is there any way to get more verbose 
error reporting?

Cheers,
Dylan




-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341