How to capture warnings with the console output? - r

Question

I am trying to capture complete console log of my R script. I want a chronological order of everything, warnings printed as they occur. I tried this:
options(warn = 1)
tmpSinkfileName <- tempfile()
sink(tmpSinkfileName, split = TRUE)
cat("Doing something\n")
warning("Hi here")
cat("Doing something else\n")
warning("Hi there")
sink()
console.out <- readChar(tmpSinkfileName, file.info(tmpSinkfileName)$size)
unlink(tmpSinkfileName)
cat(console.out)
# Doing something
# Doing something else
warnings()
# NULL
but unfortunatelly the warnings are missing in console.out. How can I do this? According to the docs, options(warn = 1) should print the warnings as they occur. Unfortunatelly, they were not captured by sink().

Answer 1

Almost got it, but it's pretty complicated and it's pretty annoying that unlike the standard output, the message output cannot be split, i.e. redirected to the file and kept in the output at the same time (UNIX tee behaviour)!
options(warn = 1)
tmpSinkfileName <- tempfile()
tmpFD <- file(tmpSinkfileName, open = "wt")
sink(tmpFD, split = TRUE)
sink(tmpFD, type = "message")
cat("Doing something\n")
warning("Hi here")
cat("Doing something else\n")
warning("Hi there")
sink(type = "message")
sink()
console.out <- readChar(tmpSinkfileName, file.info(tmpSinkfileName)$size)
unlink(tmpSinkfileName)
cat(console.out)
If I try
sink(tmpFD, type = "message", split = TRUE)
it says
Error in sink(tmpFD, type = "message", split = TRUE) : cannot split
the message connection
which is pretty annoying!

Answer 2

I wrote the following function to capture ouput and messages:
create_log <- function(logfile_name, path) {
if (file.exists(paste0(path, logfile_name))) {
file.remove(paste0(path, logfile_name))
}
fid <- file(paste0(path, logfile_name), open = "wt")
sink(fid, type = "message", split = F)
sink(fid, append = T, type = "output", split = T)
warning("Use closeAllConnections() in the end of the script")
}