CODEWITHSUNDEEP
rr-markdown
Joel Kandiah
Joel Kandiah

Reputation: 1525

How to pass errors back to the Rmarkdown::render function?

I am trying to render an Rmarkdown file through an R script. (Code for both files below). What I would like to do is to pass information back to the render function depending on where the error is. This may be that the file can't read the input dataset. I would like to do this as I would like to run the script as a cron job and would like it to send me an email telling me why I might need to re run the code or what the error is.

I have read some of the other stackoverflow similar questions and couldn't see how it did what I wanted with some testing.

The r script: (I have attempted using something like the following)

rm(list = ls())
setwd("C:/Users/joel.kandiah/Downloads")


a <- print(try(rmarkdown::render("test.Rmd", quiet = T), TRUE))
#> [1] "C:/Users/joel.kandiah/Downloads/test.nb.html"

cat(eval(a))
#> C:/Users/joel.kandiah/Downloads/test.nb.html

The Rmarkdown document:

if(!exists("data_raw")) simpleError("Dataset has not been loaded")
#> <simpleError: Dataset has not been loaded>

What I would like is to see the simple error as an object in the R script. Something akin to an exit code might also be acceptable.

Upvotes: 0

Views: 560

Answers (1)

Serkan
Serkan

Reputation: 1955

A possible approach, is the wrapping tryCatch around render in your R script.

R Script

# Render the markdown document; ####
tryCatch(
        expr = rmarkdown::render(
                "markdown.Rmd",
                clean = TRUE
        ),
        
        error = function(cond) {
                
                message(cond)
                
        },
        
        warning = function(cond) {
                
                message(cond)
                
        }
        
)

R Markdown

# Force an error; 
stop("You do not have permission to render. Admin password is needed.")

This will return the same error-message to your script.

Upvotes: 1

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