Access R code block in multiple instances

I have a code block, to perform 3 times retry of the code execution in case of a specific error. In below example if HTTP 503 error occurred during the data download from ADLS container, I want the same operation to be executed maximum of 3 times retry.

require(AzureStor)
require(stringr)
recheck <- 0
while (recheck < 3){
  recheck <- recheck + 1
  tryCatch({
    storage_download(container, file, filename, overwrite=TRUE)
    recheck <- 4  
  }, error = function(e){
    if ( sum(str_detect(e, '503')*1) > 0 ){
      print(e)
      print(paste0('An infra-level failure occured. Retry sequence number is : ', recheck))
    } else{
      recheck <<- 4
      print(e)
    }
  }
  )
}

This code works fine for me, but similar to storage_download in the above example, I have other ADLS operations like delete_blob, upload_blob, storage_upload, list_storage_files at multiple instances in the code, I have to write above mentioned code for each of these functions. I want to make the above code as a function which can be called during each of these ADLS operations. Any thoughts or suggestions would help me greatly.

Solution

The following should do the trick:

with_retries_on_failure = function (expr, retries = 3L) {
    expr = substitute(expr)

    for (try in seq_len(retries)) {
        tryCatch(
            return(eval.parent(expr)),
            error = \(e) {
                if (str_detect(conditionMessage(e), '503')) stop(e)
                message('An infra-level failure occurred. Retry sequence number is: ', try)
            }
        )
    }
}

Used as follows:

with_retries_on_failure(storage_download(container, file, filename, overwrite=TRUE))

Note the return() call, which immediately returns from the surrounding function without the need to update the loop variable. Likewise, in the case of a failure we also don’t have to update the loop variable since we are using a for loop, and we use stop() to break out of the loop for any error that is not a 503 HTTP response.