Export log file for parallel processing in R

foreach_logger.R

# This is a simple example of how you can create an external log file for monitoring parallel jobs in R, using doSNOW and foreach

library(doSNOW)
library(foreach)

n <- 10

cl <- makePSOCKcluster(5)
registerDoSNOW(cl)
writeLines(c(""), "log.txt")

results <-  foreach(i = 1:n,  .combine = rbind) %dopar% {

  x <- sample(1:10, 1)
  y <- sample(seq(0.01, 0.05, by = 0.001), 1)
  res <- c(x = x,y = y)  
  
  # Create temporary artificial delays between iterations 
  Sys.sleep(0.5)
  
  sink("log.txt", append=TRUE)
  # Change text
  cat("Iteration", i, "\n")
}

stopCluster(cl)