Feature Request: System Disk IO Counters

[michaelwalshe]

Thank you for developing and maintaining such a useful R package.

For my use-case, it would be very beneficial to have a function to return disk IO counters (read bytes, write bytes, transfers, etc) for Linux and Windows, similar to https://psutil.readthedocs.io/en/latest/#psutil.disk_io_counters. I have implemented a potential version for Linux as a bolt-on to this package, however cannot implement the Windows version as it would require updating the C source for this package and I'm not very good with C. I have a workaround using powershell, but it is less than ideal.

I'm unsure if you would prefer me to open this as PR, as I wouldn't be able to implement the Windows/OSX versions so it would be incomplete

My implementation for Linux, heavily inspired by psutil

```r ps_disk_io_counters <- function(perdisk = FALSE) { if (ps_os_name() == "WINDOWS") { return(.ps_disk_io_counters_windows(perdisk)) } else { return(.ps_disk_io_counters_linux(perdisk)) } } #' Internal disk IO counters for Linux, reads lines from diskstats if it exists #' or /sys/block as a backup .ps_disk_io_counters_linux <- function(perdisk = FALSE) { if (file.exists("/proc/diskstats")) { disk_info <- .read_procfs() } else if (dir.exists("/sys/block")) { disk_info <- .read_sysfs() } else { stop("Can't read, neither /proc/diskstats or /sys/block on this system") } # Keep all if perdisk, only keep non-partitions if perdisk=FALSE to get correct sums disk_info <- disk_info[perdisk | sapply(disk_info$name, .is_storage_device), ] if (perdisk) { return(disk_info) } else { # Sum all numeric cols, convert to df via list to ensure 1 row total_info <- data.frame(as.list(colSums(disk_info[, -1]))) # Add no name total_info$name <- NA return(total_info) } return(disk_io) } #' Whether a named drive (e.g. 'sda') is a real storage device, or a virtual one .is_storage_device <- function(name, including_virtual = TRUE) { name <- stringr::str_replace_all(name, "/", "!") if (including_virtual) { path <- file.path("/sys/block", name) } else { path <- file.path("/sys/block", name, "device") } return(dir.exists(path)) } #' Logic to read disk IO stats from /proc/diskstats .read_procfs <- function() { file <- readLines("/proc/diskstats") # Get info as list of vectors (could be different lengths) lines <- stringr::str_split(stringr::str_trim(file), "\\s+") # Pre-allocate matrix of info as NAs mat <- matrix(data = NA_character_, nrow = length(lines), ncol = 10) for (i in seq_along(lines)) { # For each line, check length and insert into matrix as appropriate line <- lines[[i]] flen <- length(line) if (flen == 15) { # Linux 2.4 mat[i, 1] <- line[[4]] # name mat[i, 2] <- line[[3]] # reads mat[i, 3:9] <- line[5:11] # reads_merged, rbytes, rtime, writes, writes_merged, wbytes, wtime mat[i, 10] <- line[[14]] # busy_time } else if (flen == 14 || flen >= 18) { # Linux 2.6+, line referring to a disk mat[i, 1] <- line[[3]] # name mat[i, 2:9] <- line[5:12] # reads, reads_merged, rbytes, rtime, writes, writes_merged, wbytes, wtime mat[i, 10] <- line[[14]] # busy_time } else if (flen == 7) { # Linux 2.6+, line referring to a partition mat[i, 1] <- line[[2]] # name mat[i, 2] <- line[[4]] # reads mat[i, 4:5] <- line[5:6] # rbytes, writes mat[i, 8] <- line[7] # wbytes } else { stop("Cannot read diskstats file") } } # Add names and convert types as appropriate return(data.frame( name = mat[, 1], read_count = as.numeric(mat[, 2]), read_merged_count = as.numeric(mat[, 3]), read_bytes = as.numeric(mat[, 4]) * 512, # Multiple by disk sector size to get bytes read_time = as.numeric(mat[, 5]), write_count = as.numeric(mat[, 6]), write_merged_count = as.numeric(mat[, 7]), write_bytes = as.numeric(mat[, 8]) * 512, # Multiple by disk sector size to get bytes write_time = as.numeric(mat[, 9]), busy_time = as.numeric(mat[, 10]) )) } #' Read disk IO from each device folder in /sys/block .read_sysfs <- function() { # Get stat files for each block blocks <- list.dirs("/sys/block/", recursive = FALSE) all_files <- list.files(blocks, full.names = TRUE) stats <- all_files[stringr::str_ends(all_files, "stat")] # Pre-allocate list for dfs disk_info <- vector(mode = "list", length = length(stats)) for (i in seq_along(stats)) { # Read in each file, get the field stat <- stats[[i]] fields <- readLines(stat) fields <- unlist(stringr::str_split(stringr::str_trim(fields), "\\s+")) # Save all info as a dataframe block_info <- data.frame( name = stringr::str_split(stat, "/")[[1]][[5]], # Extract name from stat filepath read_count = as.numeric(fields[[1]]), read_merged_count = as.numeric(fields[[2]]), read_bytes = as.numeric(fields[[3]]) * 512, # Multiple by disk sector size to get bytes read_time = as.numeric(fields[[4]]), write_count = as.numeric(fields[[5]]), write_merged_count = as.numeric(fields[[6]]), write_bytes = as.numeric(fields[[7]]) * 512, # Multiple by disk sector size to get bytes write_time = as.numeric(fields[[8]]), busy_time = as.numeric(fields[[10]]) ) disk_info[[i]] <- block_info } return(do.call(rbind, disk_info)) } ```

[gaborcsardi]

Thanks! If you could submit it as a PR, that would be great. It is ok if a function is only implemented on Linux, we can always add a Windows/macOS implementation later, if it is possible to have one.

[michaelwalshe]

Okay thanks, I'll submit this as a draft PR, though I haven't really submitted to R packages before so it may be a while as this'll need tests and documentation etc

[gaborcsardi]

Thanks! It is fine to submit a first PR w/o docs and tests.