v0.1.0 release candidate (#8)

* `usethis::use_news_md()`, update install instructions, single-quote `ps` in description, bump version

* in the release process, resolved:

```
Error in UseMethod("mutate") :
  no applicable method for 'mutate' applied to an object of class "NULL"
Calls: <Anonymous> ... eval -> eval -> syrup -> mutate_pct_cpu -> <Anonymous>"
```

...intermittently for some calls. turns out this was because the session had a longer-than-expected delay before its results were able to be `read()`--just iteratively query with additional delay until we get results.

DESCRIPTION

@@ -1,13 +1,13 @@
 Package: syrup
 Title: Measure Memory and CPU Usage for Parallel R Code
-Version: 0.0.0.9000
+Version: 0.1.0
 Authors@R: c(
  person("Simon", "Couch", , "[email protected]", role = c("aut", "cre"),
  comment = c(ORCID = "0000-0001-5676-5107")),
  person(given = "Posit Software, PBC", role = c("cph", "fnd")) 
  )
 Description: Measures memory and CPU usage of R code by regularly taking 
- snapshots of calls to the system command ps. The package provides an entry 
+ snapshots of calls to the system command 'ps'. The package provides an entry 
  point (albeit coarse) to profile usage of system resources by R code run 
  in parallel.
 License: MIT + file LICENSE

NEWS.md

@@ -0,0 +1,3 @@
+# syrup 0.1.0
+
+* Initial CRAN submission.

R/syrup.R

@@ -120,17 +120,12 @@ syrup <- function(expr, interval = .5, peak = FALSE, env = caller_env()) {
 
  # tell `sesh` to stop taking snapshots
  file.remove(keep_going_file)
- Sys.sleep(interval + .1)
+ Sys.sleep(interval + .2)
 
- # grab the result from sesh and close it
- sesh_res <- sesh$read()
- sesh$close()
+ res <- retrieve_results(sesh)
 
  withr::deferred_clear()
 
- # return the memory usage information
- res <- sesh_res$result
-
  if (identical(res$id[length(res$id)], 1) && !isTRUE(peak)) {
  rlang::warn(c(
  "!" = "`expr` evaluated fully before syrup could take a snapshot of memory usage.",

R/utils.R

@@ -40,3 +40,28 @@ calculate_pct_cpu <- function(time, user, system) {
 
  c(NA_real_, (user_diffs + system_diffs) * 100 / intervals)
 }
+
+# grab the result from sesh and close it.
+# may be a slightly longer delay before sesh is able to return, so iteratively
+# query until we get a result back.
+retrieve_results <- function(sesh, call = caller_env()) {
+ sesh_res <- sesh$read()
+ cnt <- 1
+ while (is.null(sesh_res) & cnt < 10) {
+ Sys.sleep(.2)
+ sesh_res <- sesh$read()
+ cnt <- cnt + 1
+ }
+
+ sesh$close()
+
+ if (cnt == 10) {
+ rlang::abort(
+ "Unable to retrieve resource usage results from the temporary session.",
+ .internal = TRUE,
+ call = call
+ )
+ }
+
+ sesh_res$result
+}

README.Rmd

@@ -27,6 +27,12 @@ The package name is an homage to syrupy (**SY**stem **R**esource **U**sage **P**
 
 ## Installation
 
+Install the latest release of syrup from CRAN like so:
+
+``` r
+install.packages("syrup")
+```
+
 You can install the development version of syrup like so:
 
 ``` r

README.md

@@ -23,6 +23,12 @@ The package name is an homage to syrupy (**SY**stem **R**esource
 
 ## Installation
 
+Install the latest release of syrup from CRAN like so:
+
+``` r
+install.packages("syrup")
+```
+
 You can install the development version of syrup like so:
 
 ``` r