new crashes() launcher method

NEWS.md

@@ -3,6 +3,7 @@
 * Eliminate spurious `launch_max` error from underutilized workers (#189).
 * Deprecate `launch_max` in favor of `crashes_error` (#189).
 * Look for crashes of all workers in `rotate()` instead of looking for crashes of a specific worker in `launch()` (#189).
+* Add a `crashes()` launcher method to allow plugins to detect and respond to crashes more easily.
 
 # crew 0.10.1
 

R/crew_launcher.R

@@ -321,6 +321,7 @@ crew_class_launcher <- R6::R6Class(
     #' @param reset_options See [crew_launcher()].
     #' @param garbage_collection See [crew_launcher()].
     #' @param crashes_error See [crew_launcher()].
+    #' @param launch_max Deprecated.
     #' @param tls See [crew_launcher()].
     #' @param processes See [crew_launcher()].
     #' @param r_arguments See [crew_launcher()].
@@ -646,7 +647,8 @@ crew_class_launcher <- R6::R6Class(
     #'     `mirai::daemons()` and summed over all
     #'     completed instances of the worker. Does not reflect the activity
     #'     of the currently running instance of the worker.
-    #'   * `socket`: current websocket URL of the worker.
+    #'   * `crashes`: number of consecutive times a worker
+    #'     launched without completing all its assigned tasks.
     summary = function() {
       workers <- .subset2(self, "workers")
       if (is.null(workers)) {
@@ -909,6 +911,17 @@ crew_class_launcher <- R6::R6Class(
       )
       list(abstract = TRUE)
     },
+    #' @description Return the number of consecutive times a worker
+    #'   launched without completing all its assigned tasks.
+    #' @return Non-negative integer, number of consecutive times a worker
+    #'   launched without completing all its assigned tasks.
+    #' @param index Non-negative integer, index of the worker pointing
+    #'   to a row of the data frame output of the `summary()` method
+    #'   of the launcher.
+    crashes = function(index) {
+      workers <- .subset2(private, ".workers")
+      .subset(.subset2(workers, "crashes"), index)
+    },
     #' @description Abstract worker termination method.
     #' @details Launcher plugins will overwrite this method.
     #' @return A handle to mock worker termination.

tests/local/test-crashes_error.R

@@ -6,14 +6,24 @@ test_that("crashes_error allows idle workers to exit", {
     x$launch()
     Sys.sleep(5)
   }
+  expect_equal(x$launcher$crashes(index = 1L), 0L)
   expect_equal(index, 10L)
 })
 
 test_that("crashes_error detects when there are too many crashes", {
-  x <- crew_controller_local(name = "name", crashes_error = 2L)
+  x <- crew_controller_local(
+    name = "name",
+    workers = 2L,
+    crashes_error = 2L,
+    tasks_max = 1L,
+    seconds_idle = 1
+  )
   on.exit(x$terminate())
   x$start()
-  x$push(Sys.sleep(1e3), scale = FALSE)
+  x$push(Sys.sleep(4), scale = TRUE)
+  Sys.sleep(5)
+  x$push(Sys.sleep(1e3), scale = TRUE)
+  x$wait(mode = "one")
   for (index in seq_len(10L)) {
     Sys.sleep(5)
     if (index == 3L) {
@@ -22,8 +32,15 @@ test_that("crashes_error detects when there are too many crashes", {
     } else {
       expect_silent(x$scale())
     }
+    expect_equal(x$launcher$crashes(index = 1L), 0L)
+    expect_equal(x$launcher$crashes(index = 2L), index - 1L)
     Sys.sleep(5)
-    x$launcher$workers$handle[[1L]]$kill()
+    client_summary <- x$client$summary()
+    expect_equal(client_summary$online, c(FALSE, TRUE))
+    expect_equal(client_summary$instances, c(1L, index))
+    expect_equal(client_summary$assigned, c(1L, 1L))
+    expect_equal(client_summary$complete, c(1L, 0L))
+    x$launcher$workers$handle[[2L]]$kill()
   }
   expect_equal(index, 3L)
 })

tests/testthat/test-crew_launcher.R

@@ -209,6 +209,10 @@ crew_test("launcher start()", {
   expect_equal(workers$launched, rep(FALSE, 2L))
   expect_equal(workers$assigned, rep(0L, 2L))
   expect_equal(workers$complete, rep(0L, 2L))
+  expect_equal(workers$crashes, rep(0L, 2L))
+  for (index in seq_len(2L)) {
+    expect_equal(launcher$crashes(index), 0L)
+  }
 })
 
 crew_test("launcher done()", {