test_that("request_retry() logic works as advertised", {
# TODO: I'm testing too much re: retry logic via messages.
# Classed errors should simplify things, in due course.
faux_response <- function(status_code = 200, h = NULL) {
structure(
list(
status_code = status_code,
headers = if (!is.null(h)) httr::insensitive(h)
),
class = "response"
)
}
# allows us to replay a fixed set of responses
faux_request_make <- function(responses = list(faux_response())) {
i <- 0
force(responses)
function(...) {
i <<- i + 1
responses[[i]]
}
}
# turn this: Retry 1 happens in 1.7 seconds
# Retry 1 happens in 1 seconds
# into this: Retry 1 happens in {WAIT_TIME} seconds
fix_wait_time <- function(x) {
sub(
"(?<=in )[[:digit:]]+([.][[:digit:]]+)?(?= seconds)",
"{WAIT_TIME}",
x,
perl = TRUE
)
}
# turn this: (strategy: exponential backoff, full jitter, clipped to floor of 1 seconds)
# (strategy: exponential backoff, full jitter, clipped to ceiling of 45 seconds)
# into this: (strategy: exponential backoff, full jitter)
fix_strategy <- function(x) {
sub(
", clipped to (floor|ceiling) of [[:digit:]]+([.][[:digit:]]+)? seconds",
"",
x,
perl = TRUE
)
}
local_gargle_verbosity("debug")
# 2021-03-18
# The switch to mockr::with_mock() has caused trouble interactively
# executing this test. The closures used to mock request_make() seem to
# use a common counter (i) and responses. I plan to open a mockr issue.
# Workaround in the meantime: load_all() before each interactive call to
# with_mock().
# succeed on first try
out <- with_mock(
request_make = faux_request_make(),
{
request_retry()
}
)
expect_equal(httr::status_code(out), 200)
# fail, then succeed (exponential backoff)
r <- list(faux_response(429), faux_response())
with_mock(
request_make = faux_request_make(r),
gargle_error_message = function(...) "oops",
{
msg_fail_once <- capture.output(
out <- request_retry(max_total_wait_time_in_seconds = 5),
type = "message"
)
}
)
expect_snapshot(
writeLines(fix_strategy(fix_wait_time(msg_fail_once)))
)
expect_equal(httr::status_code(out), 200)
# fail, then succeed (Retry-After header)
r <- list(
faux_response(429, h = list(`Retry-After` = 1.4)),
faux_response()
)
with_mock(
request_make = faux_request_make(r),
gargle_error_message = function(...) "oops",
{
msg_retry_after <- capture.output(
out <- request_retry(),
type = "message"
)
}
)
expect_snapshot(
writeLines(fix_strategy(fix_wait_time(msg_retry_after)))
)
expect_equal(httr::status_code(out), 200)
# make sure max_tries_total is adjustable)
r <- list(
faux_response(429),
faux_response(429),
faux_response(429),
faux_response()
)
with_mock(
request_make = faux_request_make(r[1:3]),
gargle_error_message = function(...) "oops",
{
msg_max_tries <- capture.output(
out <- request_retry(max_tries_total = 3, max_total_wait_time_in_seconds = 6),
type = "message"
)
}
)
expect_snapshot(
writeLines(fix_strategy(fix_wait_time(msg_max_tries)))
)
expect_equal(httr::status_code(out), 429)
})
test_that("backoff() obeys obvious bounds from min_wait and max_wait", {
faux_error <- function() {
structure(list(status_code = 429), class = "response")
}
# raw wait_times in U[0,1], therefore all become min_wait + U[0,1]
with_mock(
gargle_error_message = function(...) "oops",
{
wait_times <- vapply(
rep.int(1, 100),
backoff,
FUN.VALUE = numeric(1),
resp = faux_error(), min_wait = 3
)
}
) %>% suppressMessages()
expect_true(all(wait_times > 3))
expect_true(all(wait_times < 4))
# raw wait_times in U[0,6], those that are < 1 become min_wait + U[0,1] and
# those > 3 become max_wait + U[0,1]
with_mock(
gargle_error_message = function(...) "oops",
{
wait_times <- vapply(
rep.int(1, 100),
backoff,
FUN.VALUE = numeric(1),
resp = faux_error(), base = 6, max_wait = 3
)
}
) %>% suppressMessages()
expect_true(all(wait_times > 1))
expect_true(all(wait_times < 3 + 1))
})
test_that("backoff() honors Retry-After header", {
faux_429 <- function(h) {
structure(
list(
status_code = 429,
headers = httr::insensitive(h)
),
class = "response"
)
}
# play with capitalization and character vs numeric
out <- with_mock(
gargle_error_message = function(...) "oops",
{
backoff(1, faux_429(list(`Retry-After` = "1.2")))
}
) %>% suppressMessages()
expect_equal(out, 1.2)
out <- with_mock(
gargle_error_message = function(...) "oops",
{
backoff(1, faux_429(list(`retry-after` = 2.4)))
}
) %>% suppressMessages()
expect_equal(out, 2.4)
# should work even when tries_made > 1
out <- with_mock(
gargle_error_message = function(...) "oops",
{
backoff(3, faux_429(list(`reTry-aFteR` = 3.6)))
}
) %>% suppressMessages()
expect_equal(out, 3.6)
})
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