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fix no rate limiting if average is 0

This commit is contained in:
Witold Duranek 2023-01-03 16:16:05 +01:00 committed by GitHub
parent e1e86763e3
commit 0861c47e54
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2 changed files with 18 additions and 7 deletions

View File

@ -79,10 +79,12 @@ func New(ctx context.Context, next http.Handler, config dynamic.RateLimit, name
period = time.Second
}
// if config.Average == 0, in that case,
// the value of maxDelay does not matter since the reservation will (buggily) give us a delay of 0 anyway.
// Initialized at rate.Inf to enforce no rate limiting when config.Average == 0
rtl := float64(rate.Inf)
// No need to set any particular value for maxDelay as the reservation's delay
// will be <= 0 in the Inf case (i.e. the average == 0 case).
var maxDelay time.Duration
var rtl float64
if config.Average > 0 {
rtl = float64(config.Average*int64(time.Second)) / float64(period)
// maxDelay does not scale well for rates below 1,
@ -153,10 +155,6 @@ func (rl *rateLimiter) ServeHTTP(w http.ResponseWriter, r *http.Request) {
return
}
// time/rate is bugged, since a rate.Limiter with a 0 Limit not only allows a Reservation to take place,
// but also gives a 0 delay below (because of a division by zero, followed by a multiplication that flips into the negatives),
// regardless of the current load.
// However, for now we take advantage of this behavior to provide the no-limit ratelimiter when config.Average is 0.
res := bucket.Reserve()
if !res.OK() {
http.Error(w, "No bursty traffic allowed", http.StatusTooManyRequests)

View File

@ -15,6 +15,7 @@ import (
"github.com/traefik/traefik/v2/pkg/config/dynamic"
"github.com/traefik/traefik/v2/pkg/testhelpers"
"github.com/vulcand/oxy/v2/utils"
"golang.org/x/time/rate"
)
func TestNewRateLimiter(t *testing.T) {
@ -25,7 +26,16 @@ func TestNewRateLimiter(t *testing.T) {
expectedSourceIP string
requestHeader string
expectedError string
expectedRTL rate.Limit
}{
{
desc: "no ratelimit on Average == 0",
config: dynamic.RateLimit{
Average: 0,
Burst: 10,
},
expectedRTL: rate.Inf,
},
{
desc: "maxDelay computation",
config: dynamic.RateLimit{
@ -120,6 +130,9 @@ func TestNewRateLimiter(t *testing.T) {
assert.NoError(t, err)
assert.Equal(t, test.requestHeader, hd)
}
if test.expectedRTL != 0 {
assert.Equal(t, test.expectedRTL, rtl.rate)
}
})
}
}