README
¶
rate limit buffer
RateLimiter is an interface you want to use in a protect your backend from too many calls.
There are the following implementations:
- CircularBuffer: NewRateLimiter(int, time.Duration) RateLimiter
- ClientRateLimiter: NewClientRateLimiter(int, time.Duration) *ClientRateLimiter
CircularBuffer is a rate limiter that can only protect a backend from maximum number of calls. It has no idea about clients or connections. Allow(string) will ignore the string parameter, which is only used by ClientRateLimiter to match the bucket of a client. This CircularBuffer does not need to be refilled, because it is aware of the oldest of call time.Time, which will be used to check the time.Duration passed.
ClientRateLimiter implements the RateLimiter interface. ClientRateLimiter is a rate limit data structure with a simple interface and is able to do different kinds of rate limits. For example it can be used to do client based rate limits, where each client is independently counted and rate limited. The normal case in the literature is implemented as leaky bucket data structure, which can only implement the case were you want to protect your backend to get only N number requests per duration. Client based rate limits can be used to slow down user/password enumeration attacks, protect DDoS attacks that do not fill the pipe, but your software proxy.
Upgrade v0.1.x to v0.2.y
There is a breaking change, which does not break the interface. People that want to rate limit per string passed to "Allow(string) bool" have to change to ClientRateLimiter to get the same results.
Benchmarks
v0.2.*
% go test -bench=. -benchmem -cpu 1,2,4,8 | tee -a v0.1.3.txt
goos: linux
goarch: amd64
pkg: github.com/szuecs/rate-limit-buffer
BenchmarkRateLimiterAllow 10000000 155 ns/op 5 B/op 0 allocs/op
BenchmarkRateLimiterAllow-2 10000000 156 ns/op 5 B/op 0 allocs/op
BenchmarkRateLimiterAllow-4 10000000 153 ns/op 5 B/op 0 allocs/op
BenchmarkRateLimiterAllow-8 10000000 152 ns/op 5 B/op 0 allocs/op
BenchmarkClientRateLimiterAllow 1000000 1545 ns/op 143 B/op 4 allocs/op
BenchmarkClientRateLimiterAllow-2 1000000 1430 ns/op 143 B/op 4 allocs/op
BenchmarkClientRateLimiterAllow-4 1000000 1402 ns/op 143 B/op 4 allocs/op
BenchmarkClientRateLimiterAllow-8 1000000 1493 ns/op 143 B/op 4 allocs/op
BenchmarkClientRateLimiterAllowBaseData1 5000000 353 ns/op 14 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData1-2 5000000 344 ns/op 14 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData1-4 5000000 334 ns/op 14 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData1-8 5000000 328 ns/op 14 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData10 5000000 354 ns/op 14 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData10-2 5000000 326 ns/op 14 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData10-4 5000000 365 ns/op 14 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData10-8 5000000 330 ns/op 14 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData100 5000000 362 ns/op 15 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData100-2 5000000 353 ns/op 15 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData100-4 5000000 338 ns/op 15 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData100-8 5000000 348 ns/op 15 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowBaseData1000 2000000 609 ns/op 24 B/op 2 allocs/op
BenchmarkClientRateLimiterAllowBaseData1000-2 2000000 512 ns/op 24 B/op 2 allocs/op
BenchmarkClientRateLimiterAllowBaseData1000-4 2000000 533 ns/op 24 B/op 2 allocs/op
BenchmarkClientRateLimiterAllowBaseData1000-8 2000000 514 ns/op 24 B/op 2 allocs/op
BenchmarkClientRateLimiterAllowConcurrent1 5000000 403 ns/op 15 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowConcurrent1-2 5000000 344 ns/op 15 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowConcurrent1-4 5000000 359 ns/op 15 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowConcurrent1-8 5000000 362 ns/op 15 B/op 1 allocs/op
BenchmarkClientRateLimiterAllowConcurrent10 500000 3805 ns/op 159 B/op 19 allocs/op
BenchmarkClientRateLimiterAllowConcurrent10-2 1000000 2190 ns/op 159 B/op 19 allocs/op
BenchmarkClientRateLimiterAllowConcurrent10-4 1000000 1826 ns/op 159 B/op 19 allocs/op
BenchmarkClientRateLimiterAllowConcurrent10-8 1000000 1982 ns/op 159 B/op 19 allocs/op
BenchmarkClientRateLimiterAllowConcurrent100 50000 37318 ns/op 1593 B/op 199 allocs/op
BenchmarkClientRateLimiterAllowConcurrent100-2 50000 28760 ns/op 1593 B/op 199 allocs/op
BenchmarkClientRateLimiterAllowConcurrent100-4 100000 18575 ns/op 1593 B/op 199 allocs/op
BenchmarkClientRateLimiterAllowConcurrent100-8 100000 20966 ns/op 1594 B/op 199 allocs/op
BenchmarkClientRateLimiterAllowConcurrent1000 5000 350560 ns/op 15928 B/op 1990 allocs/op
BenchmarkClientRateLimiterAllowConcurrent1000-2 10000 252966 ns/op 15932 B/op 1990 allocs/op
BenchmarkClientRateLimiterAllowConcurrent1000-4 10000 192886 ns/op 15966 B/op 1990 allocs/op
BenchmarkClientRateLimiterAllowConcurrent1000-8 10000 220237 ns/op 15973 B/op 1990 allocs/op
BenchmarkClientRateLimiterAllowConcurrentAddDelete10 500000 4018 ns/op 159 B/op 19 allocs/op
BenchmarkClientRateLimiterAllowConcurrentAddDelete10-2 500000 3018 ns/op 159 B/op 19 allocs/op
BenchmarkClientRateLimiterAllowConcurrentAddDelete10-4 1000000 1813 ns/op 159 B/op 19 allocs/op
BenchmarkClientRateLimiterAllowConcurrentAddDelete10-8 500000 2181 ns/op 159 B/op 19 allocs/op
PASS
ok github.com/szuecs/rate-limit-buffer 124.119s
< v0.2.*
Not a super profiled data structure, but seems to be ok for an http router. I dropped previous concurrency tests, because these were miss leading (measuring goroutine spawn in the benchmark loop)
# 8e146dfb7ae73ae1d80c25108d64d5431c1efbe4
% go test -bench=. -benchmem -cpu 1,2,4,8
goos: darwin
goarch: amd64
pkg: github.com/szuecs/rate-limit-buffer
BenchmarkAllow 1000000 3192 ns/op 242 B/op 4 allocs/op
BenchmarkAllow-2 1000000 1715 ns/op 243 B/op 4 allocs/op
BenchmarkAllow-4 1000000 1661 ns/op 243 B/op 4 allocs/op
BenchmarkAllow-8 1000000 1430 ns/op 243 B/op 4 allocs/op
# 4879455378dd0207c7a41ec4256023562d4529cb
% go test -bench=. -benchmem -cpu 1,2,4,8
goos: darwin
goarch: amd64
pkg: github.com/szuecs/rate-limit-buffer
BenchmarkAllow 1000000 2501 ns/op 243 B/op 4 allocs/op
BenchmarkAllow-2 1000000 1468 ns/op 243 B/op 4 allocs/op
BenchmarkAllow-4 1000000 1708 ns/op 243 B/op 4 allocs/op
BenchmarkAllow-8 1000000 1405 ns/op 242 B/op 4 allocs/op
# Preprovisioned data set: 67bb879964b58763a7ca3d429f10fe5f7bbe644c
% go test -bench=BenchmarkAllowBaseData1 -benchmem -cpu 1,2,4,8
goos: darwin
goarch: amd64
pkg: github.com/szuecs/rate-limit-buffer
BenchmarkAllowBaseData1 5000000 315 ns/op 14 B/op 1 allocs/op
BenchmarkAllowBaseData1-2 5000000 296 ns/op 14 B/op 1 allocs/op
BenchmarkAllowBaseData1-4 5000000 290 ns/op 14 B/op 1 allocs/op
BenchmarkAllowBaseData1-8 5000000 288 ns/op 14 B/op 1 allocs/op
BenchmarkAllowBaseData10 5000000 319 ns/op 14 B/op 1 allocs/op
BenchmarkAllowBaseData10-2 5000000 287 ns/op 14 B/op 1 allocs/op
BenchmarkAllowBaseData10-4 5000000 283 ns/op 14 B/op 1 allocs/op
BenchmarkAllowBaseData10-8 5000000 287 ns/op 14 B/op 1 allocs/op
BenchmarkAllowBaseData100 5000000 311 ns/op 15 B/op 1 allocs/op
BenchmarkAllowBaseData100-2 5000000 305 ns/op 15 B/op 1 allocs/op
BenchmarkAllowBaseData100-4 5000000 299 ns/op 15 B/op 1 allocs/op
BenchmarkAllowBaseData100-8 5000000 303 ns/op 15 B/op 1 allocs/op
BenchmarkAllowBaseData1000 3000000 439 ns/op 21 B/op 2 allocs/op
BenchmarkAllowBaseData1000-2 3000000 404 ns/op 21 B/op 2 allocs/op
BenchmarkAllowBaseData1000-4 3000000 396 ns/op 21 B/op 2 allocs/op
BenchmarkAllowBaseData1000-8 3000000 403 ns/op 21 B/op 2 allocs/op
PASS
ok github.com/szuecs/rate-limit-buffer 53.970s
I am unsure how to measure with benchmark correctly the concurrent behavior of this data structure. It's clear that high contention will result in less throughput. 1,10,100,1000 are the number of goroutines working concurrently on this data. 300µs/op is ok for 1000 goroutines reading and writing the dataset, compared to do a proxy http call it is much faster and will almost never happen at this concurrency level.
# Concurrent/Contention tests: efcb5016a8a33a8f271ae9a5a527a0433ed727e4
% go test -bench=BenchmarkAllowConcurrent1 -benchmem -cpu 1,2,4,8
goos: darwin
goarch: amd64
pkg: github.com/szuecs/rate-limit-buffer
BenchmarkAllowConcurrent1 5000000 364 ns/op 15 B/op 1 allocs/op
BenchmarkAllowConcurrent1-2 5000000 319 ns/op 15 B/op 1 allocs/op
BenchmarkAllowConcurrent1-4 5000000 313 ns/op 15 B/op 1 allocs/op
BenchmarkAllowConcurrent1-8 5000000 332 ns/op 15 B/op 1 allocs/op
BenchmarkAllowConcurrent10 500000 3383 ns/op 159 B/op 19 allocs/op
BenchmarkAllowConcurrent10-2 500000 2204 ns/op 159 B/op 19 allocs/op
BenchmarkAllowConcurrent10-4 500000 3325 ns/op 159 B/op 19 allocs/op
BenchmarkAllowConcurrent10-8 500000 2582 ns/op 159 B/op 19 allocs/op
BenchmarkAllowConcurrent100 50000 34248 ns/op 1593 B/op 199 allocs/op
BenchmarkAllowConcurrent100-2 100000 21281 ns/op 1592 B/op 199 allocs/op
BenchmarkAllowConcurrent100-4 50000 36870 ns/op 1593 B/op 199 allocs/op
BenchmarkAllowConcurrent100-8 50000 35154 ns/op 1593 B/op 199 allocs/op
BenchmarkAllowConcurrent1000 5000 319270 ns/op 15928 B/op 1990 allocs/op
BenchmarkAllowConcurrent1000-2 10000 230893 ns/op 15936 B/op 1990 allocs/op
BenchmarkAllowConcurrent1000-4 5000 344456 ns/op 15946 B/op 1990 allocs/op
BenchmarkAllowConcurrent1000-8 3000 333466 ns/op 15996 B/op 1990 allocs/op
PASS
ok github.com/szuecs/rate-limit-buffer 42.174s
# Concurrent/Contention tests: 648a55836c24f8a3db74d710b666bbfa085cbe2a
% go test -bench=Allow -cpu 1,2,4,8 >old.txt
# Concurrent/Contention tests: 380fb9d6fe737f032ce3a1aa4f6881a60b10b273
% go test -bench=Allow -cpu 1,2,4,8 >new.txt
% benchcmp old.txt new.txt
benchmark old ns/op new ns/op delta
BenchmarkAllow 1475 1552 +5.22%
BenchmarkAllow-2 1317 1225 -6.99%
BenchmarkAllow-4 1488 1249 -16.06%
BenchmarkAllow-8 1289 1270 -1.47%
BenchmarkAllowBaseData1 368 316 -14.13%
BenchmarkAllowBaseData1-2 363 301 -17.08%
BenchmarkAllowBaseData1-4 326 299 -8.28%
BenchmarkAllowBaseData1-8 340 284 -16.47%
BenchmarkAllowBaseData10 339 334 -1.47%
BenchmarkAllowBaseData10-2 319 305 -4.39%
BenchmarkAllowBaseData10-4 311 298 -4.18%
BenchmarkAllowBaseData10-8 318 304 -4.40%
BenchmarkAllowBaseData100 357 335 -6.16%
BenchmarkAllowBaseData100-2 332 318 -4.22%
BenchmarkAllowBaseData100-4 336 320 -4.76%
BenchmarkAllowBaseData100-8 342 303 -11.40%
BenchmarkAllowBaseData1000 554 509 -8.12%
BenchmarkAllowBaseData1000-2 583 411 -29.50%
BenchmarkAllowBaseData1000-4 510 431 -15.49%
BenchmarkAllowBaseData1000-8 503 410 -18.49%
BenchmarkAllowConcurrent1 355 355 +0.00%
BenchmarkAllowConcurrent1-2 340 333 -2.06%
BenchmarkAllowConcurrent1-4 335 329 -1.79%
BenchmarkAllowConcurrent1-8 336 332 -1.19%
BenchmarkAllowConcurrent10 3836 3544 -7.61%
BenchmarkAllowConcurrent10-2 3042 1752 -42.41%
BenchmarkAllowConcurrent10-4 3604 1597 -55.69%
BenchmarkAllowConcurrent10-8 3675 1856 -49.50%
BenchmarkAllowConcurrent100 35028 35378 +1.00%
BenchmarkAllowConcurrent100-2 36003 19574 -45.63%
BenchmarkAllowConcurrent100-4 55464 16719 -69.86%
BenchmarkAllowConcurrent100-8 54492 17668 -67.58%
BenchmarkAllowConcurrent1000 389221 348280 -10.52%
BenchmarkAllowConcurrent1000-2 392405 197976 -49.55%
BenchmarkAllowConcurrent1000-4 849330 173836 -79.53%
BenchmarkAllowConcurrent1000-8 1017861 187116 -81.62%
BenchmarkAllowConcurrentAddDelete10 4174 3808 -8.77%
BenchmarkAllowConcurrentAddDelete10-2 3425 2167 -36.73%
BenchmarkAllowConcurrentAddDelete10-4 5709 1644 -71.20%
BenchmarkAllowConcurrentAddDelete10-8 5133 2141 -58.29%
v0.1.2 to v0.1.3
I fixed a race condition in high concurrent situations (go test -race -v -run=Massive .), which has a small impact on benchmarks. The system is slower under low concurrent with less CPUs and faster in high concurrent with more CPUs:
# Data collected with v0.1.2 and v0.1.3
% go test -bench=. -benchmem -cpu 1,2,4,8 | tee -a v0.1.3.txt
goos: linux
goarch: amd64
pkg: github.com/szuecs/rate-limit-buffer
# Data compare
% benchcmp -changed v0.1.2.txt v0.1.3.txt
benchmark old ns/op new ns/op delta
BenchmarkAllow 1433 1585 +10.61%
BenchmarkAllow-2 1334 1386 +3.90%
BenchmarkAllow-4 1317 1363 +3.49%
BenchmarkAllow-8 1262 1399 +10.86%
BenchmarkAllowBaseData1 340 353 +3.82%
BenchmarkAllowBaseData1-2 317 325 +2.52%
BenchmarkAllowBaseData1-4 320 338 +5.62%
BenchmarkAllowBaseData1-8 312 333 +6.73%
BenchmarkAllowBaseData10 340 355 +4.41%
BenchmarkAllowBaseData10-2 311 324 +4.18%
BenchmarkAllowBaseData10-4 312 333 +6.73%
BenchmarkAllowBaseData10-8 319 335 +5.02%
BenchmarkAllowBaseData100 344 353 +2.62%
BenchmarkAllowBaseData100-2 335 337 +0.60%
BenchmarkAllowBaseData100-4 401 333 -16.96%
BenchmarkAllowBaseData100-8 323 333 +3.10%
BenchmarkAllowBaseData1000 525 539 +2.67%
BenchmarkAllowBaseData1000-2 505 511 +1.19%
BenchmarkAllowBaseData1000-4 501 552 +10.18%
BenchmarkAllowBaseData1000-8 450 517 +14.89%
BenchmarkAllowConcurrent1 355 363 +2.25%
BenchmarkAllowConcurrent1-2 336 344 +2.38%
BenchmarkAllowConcurrent1-4 332 346 +4.22%
BenchmarkAllowConcurrent1-8 339 348 +2.65%
BenchmarkAllowConcurrent10 3575 3634 +1.65%
BenchmarkAllowConcurrent10-2 2165 2296 +6.05%
BenchmarkAllowConcurrent10-4 2163 1793 -17.11%
BenchmarkAllowConcurrent10-8 2148 1995 -7.12%
BenchmarkAllowConcurrent100 34943 35992 +3.00%
BenchmarkAllowConcurrent100-2 24132 22516 -6.70%
BenchmarkAllowConcurrent100-4 18392 18662 +1.47%
BenchmarkAllowConcurrent100-8 19484 19960 +2.44%
BenchmarkAllowConcurrent1000 338325 352712 +4.25%
BenchmarkAllowConcurrent1000-2 218878 234376 +7.08%
BenchmarkAllowConcurrent1000-4 184612 194888 +5.57%
BenchmarkAllowConcurrent1000-8 216032 215727 -0.14%
BenchmarkAllowConcurrentAddDelete10 3701 3687 -0.38%
BenchmarkAllowConcurrentAddDelete10-2 2428 2427 -0.04%
BenchmarkAllowConcurrentAddDelete10-4 1787 1812 +1.40%
BenchmarkAllowConcurrentAddDelete10-8 2059 2126 +3.25%
benchmark old bytes new bytes delta
BenchmarkAllow 128 143 +11.72%
BenchmarkAllow-2 127 143 +12.60%
BenchmarkAllow-4 127 143 +12.60%
BenchmarkAllow-8 127 143 +12.60%
BenchmarkAllowBaseData1000-8 21 24 +14.29%
BenchmarkAllowConcurrent100 1592 1593 +0.06%
BenchmarkAllowConcurrent1000-2 15928 15933 +0.03%
BenchmarkAllowConcurrent1000-8 16026 15973 -0.33%
Documentation
¶
Overview ¶
Package circularbuffer designed to be a solution for storing rate limit data as described in https://docs.google.com/document/d/19BqdCancXavg4dqrFey-brM-VWCoTvqMHS1Gmn_jsC0 and https://github.com/zalando/skipper/issues/424
Index ¶
- type CircularBuffer
- func (cb *CircularBuffer) Add(t time.Time) bool
- func (cb *CircularBuffer) Allow(ctx context.Context, s string) bool
- func (cb *CircularBuffer) Cap() int
- func (*CircularBuffer) Close()
- func (cb *CircularBuffer) Current(string) time.Time
- func (cb *CircularBuffer) Delta(string) time.Duration
- func (cb *CircularBuffer) Free() bool
- func (cb *CircularBuffer) InUse() bool
- func (cb *CircularBuffer) Len() int
- func (cb *CircularBuffer) Next() time.Time
- func (cb *CircularBuffer) Oldest(string) time.Time
- func (cb *CircularBuffer) Resize(_ string, n int)
- func (cb *CircularBuffer) RetryAfter(string) int
- type ClientRateLimiter
- func (rl *ClientRateLimiter) Allow(ctx context.Context, s string) bool
- func (rl *ClientRateLimiter) Close()
- func (rl *ClientRateLimiter) Current(s string) time.Time
- func (rl *ClientRateLimiter) DeleteOld()
- func (rl *ClientRateLimiter) Delta(s string) time.Duration
- func (rl *ClientRateLimiter) Oldest(s string) time.Time
- func (rl *ClientRateLimiter) Resize(s string, n int)
- func (rl *ClientRateLimiter) RetryAfter(s string) int
- type RateLimiter
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type CircularBuffer ¶
CircularBuffer has slots to store times as int64 and an offset, which marks the next free entry. Slots are fixed in size.
func NewCircularBuffer ¶
func NewCircularBuffer(l int, t time.Duration) *CircularBuffer
func (*CircularBuffer) Add ¶
func (cb *CircularBuffer) Add(t time.Time) bool
Add adds an element to the next free bucket in the buffer and returns true. It returns false if there is no free bucket. Example
[_ _ _ _]
^
[1 _ _ _]
^
[1 2 _ _]
^
[1 2 3 _]
^
[1 2 3 4]
^
func (*CircularBuffer) Allow ¶ added in v0.2.0
func (cb *CircularBuffer) Allow(ctx context.Context, s string) bool
Allow returns true if there is a free bucket and we should not rate limit, if not it will return false, which means ratelimit.
func (*CircularBuffer) Cap ¶
func (cb *CircularBuffer) Cap() int
func (*CircularBuffer) Close ¶ added in v0.2.0
func (*CircularBuffer) Close()
Close implements the RateLimiter interface to shutdown, nothing to do.
func (*CircularBuffer) Current ¶ added in v0.5.0
func (cb *CircularBuffer) Current(string) time.Time
Current implements the RateLimiter interface
func (*CircularBuffer) Delta ¶ added in v0.3.0
func (cb *CircularBuffer) Delta(string) time.Duration
Delta returns the diffence between the current and the oldest value in the buffer, i.e. maxHits / Delta() => rate
func (*CircularBuffer) Free ¶
func (cb *CircularBuffer) Free() bool
Free returns if there is space or the bucket is full for the current time. Example:
time.Now(): 5
timeWindow: 2
[1 2 3 4]
^
5-2 = 3 --> 2 free slots [1,2] are too old and are Free already
func (*CircularBuffer) InUse ¶
func (cb *CircularBuffer) InUse() bool
func (*CircularBuffer) Len ¶
func (cb *CircularBuffer) Len() int
func (*CircularBuffer) Next ¶ added in v0.5.0
func (cb *CircularBuffer) Next() time.Time
func (*CircularBuffer) Oldest ¶ added in v0.7.0
func (cb *CircularBuffer) Oldest(string) time.Time
Oldest implements the RateLimiter interface
func (*CircularBuffer) Resize ¶ added in v0.4.0
func (cb *CircularBuffer) Resize(_ string, n int)
Resize resizes the circular buffer to the given size. Resizing to a size <= 0 is not performed
func (*CircularBuffer) RetryAfter ¶ added in v0.5.0
func (cb *CircularBuffer) RetryAfter(string) int
RetryAfter returns how many seconds one should wait until the next request is allowed.
type ClientRateLimiter ¶ added in v0.2.0
ClientRateLimiter implements the RateLimiter interface and does rate limiting based on the the String passed to Allow(). This can be used to limit per client calls to the backend. For example you can slow down user enumeration or dictionary attacks to /login APIs.
func NewClientRateLimiter ¶ added in v0.2.0
func NewClientRateLimiter(maxHits int, d, cleanInterval time.Duration) *ClientRateLimiter
NewRateLimiter returns a new initialized RateLimitter with maxHits is the maximal number of hits per time.Duration d.
func (*ClientRateLimiter) Allow ¶ added in v0.2.0
func (rl *ClientRateLimiter) Allow(ctx context.Context, s string) bool
Allow tries to add s to a circularbuffer and returns true if we have a free bucket, if not it will return false, which means ratelimit with an additional context.Context.
func (*ClientRateLimiter) Close ¶ added in v0.2.0
func (rl *ClientRateLimiter) Close()
Close will stop the cleanup goroutine
func (*ClientRateLimiter) Current ¶ added in v0.6.0
func (rl *ClientRateLimiter) Current(s string) time.Time
func (*ClientRateLimiter) DeleteOld ¶ added in v0.2.0
func (rl *ClientRateLimiter) DeleteOld()
DeleteOld removes old entries from state bag
func (*ClientRateLimiter) Delta ¶ added in v0.3.0
func (rl *ClientRateLimiter) Delta(s string) time.Duration
Delta returns the diffence between the current and the oldest value in the buffer, i.e. maxHits / Delta() => rate
func (*ClientRateLimiter) Oldest ¶ added in v0.7.0
func (rl *ClientRateLimiter) Oldest(s string) time.Time
func (*ClientRateLimiter) Resize ¶ added in v0.4.0
func (rl *ClientRateLimiter) Resize(s string, n int)
Resize resizes the given circular buffer to the given size. Resizing to a size <= 0 is not performed
func (*ClientRateLimiter) RetryAfter ¶ added in v0.5.0
func (rl *ClientRateLimiter) RetryAfter(s string) int
RetryAfter returns how many seconds one should wait until the next request is allowed.
type RateLimiter ¶
type RateLimiter interface {
// Allow is used to get a decision if you should allow the
// call with context to pass or to ratelimit
Allow(context.Context, string) bool
// Close cleans up the RateLimiter implementation.
Close()
Oldest(string) time.Time
Delta(string) time.Duration
Resize(string, int)
// RetryAfter returns how many seconds until the next allowed request
RetryAfter(string) int
}
RateLimiter is an interface which can be used to implement rate limiting.
func NewRateLimiter ¶
func NewRateLimiter(maxHits int, d time.Duration) RateLimiter
NewRateLimiter returns a new initialized RateLimitter with maxHits as the maximal number of hits per time.Duration d. This can be used to implement maximum number of requests for a backend to protect from a known scaling limit.
Source Files