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fix: truncated window rate limits #7

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Merged
sonirico merged 1 commit into from
Nov 8, 2022
Merged

fix: truncated window rate limits #7

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37 changes: 20 additions & 17 deletions limiter_fixed_truncated_window.go
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Original file line number Diff line number Diff line change
Expand Up @@ -38,7 +38,7 @@ type FixedTruncatedWindowRateLimiter struct {

mu sync.Mutex

rate time.Duration
rate Rate
window time.Time
capacity int64
rateLimitReached bool
Expand All @@ -63,14 +63,21 @@ func (l *FixedTruncatedWindowRateLimiter) Check(ctx context.Context) (Result, er
}

func (l *FixedTruncatedWindowRateLimiter) Dump(ctx context.Context) (r Result, err error) {
l.mu.Lock()
defer l.mu.Unlock()

now := l.clock.Now()
window := now.Truncate(l.rate)

c, err := l.db.Get(ctx, window)
if TimeGTE(l.window.Add(l.rate.Duration()), now) {
l.rateLimitReached = false
l.window = now.Truncate(l.rate.Unit)
}

c, err := l.db.Get(ctx, l.window)

if c >= l.capacity {
// rate limit exceeded
r = res(l.rate-now.Sub(window), l.capacity-c)
r = res(l.window.Add(l.rate.Duration()).Sub(now), l.capacity-c)
} else {
r = res(0, l.capacity-c)
}
Expand All @@ -89,21 +96,19 @@ func (l *FixedTruncatedWindowRateLimiter) try(ctx context.Context, tokens int64)

now := l.clock.Now()

window := now.Truncate(l.rate)

if !l.window.Equal(window) {
if TimeGTE(l.window.Add(l.rate.Duration()), now) {
l.rateLimitReached = false
l.window = window
l.window = now.Truncate(l.rate.Unit)
}

ttw := l.rate - now.Sub(window)
ttw := l.window.Add(l.rate.Duration()).Sub(now)

if l.rateLimitReached {
return res(ttw, 0), ErrRateLimitExceeded
}

c, err := l.db.Inc(ctx, FixedWindowIncArgs{
Window: window,
Window: l.window,
Tokens: tokens,
Capacity: l.capacity,
TTL: ttw,
Expand Down Expand Up @@ -134,22 +139,20 @@ func (l *FixedTruncatedWindowRateLimiter) check(ctx context.Context, tokens int6

now := l.clock.Now()

window := now.Truncate(l.rate)

if !l.window.Equal(window) {
if TimeGTE(l.window.Add(l.rate.Duration()), now) {
// new window so no rate Limit
l.rateLimitReached = false
l.window = window
l.window = now.Truncate(l.rate.Unit)
return res(0, l.capacity), nil
}

ttw := l.rate - now.Sub(window)
ttw := l.window.Add(l.rate.Duration()).Sub(now)

if l.rateLimitReached {
return res(ttw, 0), ErrRateLimitExceeded
}

c, err := l.db.Get(ctx, window)
c, err := l.db.Get(ctx, l.window)

if err != nil {
return nores, err
Expand Down Expand Up @@ -177,7 +180,7 @@ func NewFixedTruncatedWindowRateLimiter(
) *FixedTruncatedWindowRateLimiter {
return &FixedTruncatedWindowRateLimiter{
capacity: args.Capacity,
rate: args.Rate.Duration(),
rate: args.Rate,
clock: args.Clock,
db: args.DB,
rateLimitReached: false,
Expand Down
48 changes: 24 additions & 24 deletions limiter_fixed_truncated_window_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -158,15 +158,15 @@ func TestNewFixedTruncatedWindowRateLimiter(t *testing.T) {
},
{
method: check,
passTime: 0,
passTime: time.Second,
expectedErr: ErrRateLimitExceeded,
expectedTtw: time.Second * 4,
expectedTtw: time.Second * 10,
expectedFreeSlots: 0,
},
{
method: try,
passTime: 0,
expectedTtw: time.Second * 4,
expectedTtw: time.Second * 9,
expectedErr: ErrRateLimitExceeded,
expectedFreeSlots: 0,
},
Expand Down Expand Up @@ -201,10 +201,10 @@ func TestNewFixedTruncatedWindowRateLimiter(t *testing.T) {
},
{
method: check,
passTime: 0,
expectedErr: nil,
expectedFreeSlots: 2,
expectedTtw: 0,
passTime: time.Second * 7,
expectedErr: ErrRateLimitExceeded,
expectedFreeSlots: 0,
expectedTtw: time.Second * 7,
},
{
method: try,
Expand Down Expand Up @@ -256,42 +256,42 @@ func TestNewFixedTruncatedWindowRateLimiter(t *testing.T) {
expectedFreeSlots: 0,
expectedErr: nil,
},
// Rate Limit is reached and 1 second passes...
{
method: check,
passTime: 0,
expectedErr: ErrRateLimitExceeded,
expectedFreeSlots: 0,
expectedTtw: time.Second * 2,
expectedTtw: time.Second * 10,
},
// Rate Limit is reached and 1 second passes...
{
method: try,
passTime: time.Second,
expectedTtw: time.Second * 2,
expectedTtw: time.Second * 10,
expectedErr: ErrRateLimitExceeded,
expectedFreeSlots: 0,
},
{
method: check,
passTime: 0,
expectedErr: ErrRateLimitExceeded,
expectedTtw: time.Second,
expectedTtw: time.Second * 9,
expectedFreeSlots: 0,
},
// Rate limit is still held. Moving 2 seconds and getting into next window
{
method: try,
passTime: time.Second * 2,
expectedTtw: time.Second,
expectedTtw: time.Second * 9,
expectedErr: ErrRateLimitExceeded,
expectedFreeSlots: 0,
},
{
method: check,
passTime: 0,
expectedErr: nil,
expectedTtw: 0,
expectedFreeSlots: 2,
passTime: time.Second * 7,
expectedErr: ErrRateLimitExceeded,
expectedTtw: time.Second * 7,
expectedFreeSlots: 0,
},
// Requests check be made again
{
Expand Down Expand Up @@ -346,24 +346,24 @@ func TestNewFixedTruncatedWindowRateLimiter(t *testing.T) {
},
{
method: dump,
passTime: 0,
passTime: time.Second * 2,
expectedErr: nil,
expectedFreeSlots: 0,
expectedTtw: time.Second * 2,
expectedTtw: time.Second * 10,
},
{
method: try,
passTime: 0,
expectedTtw: time.Second * 2,
passTime: time.Second * 8,
expectedTtw: time.Second * 8,
expectedFreeSlots: 0,
expectedErr: ErrRateLimitExceeded,
},
{
method: dump,
passTime: 0,
expectedErr: nil,
expectedFreeSlots: 0,
expectedTtw: time.Second * 2,
expectedFreeSlots: 2,
expectedTtw: 0,
},
},
},
Expand Down Expand Up @@ -403,10 +403,10 @@ func TestNewFixedTruncatedWindowRateLimiter(t *testing.T) {
},
{
method: dump,
passTime: time.Second * 2,
passTime: time.Second * 10,
expectedErr: nil,
expectedFreeSlots: 0,
expectedTtw: time.Second * 2,
expectedTtw: time.Second * 10,
},
{
method: dump,
Expand Down
27 changes: 12 additions & 15 deletions limiter_token_fixed_window_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -173,7 +173,7 @@ func TestNewTokenFixedWindowRateLimiter_WindowTruncated(t *testing.T) {
method: check,
forwardAfter: 0,
expectedFreeSlots: 6,
expectedTtw: time.Second * 4,
expectedTtw: time.Second * 10,
expectedErr: ErrRateLimitExceeded,
requestTokens: 20,
},
Expand All @@ -182,14 +182,14 @@ func TestNewTokenFixedWindowRateLimiter_WindowTruncated(t *testing.T) {
requestTokens: 7, // 21 -> Rate Limit!
forwardAfter: 0,
expectedFreeSlots: 0,
expectedTtw: time.Second * 4,
expectedTtw: time.Second * 10,
expectedErr: ErrRateLimitExceeded,
},
{
method: check,
forwardAfter: 0,
expectedFreeSlots: 0,
expectedTtw: time.Second * 4,
expectedTtw: time.Second * 10,
expectedErr: ErrRateLimitExceeded,
requestTokens: 1,
},
Expand Down Expand Up @@ -227,8 +227,8 @@ func TestNewTokenFixedWindowRateLimiter_WindowTruncated(t *testing.T) {
},
{
method: try,
requestTokens: 1, // 2
forwardAfter: time.Second * 2, // 2022-02-05 00:00:11
requestTokens: 1,
forwardAfter: time.Second * 9, // now it's 2022-02-05 00:00:09
expectedFreeSlots: 0,
expectedTtw: 0, // TODO(@sonirico): Should this be zero?
expectedErr: nil,
Expand All @@ -252,7 +252,7 @@ func TestNewTokenFixedWindowRateLimiter_WindowTruncated(t *testing.T) {
method: check,
forwardAfter: 0,
expectedFreeSlots: 0,
expectedTtw: time.Second * 9,
expectedTtw: time.Second * 10,
expectedErr: ErrRateLimitExceeded,
requestTokens: 1,
},
Expand Down Expand Up @@ -301,33 +301,31 @@ func TestNewTokenFixedWindowRateLimiter_WindowTruncated(t *testing.T) {
forwardAfter: 0,
expectedFreeSlots: 2,
expectedErr: ErrRateLimitExceeded,
expectedTtw: time.Second * 2,
expectedTtw: time.Second * 10,
requestTokens: 3,
},
// Rate Limit is reached and 1 second passes...
{
method: try,
requestTokens: 3, // 11
forwardAfter: time.Second,
expectedFreeSlots: 0,
expectedTtw: time.Second * 2,
expectedTtw: time.Second * 10,
expectedErr: ErrRateLimitExceeded,
},
{
method: check,
forwardAfter: 0,
expectedFreeSlots: 0,
expectedTtw: time.Second,
expectedTtw: time.Second * 9,
expectedErr: ErrRateLimitExceeded,
requestTokens: 1,
},
// Rate limit is still held. Moving 2 seconds and getting into next window
{
method: try,
requestTokens: 3, // 11
forwardAfter: time.Second * 2,
forwardAfter: time.Second * 9,
expectedFreeSlots: 0,
expectedTtw: time.Second,
expectedTtw: time.Second * 9,
expectedErr: ErrRateLimitExceeded,
},
{
Expand All @@ -338,7 +336,6 @@ func TestNewTokenFixedWindowRateLimiter_WindowTruncated(t *testing.T) {
expectedErr: nil,
requestTokens: 1,
},
// Requests check be made again
{
method: try,
requestTokens: 3, // 3
Expand Down Expand Up @@ -392,7 +389,7 @@ func TestNewTokenFixedWindowRateLimiter_WindowTruncated(t *testing.T) {
{
method: dump,
expectedFreeSlots: 0,
expectedTtw: time.Second * 2,
expectedTtw: time.Second * 10,
expectedErr: nil,
},
},
Expand Down
33 changes: 22 additions & 11 deletions tests/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -20,35 +20,46 @@ func main() {
redisCli := redis.NewClient(redisOpts)

rateLimit :=
pacemaker.NewFixedWindowRateLimiter(
pacemaker.FixedWindowArgs{
pacemaker.NewFixedTruncatedWindowRateLimiter(
pacemaker.FixedTruncatedWindowArgs{
Capacity: 1200,
Rate: pacemaker.Rate{
Unit: time.Hour,
Amount: 1,
Unit: time.Minute,
Amount: 3,
},
Clock: pacemaker.NewClock(),
DB: pacemaker.NewFixedWindowRedisStorage(
redisCli,
pacemaker.FixedWindowRedisStorageOpts{
Prefix: "pacemaker",
Prefix: "pacemaker-test-marcos-2",
},
),
},
)

result, err := rateLimit.Try(ctx)
result, err := rateLimit.Dump(ctx)

if err != nil {
log.Printf("error dump: '%v'", err)
}

log.Printf("Dump Result: '%v'", result)

result, err = rateLimit.Try(ctx)
if err != nil {
log.Printf("error try: '%v'", err)
}

log.Printf("Try Result: '%v'", result)

result, err = rateLimit.Dump(ctx)
for {
time.Sleep(time.Second)
result, err = rateLimit.Dump(ctx)

if err != nil {
log.Printf("error dump: '%v'", err)
}
if err != nil {
log.Printf("error dump: '%v'", err)
}

log.Printf("Dump Result: '%v'", result)
log.Printf("Dump Result: '%v'", result)
}
}
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