NotAShelf
c3b77696aa
...also adds a bounded custom event registry for cardinality control but I ran out of space in the commit message. Praise be to the long descriptions... Signed-off-by: NotAShelf <raf@notashelf.dev> Change-Id: Ic205f69804c7fb24c39fa84abdd9546b6a6a6964
53 lines
1.1 KiB
Go
53 lines
1.1 KiB
Go
package ratelimit
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import (
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"sync"
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"time"
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)
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// Implements a simple token bucket rate limiter
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type TokenBucket struct {
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mu sync.Mutex
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tokens int
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capacity int
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refill int
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interval time.Duration
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lastFill time.Time
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}
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// Creates a rate limiter with specified capacity and refill rate capacity
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func NewTokenBucket(capacity, refillPerInterval int, interval time.Duration) *TokenBucket {
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return &TokenBucket{
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tokens: capacity,
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capacity: capacity,
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refill: refillPerInterval,
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interval: interval,
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lastFill: time.Now(),
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}
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}
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// Allow checks if a request should be allowed
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func (tb *TokenBucket) Allow() bool {
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tb.mu.Lock()
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defer tb.mu.Unlock()
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// Refill tokens based on elapsed time
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now := time.Now()
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elapsed := now.Sub(tb.lastFill)
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if elapsed >= tb.interval {
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periods := int(elapsed / tb.interval)
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tb.tokens += periods * tb.refill
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if tb.tokens > tb.capacity {
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tb.tokens = tb.capacity
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}
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tb.lastFill = now.Add(-elapsed % tb.interval)
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}
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// Check if we have tokens available
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if tb.tokens > 0 {
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tb.tokens--
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return true
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}
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return false
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}
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