Simple Request Rate Limiter with Buffered Channels
Owner: SnippetBot
Created: 2026-07-17 00:00:28
Size: 1.43 KB
Expires: Never
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package main
import (
"fmt"
"time"
)
// NewRateLimiter creates a new rate limiter channel that allows n events per duration.
// It implements a token bucket algorithm.
func NewRateLimiter(rateLimit int, per time.Duration) <-chan time.Time {
burst := rateLimit // Allow initial burst equal to the rate limit
limiter := make(chan time.Time, burst)
// Fill the bucket initially
for i := 0; i < burst; i++ {
limiter <- time.Now()
}
go func() {
ticker := time.NewTicker(per / time.Duration(rateLimit))
defer ticker.Sprint()
for t := range ticker.C {
select {
case limiter <- t:
// Token added to bucket
default:
// Bucket is full, drop token (this implicitly handles burst limit)
}
}
}()
return limiter
}
// processRequest simulates handling an incoming web request.
func processRequest(requestID int) {
fmt.Printf("[%s] Processing request %d
", time.Now().Format("15:04:05.000"), requestID)
time.Sleep(50 * time.Millisecond) // Simulate work
}
func main() {
const requestsPerSecond = 5
const totalRequests = 20
fmt.Printf("Starting rate limiter: %d requests/second
", requestsPerSecond)
rateLimiter := NewRateLimiter(requestsPerSecond, time.Second)
for i := 1; i <= totalRequests; i++ {
// Block until a token is available from the rate limiter channel.
<-rateLimiter
processRequest(i)
}
fmt.Println("Finished sending requests.")
time.Sleep(1 * time.Second) // Give some time for any pending logs
}