43 lines
1.2 KiB
Go
43 lines
1.2 KiB
Go
package g8
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import (
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"sync"
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"time"
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)
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// RateLimiter is a fixed rate limiter
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type RateLimiter struct {
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maximumExecutionsPerSecond int
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executionsLeftInWindow int
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windowStartTime time.Time
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mutex sync.Mutex
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}
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// NewRateLimiter creates a RateLimiter
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func NewRateLimiter(maximumExecutionsPerSecond int) *RateLimiter {
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return &RateLimiter{
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windowStartTime: time.Now(),
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executionsLeftInWindow: maximumExecutionsPerSecond,
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maximumExecutionsPerSecond: maximumExecutionsPerSecond,
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}
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}
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// Try updates the number of executions if the rate limit quota hasn't been reached and returns whether the
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// attempt was successful or not.
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//
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// Returns false if the execution was not successful (rate limit quota has been reached)
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// Returns true if the execution was successful (rate limit quota has not been reached)
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func (r *RateLimiter) Try() bool {
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r.mutex.Lock()
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defer r.mutex.Unlock()
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if time.Now().Add(-time.Second).After(r.windowStartTime) {
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r.windowStartTime = time.Now()
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r.executionsLeftInWindow = r.maximumExecutionsPerSecond
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}
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if r.executionsLeftInWindow == 0 {
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return false
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}
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r.executionsLeftInWindow--
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return true
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}
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