73 lines
1.2 KiB
Go
73 lines
1.2 KiB
Go
package mqttforward
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import (
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"crypto/sha256"
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"encoding/hex"
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"sync"
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"time"
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)
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const dedupTTL = 15 * time.Second
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type DedupQueue struct {
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mu sync.Mutex
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entries map[string]time.Time
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stopCh chan struct{}
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}
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func NewDedupQueue() *DedupQueue {
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return &DedupQueue{
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entries: make(map[string]time.Time),
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stopCh: make(chan struct{}),
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}
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}
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func (dq *DedupQueue) TryForward(topic string, payload []byte) bool {
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hash := dedupHash(topic, payload)
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now := time.Now()
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dq.mu.Lock()
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defer dq.mu.Unlock()
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if expiry, ok := dq.entries[hash]; ok && now.Before(expiry) {
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return false
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}
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dq.entries[hash] = now.Add(dedupTTL)
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return true
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}
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func (dq *DedupQueue) Start() {
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go func() {
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ticker := time.NewTicker(dedupTTL)
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defer ticker.Stop()
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for {
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select {
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case <-ticker.C:
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dq.cleanup()
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case <-dq.stopCh:
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return
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}
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}
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}()
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}
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func (dq *DedupQueue) Stop() {
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close(dq.stopCh)
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}
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func (dq *DedupQueue) cleanup() {
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now := time.Now()
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dq.mu.Lock()
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defer dq.mu.Unlock()
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for hash, expiry := range dq.entries {
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if now.After(expiry) {
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delete(dq.entries, hash)
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}
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}
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}
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func dedupHash(topic string, payload []byte) string {
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h := sha256.New()
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h.Write([]byte(topic))
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h.Write(payload)
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return hex.EncodeToString(h.Sum(nil))
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}
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