146 lines
3.4 KiB
Go
146 lines
3.4 KiB
Go
package events
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import (
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"context"
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"fmt"
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"log"
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"strings"
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"sync"
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"time"
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"github.com/redis/go-redis/v9"
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)
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const (
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// MetaEventsStream is the Redis stream name for metadata events
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MetaEventsStream = "meta:events"
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)
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// MetaPublisher subscribes to Redis keyspace notifications
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// and publishes metadata change events to the meta:events stream
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type MetaPublisher struct {
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client *redis.Client
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ctx context.Context
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cancel context.CancelFunc
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wg sync.WaitGroup
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running bool
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mu sync.RWMutex
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}
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// NewMetaPublisher creates a new MetaPublisher
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func NewMetaPublisher(client *redis.Client) *MetaPublisher {
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ctx, cancel := context.WithCancel(context.Background())
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return &MetaPublisher{
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client: client,
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ctx: ctx,
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cancel: cancel,
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}
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}
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// Start begins subscribing to keyspace notifications
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func (p *MetaPublisher) Start() error {
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p.mu.Lock()
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if p.running {
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p.mu.Unlock()
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return nil
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}
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p.running = true
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p.mu.Unlock()
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// Clear the stream on startup - consumers will re-bootstrap from Redis keys
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// This ensures the stream only contains events from the current session
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ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancel()
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if err := p.client.Del(ctx, MetaEventsStream).Err(); err != nil {
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log.Printf("[MetaPublisher] Warning: failed to clear stream on startup: %v", err)
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} else {
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log.Printf("[MetaPublisher] Cleared %s stream for fresh start", MetaEventsStream)
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}
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p.wg.Add(1)
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go p.subscribeLoop()
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log.Println("[MetaPublisher] Started - listening for keyspace notifications")
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return nil
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}
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// Stop stops the publisher
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func (p *MetaPublisher) Stop() error {
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p.mu.Lock()
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if !p.running {
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p.mu.Unlock()
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return nil
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}
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p.running = false
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p.mu.Unlock()
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p.cancel()
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p.wg.Wait()
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log.Println("[MetaPublisher] Stopped")
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return nil
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}
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// IsRunning returns true if the publisher is running
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func (p *MetaPublisher) IsRunning() bool {
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p.mu.RLock()
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defer p.mu.RUnlock()
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return p.running
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}
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// subscribeLoop subscribes to keyspace notifications and publishes events
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func (p *MetaPublisher) subscribeLoop() {
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defer p.wg.Done()
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// Subscribe to all file:* keyspace events
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// Pattern: __keyspace@0__:file:*
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pattern := "__keyspace@0__:file:*"
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pubsub := p.client.PSubscribe(p.ctx, pattern)
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defer pubsub.Close()
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log.Printf("[MetaPublisher] Subscribed to pattern: %s", pattern)
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ch := pubsub.Channel()
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for {
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select {
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case <-p.ctx.Done():
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return
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case msg := <-ch:
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if msg == nil {
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continue
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}
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// msg.Channel: __keyspace@0__:file:midhash256:abc123/tmdb
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// msg.Payload: set, del, expire, etc.
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p.publishEvent(msg.Channel, msg.Payload)
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}
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}
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}
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// publishEvent publishes a keyspace event to the meta:events stream
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func (p *MetaPublisher) publishEvent(channel, operation string) {
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// Extract key from channel: __keyspace@0__:file:xxx/field -> file:xxx/field
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key := strings.TrimPrefix(channel, "__keyspace@0__:")
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// Skip index key and non-file keys
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if strings.Contains(key, "__index__") || !strings.HasPrefix(key, "file:") {
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return
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}
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// Build event fields
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fields := map[string]interface{}{
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"type": operation, // "set", "del", "expire"
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"key": key, // "file:midhash256:abc123/tmdb"
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"ts": fmt.Sprintf("%d", time.Now().UnixMilli()),
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}
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// Add to stream (no MaxLen - stream is cleared on meta-core restart)
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_, err := p.client.XAdd(p.ctx, &redis.XAddArgs{
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Stream: MetaEventsStream,
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Values: fields,
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}).Result()
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if err != nil {
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log.Printf("[MetaPublisher] Error publishing event: %v", err)
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}
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}
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