53 lines
1.3 KiB
Go
53 lines
1.3 KiB
Go
// Package dedup provides idempotent event acceptance via Redis SETNX.
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//
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// Key shape: dedup:{workspace_id}:{message_id}
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// TTL: 24h by default (configurable)
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//
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// CheckAndSet returns true when the message_id is new (first time seen).
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// If it returns false the caller MUST drop the event silently and return 200.
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package dedup
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import (
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"context"
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"fmt"
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"time"
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"github.com/redis/rueidis"
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)
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type Dedup interface {
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CheckAndSet(ctx context.Context, workspaceID, messageID string) (bool, error)
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}
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type redisDedup struct {
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client rueidis.Client
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ttl time.Duration
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}
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func New(client rueidis.Client, ttl time.Duration) Dedup {
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return &redisDedup{client: client, ttl: ttl}
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}
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func key(workspaceID, messageID string) string {
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return fmt.Sprintf("dedup:%s:%s", workspaceID, messageID)
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}
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func (d *redisDedup) CheckAndSet(ctx context.Context, workspaceID, messageID string) (bool, error) {
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k := key(workspaceID, messageID)
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cmd := d.client.B().Set().Key(k).Value("1").
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Nx().
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Ex(d.ttl).
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Build()
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resp := d.client.Do(ctx, cmd)
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err := resp.Error()
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// SET NX returns nil reply when the key already exists; rueidis surfaces
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// that as a "redis nil" error, which is *not* a real failure.
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if rueidis.IsRedisNil(err) {
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return false, nil
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}
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if err != nil {
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return false, fmt.Errorf("dedup setnx: %w", err)
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}
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return true, nil
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}
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