43 lines
1.3 KiB
Go
43 lines
1.3 KiB
Go
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package repository
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import (
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"context"
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"time"
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"github.com/Wei-Shaw/sub2api/internal/service"
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"github.com/redis/go-redis/v9"
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)
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const leaderLockKeyPrefix = "leader:lock:"
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// leaderLockReleaseScript releases a leader lock only when the caller still owns
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// it (compare-and-delete by owner token). This prevents a previous holder whose
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// lock already expired — and was re-acquired by another instance — from deleting
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// the new owner's lock.
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var leaderLockReleaseScript = redis.NewScript(`
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if redis.call("GET", KEYS[1]) == ARGV[1] then
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return redis.call("DEL", KEYS[1])
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end
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return 0
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`)
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type leaderLockCache struct {
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rdb *redis.Client
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}
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// NewLeaderLockCache returns a Redis-backed implementation of
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// service.LeaderLockCache used by periodic background jobs to elect a single
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// runner across instances.
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func NewLeaderLockCache(rdb *redis.Client) service.LeaderLockCache {
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return &leaderLockCache{rdb: rdb}
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}
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func (c *leaderLockCache) TryAcquireLeaderLock(ctx context.Context, key, owner string, ttl time.Duration) (bool, error) {
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return c.rdb.SetNX(ctx, leaderLockKeyPrefix+key, owner, ttl).Result()
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}
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func (c *leaderLockCache) ReleaseLeaderLock(ctx context.Context, key, owner string) error {
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return leaderLockReleaseScript.Run(ctx, c.rdb, []string{leaderLockKeyPrefix + key}, owner).Err()
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}
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