migrate from github

pkg/lock/redis_lock.go

@@ -0,0 +1,58 @@
+package lock
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/XingfenD/yoresee_doc/pkg/errs"
+	"github.com/XingfenD/yoresee_doc/pkg/storage"
+)
+
+// distributed lock, depredated by usage of singleflight
+type DistributedLock struct {
+	key        string
+	value      string
+	expiration time.Duration
+}
+
+func NewDistributedLock(key string, expiration time.Duration) *DistributedLock {
+	return &DistributedLock{
+		key:        key,
+		value:      fmt.Sprintf("%d", time.Now().UnixNano()),
+		expiration: expiration,
+	}
+}
+
+func (dl *DistributedLock) Lock(ctx context.Context) error {
+	success, err := storage.SetNX(ctx, dl.key, dl.value, dl.expiration)
+	if err != nil {
+		return err
+	}
+	if !success {
+		return errs.Detail(errs.ErrLockAcquireFailed, dl.key)
+	}
+	return nil
+}
+
+func (dl *DistributedLock) TryLock(ctx context.Context) (bool, error) {
+	return storage.SetNX(ctx, dl.key, dl.value, dl.expiration)
+}
+
+func (dl *DistributedLock) Unlock(ctx context.Context) error {
+	script := `
+		if redis.call("get", KEYS[1]) == ARGV[1] then
+			return redis.call("del", KEYS[1])
+		else
+			return 0
+		end
+	`
+	result, err := storage.GetRedis().Eval(ctx, script, []string{dl.key}, dl.value).Result()
+	if err != nil {
+		return err
+	}
+	if result.(int64) == 0 {
+		return errs.Detail(errs.ErrLockNotHeld, dl.key)
+	}
+	return nil
+}