Gorm What is the correct way to lock when using FirstOrCreate?

What is the correct way to lock when using FirstOrCreate?

Hi, I'm using FirstOrCreate in order to perform a pretty standard upsert operation. It seems that its implementation doesn't lock the involved table (at least from what it looks like here), so I was wondering, what is the correct syntax to use to perform locking (specifically for postgres, but it'd be great writing this at a higher abstraction level so that I don't couple the code with the dbms).

Right now I'm using a very hackish workaround that looks like:

func upsertModelWithRetry(name string, retry bool) (*Model, error) {
    obj := Model{
        Name: name,
    }

    if res := db.Where(Model{Name: name}).Assign(obj).FirstOrCreate(&obj); res.Error != nil {
        if retry && strings.Contains(res.Error.Error(), "duplicate key value violates unique constraint") {
            // don't retry a second time in order to avoid recursion
            return upsertModelWithRetry(name, false)
        } else {
            return nil, res.Error
        }
    }

    return &dev, nil
}

func UpsertModel(name string) (*Model, error) {
    return upsertModelWithRetry(name, true)
}

The document you expected this should be explained

https://gorm.io/docs/advanced_query.html#FirstOrCreate

Expected answer

Code snippet or link to some related documentation would be great, thanks :)

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