在Go中使用交易

Question

When a user registers, my app does two things - it adds the user to the database and it sends a verification email:

...
err := collection("users").Insert(&u);
if err != nil {
    WriteServerError(w, err)
    return
}

if err = sendVerificationEmail(&u); err != nil {
    WriteServerError(w, err)
}
...

I wouldn't want to add the user to the database if the email does not get sent nor would I want to send the email if the user didn't get added to the database (the latter is of course taken care of with the code blocks in this order).

Assuming Go supports transactions, is it worth bothering with for something like this? If so then could someone give me some pointers as to how I would convert this code above?

I could use nested statements but this could get very ugly.

Answer 1

There is no "transaction" in Go. The better you can do is to take the steps in the right order:

1. Insert the user in the database
2. If the insertion failed, return
3. Send the email
4. If the email failed, remove the user

That said, generally speaking, there is no need to go to step 4. The common approach to this problem is to have a "I didn't get the verification email, please send another." button somewhere along your registration/login pages. You can't even be sure that your email arrived even if you sent it correctly: it could be filtered by the anti-spam, deleted by a missclick, etc.