What to use for email parsing?

Question

Python

Hey!
Perhaps you have already encountered this, but this is my first time, tell me what to read and which way to go.
I have a VDS server. on it there is a domain and the e-mail server is organized. To view the mail, I screwed biz.mail.ru there.
Now, I have a task so that when a letter arrives at a certain mail, a bot in the telegram group writes a message. There are no problems with the bot, I can do it. The question is how to receive a new letter.
I have a couple of ideas so far.
The first is to use a simple python script to parse the number of letters in the mailbox via pop3, but here you need to set cron to, for example, every minute. Firstly, this is a so-so idea, and secondly, I would like to receive information about a new letter faster than within a minute.
The second is callbacks. However, here I don’t know how to approach this, how to set it up, and are there any callbacks for such a task at all?
The third one is essentially the same as the first one, but in an endless loop, which is also not very good for the server, I think.

What other options, where to dig and what to read?

Answer 1

Since you have a separate user for this, you can add a line like
username: "|/usr/local/bin/processmail.php" to /etc/aliases,
so the body of the letter with all the headers for the username user will be sent through the pipe to the script / usr/local/bin/processmail.php