tasks.py

# -*- coding: utf-8 -*-
from app import create_app
from flask_mailman import EmailMessage
from smtplib import SMTPRecipientsRefused
from smtplib import SMTPServerDisconnected
from smtplib import SMTPDataError
from json.decoder import JSONDecodeError

import logging
import time
import requests

app = create_app()
app.app_context().push()


logger = logging.getLogger("[QUEUE]")


def background_task(
    channel_url, text, subscribers, subject, mfrom, send_uid, attachments=[]
):
    logger.info(
        'Start send "{subject}" to {subscribers} recipients through channel "{channel}".'.format(  #  noqa
            subject=subject, subscribers=len(subscribers), channel=channel_url
        )
    )
    max_retries = 3  # Numero massimo di tentativi
    for i, mto in enumerate(subscribers):
        attempt = 0  # Contatore dei tentativi
        while attempt < max_retries:
            try:
                attempt += 1
                with app.mail.get_connection() as conn:
                    msg = EmailMessage(
                        from_email=mfrom,
                        to=[mto],
                        body=text,
                        subject=subject,
                        connection=conn,
                    )
                    msg.content_subtype = "html"
                    for attachment in attachments:
                        msg.attach(
                            filename=attachment.get("filename", ""),
                            content=attachment.get("data", ""),
                            mimetype=attachment.get("content_type", ""),
                        )
                    try:
                        msg.send()
                    except SMTPRecipientsRefused:
                        logger.info("[SKIP] - {}: invalid address.".format(mto))
                    if (i + 1) % 1000 == 0:
                        logger.info(
                            "- Sending status: {}/{}".format(i + 1, len(subscribers))
                        )
                break
            except (SMTPServerDisconnected, SMTPDataError) as e:
                logger.error(f"Message not sent to {mto} for problems with smtp:")
                logger.exception(e)
                logger.error(
                    f"waiting 5 seconds before retry. Remaining attempts: {max_retries - attempt}\n"
                )
                time.sleep(5)
            except Exception as e:
                logger.error(f"Message not sent to {mto}:")
                logger.exception(e)
                logger.error(
                    f"waiting 5 seconds before retry. Remaining attempts: {max_retries - attempt}\n"
                )
                time.sleep(5)
        else:
            logger.error(f"Message not sent: no more attempts. Stop sending messages.")
            logger.error("Following addresses didn't received the message:")
            for mto in subscribers[i:]:
                logger.error(f"- {mto}")
            send_complete(channel_url=channel_url, send_uid=send_uid, error=True)
            return
    send_complete(channel_url=channel_url, send_uid=send_uid)
    logger.info("Task complete.")


def send_complete(channel_url, send_uid, error=None):
    if not send_uid:
        return
    url = "{}/@send-complete".format(channel_url)
    data = {"send_uid": send_uid}
    if error:
        data["error"] = error
    res = requests.post(
        url,
        headers={
            "Accept": "application/json",
            "Content-Type": "application/json",
        },
        json=data,
    )
    if res.status_code != 204:
        logger.error(
            'Unable to update status to remote: received "{code}" instead a "204".'.format(  # noqa
                code=res.status_code
            )
        )
        logger.error("Called url: {}.".format(url))
        logger.error("Parameters: {}.".format(data))
        try:
            logger.error("Error: {}.".format(res.json()))
        except JSONDecodeError:
            logger.error("Error: {}.".format(res.text))