notifications-api/app/celery/process_ses_receipts_tasks.py

import enum
from datetime import datetime, timedelta
from json import decoder

import iso8601
import requests
import traceback
from celery.exceptions import Retry
from flask import Blueprint, current_app, json, jsonify, request
from sqlalchemy.orm.exc import NoResultFound

from app import notify_celery, statsd_client, redis_store
from app.celery.validate_sns import validate_sns_message
from app.config import QueueNames
from app.dao import notifications_dao
from app.errors import InvalidRequest, register_errors
from app.models import NOTIFICATION_PENDING, NOTIFICATION_SENDING
from app.notifications.notifications_ses_callback import (
    _check_and_queue_complaint_callback_task,
    check_and_queue_callback_task,
    determine_notification_bounce_type,
    get_aws_responses,
    handle_complaint,
)

ses_callback_blueprint = Blueprint('notifications_ses_callback', __name__)
DEFAULT_MAX_AGE = timedelta(days=10000)

register_errors(ses_callback_blueprint)
class SNSMessageType(enum.Enum):
    SubscriptionConfirmation = 'SubscriptionConfirmation'
    Notification = 'Notification'
    UnsubscribeConfirmation = 'UnsubscribeConfirmation'


class InvalidMessageTypeException(Exception):
    pass


def verify_message_type(message_type: str):
    try:
        SNSMessageType(message_type)
    except ValueError:
        raise InvalidMessageTypeException(f'{message_type} is not a valid message type.')


# 400 counts as a permanent failure so SNS will not retry.
# 500 counts as a failed delivery attempt so SNS will retry.
# See https://docs.aws.amazon.com/sns/latest/dg/DeliveryPolicies.html#DeliveryPolicies
# This should not be here, it used to be in notifications/notifications_ses_callback. It then
# got refactored into a task, which is fine, but it created a circular dependency. Will need
# to investigate why GDS extracted this into a lambda
@ses_callback_blueprint.route('/notifications/email/ses', methods=['POST'])
def sns_callback_handler():
    message_type = request.headers.get('x-amz-sns-message-type')
    try:
        verify_message_type(message_type)
    except InvalidMessageTypeException:
        current_app.logger.exception(f"Response headers: {request.headers}\nResponse data: {request.data}")
        raise InvalidRequest("SES-SNS callback failed: invalid message type", 400)

    try:
        message = json.loads(request.data.decode('utf-8'))
    except decoder.JSONDecodeError:
        current_app.logger.exception(f"Response headers: {request.headers}\nResponse data: {request.data}")
        raise InvalidRequest("SES-SNS callback failed: invalid JSON given", 400)

    try:
        validate_sns_message(message)
    except Exception as err:
        current_app.logger.error(f"SES-SNS callback failed: validation failed! Response headers: {request.headers}\nResponse data: {request.data}\nError: Signature validation failed with error {err}")
        raise InvalidRequest("SES-SNS callback failed: validation failed", 400)

    if message.get('Type') == 'SubscriptionConfirmation':
        url = message.get('SubscribeUrl') if 'SubscribeUrl' in message else message.get('SubscribeURL')
        response = requests.get(url)
        try:
            response.raise_for_status()
        except Exception as e:
            current_app.logger.warning(f"Attempt to raise_for_status()SubscriptionConfirmation Type message files for response: {response.text} with error {e}")
            raise e

        return jsonify(
            result="success", message="SES-SNS auto-confirm callback succeeded"
        ), 200

    # TODO remove after smoke testing on prod is implemented
    current_app.logger.info(f"SNS message: {message} is a valid delivery status message. Attempting to process it now.")
    
    process_ses_results.apply_async([{"Message": message.get("Message")}], queue=QueueNames.NOTIFY)

    return jsonify(
        result="success", message="SES-SNS callback succeeded"
    ), 200


@notify_celery.task(bind=True, name="process-ses-result", max_retries=5, default_retry_delay=300)
def process_ses_results(self, response):
    try:
        ses_message = json.loads(response["Message"])
        notification_type = ses_message["notificationType"]
        # TODO remove after smoke testing on prod is implemented
        current_app.logger.info(f"Attempting to process SES delivery status message from SNS with type: {notification_type} and body: {ses_message}")
        bounce_message = None

        if notification_type == 'Bounce':
            bounce_message = determine_notification_bounce_type(ses_message)
        elif notification_type == 'Complaint':
            _check_and_queue_complaint_callback_task(*handle_complaint(ses_message))
            return True

        aws_response_dict = get_aws_responses(ses_message)

        notification_status = aws_response_dict["notification_status"]
        reference = ses_message["mail"]["messageId"]

        try:
            notification = notifications_dao.dao_get_notification_by_reference(reference)
        except NoResultFound:
            message_time = iso8601.parse_date(ses_message["mail"]["timestamp"]).replace(tzinfo=None)
            if datetime.utcnow() - message_time < timedelta(minutes=5):
                current_app.logger.info(
                    f"notification not found for reference: {reference} (while attempting update to {notification_status}). "
                    f"Callback may have arrived before notification was persisted to the DB. Adding task to retry queue"
                )
                self.retry(queue=QueueNames.RETRY)
            else:
                current_app.logger.warning(
                    "notification not found for reference: {} (while attempting update to {})".format(reference, notification_status)
                )
            return

        if bounce_message:
            current_app.logger.info(f"SES bounce for notification ID {notification.id}: {bounce_message}")

        if notification.status not in {NOTIFICATION_SENDING, NOTIFICATION_PENDING}:
            notifications_dao._duplicate_update_warning(
                notification, 
                notification_status
            )
            return

        notifications_dao._update_notification_status(
            notification=notification,
            status=notification_status,
            provider_response=aws_response_dict["provider_response"],
        )

        if not aws_response_dict["success"]:
            current_app.logger.info(
                "SES delivery failed: notification id {} and reference {} has error found. Status {}".format(
                    notification.id, reference, aws_response_dict["message"]
                )
            )
        else:
            current_app.logger.info(
                "SES callback return status of {} for notification: {}".format(notification_status, notification.id)
            )

        statsd_client.incr("callback.ses.{}".format(notification_status))

        if notification.sent_at:
            statsd_client.timing_with_dates("callback.ses.elapsed-time", datetime.utcnow(), notification.sent_at)

        check_and_queue_callback_task(notification)

        return True

    except Retry:
        raise

    except Exception as e:
        current_app.logger.exception("Error processing SES results: {}".format(type(e)))
        self.retry(queue=QueueNames.RETRY)