Update code and readme

README.md

@@ -1,2 +1,41 @@
 # django-queued-mailer
+
 Django mail backend uses celery as email message queue
+
+### requirements
+
+Django >= 1.11, Celery >= 4.1.1
+
+### setup
+
+- add `git+https://github.com/jar3b/django-queued-mailer.git` to requirements.txt
+- install package `pip install --upgrade git+https://github.com/jar3b/django-queued-mailer.git`
+- run celery worker
+
+```
+celery -A project worker
+```
+
+### run one task at time (optional)
+
+- setup Celery routes
+
+```
+app.conf.task_queues = (
+    Queue('default', Exchange('default'), routing_key='default'),
+    Queue('qmailer_mail_queue', routing_key='qmailer.send.#'),
+)
+```
+
+- start separate worker
+
+```
+celery -A project worker -Q qmailer_mail_queue --concurrency=1
+```
+
+### configure
+
+Django settings:
+
+- `QMAILER_EMAIL_BACKEND` - set email backend, default `django.core.mail.backends.smtp.EmailBackend`
+- `QMAILER_TASK_QUEUE_NAME` - queue name for routing, default `default`, if you use separate "serial" worker as described above, you need to specify this option

queued_mailer/backend.py

@@ -1,9 +1,8 @@
 from django.core.mail.backends.base import BaseEmailBackend
 from django.utils.encoding import force_text
-from django.utils.module_loading import import_string
 
 from .logger import logger
-from .settings import EMAIL_SEND_TASK
+from .tasks import send_message
 
 
 def _get_message_recipients(email_message):
@@ -14,17 +13,14 @@ def _get_message_recipients(email_message):
 
 
 class EmailBackend(BaseEmailBackend):
-    task = None
-
     def __init__(self, fail_silently=False, **kwargs):
         super(EmailBackend, self).__init__(fail_silently, **kwargs)
-        self.task = import_string(EMAIL_SEND_TASK)
 
     def send_messages(self, email_messages):
         num_sent = 0
         for email in email_messages:
             try:
-                self.task.apply_async([email, ])
+                send_message.apply_async([email, ])
                 num_sent += 1
             except Exception as e:
                 logger.error("cannot send message %s: %r" % (_get_message_recipients(email), e))

queued_mailer/settings.py

@@ -6,8 +6,8 @@ EMAIL_BACKEND = getattr(
     "django.core.mail.backends.smtp.EmailBackend"
 )
 
-EMAIL_SEND_TASK = getattr(
+TASK_QUEUE_NAME = getattr(
     settings,
-    "QMAILER_SEND_TASK",
-    "queued_mailer.tasks.send_message"
+    "QMAILER_TASK_QUEUE_NAME",
+    "default"
 )

queued_mailer/tasks.py

@@ -1,11 +1,19 @@
-from celery.task import task
+from time import sleep
 
-from .logger import logger
-from .settings import EMAIL_BACKEND
+import celery
+from celery.utils.log import get_task_logger
+
+from .settings import TASK_QUEUE_NAME
+
+logger = get_task_logger(__name__)
 
 
-@task
-def send_message(email):
-    logger.info('TASK CALLED')
-    logger.info(EMAIL_BACKEND)
-    logger.info(email)
+@celery.task(bind=True, queue=TASK_QUEUE_NAME, acks_late=True, default_retry_delay=30)
+def send_message(self, email):
+    logger.info('task started')
+    try:
+        sleep(5)
+        logger.info('task success')
+    except Exception as e:
+        logger.info('task error')
+        raise self.retry(exc=e)