Django Post Office
Django Post Office is a simple app to send and manage your emails in Django. Some awesome features are:
- Allows you to send email asynchronously
- Multi backend support
- Supports HTML email
- Supports database based email templates
- Built in scheduling support
- Works well with task queues like RQ or Celery
- Uses multiprocessing (and threading) to send a large number of emails in parallel
- Supports multilingual email templates (i18n)
Dependencies
Installation
Install from PyPI (or you manually download from PyPI):
pip install django-post_office
Add
post_office
to your INSTALLED_APPS in django'ssettings.py
:
INSTALLED_APPS = (
# other apps
"post_office",
)
Run
migrate
:python manage.py migrate
Set
post_office.EmailBackend
as yourEMAIL_BACKEND
in django'ssettings.py
:EMAIL_BACKEND = 'post_office.EmailBackend'
Quickstart
Send a simple email is really easy:
from post_office import mail
mail.send(
'recipient@example.com', # List of email addresses also accepted
'from@example.com',
subject='My email',
message='Hi there!',
html_message='Hi <strong>there</strong>!',
)
If you want to use templates, ensure that Django's admin interface is enabled. Create an
EmailTemplate
instance via admin
and do the following:
from post_office import mail
mail.send(
'recipient@example.com', # List of email addresses also accepted
'from@example.com',
template='welcome_email', # Could be an EmailTemplate instance or name
context={'foo': 'bar'},
)
The above command will put your email on the queue so you can use the
command in your webapp without slowing down the request/response cycle too much.
To actually send them out, run python manage.py send_queued_mail
.
You can schedule this management command to run regularly via cron:
* * * * * (/usr/bin/python manage.py send_queued_mail >> send_mail.log 2>&1)
or, if you use uWSGI as application server, add this short snipped to the
project's wsgi.py
file:
from django.core.wsgi import get_wsgi_application
application = get_wsgi_application()
# add this block of code
try:
import uwsgidecorators
from django.core.management import call_command
@uwsgidecorators.timer(10)
def send_queued_mail(num):
"""Send queued mail every 10 seconds"""
call_command('send_queued_mail', processes=1)
except ImportError:
print("uwsgidecorators not found. Cron and timers are disabled")
Alternatively you can also use the decorator @uwsgidecorators.cron(minute, hour, day, month, weekday)
.
This will schedule a task at specific times. Use -1
to signal any time, it corresponds to the *
in cron.
Please note that uwsgidecorators
are available only, if the application has been started
with uWSGI. However, Django's internal ./manange.py runserver
also access this file,
therefore wrap the block into an exception handler as shown above.
This configuration is very useful in environments, such as Docker containers, where you don't have a running cron-daemon.
Usage
mail.send()
mail.send
is the most important function in this library, it takes these
arguments:
Argument | Required | Description |
recipients | Yes | list of recipient email addresses |
sender | No | Defaults to settings.DEFAULT_FROM_EMAIL ,
display name is allowed (John <john@a.com> ) |
subject | No | Email subject (if template is not specified) |
message | No | Email content (if template is not specified) |
html_message | No | HTML content (if template is not specified) |
template | No | EmailTemplate instance or name |
language | No | Language in which you want to send the email in (if you have multilingual email templates.) |
cc | No | list emails, will appear in cc field |
bcc | No | list of emails, will appear in bcc field |
attachments | No | Email attachments - A dictionary where the keys are the filenames and the values are either:
|
context | No | A dictionary, used to render templated email |
headers | No | A dictionary of extra headers on the message |
scheduled_time | No | A date/datetime object indicating when the email should be sent |
priority | No | high , medium , low or now
(send_immediately) |
backend | No | Alias of the backend you want to use.
default will be used if not specified. |
render_on_delivery | No | Setting this to True causes email to be
lazily rendered during delivery. template
is required when render_on_delivery is True.
This way content is never stored in the DB.
May result in significant space savings. |
Here are a few examples.
If you just want to send out emails without using database templates. You can
call the send
command without the template
argument.
from post_office import mail
mail.send(
['recipient1@example.com'],
'from@example.com',
subject='Welcome!',
message='Welcome home, {{ name }}!',
html_message='Welcome home, <b>{{ name }}</b>!',
headers={'Reply-to': 'reply@example.com'},
scheduled_time=date(2014, 1, 1),
context={'name': 'Alice'},
)
post_office
is also task queue friendly. Passing now
as priority into
send_mail
will deliver the email right away (instead of queuing it),
regardless of how many emails you have in your queue:
from post_office import mail
mail.send(
['recipient1@example.com'],
'from@example.com',
template='welcome_email',
context={'foo': 'bar'},
priority='now',
)
This is useful if you already use something like django-rq to send emails asynchronously and only need to store email related activities and logs.
If you want to send an email with attachments:
from django.core.files.base import ContentFile
from post_office import mail
mail.send(
['recipient1@example.com'],
'from@example.com',
template='welcome_email',
context={'foo': 'bar'},
priority='now',
attachments={
'attachment1.doc': '/path/to/file/file1.doc',
'attachment2.txt': ContentFile('file content'),
'attachment3.txt': { 'file': ContentFile('file content'), 'mimetype': 'text/plain'},
}
)
Template Tags and Variables
post-office
supports Django's template tags and variables.
For example, if you put "Hello, {{ name }}" in the subject line and pass in
{'name': 'Alice'}
as context, you will get "Hello, Alice" as subject:
from post_office.models import EmailTemplate
from post_office import mail
EmailTemplate.objects.create(
name='morning_greeting',
subject='Morning, {{ name|capfirst }}',
content='Hi {{ name }}, how are you feeling today?',
html_content='Hi <strong>{{ name }}</strong>, how are you feeling today?',
)
mail.send(
['recipient@example.com'],
'from@example.com',
template='morning_greeting',
context={'name': 'alice'},
)
# This will create an email with the following content:
subject = 'Morning, Alice',
content = 'Hi alice, how are you feeling today?'
content = 'Hi <strong>alice</strong>, how are you feeling today?'
Multilingual Email Templates
You can easily create email templates in various different languanges. For example:
template = EmailTemplate.objects.create(
name='hello',
subject='Hello world!',
)
# Add an Indonesian version of this template:
indonesian_template = template.translated_templates.create(
language='id',
subject='Halo Dunia!'
)
Sending an email using template in a non default languange is also similarly easy:
mail.send(
['recipient@example.com'],
'from@example.com',
template=template, # Sends using the default template
)
mail.send(
['recipient@example.com'],
'from@example.com',
template=template,
language='id', # Sends using Indonesian template
)
Custom Email Backends
By default, post_office
uses django's smtp.EmailBackend
. If you want to
use a different backend, you can do so by configuring BACKENDS
.
For example if you want to use django-ses:
POST_OFFICE = { 'BACKENDS': { 'default': 'smtp.EmailBackend', 'ses': 'django_ses.SESBackend', } }
You can then choose what backend you want to use when sending mail:
# If you omit `backend_alias` argument, `default` will be used
mail.send(
['recipient@example.com'],
'from@example.com',
subject='Hello',
)
# If you want to send using `ses` backend
mail.send(
['recipient@example.com'],
'from@example.com',
subject='Hello',
backend='ses',
)
Management Commands
send_queued_mail
- send queued emails, those aren't successfully sent will be marked asfailed
. Accepts the following arguments:
Argument | Description |
--processes or -p |
Number of parallel processes to send email. Defaults to 1 |
--lockfile or -L |
Full path to file used as lock file. Defaults to
/tmp/post_office.lock |
cleanup_mail
- delete all emails created before an X number of days (defaults to 90).
You may want to set these up via cron to run regularly:
* * * * * (cd $PROJECT; python manage.py send_queued_mail --processes=1 >> $PROJECT/cron_mail.log 2>&1) 0 1 * * * (cd $PROJECT; python manage.py cleanup_mail --days=30 >> $PROJECT/cron_mail_cleanup.log 2>&1)
Settings
This section outlines all the settings and configurations that you can put
in Django's settings.py
to fine tune post-office
's behavior.
Batch Size
If you may want to limit the number of emails sent in a batch (sometimes useful
in a low memory environment), use the BATCH_SIZE
argument to limit the
number of queued emails fetched in one batch.
# Put this in settings.py
POST_OFFICE = {
'BATCH_SIZE': 50
}
Default Priority
The default priority for emails is medium
, but this can be altered by
setting DEFAULT_PRIORITY
. Integration with asynchronous email backends
(e.g. based on Celery) becomes trivial when set to now
.
# Put this in settings.py
POST_OFFICE = {
'DEFAULT_PRIORITY': 'now'
}
Log Level
The default log level is 2 (logs both successful and failed deliveries)
This behavior can be changed by setting LOG_LEVEL
.
# Put this in settings.py
POST_OFFICE = {
'LOG_LEVEL': 1 # Log only failed deliveries
}
The different options are:
0
logs nothing1
logs only failed deliveries2
logs everything (both successful and failed delivery attempts)
Sending Order
The default sending order for emails is -priority
, but this can be altered by
setting SENDING_ORDER
. For example, if you want to send queued emails in FIFO order :
# Put this in settings.py
POST_OFFICE = {
'SENDING_ORDER': ['created']
}
Context Field Serializer
If you need to store complex Python objects for deferred rendering
(i.e. setting render_on_delivery=True
), you can specify your own context
field class to store context variables. For example if you want to use
django-picklefield:
# Put this in settings.py
POST_OFFICE = {
'CONTEXT_FIELD_CLASS': 'picklefield.fields.PickledObjectField'
}
CONTEXT_FIELD_CLASS
defaults to jsonfield.JSONField
.
Logging
You can configure post-office
's logging from Django's settings.py
. For
example:
LOGGING = {
"version": 1,
"disable_existing_loggers": False,
"formatters": {
"post_office": {
"format": "[%(levelname)s]%(asctime)s PID %(process)d: %(message)s",
"datefmt": "%d-%m-%Y %H:%M:%S",
},
},
"handlers": {
"post_office": {
"level": "DEBUG",
"class": "logging.StreamHandler",
"formatter": "post_office"
},
# If you use sentry for logging
'sentry': {
'level': 'ERROR',
'class': 'raven.contrib.django.handlers.SentryHandler',
},
},
'loggers': {
"post_office": {
"handlers": ["post_office", "sentry"],
"level": "INFO"
},
},
}
Threads
post-office
>= 3.0 allows you to use multiple threads to dramatically speed up
the speed at which emails are sent. By default, post-office
uses 5 threads per process.
You can tweak this setting by changing THREADS_PER_PROCESS
setting.
This may dramatically increase the speed of bulk email delivery, depending on which email backends you use. In my tests, multi threading speeds up email backends that use HTTP based (REST) delivery mechanisms but doesn't seem to help SMTP based backends.
# Put this in settings.py
POST_OFFICE = {
'THREADS_PER_PROCESS': 10
}
Performance
Caching
if Django's caching mechanism is configured, post_office
will cache
EmailTemplate
instances . If for some reason you want to disable caching,
set POST_OFFICE_CACHE
to False
in settings.py
:
## All cache key will be prefixed by post_office:template:
## To turn OFF caching, you need to explicitly set POST_OFFICE_CACHE to False in settings
POST_OFFICE_CACHE = False
## Optional: to use a non default cache backend, add a "post_office" entry in CACHES
CACHES = {
'post_office': {
'BACKEND': 'django.core.cache.backends.memcached.PyLibMCCache',
'LOCATION': '127.0.0.1:11211',
}
}
send_many()
send_many()
is much more performant (generates less database queries) when
sending a large number of emails. send_many()
is almost identical to mail.send()
,
with the exception that it accepts a list of keyword arguments that you'd
usually pass into mail.send()
:
from post_office import mail
first_email = {
'sender': 'from@example.com',
'recipients': ['alice@example.com'],
'subject': 'Hi!',
'message': 'Hi Alice!'
}
second_email = {
'sender': 'from@example.com',
'recipients': ['bob@example.com'],
'subject': 'Hi!',
'message': 'Hi Bob!'
}
kwargs_list = [first_email, second_email]
mail.send_many(kwargs_list)
Attachments are not supported with mail.send_many()
.
Running Tests
To run the test suite:
`which django-admin.py` test post_office --settings=post_office.test_settings --pythonpath=.
You can run the full test suite with:
tox
or:
python setup.py test
Changelog
Version 3.0.0
- _send_bulk now allows each process to use multiple threads to send emails. Allowing
- Added support for mimetypes in email attachments. Thanks @clickonchris!
- An EmailTemplate can now be used as defaults multiple times in one language. Thanks @sac7e!
- send_queued_mail management command will now check whether there are more queued emails to be sent before exiting.
- Drop support for Django < 1.8. Thanks @fendyh!
Full changelog can be found here.
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