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
Supports HTML email
Supports database based email templates
Built in scheduling support
Works well with task queues like RQ or Celery
Uses multiprocessing to send a large number of emails in parallel

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's settings.py:

INSTALLED_APPS = (
    # other apps
    "post_office",
)

Run syncdb:
```
python manage.py syncdb
```
Set post_office.EmailBackend as your EMAIL_BACKEND in django's settings.py:
```
EMAIL_BACKEND = 'post_office.EmailBackend'
```

If you're still on Django <= 1.6 and use South to manage your migrations, you'll need to put the following in settings.py:

SOUTH_MIGRATION_MODULES = {
    "post_office": "post_office.south_migrations",
}

Quickstart

Send a simple email is really easy:

from post_office import mail

mail.send(
    '[email protected]', # List of email addresses also accepted
    '[email protected]',
    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(
    '[email protected]', # List of email addresses also accepted
    '[email protected]',
    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)

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 <[email protected]>`)
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
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: files file-like objects full path of the file
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)
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 significat 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(
    ['[email protected]'],
    '[email protected]',
    subject='Welcome!',
    message='Welcome home, {{ name }}!',
    html_message='Welcome home, <b>{{ name }}</b>!',
    headers={'Reply-to': '[email protected]'},
    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(
    ['[email protected]'],
    '[email protected]',
    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(
    ['[email protected]'],
    '[email protected]',
    template='welcome_email',
    context={'foo': 'bar'},
    priority='now',
    attachments={
        'attachment1.doc', '/path/to/file/file1.doc',
        'attachment2.txt', ContentFile('file content'),
    }
)

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(
    ['[email protected]'],
    '[email protected]',
    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?'

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 changing EMAIL_BACKEND.

For example if you want to use django-ses:

POST_OFFICE = {
    'EMAIL_BACKEND': 'django_ses.SESBackend'
}

Management Commands

send_queued_mail - send queued emails, those aren't successfully sent will be marked as failed. 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': 5000
}

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 nothing * 1 logs only failed deliveries * 2 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"
        },
    },
}

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': '[email protected]',
    'recipients': ['[email protected]'],
    'subject': 'Hi!',
    'message': 'Hi Alice!'
}
second_email = {
    'sender': '[email protected]',
    'recipients': ['[email protected]'],
    '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=.

Changelog

Version 1.1.0

Support for Django 1.7 migrations. If you're still on Django < 1.7, South migration files are stored in south_migrations directory.

Version 1.0.0

IMPORTANT: in older versions, passing multiple recipients into mail.send() will create multiple emails, each addressed to one recipient. Starting from 1.0.0, only one email with multiple recipients will be created.
Added LOG_LEVEL setting.
mail.send() now supports cc and bcc. Thanks Ștefan Daniel Mihăilă (@stefan-mihaila)!
Improvements to admin interface; you can now easily requeue multiple emails.
Log model now stores the type of exception caught during sending.
send_templated_mail command is now deprecated.
Added EMAIL_BACKEND setting to the new dictionary-styled settings.

Version 0.8.4

send_queued_mail now accepts an extra --log-level argument.
mail.send() now accepts an extra log_level argument.
Drop unused/low cardinality indexes to free up RAM on large tables.

Version 0.8.3

send_queued_mail now accepts --lockfile argument.
Lockfile implementation has been modified to use symlink, which is an atomic operation across platforms.

Version 0.8.2

Added CONTEXT_FIELD_CLASS setting to allow other kinds of context field serializers.

Version 0.8.1

Fixed a bug that causes context to be saved when render_on_delivery is False

Version 0.8.0

Added a new setting DEFAULT_PRIORITY to set the default priority for emails. Thanks Maik Hoepfel (@maikhoepfel)!
mail.send() gains a render_on_delivery argument that may potentially result in significant storage space savings.
Uses a new locking mechanism that can detect zombie PID files.

Version 0.7.2

Made a few tweaks that makes post_office much more efficient on systems with large number of rows (millions).

Version 0.7.1

Python 3 compatibility fix.

Version 0.7.0

Added support for sending attachments. Thanks @yprez!
Added description field to EmailTemplate model to store human readable description of templates. Thanks Michael P. Jung (@bikeshedder)!
Changed django-jsonfield dependency to jsonfield for Python 3 support reasons.
Minor bug fixes.

Version 0.6.0

Support for Python 3!
Added mail.send_many() that's much more performant when sending a large number emails

Version 0.5.2

Added logging
Added BATCH_SIZE configuration option

Version 0.5.1

Fixes various multiprocessing bugs

Version 0.5.0

Email sending can now be parallelized using multiple processes (multiprocessing)
Email templates are now validated before save
Fixed a bug where custom headers aren't properly sent

Version 0.4.0

Added support for sending emails with custom headers (you'll need to run South when upgrading from earlier versions)
Added support for scheduled email sending
Backend now properly persist emails with HTML alternatives

Version 0.3.1

* IMPORTANT: mail.send now expects recipient email addresses as the first: argument. This change is to allow optional sender parameter which defaults to settings.DEFAULT_FROM_EMAIL

Fixed a bug where all emails sent from mail.send have medium priority

Version 0.3.0

IMPORTANT: added South migration. If you use South and had post-office installed before 0.3.0, you may need to manually resolve migration conflicts
Allow unicode messages to be displayed in /admin
Introduced a new mail.send function that provides a nicer API to send emails
created fields now use auto_now_add
last_updated fields now use auto_now

Version 0.2.1

Fixed typo in admin.py

Version 0.2

Allows sending emails via database backed templates

Version 0.1.5

Errors when opening connection in Email.dispatch method are now logged

unkvuzutop / django-post_office Goto Github PK