rer.newsletterdispatcher.flask

A separate mail dispatcher for rer.newsletter.

This is useful when you have channels with a lot of subscriptions (we had some with > 70000) and don't want to block Plone instances to do this long job.

The dispatcher is a combination of three pieces:

• Flask app with flask-mail
• Redis (for job queues)
• Rq (a python library to manage redis queues and execute jobs)

These are three different processes that need to run together.

Installation

All dependencies are managed with buildout. There are two profiles for development and production environments.

The best way to install this application is with virtualenv or pyenv.

Once we activated the virtualenv, we need to install basic requirements:

> pip install -r requirements.txt

After that, you need to choose with profile you want to use (production.cfg or development.cfg):

> ln -s development.cfg buildout.cfg

And last but not least, you have to run the buildout:

> bin/buildout -N

This will install all needed dependencies and after that, you will find all needed scripts into bin folder.

Run

In development mode you need to start all services individually:

• bin/redis-server to start redis server
• bin/rq worker to start rq (it needs a working redis instance)
• make dev to start Flask app in development mode

In production mode we use supervisor to manage all processes in background, so you only need to start redis daemon with:

> bin/supervisord

And it will start and manage all services.

Custom configurations

You can add a custom configuration for Flask app by adding the environments variables

For example if you want to customize Flask-Mail mail server address (default is localhost), you can create this environment variable:

export RER_NEWSLETTERDISPATCHER_MAIL_SERVER="myserver.net"

You can set base Flask config parameters and some application-related ones:

• RER_NEWSLETTERDISPATCHER_MAIL_SERVER (mailserver address)
• RER_NEWSLETTERDISPATCHER_MAIL_PORT (mailserver port, 25 by default)[optional]
• RER_NEWSLETTERDISPATCHER_MAIL_USERNAME (mailserver client username)[optional]
• RER_NEWSLETTERDISPATCHER_MAIL_PASSWORD (mailserver cliend password)[optional]
• RER_NEWSLETTERDISPATCHER_SENTRY_DSN (sentry dsn value)
• RER_NEWSLETTERDISPATCHER_REDIS_PORT (port where redis should listen. Default is 6379 but it's better to change it)

Custom buildout configurations

You can run a buildout with some custom configurations like ports.

To do this, you only need to extend another buildout (for example production.cfg) and add your additional customizations:

[buildout]
extends =
    production.cfg

[ports]
gunicorn = 1111
redis = 2222

After that you only need to re-run buildout with:

bin/buildout -Nc name_of_cfg_file.cfg

Usage

Flask app is a simple rest api with only one endpoint (/add-to-queue) that takes a list of parameters and add a job to the queue with these parameters.

Once the job is ready to be executed, it will send a list of emails with infos passed in parameters.

Needed parameters for this route are:

• channel_url
• mfrom
• send_uid
• subject
• subscribers
• text

You can also attach some files to the POST call and they will be send as mail attachments.

There is already a plugin for rer.newsletter called rer.newsletterplugin.flask that do this job.

Security

By default, this app accept only calls from localhost, so it does not need any other complex mechanisms. It should run on the same sever where runs your Plone instances.

Credits

Developed with the support of Regione Emilia Romagna;

Regione Emilia Romagna supports the PloneGov initiative.

Authors

This product was developed by RedTurtle Technology team.