Email Delivery Engine in Elixir

This project provides an Elixir based background processing engine for email delivery. It uses Exq job processing library, Quantum cron-like job scheduler, Timex date/time library, Mailman mailer, UUID generator, Mongodb driver and HTTPotion HTTP client.

Requirements

Erlang, Elixir and Redis

Example for Ubuntu 12.04 or newer / Debian 7:

$ cd /tmp
$ wget https://packages.erlang-solutions.com/erlang-solutions_1.0_all.deb
$ sudo dpkg -i erlang-solutions_1.0_all.deb
$ sudo apt-get update
$ sudo apt-get install erlang elixir redis-server

MongoDB

Follow the instructions on Install MongoDB Community Edition on Linux.

Installation

Get the sources:

$ git clone https://github.com/itp-world/email-bpe-elixir.git
$ cd email-bpe-elixir

Get dependencies and compile:

$ mix deps.get
$ mix compile

Startup

Job Processing:

$ mix run --no--halt (Stop with CTRL-C)

UI Dashboard:

Disabled in case of potential memory leak in Exq.Middleware.Stat currently!

$ mix exq.ui (Stop with CTRL-C)

Open http://localhost:4040 in your preferred browser.

Debugging:

$ iex -S mix run (Stop with CTRL-C)
iex([email protected])1> :observer.start()

A GUI will open with a lot of information about the running state of the app.

Erlang VM crash dumps:

$ erl -s crashdump_viewer

This starts the Crashdump Viewer GUI and loads the given file. If no file name is given, a file dialog will be opened where the file can be selected.

Email delivery service

To run the email delivery engine a template engine service is needed to create the HTML body of the EML files. For a quick start use the bpe-service-freemarker project. After its setup and start execute in different terminals the following commands:

• Terminal #1 - Start Ratpack/Freemarker

  $ cd /path/to/bpe-service-freemarker
  $ gradle installApp
  $ ./build/install/service-freemarker/bin/service-freemarker

• Terminal #2 - Start Background processing engine for email delivery

  $ cd /path/to/email-bpe-elixir
  $ mix run --no-halt

• Terminal #3 - Create and enqueue a job

  $ cd /path/to/email-bpe-elixir
  $ mix bpe.jobs.create -j 1 -r 10000
  $ mix bpe.enqueue.job_poller_worker

The generated EML files are located under /path/to/email-bpe-elixir/tmp/smtp.

Jobs Generation

$ mix bpe.jobs.create
Usage: mix bpe.jobs.create <options>

  Options:
  --help       -h             this help
  --jobs       -j <Integer>   number of jobs
  --recipients -r <Integer>   number of recipients per job
  --sendat        <DateTime>  UTC date emails are sent to recipients, optional
                              e.g. 2016-02-05T14:59:38Z (ISO 8601)
  --nosendtime    <String>    optional UTC time interval during which no emails
                              are allowed to be sent, format "HH:MM HH:MM"

Enqueue Job Poller Worker

$ mix bpe.enqueue.job_poller_worker

(Un)Subscribe Exq Queues

You need to guarantee epmd (Erlang Port Mapper Daemon) is running on a port that is not blocked (you can run epmd -d for debug info) and you need to ensure all machines have a ~/.erlang.cookie file with exactly the same value.

$ mix bpe.client.queue_manager
Usage: mix bpe.client.queue_manager <options>

  Options:
  --help   -h            this help
  --node   -n <String>   node name of the BPE instance
  --queue  -q <String>   exq queue name to (un)subscribe
  --worker -w <Integer>  number of workers for subscription (optional)
  --(un)subscribe        (un)subscribes the queue

Reset BPE

$ mix bpe.reset

This will reset Redis / MongoDB and delete the ./tmp/ directory.