TAKASAGO-EMAIL-SENDER

Microservice for Distributing Email Messages

MAILGUN

For the time being, Mailgun is too expensive so intentionally it was not implemented

SMTP

Is tested to be working with a GMail account

Configuration

These variables must be present in the environment

FROM is the sender address

FROM=someone@gmail.com

SENDEMAIL_DIRECTORY is the directory on a docker container where the emails are stored

SENDEMAIL_DIRECTORY=/emails

SENDEMAIL

It is possible also to just create JSON files in a given directory and let a bash script send the emails using any schedule tool, such as crontab

SENDEMAIL_DIRECTORY=/home/ubuntu/emails

sendemail program has these dependencies that need to be installed before using it

sudo apt-get install -y sendemail libnet-ssleay-perl libio-socket-ssl-perl

Usage

Make use of the exported functions in email_utils package

To send sync email with immediate response on the outcome

func SendEmail(nc *nats.Conn, timeout time.Duration, params struct {
	Recipients []string
	Subject    string
	Body       string
	IsHTML     bool
}) error 

To send async email messages in a queue

func SendEmailQueue(sc stan.Conn, params struct {
	Recipients []string
	Subject    string
	Body       string
	IsHTML     bool
}) error 

type EmailMessage struct {
	From    string   `json:"from"`
	Tos     []string `json:"tos"`
	Subject string   `json:"subject"`
	Body    string   `json:"body"`
}

Running

From a docker compose file

  nats-server:
    image: nats-streaming:0.12.2
    restart: always
    command: "--store=FILE --dir=/files/nats-data -m 8222"
    expose:
      - 4222

  email-sender:
    image: takasago/email-sender:latest
    env_file:
      - .env
    command: "-v=2 -log_dir=/files -logtostderr"
    volumes:
      - $HOME/data/files:/files

Sendemail

sudo apt-get install -y sendemail libnet-ssleay-perl libio-socket-ssl-perl

To send a message

cat mailbody.txt | sendemail -l email.log \
    -f "sender@domain.com"  \
    -u "Email Test - Ignore"  \
    -t "receiver@domain.com"  \
    -cc "receiver2@domain.com"  \
    -bcc "receiver3@domain.com"  \
    -s "smtp.gmail.com:587"  \
    -o tls=yes  \
    -xu "youremail@gmail.com"  \
    -xp "Email Password" 

.env settings

# email settings
FROM=whatever@example.com
SENDEMAIL_DIRECTORY=/emails

Docker Compose Settings

  email-sender:
    image: takasago/email-sender:latest
    env_file:
      - .env
    command: "-v=2 -log_dir=/files -logtostderr"
    volumes:
      - /home/ubuntu/data/files:/files
      - /home/ubuntu/emails:/emails

Crontab

# process email messages each minute based in the file queue
* * * * * /usr/bin/pgrep -f $HOME/sender_crontab.sh > /dev/null 2> /dev/null || $HOME/sender_crontab.sh HOME/emails/ >> email.log

~$ cat sender_crontab.sh
#!/usr/bin/env bash

cd $HOME/emails

sudo $HOME/scripts/send.sh .