golang project provided to handle mailer service and has been integrated with rabbitmq, on channel mailer_queue and templateing with file .html, for provider sending email using smtp2go for the testing with template of .env is ready on this project,

the project using enqueue concept that set in file rabbitmq/rabbitmq.go will be automatically send message after consumming message from channel set on file .env

for example of list template email to send you can see in file templates/*_template.html for the lsit of template that will using message with variable tag on the message from channel for list of tag you can see at the file handlers/handlers.go and here this of list the tag

1. login
2. send_code
3. reset_password
4. api_key

that must be the same name on file templates/*_template.html, and if you want to customize the project you can update the file list

1. handlers -> file to handle tag of message from consuming message from queue
2. interfaces -> file to handling interfaces message like all variable they have
3. mailes -> file to handling send mail with configuration template from message
4. rabbitmq -> file to handling configuration of queue and subcribe to channel has been declared on rabbitmq queue
5. templates -> file to handling templating style to show for user
6. token -> file to handling decrypted message jwt from queue channel

flow of system on this project just like this :

the flow of system is started from your project

-> publish message json to rabbitmq channel when has been encrypted with jwt private key (example of json you see after this)
-> mailer service subcribe to channel and consume the message
-> message will decrypted first to check the tag 
-> system will generate template of message with using json message after decryption
-> system will send message to target email

project will using dual decrypted when first decrypted is for to get tag group that using Record interfaces and then project will decrypt again using file in interfaces to get list of json messages when is suitable on tag and handlers

example of json data
{
    record: {
        email: string, // email address user
        tag: string, // tag is for description to generate file
        subject: string // subject of message to subject on email send
    },
    iss: 'name_project',
    iat: <Time on Integer>,
    exp: <Time on Integer>,
    jti: SecureRandom.hex(10)
}

Setup for this project is simple, you must prepare the configuration on file .env, configuration channel on the rabbitmq, the list of configuration you must following the step :

1. RabbitMQ

configuration rabbitmq you can follow this link https://www.rabbitmq.com/download.html

or you want to easly install RabbitMQ configuration you can running command on your terminal using

$ cd config && docker-compose up -Vd

after your config for rabbitmq installation don't forget to update sthe file .env on variable RABBITMQ_HOST with host to your rabbitmq has installed

2. Channel configuration

Channel configration you can using file in config/rabbitmq_channel.yaml on your project because this project just for consuming from config channel when you set in rabbitmq you can create channel in rabbitmq in exchange and queue and don't forget to set the queue_name when you has been config in file .env

3. SMTP

Mailer using github.com/go-mail/mail for the package and for the configuration you can set in file .env on list variable in below

SMTP_HOST={smtp host }
SMTP_PORT={ smtp port }
SMTP_USER={ smtp username }
SMTP_PASS={ smtp password }
SMTP_SENDER_EMAIL={ smtp sender email }
SMTP_SENDER_NAME={ smttp sender name }

don't forget to change that smtp configuration with your smtp mailer you have, but on sender email must using activated email like alone@gmail.com or something else, if you want to customize that configuration you can change in file mailers/mailers.go

4. JWT

configuration jwt is easy, you just need to generate the jwt_public_key and jwt_private_key and set the algorithm on file .env, you can follow the step :

• Generate Private Key

$ openssl genpkey -algorithm RSA -out private_key.pem

• Generate Public Key

$ openssl rsa -in private_key.pem -pubout -out public_key.pem

but in this project you must to convert that file output to base64 configuration private_key or public_key

• Convert private key to base64

$ openssl base64 -in private_key.pem

• Convert Public key to base64

$ openssl rsa -in private_key.pem -pubout -outform DER | openssl base64 -A

after that you can set that private_key on your project to protect the message from your project for executing on this mailer-service, and for mailer-service you can must to using that public_key to decrypted the message from your project after consuming channel has you declared in file .env

setup notification is using firebase with get server key the base config of notification is on folder notificaiton/notification.go

format payload on jwt encode is

{
  "record": {
    "users": {
      "email": "<email_user>",
      "device_token": [
        "<string>"
      ]
    },
    "title": "<string>",
    "message": "<string>"
  },
  "sub": "<string>",
  "aud": "'<string>'",
  "iss": "<string>",
  "iat": "timestamp",
  "exp": "timestamp",
  "jti": "generateString"
}

project mailer-service you can run using the following command

download all depenencies project using the following command

$ go mod download

completely setup configuration for your project

after all is ready, run the following command

$ go run mailer.go

$ go run push_notif.go