How Meilix Generator sends Email Notifications with SendGrid

We wanted to notify the users once the build was ready for download. To solve this we attempted making an email server on Meilix Generator but that can send email when it starts but it would take around 20 minutes to get the build ready so we thought of checking the deploy link status and send email whenever the link status was available (200) but the problem with this method was that the link can be pre available if ISO is rebuilt for same event.

Then, we attempted sending mail by Travis CI but the problem in that was closed SMTP ports (they have a strict policy about that) then we thought that Travis CI can trigger the Sendgrid which can send email to the user with the help of API.

We will use this code so that once the deployment of ISO by Travis CI is done it can execute the email script which requests Sendgrid to send email to the user.

after_deploy:
  - ./mail.py

 

We can create code using code generation service of Sendgrid we are going to choose python as it is easier to manipulate strings in python and we are going to use email as an environment variable.

After generation of python 3 code from the sendgrid website we are going to edit the message and email and hide the API key as an environment variable and create an authorization string to be used there too.

The URL will be generated by the below script as the body of url remains same only two things will change the TRAVIS_TAG which is event name and date.

date = datetime.datetime.now().strftime('%Y%m%d')
url="https://github.com/xeon-zolt/meilix/releases/download/"+os.environ["TRAVIS_TAG"]+"/meilix-zesty-"+date+"-i386.iso"

 

We can use this to hide the api key and use it as an environment variable because if the api key is visible in logs anyone can use it to exploit it and use it for spamming purpose.

authorization = "Bearer " + os.environ["mail_api_key"]
headers = {
    'authorization': authorization,

 

The main thing left to edit in the script is the message which is in the payload and is a string type so we are going to use the email received by Meilix generator as an environment variable and concatenate it with the payload string the message sent is in the value which is in the HTML format and we add the generated URL in similar way we added email variable to string.

payload = "{\"personalizations\":[{\"to\":[{\"email\":\"" + os.environ["email"] + "\"}],\"subject\":\"Your ISO is Ready\"}],\"from\":{\"email\":\"[email protected]\",\"name\":\"Meilix Generator\"},\"reply_to\":{\"email\":\"[email protected]\",\"name\":\"Meilix Generator\"},\"subject\":\"Your ISO is ready\",\"content\":[{\"type\":\"text/html\",\"value\":\"<html><p>Hi,<br>Your ISO is ready<br>URL : "+url+"<br><br>Thank You,<br>Meilix Generator Team</p></html>\"}]}"

 

The sent email looks like this

References

Generating responsive email using mjml in Yaydoc

In Yaydoc, an email with a download, preview and deploy link will be sent to the user after documentation is generated. But then initially, Yaydoc was sending email in plain text without any styling, so I decided to make an attractive HTML email template for it. The problem with HTML email is adding custom CSS and making it responsive, because the emails will be seen on various devices like mobile, tablet and desktops. When going through the GitHub trending list, I came across mjml and was totally stunned by it’s capabilities. Mjml is a responsive email generation framework which is built using React (popular front-end framework maintained by Facebook)

Install mjml to your system using npm.

npm init -y && npm install mjml

Then add mjml to your path

export PATH="$PATH:./node_modules/.bin”

Mjml has a lot of react components pre-built for creating the responsive email. For example mj-text, mj-image, mj-section etc…

Here I’m sharing the snippet used for generating email in Yaydoc.

<mjml>
  <mj-head>
    <mj-attributes>
      <mj-all padding="0" />
      <mj-class name="preheader" color="#CB202D" font-size="11px" font-family="Ubuntu, Helvetica, Arial, sans-serif" padding="0" />
    </mj-attributes>
    <mj-style inline="inline">
      a { text-decoration: none; color: inherit; }
 
    </mj-style>
  </mj-head>
  <mj-body>
    <mj-container background-color="#ffffff">
 
      <mj-section background-color="#CB202D" padding="10px 0">
        <mj-column>
          <mj-text align="center" color="#ffffff" font-size="20px" font-family="Lato, Helvetica, Arial, sans-serif" padding="18px 0px">Hey! Your documentation generated successfully<i class="fa fa-address-book-o" aria-hidden="true"></i>
 
          </mj-text>
        </mj-column>
      </mj-section>
      <mj-section background-color="#ffffff" padding="20px 0">
        <mj-column>
          <mj-image src="http://res.cloudinary.com/template-gdg/image/upload/v1498552339/play_cuqe89.png" width="85px" padding="0 25px">
</mj-image>
 
          <mj-text align="center" color="#EC652D" font-size="20px" font-family="Lato, Helvetica, Arial, sans-serif" vertical-align="top" padding="20px 25px">
            <strong><a>Preview it</a></strong>
            <br />
          </mj-text>
        </mj-column>
        <mj-column>
          <mj-image src="http://res.cloudinary.com/template-gdg/image/upload/v1498552331/download_ktlqee.png" width="100px" padding="0 25px" >
        </mj-image>
          <mj-text align="center" color="#EC652D" font-size="20px" font-family="Lato, Helvetica, Arial, sans-serif" vertical-align="top" padding="20px 25px">
            <strong><a>Download it</a></strong>
            <br />
          </mj-text>
        </mj-column>
        <mj-column>
          <mj-image src="http://res.cloudinary.com/template-gdg/image/upload/v1498552325/deploy_yy3oqw.png" width="100px" padding="0px 25px" >
        </mj-image>
          <mj-text align="center" color="#EC652D" font-size="20px" font-family="Lato, Helvetica, Arial, sans-serif" vertical-align="top" padding="20px 25px">
 
            <strong><a>Deploy it</a></strong>
            <br />
          </mj-text>
        </mj-column>
      </mj-section>
      <mj-section background-color="#333333" padding="10px">
        <mj-column>
        <mj-text align="center" color="#ffffff" font-size="20px" font-family="Lato, Helvetica, Arial, sans-serif" padding="18px 0px">Thanks for using Yaydoc<i class="fa fa-address-book-o" aria-hidden="true"></i>
        </mj-column>
        </mj-text>
      </mj-section>
    </mj-container>
  </mj-body>
</mjml>

The main goal of this example is to make a responsive email which looks like the image given below. So, In mj-head tag, I have imported all the necessary fonts using the mj-class tag and wrote my custom CSS in mj-style. Then I made a container with one row and one column using mj-container, mj-section and mj-column tag and changed the container background color to #CB202D using background-color attribute, then In that container I wrote a heading which says `Hey! Your documentation generated successfully`  with mj-text tag, Then you will get the red background top bar with the success message. Then moving on to the second part, I made a container with three columns and added one image to each column using mj-image tag by specifying image URL as src attribute, added the corresponding text below the mj-image tag using the mj-text tag. At last,  I  made one more container as the first one with different message saying `Thanks for using yaydoc`  with background color #333333

At last, transpile your mjml code to HTML by executing the following command.

mjml -r index.mjml -o index.html

Rendered Email
Resources:

Sending mails using Sendgrid on Nodejs

The open-event webapp generator project needs to send an email to the user notifying him whenever generating the webapp is finished, containing the links to the preview and zip download.

For sending emails, the easiest service we found we could use was SendGrid  which provides upto 15000 free emails a month for students who have a Github Education Pack. (It anyway provides 10000 free emails to all users).

To use sendgrid, it’s best to use the sendgrid npm module that SendGrid officially builds. To get that installed just use the following command –

npm install --save sendgrid

Also, once you have made an account on Sendgrid, create an API key, and save it as an environment variable (so that your API key is not exposed in your code). For example in our project, we save it in the environment variable SENDGRID_API_KEY
To make it permanent you can add it to your ~/.profile file

export SEDGRID_API_KEY=xxxxxxxxxxxxxxxxxxx

The actual sending takes place in the mailer.js script in our project.

Basically we are using the mail helper class provided in the sendgrid module, and the bare minimum code required to send a mail is as follows

  var helper = require('sendgrid').mail
  from_email = new helper.Email([email protected]')
  to_email = new helper.Email([email protected]')
  subject = 'Hello World from the SendGrid Node.js Library!'
  content = new helper.Content('text/plain', 'Hello, Email!')
  mail = new helper.Mail(from_email, subject, to_email, content)
 
  var sg = require('sendgrid')(process.env.SENDGRID_API_KEY);
  var request = sg.emptyRequest({
    method: 'POST',
    path: '/v3/mail/send',
    body: mail.toJSON()
  });
 
  sg.API(request, function(error, response) {
    console.log(response.statusCode)
    console.log(response.body)
    console.log(response.headers)
  })

You need to replace the to and from emails to your requirements.

Also as you can see in our project’s code, if you want to send HTML formatted data, you can change the content type from text/plain to text/html and then add any html content (as a string) into the content.