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