How to send email using AWS SES and custom template in Golang

Introduction

In this article, you will learn How to send an email with custom templates using AWS’s Simple Mail Services(SES).

After implementing it in one of our company’s projects, I thought it could be useful for others too, So I decided to write on this topic.

So, let’s start…

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Creating Custom HTML Template

We are going to create an HTML template that will bind dynamic variables. let’s create an Html file with the name email-template.html.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
</head>
<body>
<p> Hello {{.FirstName}} {{.LastName}} </p>
<p> Welcome to AWS Simple Mail Services with static Templates World. </p>
<p> Best Regards from, </p>
<p> Your Friend </p>

</body>
</html>

In the above code snippet, We will bind the user’s first name in {{.FirstName}} and last name in {{.LastName}}.

Parse HTML Template

import (
   "html/template"
   "io/ioutil"
)
func getHTMLTemplate() string {
   var templateBuffer bytes.Buffer

   type EmailData struct {
      FirstName string
      LastName  string
   }

   // You can bind custom data here as per requirements.
   data := EmailData{
      FirstName: "John",
      LastName:  "Doe",
   }
   htmlData, err := ioutil.ReadFile("email-template.html")

   htmlTemplate := template.Must(template.New("email.html").Parse(string(htmlData)))

   err = htmlTemplate.ExecuteTemplate(&templateBuffer, "email.html", data)

   if err != nil {
      log.Fatal(err)
      return ""
   }

   return templateBuffer.String()
}

Here we created templateBuffer that will be used by SES email templates.

EmailData: Contains data that will bind to the HTML template.

htmlData: Read HTML file using ioutil’s ReadFile method and store bytes in htmlData.

htmlTemplate : Parse htmlData to new “email.html” template.

templateBuffer: ExecuteTemplate applies the HTML template with the specified data object and writes the output to templateBuffer.

Generate SES’s Email Template

We will import aws-sdk-go’s aws and ses packages for sending emails.

import (
   "bytes"
   "github.com/aws/aws-sdk-go/aws"
   "github.com/aws/aws-sdk-go/service/ses"
)
func GenerateSESTemplate() (template *ses.SendEmailInput) {

   html := getHTMLTemplate()

   title := "Sample Email"

   template = &ses.SendEmailInput{
      Destination: &ses.Destination{
         CcAddresses: []*string{},
         ToAddresses: []*string{
            aws.String(&receiver),
         },
      },
      Message: &ses.Message{
         Body: &ses.Body{
            Html: &ses.Content{
               Charset: aws.String("utf-8"),
               Data:    aws.String(html),
            },
         },
         Subject: &ses.Content{
            Charset: aws.String("utf-8"),
            Data:    aws.String(title),
         },
      },
      Source: aws.String(&sender),
   }

   return
}

html: get the template from getHTMLTemplate()

template: It contains a request for a formatted email from SendEmailInput. We can also add a Text field in the Message Body.

Send Email

import (
   "github.com/aws/aws-sdk-go/aws"
   "github.com/aws/aws-sdk-go/aws/awserr"
   "github.com/aws/aws-sdk-go/service/ses"
)
func SendEmail() {

   emailTemplate := GenerateSESTemplate()

   sess, err := session.NewSession(&aws.Config{
      Region:      aws.String(&region),
      Credentials: credentials.NewStaticCredentials(&accessKeyId, &secretAccessKey, ""),
   })

   if err != nil {
      log.Fatal(err)
   }

   service := ses.New(sess)

   // Attempt to send the email.
   _, err = service.SendEmail(emailTemplate)

   if err != nil {
      if aerr, ok := err.(awserr.Error); ok {
         log.Fatal(aerr.Error())
      } else {
         log.Fatal(err)
      }
   }
}

SendEmail gets email data from GenerateSESTemplate() and sends an email with that data using SES’s SendEmail() method.

That’s it. Now you can send emails by changing your sender and receiver in the email template.

The email will look like below,

Conclusion

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Sumita Kevat

Sumita is an experienced software developer with 5+ years in web development. Proficient in front-end and back-end technologies for creating scalable and efficient web applications. Passionate about staying current with emerging technologies to deliver.