DEV Community: Vasanth Korada

Send an Email through AWS SES with GoLang

Vasanth Korada — Fri, 05 May 2023 05:41:36 +0000

Hello Gophers,

Video tutorial for the below tutorial

In this blog, we are going to see how to send a message to an email address with Golang and AWS-SDK for Go. The AWS SDK for Go provides APIs and utilities that developers can use to build Go applications that use AWS services. We are going to use AWS SES (Simple Email Service) to send an email.

Install the AWS SDK for Go



$ go get -u github.com/aws/aws-SDK-go/...

Get your AWS Access Keys

Open the IAM console.
On the navigation menu, choose Users.
Choose your IAM user name (not the check box).
Open the Security credentials tab, and then choose to Create access key.
To see the new access key, choose Show. Your credentials resemble the following: Access key ID: AKIAIOSFODNN7EXAMPLE Secret access key: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
To download the key pair, choose the Download .csv file. Store the keys in a secure location.

Config Setup

Your AWS config and credentials will be stored under ~/.aws/config and ~/.aws/credentials. Those are the default values for your AWS SDK Environment. If you want you can edit them.
Run the below command in the terminal to let the Go Program know that it should pick up the AWS config from the ~/.aws directory



$ export AWS_SDK_LOAD_CONFIG=true

Execution

Now let us jump into the execution part:

First verify your sender email address in the AWS SES Console. If your AWS SES is in Sandbox then you also need to verify the receiver email address as well.

Setup your Go Project and in your .go file add the below import statements



package main

import (
    "fmt"

    "github.com/aws/aws-sdk-go/aws"
    "github.com/aws/aws-sdk-go/aws/awserr"
    "github.com/aws/aws-sdk-go/aws/session"
    "github.com/aws/aws-sdk-go/service/ses"
)

Define the required const variables for AWS SES to send an email: ```

const ( Sender = "sender@gmail.com" Recipient = "receiver@gmail.com" Subject = "Vasanth through Amazon SES (AWS SDK for Go)" HtmlBody = "

Amazon SES Test Email (AWS SDK for Go)

This email was sent with " + "Amazon SES using the " + "AWS SDK for Go.

In your function first, create an AWS session

    sess, err := session.NewSessionWithOptions(session.Options{
        Profile: "ProfileName",
    })

    if err != nil {
        panic(err)
    }```



You can find your profile name in the ~/.aws/config file. It automatically creates a session if you follow the setup carefully at the start of this blog. And also check if there is an error or not while creating the session.

- Create a service from AWS Session

svc := ses.New(sess)




- Define your SES Email Input

input := &ses.SendEmailInput{ Destination: &ses.Destination{ CcAddresses: []*string{}, ToAddresses: []*string{ aws.String(Recipient), }, }, Message: &ses.Message{ Body: &ses.Body{ Html: &ses.Content{ Charset: aws.String(CharSet), Data: aws.String(HtmlBody), }, Text: &ses.Content{ Charset: aws.String(CharSet), Data: aws.String(TextBody), }, }, Subject: &ses.Content{ Charset: aws.String(CharSet), Data: aws.String(Subject), }, }, Source: aws.String(Sender), }




Here we used our previously defined const variables to frame up our Email Input. We use AWS and see from the SDK to define our email input. For ses content we are passing Charset and Data. And remaining all is straightforward as we can understand by looking at the code.

- After we have framed our SES SendEmailInput. Now we are going to send the email.

result, err := svc.SendEmail(input)




With the above-created service from the session, we are calling the SendEmail Function.

- We will now check if there is an error while sending the email with the below with the help of given pre-defined ErrCodes given by the AWS SDK

if err != nil { if aerr, ok := err.(awserr.Error); ok { switch aerr.Code() { case ses.ErrCodeMessageRejected: fmt.Println(ses.ErrCodeMessageRejected, aerr.Error()) case ses.ErrCodeMailFromDomainNotVerifiedException: fmt.Println(ses.ErrCodeMailFromDomainNotVerifiedException, aerr.Error()) case ses.ErrCodeConfigurationSetDoesNotExistException: fmt.Println(ses.ErrCodeConfigurationSetDoesNotExistException, aerr.Error()) default: fmt.Println(aerr.Error()) } } else { fmt.Println(err.Error()) }

return

}




- Now if there is no error while sending the email we are going to print the result

fmt.Println("Email Sent to address: " + Recipient) fmt.Println(result)




- After executing the above program

$ go run main.go




I can receive the message-id

{ MessageId: "0100017fa720252b-b635338c-fa69-49a9-9285-3c87920b-000000" }




Finally, This is how we can send an email with AWS SES with GoLang and AWS-SDK for Go.

Thanks for reading :)

Get Objects from AWS S3 Bucket with GoLang

Vasanth Korada — Fri, 05 May 2023 05:34:22 +0000

Hello Gophers,

In this blog, we are going to see how to list down all the objects from an AWS S3 Bucket with AWS GO SDK v2. The AWS SDK for Go provides APIs and utilities that developers can use to build Go applications that use AWS services.

Video tutorial for this blog:

Get your AWS Access Keys

Open the IAM console.
On the navigation menu, choose Users.
Choose your IAM user name (not the check box).
Open the Security credentials tab, and then choose to Create access key.
To see the new access key, choose Show. Your credentials resemble the following: Access key ID: AKIAIOSFODNN7EXAMPLE Secret access key: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
To download the key pair, choose the Download .csv file. Store the keys in a secure location.

Config Setup

Your AWS config and credentials will be stored under ~/.aws/config and ~/.aws/credentials. Those are the default values for your AWS SDK Environment. If you want you can edit them.
Run the below command in the terminal to let the Go Program know that it should pick up the AWS config from the ~/.aws directory



$ export AWS_SDK_LOAD_CONFIG=true

Setup

First create a bucket in the AWS S3 Console as in the below pictorial representation. Here I am creating a bucket with the name infytech2

Make sure you allow public access while creating the bucket

You can go with all the default options selected and click on Create Bucket Button.

Upload an object

Now upload any of the files or folders in your system into the bucket by clicking on the Upload Button as shown below.

Execution

To get started initialize your local project by running the following Go command.



$ go mod init aws_s3

The following commands show how to retrieve the standard set of SDK modules to use in your application.



$ go get github.com/aws/aws-sdk-go-v2
$ go get github.com/aws/aws-sdk-go-v2/config

This will retrieve the core SDK module, and the config module which is used for loading the AWS shared configuration.

Next you can install one or more AWS service API clients required by your application. All API clients are located under github.com/aws/aws-sdk-go-v2/service . In this example, we retrieve the Amazon S3 API client.



$ go get github.com/aws/aws-sdk-go-v2/service/s3

Now in main.go file setup the import statements



package main

import (
    "context"
    "log"
    "github.com/aws/aws-sdk-go-v2/aws"
    "github.com/aws/aws-sdk-go-v2/config"
    "github.com/aws/aws-sdk-go-v2/service/s3"
)

Now in your main function
Load the AWS Config



cfg, err := config.LoadDefaultConfig(context.TODO(), config.WithSharedConfigProfile("VasanthK"))

Initialise a s3 Client



client := s3.NewFromConfig(cfg)

Call ListObjects with the help of the client and bucket name specified which returns the list of objects from a particular bucket



    output, err := client.ListObjectsV2(context.TODO(), &s3.ListObjectsV2Input{
        Bucket: aws.String("infytech1"),
    })

Finally print out the objects from the bucket into the console with Object name and its Size



    for _, object := range output.Contents {
        log.Printf("key=%s size=%d", aws.ToString(object.Key), object.Size)
    }

Output



All Objects in infytech2 bucket
key=thumbnail.png size=149021

Entire Code File



package main

import (
    "context"
    "log"

    "github.com/aws/aws-sdk-go-v2/aws"
    "github.com/aws/aws-sdk-go-v2/config"
    "github.com/aws/aws-sdk-go-v2/service/s3"
)

func main() {

    cfg, err := config.LoadDefaultConfig(context.TODO(), config.WithSharedConfigProfile("VasanthK"))

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

    client := s3.NewFromConfig(cfg)

    output, err := client.ListObjectsV2(context.TODO(), &s3.ListObjectsV2Input{
        Bucket: aws.String("infytech2"),
    })

    if err != nil {
        log.Fatal(err)
    }
    log.Println("All Objects in infytech2 bucket")

    for _, object := range output.Contents {
        log.Printf("key=%s size=%d", aws.ToString(object.Key), object.Size)
    }
}

Finally thanks for reading Subscribe %[https://www.youtube.com/c/INFYTECH\]