AWS S3 (SDK v2) in Go Quickly example

Requirements

Get your AWS key and secrets from an Iam user in your AWS console and set as environments vars

AWS_KEY= <aws iam user key>
AWS_SECRET= <aws iam user secret>

Install the go dependencies

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

Code

1. Create a struct for manage the AWS Client It's a good practice to get this struct on an independent file to used if we want to implement mor3 AWS services.

File: manager.go
Parameters:
region: the AWS region (ex. us-east-1)

const AwsKeyEnv = "AWS_KEY"
const AwsSecretEnv = "AWS_SECRET"

type AwsConfigClient struct {
    config aws.Config
    region string
}

func NewAwsConfigClient(region string) (*AwsConfigClient, error) {
    key := os.Getenv(AwsKeyEnv)
    secret := os.Getenv(AwsSecretEnv)
    prov := credentials.NewStaticCredentialsProvider(key, secret, "")
    cfg, err := config.LoadDefaultConfig(context.TODO(),
        config.WithRegion(region),
        config.WithCredentialsProvider(prov),
    )
    if err != nil {
        return nil, err
    }
    return &AwsConfigClient{
        config: cfg,
    }, err
}

1. Create a struct for manager the common types. File: s3.go Parameters: cfg : An instance from the struct config (step 1) bucket: the name of the AWS Bucket

type AwsS3Client struct {
    config aws.Config
    bucket string
    s3     *s3.Client
}

func NewAwsS3Client(cfg *AwsConfigClient, bucket string) (*AwsS3Client, error) {
    client := s3.NewFromConfig(cfg.config)
    return &AwsS3Client{
        config: cfg.config,
        bucket: bucket,
        s3:     client,
    }, nil
}

Upload a file to an AWS bucket

Parameters:
path : the path and the file we want to upload (example: /files/test.txt)

func (cli *AwsS3Client) UploadObject(path string) (*manager.UploadOutput, error) {
file, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    defer file.Close()
    client := s3.NewFromConfig(cli.config)
    uploader := manager.NewUploader(client)
    result, err := uploader.Upload(context.TODO(), &s3.PutObjectInput{
        Bucket: aws.String(cli.bucket),
        Key:    aws.String(filepath.Base(path)),
        Body:   file,
    })
    if err != nil {
        return nil, err
    }
    return result, nil
}

Download a file from AWS bucket

Parameters:
fileName : the name of the file in the AWS bucket

func (cli *AwsS3Client) Download(fileName string) (*manager.UploadOutput, error) {
    client := s3.NewFromConfig(cli.config)
    downloader := manager.NewDownloader(client)
    file, err := os.Create(fileName)
    if err != nil {
        return nil, err
    }
    defer file.Close()
    _, err = downloader.Download(context.TODO(), file, &s3.GetObjectInput{
        Bucket: aws.String(cli.bucket),
        Key:    aws.String(fileName),
    })
    return nil, nil
}

Delete a file from AWS bucket

Parameters:
fileName : the name of the file in the AWS bucket

func (cli *AwsS3Client) DeleteObject(fileName string) error {
    objectIds := []types.ObjectIdentifier{
        {Key: aws.String(fileName)},
    }
    _, err := cli.s3.DeleteObjects(context.TODO(), &s3.DeleteObjectsInput{
        Bucket: aws.String(cli.bucket),
        Delete: &types.Delete{Objects: objectIds},
    })
    return err
}

Get the AWS files list

func (cli *AwsS3Client) GetObjects() ([]types.Object, error) {
    output, err := cli.s3.ListObjectsV2(context.TODO(), &s3.ListObjectsV2Input{
        Bucket: aws.String(cli.bucket),
    })
    if err != nil {
        return nil, err
    }
    data := make([]types.Object, len(output.Contents))
    for i, object := range output.Contents {
        data[i] = object
    }
    return data, nil
}

GitHub code example

AWS s3 files

Related links

AWS S3 official documentation
AWS S3 official examples