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Golang SDK

This guide shows you how to integrate the S3 compatible storage layer using Go SDK. We will be using the [minio-go] (https://github.com/minio/minio-go) client to interact with the S3 compatible APIs.

Prerequisites​

  • You need to have Go installed on your system. You can follow the instructions from here.
  • You need to have an access key ID and secret access key. You can create these keys from the dashboard.

Install minio-go​

You need to install the minio-go client on your system.

go get github.com/minio/minio-go/v7

Operations​

Create a client​

package main

import (
    "fmt"

    "github.com/minio/minio-go/v7"
    "github.com/minio/minio-go/v7/pkg/credentials"
)

func main() {
        // Initialize minio client object.
        s3Client, err := minio.New("https://buckets.chainsafe.io", &minio.Options{
            Creds:  credentials.NewStaticV4("YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY", ""),
            Secure: true,
        })
        if err != nil {
                fmt.Println(err)
                return
        }
}

Create a bucket​

Creates a new bucket.

// Create a bucket at region 'us-east-1' with object locking enabled.
err = minioClient.MakeBucket(context.Background(), "mybucket", minio.MakeBucketOptions{Region: "us-east-1", ObjectLocking: true})
if err != nil {
    fmt.Println(err)
    return
}
fmt.Println("Successfully created mybucket.")

List buckets​

Lists all buckets.

buckets, err := minioClient.ListBuckets(context.Background())
if err != nil {
    fmt.Println(err)
    return
}
for _, bucket := range buckets {
    fmt.Println(bucket)
}

Bucket Exists​

Checks if a bucket exists and you have permission to access it.

found, err := minioClient.BucketExists(context.Background(), "mybucket")
if err != nil {
    fmt.Println(err)
    return
}
if found {
    fmt.Println("Bucket found")
}

Remove a bucket​

Removes a bucket.

err = minioClient.RemoveBucket(context.Background(), "mybucket")
if err != nil {
    fmt.Println(err)
    return
}
fmt.Println("Successfully removed mybucket.")

List Objects​

Lists all objects in a bucket.

ctx, cancel := context.WithCancel(context.Background())

defer cancel()

objectCh := minioClient.ListObjects(ctx, "mybucket", minio.ListObjectsOptions{
       Prefix: "myprefix",
       Recursive: true,
})
for object := range objectCh {
    if object.Err != nil {
        fmt.Println(object.Err)
        return
    }
    fmt.Println(object)
}

Get object​

Gets an object from a bucket.

object, err := minioClient.GetObject(context.Background(), "mybucket", "myobject", minio.GetObjectOptions{})
if err != nil {
    fmt.Println(err)
    return
}
defer object.Close()

localFile, err := os.Create("/tmp/local-file.jpg")
if err != nil {
    fmt.Println(err)
    return
}
defer localFile.Close()

if _, err = io.Copy(localFile, object); err != nil {
    fmt.Println(err)
    return
}

Put object​

Puts an object in a bucket.

file, err := os.Open("my-testfile")
if err != nil {
    fmt.Println(err)
    return
}
defer file.Close()

fileStat, err := file.Stat()
if err != nil {
    fmt.Println(err)
    return
}

uploadInfo, err := minioClient.PutObject(context.Background(), "mybucket", "myobject", file, fileStat.Size(), minio.PutObjectOptions{ContentType:"application/octet-stream"})
if err != nil {
    fmt.Println(err)
    return
}
fmt.Println("Successfully uploaded bytes: ", uploadInfo)

Object Exist​

Checks if an object exists in a bucket.

objInfo, err := minioClient.StatObject(context.Background(), "mybucket", "myobject", minio.StatObjectOptions{})
if err != nil {
fmt.Println(err)
return
}
fmt.Println(objInfo)

Copy object​

Copies an object from source bucket to destination bucket.


srcOpts := minio.CopySrcOptions{
    Bucket: "my-sourcebucketname",
    Object: "my-sourceobjectname",
}

// Destination object
dstOpts := minio.CopyDestOptions{
    Bucket: "my-bucketname",
    Object: "my-objectname",
}

// Copy object call
uploadInfo, err := minioClient.CopyObject(context.Background(), dst, src)
if err != nil {
    fmt.Println(err)
    return
}

fmt.Println("Successfully copied object:", uploadInfo)

Remove object​

Removes an object from a bucket.

bucketName := "mybucket"
document1Key := "myobject"
err = client.RemoveObject(ctx, bucketName, document1Key, minio.RemoveObjectOptions{})
if err != nil {
    fmt.Println("error deleting the bucket object: ", err.Error())
}

NOTE:

We only support a limited set of S3 functionalities as of now but we intend to expand these functionalities in the coming months. If there is a specific functionality that you would like to request, please email colin@chainsafe.io. You need to set buckets.chainsafe.io:443 endpoint to your library of choice. You need to set the region for s3 client library to us-east-1