Versioning applies to all objects in a bucket.

By versioning, you can restore an object in the bucket to any of its historical versions if it is accidentally overwritten or deleted. A bucket can be in the following three versioning states: not versioned (default), enabled, and suspended.

For more information about versioning, see Introduction to versioning in the Developer Guide.

Set the versioning state of a bucket

You can run the following code to set the versioning state of a bucket to enabled or suspended: 
package main

import (
  "fmt"
  "os"

  "github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func main() {
  // Creates an OSSClient instance.
  client, err := oss.New("<yourEndpoint>", "<yourAccessKeyId>", "<yourAccessKeySecret>")
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }

  // Creates a bucket.
  err = client.CreateBucket("<yourBucketName>")
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }
  // Sets the versioning state of the bucket to Enabled or Suspended. In this example, the versioning states is set to Enabled.
  config := oss.VersioningConfig{Status: "Enabled"}
  err = client.SetBucketVersioning("<yourBucketName>", config)
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }
}

For more information about setting the versioning state of a bucket, see PutBucketVersioning.

Obtain the versioning state of a bucket

You can run the following code to obtain the versioning state of a bucket: 
package main

import (
  "fmt"
  "os"

  "github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func main() {
  // Creates an OSSClient instance.
  client, err := oss.New("<yourEndpoint>", "<yourAccessKeyId>", "<yourAccessKeySecret>")
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }

  // Obtains the versioning state of the bucket.
  ret, err := client.GetBucketVersioning("<yourBucketName>")
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }
  // Prints the versioning state of the bucket.
  fmt.Println("The bucket Versioning status:", ret.Status)
}

For more information about obtaining the versioning state of a bucket, see GetBucketVersioning.

List the versions of all objects in a bucket

Run the following code to list the versions of all objects (including delete markers) in a specified bucket: 
package main

import (
  "fmt"
  "net/http"
  "os"
  "strings"

  "github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func main() {
  // Creates an OSSClient instance.
  client, err := oss.New("<yourEndpoint>", "<yourAccessKeyId>", "<yourAccessKeySecret>")
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }

  // Obtains the bucket.
  bucket, err := client.Bucket("<yourBucketName>")
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }

  // Lists objects with the specified prefix.
  ret, err := bucket.ListObjectVersions(oss.Prefix("yourObjectPrefix"))
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }

  // Prints the object information.
  for _, object := range ret.ObjectVersions {
    fmt.Println("Object:", object)
  }
  // Prints the delete markers.
  for _, marker := range ret.ObjectDeleteMarkers {
    fmt.Println("Delete Markers:", marker)
  }
}

For more information about listing the versions of all objects (including delete markers) in a bucket, see GetBucketVersions (ListObjectVersions).