Configure bucket policies to authorize or restrict user access to OSS by using OSS SDK for Go-Object Storage Service(OSS)-阿里云帮助中心

Bucket policies grant or restrict access for anonymous or authenticated users, such as Alibaba Cloud accounts, RAM users, and RAM roles, to specific Object Storage Service (OSS) resources. For example, you can grant read-only permissions on specific OSS resources to a RAM user of another Alibaba Cloud account.

Notes

Before you configure bucket policies, familiarize yourself with this feature. For more information, see Bucket Policy.
The sample code in this topic uses the region ID cn-hangzhou of the China (Hangzhou) region. By default, the public endpoint is used. To access resources in a bucket from other Alibaba Cloud services in the same region, use an internal endpoint. For more information about OSS regions and endpoints, see OSS regions and endpoints.
In this topic, access credentials are obtained from environment variables. For more information, see Configure access credentials.
The oss:PutBucketPolicy permission is required to configure a bucket policy. The oss:GetBucketPolicy permission is required to query a bucket policy. The oss:DeleteBucketPolicy permission is required to delete a bucket policy. For more information, see Authorize custom policies for RAM users.

Sample code

Configure a bucket policy

The following sample code configures a bucket policy.

package main

import (
	"context"
	"flag"
	"log"
	"strings"

	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss"
	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss/credentials"
)

// Define global variables.
var (
	region     string // Region in which the bucket is located.
	bucketName string // Name of the bucket.
)

// Specify the init function used to initialize command line parameters.
func init() {
	flag.StringVar(&region, "region", "", "The region in which the bucket is located.")
	flag.StringVar(&bucketName, "bucket", "", "The name of the bucket.")
}

func main() {
	// Parse command line parameters.
	flag.Parse()

	// Check whether the name of the bucket is specified.
	if len(bucketName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, bucket name required")
	}

	// Check whether the region is specified.
	if len(region) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, region required")
	}

	// Load the default configurations and specify the credential provider and region.
	cfg := oss.LoadDefaultConfig().
		WithCredentialsProvider(credentials.NewEnvironmentVariableCredentialsProvider()).
		WithRegion(region)

	// Create an OSS client.
	client := oss.NewClient(cfg)

	// Define the bucket policy.
	policy := `{
		"Version": "1",
		"Statement": [
			{
				"Action": [
					"oss:PutObject",
					"oss:GetObject"
				],
				"Effect": "Deny",
				"Principal": ["1234567890"],
				"Resource": ["acs:oss:*:1234567890:*/*"]
			}
		]
	}`

	// Create a request to configure a bucket policy.
	request := &oss.PutBucketPolicyRequest{
		Bucket: oss.Ptr(bucketName),       // Name of the bucket.
		Body:   strings.NewReader(policy), // The bucket policy.
	}

	// Perform the operation to configure the bucket policy.
	result, err := client.PutBucketPolicy(context.TODO(), request)
	if err != nil {
		log.Fatalf("failed to put bucket policy %v", err)
	}

	// Display the result.
	log.Printf("put bucket policy result:%#v\n", result)
}

Query a bucket policy

The following sample code queries a bucket policy.

package main

import (
	"context"
	"flag"
	"log"

	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss"
	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss/credentials"
)

// Define global variables.
var (
	region     string // Region in which the bucket is located.
	bucketName string // Name of the bucket.
)

// Specify the init function used to initialize command line parameters.
func init() {
	flag.StringVar(&region, "region", "", "The region in which the bucket is located.")
	flag.StringVar(&bucketName, "bucket", "", "The name of the bucket.")
}

func main() {
	// Parse command line parameters.
	flag.Parse()

	// Check whether the name of the bucket is specified.
	if len(bucketName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, bucket name required")
	}

	// Check whether the region is specified.
	if len(region) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, region required")
	}

	// Load the default configurations and specify the credential provider and region.
	cfg := oss.LoadDefaultConfig().
		WithCredentialsProvider(credentials.NewEnvironmentVariableCredentialsProvider()).
		WithRegion(region)

	// Create an OSS client.
	client := oss.NewClient(cfg)

	// Create a request to query the bucket policy.
	request := &oss.GetBucketPolicyRequest{
		Bucket: oss.Ptr(bucketName),
	}

	// Make the query request.
	result, err := client.GetBucketPolicy(context.TODO(), request)
	if err != nil {
		log.Fatalf("failed to get bucket policy %v", err)
	}

	// Display the result.
	log.Printf("get bucket policy result:%#v\n", result)
}

Delete a bucket policy

The following sample code deletes a bucket policy.

package main

import (
	"context"
	"flag"
	"log"

	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss"
	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss/credentials"
)

// Define global variables.
var (
	region     string // Region in which the bucket is located.
	bucketName string // Name of the bucket.
)

// Specify the init function used to initialize command line parameters.
func init() {
	flag.StringVar(&region, "region", "", "The region in which the bucket is located.")
	flag.StringVar(&bucketName, "bucket", "", "The name of the bucket.")
}

func main() {
	// Parse command line parameters.
	flag.Parse()

	// Check whether the name of the bucket is specified.
	if len(bucketName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, bucket name required")
	}

	// Check whether the region is specified.
	if len(region) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, region required")
	}

	// Load the default configurations and specify the credential provider and region.
	cfg := oss.LoadDefaultConfig().
		WithCredentialsProvider(credentials.NewEnvironmentVariableCredentialsProvider()).
		WithRegion(region)

	// Create an OSS client.
	client := oss.NewClient(cfg)

	// Create a request to delete the bucket policy.
	request := &oss.DeleteBucketPolicyRequest{
		Bucket: oss.Ptr(bucketName),
	}

	// Delete the bucket policy.
	result, err := client.DeleteBucketPolicy(context.TODO(), request)
	if err != nil {
		log.Fatalf("failed to delete bucket policy %v", err)
	}

	// Display the result.
	log.Printf("delete bucket policy result:%#v\n", result)
}

References

For the complete sample code for configuring a bucket policy, visit GitHub example.
For the API operation used to configure a bucket policy, see PutBucketPolicy.
For the complete sample code for querying a bucket policy, visit GitHub example.
For the API operation used to query a bucket policy, see GetBucketPolicy.
For the complete sample code for deleting a bucket policy, visit GitHub example.
For the API operation used to delete a bucket policy, see DeleteBucketPolicy.