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Object Storage Service:Configure bucket policies by using OSS SDK for Python

Last Updated:Feb 26, 2024

A bucket policy allows you to authorize or restrict access of anonymous users or identified 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.

Usage notes

  • Before you configure bucket policies, make sure that you are familiar with this feature. For more information, see Bucket policies.

  • In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS from other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about OSS regions and endpoints, see Regions and endpoints.

  • In this topic, access credentials are obtained from environment variables. For more information about how to configure access credentials, see Configure access credentials.

  • In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient instance by using custom domain names or Security Token Service (STS), see Initialization.

  • To configure a bucket policy, you must have the oss:PutBucketPolicy permission. To query bucket policies, you must have the oss:GetBucketPolicy permission. To delete a bucket policy, you must have the oss:DeleteBucketPolicy permission. For more information, see Attach a custom policy to a RAM user.

Configure a bucket policy

The following sample code provides an example on how to configure a bucket policy:

# -*- coding: utf-8 -*-

import oss2
from oss2.credentials import EnvironmentVariableCredentialsProvider
import json

# Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
auth = oss2.ProviderAuth(EnvironmentVariableCredentialsProvider())
# In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
# Specify the name of the bucket. 
bucket = oss2.Bucket(auth, 'http://oss-cn-hangzhou.aliyuncs.com', 'examplebucket')
# In the following example, the bucket owner whose UID is 174649585760xxxx uses a bucket policy to authorize a RAM user whose UID is 20214760404935xxxx to list all objects in the examplebucket bucket. 
policy_text = '{"Statement": [{"Effect": "Allow", "Action": ["oss:GetObject", "oss:ListObjects"], "Principal": ["20214760404935xxxx"], "Resource": ["acs:oss:*:174649585760xxxx:examplebucket/*"]}], "Version": "1"}'

# Configure the bucket policy. 
bucket.put_bucket_policy(policy_text)

Query bucket policies

The following sample code shows how to query bucket policies:

# -*- coding: utf-8 -*-

import oss2
from oss2.credentials import EnvironmentVariableCredentialsProvider
import json
# Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
auth = oss2.ProviderAuth(EnvironmentVariableCredentialsProvider())
# In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
# Specify the name of the bucket. 
bucket = oss2.Bucket(auth, 'http://oss-cn-hangzhou.aliyuncs.com', 'yourBucketName')

# Query the configurations of the bucket policies. 
result = bucket.get_bucket_policy()
policy_json = json.loads(result.policy) 
print("Get policy text: ", policy_json)

Delete a bucket policy

The following sample code provides an example on how to delete a bucket policy:

# -*- coding: utf-8 -*-

import oss2
from oss2.credentials import EnvironmentVariableCredentialsProvider
# Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
auth = oss2.ProviderAuth(EnvironmentVariableCredentialsProvider())
# In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
# Specify the name of the bucket. 
bucket = oss2.Bucket(auth, 'http://oss-cn-hangzhou.aliyuncs.com', 'yourBucketName')

# Delete the bucket policy. 
result = bucket.delete_bucket_policy()
assert int(result.status)//100 == 2

References

  • For the complete sample code that is used to manage bucket policies, visit GitHub.

  • For more information about the API operation that you can call to configure a bucket policy, see PutBucketPolicy.

  • For more information about the API operation that you can call to query bucket policies, see GetBucketPolicy.

  • For more information about the API operation that you can call to delete a bucket policy, see DeleteBucketPolicy.