Obtaining the Policy of a Bucket (SDK for Python)

Function

OBS provides access control over buckets. You can use an access policy to define whether a user can perform certain operations on a specific bucket. OBS access control can be implemented using IAM permissions, bucket policies, and ACLs. For more information, see Introduction to OBS Access Control.

A bucket policy is applied to a configured bucket and the objects in it. You can use a bucket policy to grant permissions for the bucket and the objects in it to IAM users or other accounts. If you want IAM users to have different permissions for different buckets, you can configure required bucket policies.

This API returns the policy of a bucket.

Restrictions

OBS returns "404 NoSuchBucketPolicy" when you call this API in the following scenarios:
- The specified bucket policy does not exist.
- The standard policy of the specified bucket is set to Private and no advanced policies are configured.
To obtain the policy of a bucket, you must be the bucket owner or have the required permission (obs:bucket:GetBucketPolicy in IAM or GetBucketPolicy in a bucket policy). For details, see Introduction to OBS Access Control, IAM Custom Policies, and Creating a Custom Bucket Policy.
The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.

Method

ObsClient.getBucketPolicy(bucketName, extensionHeaders)

Request Parameters

Parameter	Type	Mandatory (Yes/No)	Description
bucketName	str	Yes	Explanation: Bucket name Restrictions: A bucket name must be unique across all accounts and regions. A bucket name: Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed. Cannot be formatted as an IP address. Cannot start or end with a hyphen (-) or period (.). Cannot contain two consecutive periods (..), for example, my..bucket. Cannot contain periods (.) and hyphens (-) adjacent to each other, for example, my-.bucket or my.-bucket. If you repeatedly create buckets of the same name in the same region, no error will be reported and the bucket properties comply with those set in the first creation request. Default value: None
extensionHeaders	dict	No	Explanation: Extension headers. Value range: See User-defined Header (SDK for Python). Default value: None

Parameter

Type

Mandatory (Yes/No)

Description

bucketName

str

Yes

Explanation:

Bucket name

Restrictions:

A bucket name must be unique across all accounts and regions.
A bucket name:
- Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed.
- Cannot be formatted as an IP address.
- Cannot start or end with a hyphen (-) or period (.).
- Cannot contain two consecutive periods (..), for example, my..bucket.
- Cannot contain periods (.) and hyphens (-) adjacent to each other, for example, my-.bucket or my.-bucket.
If you repeatedly create buckets of the same name in the same region, no error will be reported and the bucket properties comply with those set in the first creation request.

Default value:

None

extensionHeaders

dict

Explanation:

Extension headers.

Value range:

See User-defined Header (SDK for Python).

Default value:

None

Responses

Type	Description
GetResult	Explanation: SDK common results

Type

Description

GetResult

Explanation:

SDK common results

**Table 1** GetResult
Parameter	Type	Description
status	int	Explanation: HTTP status code Value range: A status code is a group of digits ranging from 2xx (indicating successes) to 4xx or 5xx (indicating errors). It indicates the status of a response. For more information, see Status Code. Default value: None
reason	str	Explanation: Reason description. Default value: None
errorCode	str	Explanation: Error code returned by the OBS server. If the value of status is less than 300, this parameter is left blank. Default value: None
errorMessage	str	Explanation: Error message returned by the OBS server. If the value of status is less than 300, this parameter is left blank. Default value: None
requestId	str	Explanation: Request ID returned by the OBS server Default value: None
indicator	str	Explanation: Error indicator returned by the OBS server. Default value: None
hostId	str	Explanation: Requested server ID. If the value of status is less than 300, this parameter is left blank. Default value: None
resource	str	Explanation: Error source (a bucket or an object). If the value of status is less than 300, this parameter is left blank. Default value: None
header	list	Explanation: Response header list, composed of tuples. Each tuple consists of two elements, respectively corresponding to the key and value of a response header. Default value: None
body	object	Explanation: Result content returned after the operation is successful. If the value of status is larger than 300, the value of body is null. The value varies with the API being called. For details, see Bucket-Related APIs (SDK for Python) and Object-Related APIs (SDK for Python). Default value: None

GetResult.body Type	Description
Policy	Explanation: Bucket policy

GetResult.body Type

Description

Policy

Explanation:

Bucket policy

**Table 2** Policy
Parameter	Type	Description
policyJSON	str	Explanation: Policy information in JSON format Restrictions: The bucket name contained in the Resource parameter of the policy must be the one specified for the current bucket policy. For details about the policy format, see Bucket Policy Parameters. Default value: None

Code Examples

This example returns the policy of bucket examplebucket.

    
     
       
       
         from obs import ObsClient
import os
import traceback

# Obtain an AK and SK pair using environment variables or import the AK and SK pair in other ways. Using hard coding may result in leakage.
# Obtain an AK and SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
ak = os.getenv("AccessKeyID")
sk = os.getenv("SecretAccessKey")
# (Optional) If you use a temporary AK and SK pair and a security token to access OBS, obtain them from environment variables.
# security_token = os.getenv("SecurityToken")
# Set server to the endpoint corresponding to the bucket. CN-Hong Kong is used here as an example. Replace it with the one in use.
server = "https://obs.ap-southeast-1.myhuaweicloud.com" 

# Create an obsClient instance.
# If you use a temporary AK and SK pair and a security token to access OBS, you must specify security_token when creating an instance.
obsClient = ObsClient(access_key_id=ak, secret_access_key=sk, server=server)
try:
    bucketName="examplebucket"
    # Obtain the bucket policy.
    resp = obsClient.getBucketPolicy(bucketName)
    # If status code 2xx is returned, the API is called successfully. Otherwise, the API call fails.
    if resp.status < 300:
        print('Get Bucket Policy Succeeded')
        print('requestId:', resp.requestId)
        print('policyJSON:', resp.body.policyJSON)
    else:
        print('Get Bucket Policy Failed')
        print('requestId:', resp.requestId)
        print('errorCode:', resp.errorCode)
        print('errorMessage:', resp.errorMessage)
except:
    print('Get Bucket Policy Failed')
    print(traceback.format_exc())

        

      

    
   