Bucket is the globally unique namespace of TOS, which is equivalent to a data container and is used to store object data. This article describes how to obtain bucket metadata and determine whether a bucket exists.

Precautions

Before you can get the bucket metadata, you must have the tos: HeadBucketpermission. For specific operations, please refer to Overview.

If the bucket does not exist, the interface returns a 404, which is also commonly used to determine whether a bucket exists.

Sample code

The following code is used to obtain bucket-test metadata.

import http​
​
import os​
import tos​
​
# Retrieve AKSK information from environment variables.​
ak = os.getenv('TOS_ACCESS_KEY')​
sk = os.getenv('TOS_SECRET_KEY')​
endpoint = "your endpoint"​
region = "your region"​
bucket_name = 'bucket-test'​
​
try:​
    client = tos.TosClientV2(ak, sk, endpoint, region)​
    head_bucket_out = client.head_bucket(bucket_name)​
    print('region: ', head_bucket_out.region)​
    print('storageClass: ', head_bucket_out.storage_class)​
    print('azRedundancy: ', head_bucket_out.az_redundancy)​
except tos.exceptions.TosClientError as e:​
    # Operation failed, catch client error, usually caused by invalid request parameters or network issues​
    print('fail with client error, message:{}, cause: {}'.format(e.message, e.cause))​
except tos.exceptions.TosServerError as e:​
    if e.status_code == http.HTTPStatus.NOT_FOUND:​
        # The HTTP status code 404 indicates that the bucket does not exist.​
        print('bucket not exist')​
    elif e.status_code == http.HTTPStatus.FORBIDDEN:​
        # The HTTP status code 403 indicates that the user does not have the HeadBucket permission.​
        print('do not have head bucket policy')​
    else:​
        # # Operation failed, catch server error, detailed error information can be obtained from the response​
        print('fail with server error, code: {}'.format(e.code))​
        # request id can be used to locate specific issues, it is strongly recommended to save it in the log.​
        print('error with request id: {}'.format(e.request_id))​
        print('error with message: {}'.format(e.message))​
        print('error with http code: {}'.format(e.status_code))​
        print('error with ec: {}'.format(e.ec))​
        print('error with request url: {}'.format(e.request_url))​
except Exception as e:​
    print('fail with unknown error: {}'.format(e))​