Assembling Parts (SDK for Python)
Function
This API assembles the uploaded parts to compete the multipart upload. Before performing this operation, you cannot download the uploaded data. When assembling parts, you need to copy the additional message header information recorded during the multipart upload initiation to the object metadata. Such information is processed the same way the information in a common object upload is processed. In the case of assembling parts concurrently, last write wins is applied, but the time of last write is defined as the time when a multipart upload was initiated.
As long as the multipart upload is not aborted, all uploaded parts occupy the space. However, after you assembled the specified parts, those uploaded but not assembled will be deleted to free up space.
When assembling parts, OBS creates an object by putting part numbers in ascending order. If any object metadata is provided in the initiation of the multipart upload, OBS will associate the metadata with the object. After the multipart upload is complete, the parts will no longer exist. A part assembling request must contain the upload ID, part numbers, and a list of corresponding ETag values. In response to the request, the ETag that uniquely identifies the assembled parts is contained. This ETag is not the MD5 hash value of the entire object.
Restrictions
- To assemble parts, you must be the bucket owner or have the required permission (obs:object:PutObject in IAM or PutObject in a bucket policy). For details, see Introduction to OBS Access Control, IAM Custom Policies, and Configuring an Object Policy.
- The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.
- After a multipart upload is complete, the uploaded parts that are not assembled will be automatically deleted and cannot be recovered. Before assembling parts, use the API for listing uploaded parts to check all parts to ensure that no part is missed.
Method
ObsClient.completeMultipartUpload(bucketName, objectKey, uploadId, completeMultipartUploadRequest)
Request Parameters
Parameter |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
bucketName |
str |
Yes |
Explanation: Bucket name Restrictions:
Default value: None |
objectKey |
str |
Yes |
Explanation: Object name. An object is uniquely identified by an object name in a bucket. An object name is a complete path that does not contain the bucket name. For example, if the address for accessing the object is examplebucket.obs.ap-southeast-1.myhuaweicloud.com/folder/test.txt, the object name is folder/test.txt. Value range: The value must contain 1 to 1,024 characters. Default value: None
NOTE:
The object URL is in the following format: https://Bucket name.Domain name/Folder directory level/Object name. If this object is stored in the root directory of the bucket, its URL does not contain the folder directory level. |
uploadId |
str |
Yes |
Explanation: Multipart upload ID, for example, 000001648453845DBB78F2340DD460D8 Value range: The value must contain 32 characters. Default value: None |
completeMultipartUploadRequest |
Yes |
Explanation: Request parameters for assembling parts. For details, see Table 2. |
|
isAttachCrc64 |
bool |
No |
Explanation: Whether to calculate the CRC64 value of the entire object based on the CRC64 value of each part. Restrictions:
Value range:
Default value: False |
encoding_type |
str |
No |
Explanation: Encoding type for key in the response. If key in the response contains control characters that are not supported by the XML 1.0 standard, you can specify this parameter to encode key. Value range: url Default value: None. If you leave this parameter blank, encoding is not applied to Key. |
Parameter |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
parts |
list of CompletePart |
Yes |
Explanation: List of parts to be assembled. For details, see Table 3. |
Parameter |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
partNum |
int |
Yes |
Explanation: Part number Value range: [1,10000] Default value: None |
etag |
str |
Yes |
Explanation: ETag of a part. It is calculated by encoding the 128-bit MD5 value of the part using Base64. Value range: The value must contain 32 characters. Default value: None |
crc64 |
int or str or long |
No |
Explanation: CRC64 value of a part. It is calculated based on the ECMA-182 standard. Restrictions: This parameter is not supported for POSIX or SFS objects. Value range: A 64-bit CRC value calculated based on the ECMA-182 standard. Default value: None |
size |
int |
No |
Explanation: Part size. Restrictions: This parameter is mandatory when the value of crc64 is specified. Value range: The value ranges from 100 KB to 5 GB, in bytes. Default value: None |
Responses
Type |
Description |
---|---|
Explanation: SDK common results |
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, this parameter is left blank. 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 |
---|---|
Explanation: Response to the request for assembling parts. For details, see Table 7. |
Parameter |
Type |
Description |
---|---|---|
etag |
str |
Explanation: The ETag that uniquely identifies the object after its parts were assembled, calculated based on the ETag of each part. Restrictions: If an object is encrypted using server-side encryption, the ETag is not the MD5 value of the object. Value range: The value must contain 32 characters. Default value: None |
crc64 |
str |
Explanation: A 64-bit CRC value calculated based on the ECMA-182 standard. It uniquely identifies an object and can be used to check the integrity of the object content. If an object has different CRC64 values when being uploaded and downloaded, its content has been changed. CRC64 reflects changes to the contents of the object, not its metadata. Restrictions:
Value range: A 64-bit CRC value calculated based on the ECMA-182 standard. Default value: None |
bucket |
str |
Explanation: Bucket in which parts are assembled Restrictions:
Default value: None |
key |
str |
Explanation: Object name obtained after part assembling. An object is uniquely identified by an object name in a bucket. An object name is a complete path that does not contain the bucket name. For example, if the address for accessing the object is examplebucket.obs.ap-southeast-1.myhuaweicloud.com/folder/test.txt, the object name is folder/test.txt. Value range: The value must contain 1 to 1,024 characters. Default value: None |
location |
str |
Explanation: URL of the generated object after part assembling Example: https://example-Bucket.obs.regions.myhuaweicloud.com/example-Object Default value: None |
versionId |
str |
Explanation: Version ID of the object obtained after part assembling Value range: The value must contain 32 characters. Default value: None |
crc64 |
str |
Explanation: A 64-bit CRC value calculated based on the ECMA-182 standard. It uniquely identifies an object and can be used to check the integrity of the object content. If an object has different CRC64 values when being uploaded and downloaded, its content has been changed. CRC64 reflects changes to the contents of the object, not its metadata. Restrictions:
Value range: A 64-bit CRC value calculated based on the ECMA-182 standard. Default value: None |
sseKms |
str |
Explanation: SSE-KMS algorithm Value range: kms Default value: None |
sseKmsKey |
str |
Explanation: ID of the KMS master key when SSE-KMS is used Value range: Valid value formats are as follows:
In the preceding formats:
Default value:
|
sseC |
str |
Explanation: SSE-C algorithm Value range: AES256 Default value: None |
sseCKeyMd5 |
str |
Explanation: MD5 value of the key for encrypting objects when SSE-C is used. This value is used to check whether any error occurs during the transmission of the key. Restrictions: The value is encrypted by MD5 and then encoded by Base64, for example, 4XvB3tbNTN+tIEVa0/fGaQ==. Default value: None |
objectUrl |
str |
Explanation: Full path to the obtained object after part assembling Default value: None |
encoding_type |
str |
Explanation: Encoding type for Key in the response. If Key in the response contains control characters that are not supported by the XML 1.0 standard, you can specify this parameter to encode Key. Value range: url Default value: None. If you leave this parameter blank, encoding is not applied to Key. |
Code Examples
This example assembles the parts previously uploaded to a bucket.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 |
from obs import ObsClient from obs import CompleteMultipartUploadRequest, CompletePart 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. Here uses CN-Hong Kong 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: # Specify the list of parts to be assembled by configuring completeMultipartUploadRequest. Each part contains partNum and etag. part1 = CompletePart(partNum='partNumber1', etag='etag1') part2 = CompletePart(partNum='partNumber2', etag='etag2') completeMultipartUploadRequest = CompleteMultipartUploadRequest(parts=[part1, part2]) bucketName = "examplebucket" objectKey = "objectname" # Specify the ID of the multipart upload. uploadId = "your uploadid" # Assemble the parts uploaded to the bucket. resp = obsClient.completeMultipartUpload(bucketName, objectKey, uploadId, completeMultipartUploadRequest, encoding_type='url') # If status code 2xx is returned, the API is called successfully. Otherwise, the API call fails. if resp.status < 300: print('Complete Multipart Upload Succeeded') print('requestId:', resp.requestId) print('etag:', resp.body.etag) print('bucket:', resp.body.bucket) print('key:', resp.body.key) print('location:', resp.body.location) print('versionId:', resp.body.versionId) else: print('Complete Multipart Upload Failed') print('requestId:', resp.requestId) print('errorCode:', resp.errorCode) print('errorMessage:', resp.errorMessage) except: print('Complete Multipart Upload Failed') print(traceback.format_exc()) |
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