Obtaining Data Cursors
Function
This API is used to obtain data cursors.
Calling Method
For details, see Calling APIs.
URI
GET /v2/{project_id}/cursors
Parameter |
Mandatory |
Type |
Description |
---|---|---|---|
project_id |
Yes |
String |
Project ID |
Parameter |
Mandatory |
Type |
Description |
---|---|---|---|
stream-name |
Yes |
String |
Name of the stream |
partition-id |
Yes |
String |
Partition identifier of the stream.Two partition ID formats are available:- shardId-0000000000- 0For example, if a stream has three partitions, the partition IDs are 0, 1, and 2, or shardId-0000000000, shardId-0000000001, and shardId-0000000002. |
cursor-type |
No |
String |
Cursor type.- AT_SEQUENCE_NUMBER: Data is read from the position denoted by a specific sequence number (that is defined by starting-sequence-number). This type is the default cursor type.- AFTER_SEQUENCE_NUMBER: Data is read right after the position denoted by a specific sequence number (that is defined by starting-sequence-number).- TRIM_HORIZON: Data is read from the earliest valid record stored in the partition. For example, a tenant used a DIS stream to upload three pieces of data A1, A2, and A3. Assuming that A1 expires but A2 and A3 are still valid after a period of time, if the tenant specifies TRIM_HORIZON for downloading data, only A2 and A3 can be downloaded.- LATEST: Data is read just after the most recent record in the partition. This setting ensures that you always read the most recent data in the partition.- AT_TIMESTAMP: Data is read from the position denoted by a specific timestamp. Enumeration values:
|
starting-sequence-number |
No |
String |
Sequence number. A sequence number is the unique identifier of each record. DIS automatically allocates a sequence number when the data producer calls the PutRecords operation to add data to the DIS stream. The sequence number of the same partition key usually changes with time. A longer interval between PutRecords requests results in a larger sequence number.The sequence number is closely related to cursor types AT_SEQUENCE_NUMBER and AFTER_SEQUENCE_NUMBER. The two parameters determine the location of the data to be accessed.Value range: 0 to 9223372036854775807 |
timestamp |
No |
Long |
Timestamp when the data record starts to be read, which is closely related to cursor type AT_TIMESTAMP. The two parameters determine the position of the data to be read. Note: This timestamp is accurate to milliseconds. |
Request Parameters
Parameter |
Mandatory |
Type |
Description |
---|---|---|---|
X-Auth-Token |
Yes |
String |
User token. It can be obtained by calling the IAM API used to obtain a user token. The value of X-Subject-Token in the response header is the user token. |
Response Parameters
Status code: 200
Parameter |
Type |
Description |
---|---|---|
partition_cursor |
String |
Data cursor Value: 1 to 512 characters. Note: The validity period of a cursor is 5 minutes. Minimum: 1 Maximum: 512 |
Example Requests
Obtaining Data Cursors
GET https://{Endpoint}/v2/{project_id}/cursors
Example Responses
Status code: 200
Normal response
{ "partition_cursor" : "eyJnZXRJdGVyYXRvclBhcmFtIjp7InN0cmVhbS1uYW1lIjoianpjIiwicGFydGl0aW9uLWlkIjoiMCIsImN1cnNvci10eXBlIjoiQVRfU0VRVUVOQ0VfTlVNQkVSIiwic3RhcnRpbmctc2VxdWVuY2UtbnVtYmVyIjoiMTAifSwiZ2VuZXJhdGVUaW1lc3RhbXAiOjE1MDYxNTk1NjM0MDV9" }
SDK Sample Code
The SDK sample code is as follows.
Java
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package com.huaweicloud.sdk.test; import com.huaweicloud.sdk.core.auth.ICredential; import com.huaweicloud.sdk.core.auth.BasicCredentials; import com.huaweicloud.sdk.core.exception.ConnectionException; import com.huaweicloud.sdk.core.exception.RequestTimeoutException; import com.huaweicloud.sdk.core.exception.ServiceResponseException; import com.huaweicloud.sdk.dis.v2.region.DisRegion; import com.huaweicloud.sdk.dis.v2.*; import com.huaweicloud.sdk.dis.v2.model.*; public class ShowCursorSolution { public static void main(String[] args) { // The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security. // In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment String ak = System.getenv("CLOUD_SDK_AK"); String sk = System.getenv("CLOUD_SDK_SK"); ICredential auth = new BasicCredentials() .withAk(ak) .withSk(sk); DisClient client = DisClient.newBuilder() .withCredential(auth) .withRegion(DisRegion.valueOf("<YOUR REGION>")) .build(); ShowCursorRequest request = new ShowCursorRequest(); request.withStreamName("<stream-name>"); request.withPartitionId("<partition-id>"); request.withCursorType(ShowCursorRequest.CursorTypeEnum.fromValue("<cursor-type>")); request.withStartingSequenceNumber("<starting-sequence-number>"); request.withTimestamp(<timestamp>L); try { ShowCursorResponse response = client.showCursor(request); System.out.println(response.toString()); } catch (ConnectionException e) { e.printStackTrace(); } catch (RequestTimeoutException e) { e.printStackTrace(); } catch (ServiceResponseException e) { e.printStackTrace(); System.out.println(e.getHttpStatusCode()); System.out.println(e.getRequestId()); System.out.println(e.getErrorCode()); System.out.println(e.getErrorMsg()); } } } |
Python
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# coding: utf-8 import os from huaweicloudsdkcore.auth.credentials import BasicCredentials from huaweicloudsdkdis.v2.region.dis_region import DisRegion from huaweicloudsdkcore.exceptions import exceptions from huaweicloudsdkdis.v2 import * if __name__ == "__main__": # The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security. # In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment ak = os.environ["CLOUD_SDK_AK"] sk = os.environ["CLOUD_SDK_SK"] credentials = BasicCredentials(ak, sk) client = DisClient.new_builder() \ .with_credentials(credentials) \ .with_region(DisRegion.value_of("<YOUR REGION>")) \ .build() try: request = ShowCursorRequest() request.stream_name = "<stream-name>" request.partition_id = "<partition-id>" request.cursor_type = "<cursor-type>" request.starting_sequence_number = "<starting-sequence-number>" request.timestamp = <timestamp> response = client.show_cursor(request) print(response) except exceptions.ClientRequestException as e: print(e.status_code) print(e.request_id) print(e.error_code) print(e.error_msg) |
Go
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package main import ( "fmt" "github.com/huaweicloud/huaweicloud-sdk-go-v3/core/auth/basic" dis "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/dis/v2" "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/dis/v2/model" region "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/dis/v2/region" ) func main() { // The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security. // In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment ak := os.Getenv("CLOUD_SDK_AK") sk := os.Getenv("CLOUD_SDK_SK") auth := basic.NewCredentialsBuilder(). WithAk(ak). WithSk(sk). Build() client := dis.NewDisClient( dis.DisClientBuilder(). WithRegion(region.ValueOf("<YOUR REGION>")). WithCredential(auth). Build()) request := &model.ShowCursorRequest{} request.StreamName = "<stream-name>" request.PartitionId = "<partition-id>" cursorTypeRequest:= model.GetShowCursorRequestCursorTypeEnum().<CURSOR_TYPE> request.CursorType = &cursorTypeRequest startingSequenceNumberRequest:= "<starting-sequence-number>" request.StartingSequenceNumber = &startingSequenceNumberRequest timestampRequest:= int64(<timestamp>) request.Timestamp = ×tampRequest response, err := client.ShowCursor(request) if err == nil { fmt.Printf("%+v\n", response) } else { fmt.Println(err) } } |
More
For SDK sample code of more programming languages, see the Sample Code tab in API Explorer. SDK sample code can be automatically generated.
Status Codes
Status Code |
Description |
---|---|
200 |
Normal response |
Error Codes
See Error Codes.
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