How do I initialize an OTSClient instance for SDK for .NET? - Tablestore

OTSClient is a client for Tablestore. OTSClient provides various methods for you to manage tables and perform read and write operations on a single row or multiple rows. To use Tablestore SDK for .NET to initiate a request, you must initialize an OTSClient instance and modify the default configurations of the OTSClient instance based on your business requirements.

Usage notes

Tablestore SDK for .NET supports multithreading. We recommend that you use the same OTSClient instance among the multiple threads of a task.

Preparations

Before you initialize an OTSClient instance, you must configure an AccessKey pair, obtain the endpoint of your Tablestore instance, and install Tablestore SDK for .NET.

Configure an AccessKey pair

To access Tablestore, you must have a valid AccessKey pair to verify your identity. The following table describes three methods that you can use to obtain an AccessKey pair. To ensure the security of your AccessKey pair, we recommend that you configure the AccessKey pair in the environment variables of your operating system.

Obtain an AccessKey pair.

Important

To prevent security risks caused by the leak of the AccessKey pair of your Alibaba Cloud account, we recommend that you create a RAM user that has the permissions to access Tablestore and use the AccessKey pair of the RAM user to access Tablestore.

Method	Procedure
AccessKey pair of an Alibaba Cloud account	Create an Alibaba Cloud account on the Alibaba Cloud official website. Create an AccessKey pair that consists of an AccessKey ID and an AccessKey secret. For more information, see Create an AccessKey pair.
AccessKey pair of a RAM user that has the permissions to access Tablestore	Log on to the RAM console by using an Alibaba Cloud account. Then, create a RAM user or find an existing RAM user. Use the Alibaba Cloud account to grant access permissions on Tablestore to the RAM user. For more information, see Use a RAM policy to grant permissions to a RAM user. Use the AccessKey pair of the RAM user to access Tablestore. For more information, see Create an AccessKey pair.
Temporary access credentials that are obtained from Security Token Service (STS)	Obtain temporary access credentials from the application server. The temporary access credentials consist of a temporary AccessKey ID, a temporary AccessKey secret, and a security token. The application server accesses RAM or STS to obtain the temporary access credentials and returns the temporary access credentials to you. Use the temporary access credentials to access Tablestore.

Configure environment variables.
Tablestore uses the OTS_AK_ENV and OTS_SK_ENV environment variables to store an AccessKey pair. The OTS_AK_ENV environment variable stores the AccessKey ID of an Alibaba Cloud account or a RAM user. The OTS_SK_ENV environment variable stores the AccessKey secret of an Alibaba Cloud account or a RAM user. Configure the environment variables based on the AccessKey pair that you want to use.
- Configure environment variables in Linux and macOS
  Run the following commands to configure environment variables. Replace <ACCESS_KEY_ID> with your AccessKey ID and <ACCESS_KEY_SECRET> with your AccessKey secret.
```
export OTS_AK_ENV=<ACCESS_KEY_ID>
export OTS_SK_ENV=<ACCESS_KEY_SECRET>
```
- Configure environment variables in Windows
  In the System Variable section of the Environment Variable dialog box, add the OTS_AK_ENV and OTS_SK_ENV environment variables, and set the OTS_AK_ENV environment variable to the AccessKey ID and the OTS_SK_ENV environment variable to the AccessKey secret that you obtained. Then, save the configurations.

Obtain the endpoint of a Tablestore instance

After you create a Tablestore instance, you must obtain an endpoint of the instance. This way, you can use the endpoint to access the instance.

An endpoint is a domain name that is used to access a Tablestore instance in a region. For example, https://sun.cn-hangzhou.ots.aliyuncs.com is the public endpoint that is used to access the instance named sun in the China (Hangzhou) region over HTTPS. For more information, see Endpoints.

If the Tablestore service is not activated, activate the service. For more information, see Step 1: Activate Tablestore.
Create a Tablestore instance. For more information, see Step 2: Create an instance.
Obtain an endpoint of the created instance.
1. Log on to the Tablestore console.
2. On the Overview page, find the instance that you created and click the name of the instance.
3. On the Instance Details tab, view the endpoints of the instance in the Instance Access URL section.

Install Tablestore SDK for .NET

For more information, see Install Tablestore SDK for .NET.

Initialize an OTSClient instance

To use Tablestore SDK for .NET, you must first create an OTSClient instance. Then, you can call the methods of the OTSClient instance to access Tablestore.

Important

The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. We recommend that you use the AccessKey pair of a RAM user to call API operations or perform routine O&M. We recommend that you do not hard-code the AccessKey ID and AccessKey secret into your project code. Otherwise, the AccessKey pair may be leaked and the security of all resources in your account is compromised. In the following examples, the AccessKey pair is configured in the environment variables to verify your identify.

Syntax

/// <summary>
/// The function used to create an OTSClient instance. 
/// </summary>
/// <param name="endPoint">The endpoint of the Tablestore instance, which must start with https://. Example: https://instance.cn-hangzhou.ots.aliyun.com:80 </param>
/// <param name="accessKeyID"> The AccessKey ID that is used to access the Tablestore instance. You can obtain an AccessKey ID on the Alibaba Cloud official website. </param>
/// <param name="accessKeySecret"> The AccessKey secret that is used to access the Tablestore instance. You can obtain an AccessKey secret on the Alibaba Cloud official website. </param>
/// <param name="instanceName"> The name of the Tablestore instance. You can customize the instance name in the Tablestore console. </param>
public OTSClient(string endPoint, string accessKeyID, string accessKeySecret, string instanceName);

/// <summary>
/// Create an OTSClient instance by configuring the instance of the OTSClientConfig class on the client. 
/// </summary>
/// <param name="config">The instance for client configurations.</param>
public OTSClient(OTSClientConfig config);

Example

Use the endpoint of a Tablestore instance to create a client.

// Create an OTSClientConfig object. 
public static string AccessKeyId = Environment.GetEnvironmentVariable("OTS_AK_ENV");
public static string AccessKeySecret = Environment.GetEnvironmentVariable("OTS_SK_ENV");
var config = new OTSClientConfig(Endpoint, AccessKeyId, AccessKeySecret, InstanceName);
// Disable logging. By default, logging is enabled. 
config.OTSDebugLogHandler = null;
config.OTSErrorLogHandler = null;
// Create an OTSClient object by using OTSClientConfig. 
var otsClient = new OTSClient(config);

The following table describes the parameters.

Parameter	Example	Description
Endpoint	https://myinstance.cn-hangzhou.ots.aliyuncs.com	The endpoint that is used to access the Tablestore instance. For more information about how to obtain the endpoint, see the Obtain the endpoint of a Tablestore instance section of this topic.
AccessKeyId	Environment.GetEnvironmentVariable("OTS_AK_ENV")	The AccessKey pair that is used to access the Tablestore instance. Obtain the AccessKey pair by using environment variables. Make sure that the environment variables are configured. For more information, see the Configure an AccessKey pair section of this topic.
AccessKeySecret	Environment.GetEnvironmentVariable("OTS_SK_ENV")
InstanceName	myinstance	The name of the Tablestore instance that you want to access. For more information, see Instance.

Configure the OTSClient instance.

To modify the default configurations of the OTSClient instance, import the required parameters when you create the OTSClient instance, such as those that specify the maximum number of connections and retry policy. The following table describes the parameters that you can configure when you create the OTSClient instance.

Parameter	Description
ConnectionLimit	The maximum number of connections allowed to the Tablestore instance. Default value: 300.
OTSDebugLogHandler	The function to process debug logs, which is used to display the logs of normal requests and responses. Default value: defaultOTSDebugLogHandler. To disable the function, set this parameter to null.
OTSErrorLogHandler	The function to process error logs, which is used to display the logs of errors returned by Tablestore. Default value: defaultOTSErrorLogHandler. To disable the function, set this parameter to null.
RetryPolicy	The retry policy. Default value: DefaultRetryPolicy. You can also customize the retry policy. To disable the retry policy, set this parameter to null.

FAQ

What do I do if the Signature mismatch error is reported when I use Tablestore SDKs?