Use SDK for Java to query instances that are created in a specific region - ApsaraDB for MongoDB

This topic describes how to call APIs by using SDKs to query instances that are created in a specific region.

View API documentation

You can refer to List of operations by function to select APIs that you can call to query instances created in a specific region. For example, you can call the DescribeDBInstances operation to query instances in a specific region. For more information about the DescribeDBInstances operation, see DescribeDBInstances. You can refer to the DescribeDBInstances topic to learn about the request parameters that you must configure and the permissions that you must grant to a Resource Access Management (RAM) user.

Create a RAM user and grant permissions to the RAM user

Identities

You can call the operation by using one of the following identities: Alibaba Cloud account, Resource Access Management (RAM) role, and RAM user. For more information about the differences between the identities, see Identity, credential, and authorization. In this example, a RAM user is used to call the DescribeDBInstances operation. Log on to the RAM console. Then, create a RAM user that you want to use to call the DescribeDBInstances operation and record the AccessKey pair information of the RAM user. For more information, see Create a RAM user.

Authorization

Go to the Users page of the RAM console. Then, find the RAM user that you want to manage and click Add Permissions in the Actions column.
In the Policy section of the Grant Permission panel, enter MongoDB in the search field and then select the policy that you want to attach to the RAM user.
Note
AliyunMongoDBFullAccess: provides full access to ApsaraDB for MongoDB.
AliyunMongoDBReadOnlyAccess: provides read-only access to ApsaraDB for MongoDB.
For information about how to create a custom policy, see RAM authorization.
Click Grant permissions.

Credential

By default, an AccessKey pair is generated when you create a RAM user. You can also go to the user details page to create an AccessKey pair. On the Authentication tab of the page, click Create AccessKey. For more information, see Create an AccessKey pair.

Call the DescribeDBInstances operation

In this section, SDK for Java is used to call the DescribeDBInstances operation.

Configure environment variables

You can configure the AccessKey pair in environment variables. This way, the AccessKey pair is not hard-coded in the code, and your service is not exposed to risks.

For more information about how to configure environment variables, see Configure environment variables in Linux, macOS, and Windows.

Download the sample code

Go to the DescribeDBInstances page.
On the Parameters tab of the page, configure required parameters.
- RegionId: the region ID. This parameter specifies the region of the instances that you want to query.
On the SDK Sample Code tab of the page, select V2.0 for SDK Version and Java for Languages. Then, click Download Project to download the sample code package.
Decompress the sample code package on your computer and access the alibabacloud_sample directory.

Open and run the project

Use IntelliJ IDEA to load the project. After the relevant dependencies are loaded, open the src/main/java/com/aliyun/sample/Sample.java file. Add the code that is used to print the returned values based on the comments in the code.

In the upper-right corner of the IDE, click Run to view the output logs. In this example, the following content is returned:

{
  "headers": {
    "access-control-allow-origin": "*",
    "date": "Wed, 26 Jul 2023 05:45:58 GMT",
    "keep-alive": "timeout=25",
    "transfer-encoding": "chunked",
    "vary": "Accept-Encoding",
    "x-acs-request-id": "CF00C412-4BB5-5D02-803C-46D0AF71DC23",
    "connection": "keep-alive",
    "content-type": "application/json;charset=utf-8",
    "access-control-expose-headers": "*",
    "x-acs-trace-id": "48df4a01d258338ee5327a6a48628426"
  },
  "statusCode": 200,
  "body": {
    "DBInstances": {
      "DBInstance": [
        {
          "capacityUnit": "",
          "chargeType": "PostPaid",
          "creationTime": "2023-07-25T06:32:25Z",
          "DBInstanceClass": "mdb.shard.2x.xlarge.d",
          "DBInstanceId": "dds-***",
          "DBInstanceStatus": "Running",
          "DBInstanceStorage": 500,
          "DBInstanceType": "replicate",
          "engine": "MongoDB",
          "engineVersion": "5.0",
          "expireTime": "2999-09-08T16:00Z",
          "kindCode": "18",
          "lockMode": "Unlock",
          "mongosList": { "mongosAttribute": [] },
          "networkType": "VPC",
          "regionId": "cn-shanghai",
          "replicationFactor": "3",
          "resourceGroupId": "rg-***",
          "shardList": { "shardAttribute": [] },
          "storageType": "cloud_essd1",
          "tags": { "tag": [] },
          "zoneId": "cn-shanghai-m"
        }
      ]
    },
    "pageNumber": 1,
    "pageSize": 30,
    "requestId": "CF00C412-4BB5-5D02-803C-***",
    "totalCount": 3
  }
}