Use DescribeOrderableDBInstanceOptions with an AWS SDK or CLI

    /// <summary>
    /// Get a list of orderable DB instance options for a specific
    /// engine and engine version.
    /// </summary>
    /// <param name="engine">Name of the engine.</param>
    /// <param name="engineVersion">Version of the engine.</param>
    /// <returns>List of OrderableDBInstanceOptions.</returns>
    public async Task<List<OrderableDBInstanceOption>> DescribeOrderableDBInstanceOptionsPagedAsync(string engine, string engineVersion)
    {
        // Use a paginator to get a list of DB instance options.
        var results = new List<OrderableDBInstanceOption>();
        var paginateInstanceOptions = _amazonRDS.Paginators.DescribeOrderableDBInstanceOptions(
            new DescribeOrderableDBInstanceOptionsRequest()
            {
                Engine = engine,
                EngineVersion = engineVersion,
            });
        // Get the entire list using the paginator.
        await foreach (var instanceOptions in paginateInstanceOptions.OrderableDBInstanceOptions)
        {
            results.Add(instanceOptions);
        }
        return results;
    }

        Aws::Client::ClientConfiguration clientConfig;
        // Optional: Set to the AWS Region (overrides config file).
        // clientConfig.region = "us-east-1";

    Aws::RDS::RDSClient client(clientConfig);


//! Routine which gets available DB instance classes, displays the list
//! to the user, and returns the user selection.
/*!
 \sa chooseDBInstanceClass()
 \param engineName: The DB engine name.
 \param engineVersion: The DB engine version.
 \param dbInstanceClass: String for DB instance class chosen by the user.
 \param client: 'RDSClient' instance.
 \return bool: Successful completion.
 */
bool AwsDoc::Aurora::chooseDBInstanceClass(const Aws::String &engine,
                                           const Aws::String &engineVersion,
                                           Aws::String &dbInstanceClass,
                                           const Aws::RDS::RDSClient &client) {
    std::vector<Aws::String> instanceClasses;
    Aws::String marker; // The marker is used for pagination.
    do {
        Aws::RDS::Model::DescribeOrderableDBInstanceOptionsRequest request;
        request.SetEngine(engine);
        request.SetEngineVersion(engineVersion);
        if (!marker.empty()) {
            request.SetMarker(marker);
        }

        Aws::RDS::Model::DescribeOrderableDBInstanceOptionsOutcome outcome =
                client.DescribeOrderableDBInstanceOptions(request);

        if (outcome.IsSuccess()) {
            const Aws::Vector<Aws::RDS::Model::OrderableDBInstanceOption> &options =
                    outcome.GetResult().GetOrderableDBInstanceOptions();
            for (const Aws::RDS::Model::OrderableDBInstanceOption &option: options) {
                const Aws::String &instanceClass = option.GetDBInstanceClass();
                if (std::find(instanceClasses.begin(), instanceClasses.end(),
                              instanceClass) == instanceClasses.end()) {
                    instanceClasses.push_back(instanceClass);
                }
            }
            marker = outcome.GetResult().GetMarker();
        }
        else {
            std::cerr << "Error with Aurora::DescribeOrderableDBInstanceOptions. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            return false;
        }
    } while (!marker.empty());

    std::cout << "The available DB instance classes for your database engine are:"
              << std::endl;
    for (int i = 0; i < instanceClasses.size(); ++i) {
        std::cout << "   " << i + 1 << ": " << instanceClasses[i] << std::endl;
    }

    int choice = askQuestionForIntRange(
            "Which DB instance class do you want to use? ",
            1, static_cast<int>(instanceClasses.size()));
    dbInstanceClass = instanceClasses[choice - 1];
    return true;
}

import (
	"context"
	"errors"
	"log"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/service/rds"
	"github.com/aws/aws-sdk-go-v2/service/rds/types"
)

type DbClusters struct {
	AuroraClient *rds.Client
}



// GetOrderableInstances uses a paginator to get DB instance options that can be used to create DB instances that are
// compatible with a set of specifications.
func (clusters *DbClusters) GetOrderableInstances(ctx context.Context, engine string, engineVersion string) (
	[]types.OrderableDBInstanceOption, error) {

	var output *rds.DescribeOrderableDBInstanceOptionsOutput
	var instances []types.OrderableDBInstanceOption
	var err error
	orderablePaginator := rds.NewDescribeOrderableDBInstanceOptionsPaginator(clusters.AuroraClient,
		&rds.DescribeOrderableDBInstanceOptionsInput{
			Engine:        aws.String(engine),
			EngineVersion: aws.String(engineVersion),
		})
	for orderablePaginator.HasMorePages() {
		output, err = orderablePaginator.NextPage(ctx)
		if err != nil {
			log.Printf("Couldn't get orderable DB instances: %v\n", err)
			break
		} else {
			instances = append(instances, output.OrderableDBInstanceOptions...)
		}
	}
	return instances, err
}

    public static void describeDBEngines(RdsClient rdsClient) {
        try {
            DescribeDbEngineVersionsRequest engineVersionsRequest = DescribeDbEngineVersionsRequest.builder()
                    .engine("aurora-mysql")
                    .defaultOnly(true)
                    .maxRecords(20)
                    .build();

            DescribeDbEngineVersionsResponse response = rdsClient.describeDBEngineVersions(engineVersionsRequest);
            List<DBEngineVersion> engines = response.dbEngineVersions();

            // Get all DBEngineVersion objects.
            for (DBEngineVersion engineOb : engines) {
                System.out.println("The name of the DB parameter group family for the database engine is "
                        + engineOb.dbParameterGroupFamily());
                System.out.println("The name of the database engine " + engineOb.engine());
                System.out.println("The version number of the database engine " + engineOb.engineVersion());
            }

        } catch (RdsException e) {
            System.out.println(e.getLocalizedMessage());
            System.exit(1);
        }
    }

Example 1: This example lists the DB engine versions that support a specific DB instance class in an AWS Region.

$params = @{
  Engine = 'aurora-postgresql'
  DBInstanceClass = 'db.r5.large'
  Region = 'us-east-1'
}
Get-RDSOrderableDBInstanceOption @params

Example 2: This example lists the DB instance classes that are supported for a specific DB engine version in an AWS Region.

$params = @{
  Engine = 'aurora-postgresql'
  EngineVersion = '13.6'
  Region = 'us-east-1'
}
Get-RDSOrderableDBInstanceOption @params

class AuroraWrapper:
    """Encapsulates Aurora DB cluster actions."""

    def __init__(self, rds_client):
        """
        :param rds_client: A Boto3 Amazon Relational Database Service (Amazon RDS) client.
        """
        self.rds_client = rds_client

    @classmethod
    def from_client(cls):
        """
        Instantiates this class from a Boto3 client.
        """
        rds_client = boto3.client("rds")
        return cls(rds_client)


    def get_orderable_instances(self, db_engine, db_engine_version):
        """
        Gets DB instance options that can be used to create DB instances that are
        compatible with a set of specifications.

        :param db_engine: The database engine that must be supported by the DB instance.
        :param db_engine_version: The engine version that must be supported by the DB instance.
        :return: The list of DB instance options that can be used to create a compatible DB instance.
        """
        try:
            inst_opts = []
            paginator = self.rds_client.get_paginator(
                "describe_orderable_db_instance_options"
            )
            for page in paginator.paginate(
                Engine=db_engine, EngineVersion=db_engine_version
            ):
                inst_opts += page["OrderableDBInstanceOptions"]
        except ClientError as err:
            logger.error(
                "Couldn't get orderable DB instances. Here's why: %s: %s",
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return inst_opts

    pub async fn get_instance_classes(&self) -> Result<Vec<String>, ScenarioError> {
        let describe_orderable_db_instance_options_items = self
            .rds
            .describe_orderable_db_instance_options(
                DB_ENGINE,
                self.engine_version
                    .as_ref()
                    .expect("engine version for db instance options")
                    .as_str(),
            )
            .await;

        describe_orderable_db_instance_options_items
            .map(|options| {
                options
                    .iter()
                    .filter(|o| o.storage_type() == Some("aurora"))
                    .map(|o| o.db_instance_class().unwrap_or_default().to_string())
                    .collect::<Vec<String>>()
            })
            .map_err(|err| ScenarioError::new("Could not get available instance classes", &err))
    }

    pub async fn describe_orderable_db_instance_options(
        &self,
        engine: &str,
        engine_version: &str,
    ) -> Result<Vec<OrderableDbInstanceOption>, SdkError<DescribeOrderableDBInstanceOptionsError>>
    {
        self.inner
            .describe_orderable_db_instance_options()
            .engine(engine)
            .engine_version(engine_version)
            .into_paginator()
            .items()
            .send()
            .try_collect()
            .await
    }

#[tokio::test]
async fn test_scenario_get_instance_classes() {
    let mut mock_rds = MockRdsImpl::default();

    mock_rds
        .expect_create_db_cluster_parameter_group()
        .return_once(|_, _, _| {
            Ok(CreateDbClusterParameterGroupOutput::builder()
                .db_cluster_parameter_group(DbClusterParameterGroup::builder().build())
                .build())
        });

    mock_rds
        .expect_describe_orderable_db_instance_options()
        .with(eq("aurora-mysql"), eq("aurora-mysql8.0"))
        .return_once(|_, _| {
            Ok(vec![
                OrderableDbInstanceOption::builder()
                    .db_instance_class("t1")
                    .storage_type("aurora")
                    .build(),
                OrderableDbInstanceOption::builder()
                    .db_instance_class("t1")
                    .storage_type("aurora-iopt1")
                    .build(),
                OrderableDbInstanceOption::builder()
                    .db_instance_class("t2")
                    .storage_type("aurora")
                    .build(),
                OrderableDbInstanceOption::builder()
                    .db_instance_class("t3")
                    .storage_type("aurora")
                    .build(),
            ])
        });

    let mut scenario = AuroraScenario::new(mock_rds);
    scenario
        .set_engine("aurora-mysql", "aurora-mysql8.0")
        .await
        .expect("set engine");

    let instance_classes = scenario.get_instance_classes().await;

    assert_eq!(
        instance_classes,
        Ok(vec!["t1".into(), "t2".into(), "t3".into()])
    );
}

#[tokio::test]
async fn test_scenario_get_instance_classes_error() {
    let mut mock_rds = MockRdsImpl::default();

    mock_rds
        .expect_describe_orderable_db_instance_options()
        .with(eq("aurora-mysql"), eq("aurora-mysql8.0"))
        .return_once(|_, _| {
            Err(SdkError::service_error(
                DescribeOrderableDBInstanceOptionsError::unhandled(Box::new(Error::new(
                    ErrorKind::Other,
                    "describe_orderable_db_instance_options_error",
                ))),
                Response::new(StatusCode::try_from(400).unwrap(), SdkBody::empty()),
            ))
        });

    let mut scenario = AuroraScenario::new(mock_rds);
    scenario.engine_family = Some("aurora-mysql".into());
    scenario.engine_version = Some("aurora-mysql8.0".into());

    let instance_classes = scenario.get_instance_classes().await;

    assert_matches!(
        instance_classes,
        Err(ScenarioError {message, context: _}) if message == "Could not get available instance classes"
    );
}