# Hello Amazon EC2
<a name="example_ec2_Hello_section"></a>

The following code examples show how to get started using Amazon EC2.

------
#### [ .NET ]

**Amazon SDK for .NET (v4)**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [Amazon Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/dotnetv4/EC2#code-examples). 

```
namespace EC2Actions;

public class HelloEc2
{
    /// <summary>
    /// HelloEc2 lists the existing security groups for the default users.
    /// </summary>
    /// <param name="args">Command line arguments</param>
    /// <returns>Async task.</returns>
    static async Task Main(string[] args)
    {
        // Set up dependency injection for Amazon Elastic Compute Cloud (Amazon EC2).
        using var host = Microsoft.Extensions.Hosting.Host.CreateDefaultBuilder(args)
            .ConfigureServices((_, services) =>
                services.AddAWSService<IAmazonEC2>()
                .AddTransient<EC2Wrapper>()
            )
            .Build();

        // Now the client is available for injection.
        var ec2Client = host.Services.GetRequiredService<IAmazonEC2>();

        try
        {
            // Retrieve information for up to 10 Amazon EC2 security groups.
            var request = new DescribeSecurityGroupsRequest { MaxResults = 10 };
            var securityGroups = new List<SecurityGroup>();

            var paginatorForSecurityGroups =
                ec2Client.Paginators.DescribeSecurityGroups(request);

            await foreach (var securityGroup in paginatorForSecurityGroups.SecurityGroups)
            {
                securityGroups.Add(securityGroup);
            }

            // Now print the security groups returned by the call to
            // DescribeSecurityGroupsAsync.
            Console.WriteLine("Welcome to the EC2 Hello Service example. " +
                              "\nLet's list your Security Groups:");
            securityGroups.ForEach(group =>
            {
                Console.WriteLine(
                    $"Security group: {group.GroupName} ID: {group.GroupId}");
            });
        }
        catch (AmazonEC2Exception ex)
        {
            Console.WriteLine($"An Amazon EC2 service error occurred while listing security groups. {ex.Message}");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"An error occurred while listing security groups. {ex.Message}");
        }
    }
}
```
+  For API details, see [DescribeSecurityGroups](https://docs.amazonaws.cn/goto/DotNetSDKV4/ec2-2016-11-15/DescribeSecurityGroups) in *Amazon SDK for .NET API Reference*. 

------
#### [ C\$1\$1 ]

**SDK for C\$1\$1**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [Amazon Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/ec2/hello_ec2#code-examples). 
Code for the CMakeLists.txt CMake file.  

```
# Set the minimum required version of CMake for this project.
cmake_minimum_required(VERSION 3.13)

# Set the AWS service components used by this project.
set(SERVICE_COMPONENTS ec2)

# Set this project's name.
project("hello_ec2")

# Set the C++ standard to use to build this target.
# At least C++ 11 is required for the AWS SDK for C++.
set(CMAKE_CXX_STANDARD 11)

# Use the MSVC variable to determine if this is a Windows build.
set(WINDOWS_BUILD ${MSVC})

if (WINDOWS_BUILD) # Set the location where CMake can find the installed libraries for the AWS SDK.
    string(REPLACE ";" "/aws-cpp-sdk-all;" SYSTEM_MODULE_PATH "${CMAKE_SYSTEM_PREFIX_PATH}/aws-cpp-sdk-all")
    list(APPEND CMAKE_PREFIX_PATH ${SYSTEM_MODULE_PATH})
endif ()

# Find the AWS SDK for C++ package.
find_package(AWSSDK REQUIRED COMPONENTS ${SERVICE_COMPONENTS})

if (WINDOWS_BUILD AND AWSSDK_INSTALL_AS_SHARED_LIBS)
     # Copy relevant AWS SDK for C++ libraries into the current binary directory for running and debugging.

     # set(BIN_SUB_DIR "/Debug") # If you are building from the command line, you may need to uncomment this
                                    # and set the proper subdirectory to the executables' location.

     AWSSDK_CPY_DYN_LIBS(SERVICE_COMPONENTS "" ${CMAKE_CURRENT_BINARY_DIR}${BIN_SUB_DIR})
endif ()

add_executable(${PROJECT_NAME}
        hello_ec2.cpp)

target_link_libraries(${PROJECT_NAME}
        ${AWSSDK_LINK_LIBRARIES})
```
Code for the hello\$1ec2.cpp source file.  

```
#include <aws/core/Aws.h>
#include <aws/ec2/EC2Client.h>
#include <aws/ec2/model/DescribeInstancesRequest.h>
#include <iomanip>
#include <iostream>

/*
 *  A "Hello EC2" starter application which initializes an Amazon Elastic Compute Cloud (Amazon EC2) client and describes
 *  the Amazon EC2 instances.
 *
 *  main function
 *
 *  Usage: 'hello_ec2'
 *
 */

int main(int argc, char **argv) {
    (void)argc;
    (void)argv;

    Aws::SDKOptions options;
    // Optionally change the log level for debugging.
//   options.loggingOptions.logLevel = Utils::Logging::LogLevel::Debug;
    Aws::InitAPI(options); // Should only be called once.
    int result = 0;
    {
        Aws::Client::ClientConfiguration clientConfig;
        // Optional: Set to the AWS Region (overrides config file).
        // clientConfig.region = "us-east-1";

        Aws::EC2::EC2Client ec2Client(clientConfig);
        Aws::EC2::Model::DescribeInstancesRequest request;
        bool header = false;
        bool done = false;
        while (!done) {
            Aws::EC2::Model::DescribeInstancesOutcome outcome = ec2Client.DescribeInstances(request);
            if (outcome.IsSuccess()) {
                if (!header) {
                    std::cout << std::left <<
                              std::setw(48) << "Name" <<
                              std::setw(20) << "ID" <<
                              std::setw(25) << "Ami" <<
                              std::setw(15) << "Type" <<
                              std::setw(15) << "State" <<
                              std::setw(15) << "Monitoring" << std::endl;
                    header = true;
                }

                const std::vector<Aws::EC2::Model::Reservation> &reservations =
                        outcome.GetResult().GetReservations();

                for (const auto &reservation: reservations) {
                    const std::vector<Aws::EC2::Model::Instance> &instances =
                            reservation.GetInstances();
                    for (const auto &instance: instances) {
                        Aws::String instanceStateString =
                                Aws::EC2::Model::InstanceStateNameMapper::GetNameForInstanceStateName(
                                        instance.GetState().GetName());

                        Aws::String typeString =
                                Aws::EC2::Model::InstanceTypeMapper::GetNameForInstanceType(
                                        instance.GetInstanceType());

                        Aws::String monitorString =
                                Aws::EC2::Model::MonitoringStateMapper::GetNameForMonitoringState(
                                        instance.GetMonitoring().GetState());
                        Aws::String name = "Unknown";

                        const std::vector<Aws::EC2::Model::Tag> &tags = instance.GetTags();
                        auto nameIter = std::find_if(tags.cbegin(), tags.cend(),
                                                     [](const Aws::EC2::Model::Tag &tag) {
                                                         return tag.GetKey() == "Name";
                                                     });
                        if (nameIter != tags.cend()) {
                            name = nameIter->GetValue();
                        }
                        std::cout <<
                                  std::setw(48) << name <<
                                  std::setw(20) << instance.GetInstanceId() <<
                                  std::setw(25) << instance.GetImageId() <<
                                  std::setw(15) << typeString <<
                                  std::setw(15) << instanceStateString <<
                                  std::setw(15) << monitorString << std::endl;
                    }
                }

                if (!outcome.GetResult().GetNextToken().empty()) {
                    request.SetNextToken(outcome.GetResult().GetNextToken());
                } else {
                    done = true;
                }
            } else {
                std::cerr << "Failed to describe EC2 instances:" <<
                          outcome.GetError().GetMessage() << std::endl;
                result = 1;
                break;
            }
        }
    }


    Aws::ShutdownAPI(options); // Should only be called once.
    return result;
}
```
+  For API details, see [DescribeSecurityGroups](https://docs.amazonaws.cn/goto/SdkForCpp/ec2-2016-11-15/DescribeSecurityGroups) in *Amazon SDK for C\$1\$1 API Reference*. 

------
#### [ Java ]

**SDK for Java 2.x**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [Amazon Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/ec2#code-examples). 

```
    /**
     * Asynchronously describes the security groups for the specified group ID.
     *
     * @param groupName the name of the security group to describe
     * @return a {@link CompletableFuture} that represents the asynchronous operation
     *         of describing the security groups. The future will complete with a
     *         {@link DescribeSecurityGroupsResponse} object that contains the
     *         security group information.
     */
    public CompletableFuture<String> describeSecurityGroupArnByNameAsync(String groupName) {
        DescribeSecurityGroupsRequest request = DescribeSecurityGroupsRequest.builder()
            .groupNames(groupName)
            .build();

        DescribeSecurityGroupsPublisher paginator = getAsyncClient().describeSecurityGroupsPaginator(request);
        AtomicReference<String> groupIdRef = new AtomicReference<>();
        return paginator.subscribe(response -> {
            response.securityGroups().stream()
                .filter(securityGroup -> securityGroup.groupName().equals(groupName))
                .findFirst()
                .ifPresent(securityGroup -> groupIdRef.set(securityGroup.groupId()));
        }).thenApply(v -> {
            String groupId = groupIdRef.get();
            if (groupId == null) {
                throw new RuntimeException("No security group found with the name: " + groupName);
            }
            return groupId;
        }).exceptionally(ex -> {
            logger.info("Failed to describe security group: " + ex.getMessage());
            throw new RuntimeException("Failed to describe security group", ex);
        });
    }
```
+  For API details, see [DescribeSecurityGroups](https://docs.amazonaws.cn/goto/SdkForJavaV2/ec2-2016-11-15/DescribeSecurityGroups) in *Amazon SDK for Java 2.x API Reference*. 

------
#### [ JavaScript ]

**SDK for JavaScript (v3)**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [Amazon Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/ec2#code-examples). 

```
import { DescribeSecurityGroupsCommand, EC2Client } from "@aws-sdk/client-ec2";

// Call DescribeSecurityGroups and display the result.
export const main = async () => {
  const client = new EC2Client();
  try {
    const { SecurityGroups } = await client.send(
      new DescribeSecurityGroupsCommand({}),
    );

    const securityGroupList = SecurityGroups.slice(0, 9)
      .map((sg) => ` • ${sg.GroupId}: ${sg.GroupName}`)
      .join("\n");

    console.log(
      "Hello, Amazon EC2! Let's list up to 10 of your security groups:",
    );
    console.log(securityGroupList);
  } catch (err) {
    console.error(err);
  }
};

// Call function if run directly.
import { fileURLToPath } from "node:url";
if (process.argv[1] === fileURLToPath(import.meta.url)) {
  main();
}
```
+  For API details, see [DescribeSecurityGroups](https://docs.amazonaws.cn/AWSJavaScriptSDK/v3/latest/client/ec2/command/DescribeSecurityGroupsCommand) in *Amazon SDK for JavaScript API Reference*. 

------
#### [ Kotlin ]

**SDK for Kotlin**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [Amazon Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/kotlin/services/ec2#code-examples). 

```
suspend fun describeEC2SecurityGroups(groupId: String) {
    val request =
        DescribeSecurityGroupsRequest {
            groupIds = listOf(groupId)
        }

    Ec2Client.fromEnvironment { region = "us-west-2" }.use { ec2 ->
        val response = ec2.describeSecurityGroups(request)
        response.securityGroups?.forEach { group ->
            println("Found Security Group with id ${group.groupId}, vpc id ${group.vpcId} and description ${group.description}")
        }
    }
}
```
+  For API details, see [DescribeSecurityGroups](https://sdk.amazonaws.com/kotlin/api/latest/index.html) in *Amazon SDK for Kotlin API reference*. 

------
#### [ Python ]

**SDK for Python (Boto3)**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [Amazon Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/python/example_code/ec2#code-examples). 

```
def hello_ec2(ec2_client):
    """
    Use the AWS SDK for Python (Boto3) to list the security groups in your account.
    This example uses the default settings specified in your shared credentials
    and config files.

    :param ec2_client: A Boto3 EC2 client. This client provides low-level
                       access to AWS EC2 services.
    """
    print("Hello, Amazon EC2! Let's list up to 10 of your security groups:")
    try:
        paginator = ec2_client.get_paginator("describe_security_groups")
        response_iterator = paginator.paginate(PaginationConfig={'MaxItems': 10}) # List only 10 security groups.
        logging.basicConfig(level=logging.INFO) # Enable logging.
        for page in response_iterator:
            for sg in page["SecurityGroups"]:
                logger.info(f"\t{sg['GroupId']}: {sg['GroupName']}")
    except ClientError as err:
        logger.error("Failed to list security groups.")
        if err.response["Error"]["Code"] == "AccessDeniedException":
            logger.error("You do not have permission to list security groups.")
        raise


if __name__ == "__main__":
    hello_ec2(boto3.client("ec2"))
```
+  For API details, see [DescribeSecurityGroups](https://docs.amazonaws.cn/goto/boto3/ec2-2016-11-15/DescribeSecurityGroups) in *Amazon SDK for Python (Boto3) API Reference*. 

------
#### [ Ruby ]

**SDK for Ruby**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [Amazon Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/ruby/example_code/ec2#code-examples). 

```
require 'aws-sdk-ec2'
require 'logger'

# EC2Manager is a class responsible for managing EC2 operations
# such as listing all EC2 instances in the current AWS account.
class EC2Manager
  def initialize(client)
    @client = client
    @logger = Logger.new($stdout)
  end

  # Lists and prints all EC2 instances in the current AWS account.
  def list_instances
    @logger.info('Listing instances')

    instances = fetch_instances

    if instances.empty?
      @logger.info('You have no instances')
    else
      print_instances(instances)
    end
  end

  private

  # Fetches all EC2 instances using pagination.
  #
  # @return [Array<Aws::EC2::Types::Instance>] List of EC2 instances.
  def fetch_instances
    paginator = @client.describe_instances
    instances = []

    paginator.each_page do |page|
      page.reservations.each do |reservation|
        reservation.instances.each do |instance|
          instances << instance
        end
      end
    end

    instances
  end

  # Prints details of the given EC2 instances.
  #
  # @param instances [Array<Aws::EC2::Types::Instance>] List of EC2 instances to print.
  def print_instances(instances)
    instances.each do |instance|
      @logger.info("Instance ID: #{instance.instance_id}")
      @logger.info("Instance Type: #{instance.instance_type}")
      @logger.info("Public IP: #{instance.public_ip_address}")
      @logger.info("Public DNS Name: #{instance.public_dns_name}")
      @logger.info("\n")
    end
  end
end

if $PROGRAM_NAME == __FILE__
  ec2_client = Aws::EC2::Client.new(region: 'us-west-2')
  manager = EC2Manager.new(ec2_client)
  manager.list_instances
end
```
+  For API details, see [DescribeSecurityGroups](https://docs.amazonaws.cn/goto/SdkForRubyV3/ec2-2016-11-15/DescribeSecurityGroups) in *Amazon SDK for Ruby API Reference*. 

------
#### [ Rust ]

**SDK for Rust**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [Amazon Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/rustv1/examples/ec2#code-examples). 

```
async fn show_security_groups(client: &aws_sdk_ec2::Client, group_ids: Vec<String>) {
    let response = client
        .describe_security_groups()
        .set_group_ids(Some(group_ids))
        .send()
        .await;

    match response {
        Ok(output) => {
            for group in output.security_groups() {
                println!(
                    "Found Security Group {} ({}), vpc id {} and description {}",
                    group.group_name().unwrap_or("unknown"),
                    group.group_id().unwrap_or("id-unknown"),
                    group.vpc_id().unwrap_or("vpcid-unknown"),
                    group.description().unwrap_or("(none)")
                );
            }
        }
        Err(err) => {
            let err = err.into_service_error();
            let meta = err.meta();
            let message = meta.message().unwrap_or("unknown");
            let code = meta.code().unwrap_or("unknown");
            eprintln!("Error listing EC2 Security Groups: ({code}) {message}");
        }
    }
}
```
+  For API details, see [DescribeSecurityGroups](https://docs.rs/aws-sdk-ec2/latest/aws_sdk_ec2/client/struct.Client.html#method.describe_security_groups) in *Amazon SDK for Rust API reference*. 

------
#### [ Swift ]

**SDK for Swift**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [Amazon Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/swift/example_code/ec2#code-examples). 
The `Package.swift` file.  

```
// swift-tools-version: 5.9
//
// The swift-tools-version declares the minimum version of Swift required to
// build this package.

import PackageDescription

let package = Package(
    name: "hello-ec2",
    // Let Xcode know the minimum Apple platforms supported.
    platforms: [
        .macOS(.v13),
        .iOS(.v15)
    ],
    dependencies: [
        // Dependencies declare other packages that this package depends on.
        .package(
            url: "https://github.com/awslabs/aws-sdk-swift",
            from: "1.0.0"),
        .package(
            url: "https://github.com/apple/swift-argument-parser.git",
            branch: "main"
        )
    ],
    targets: [
        // Targets are the basic building blocks of a package, defining a module or a test suite.
        // Targets can depend on other targets in this package and products
        // from dependencies.
        .executableTarget(
            name: "hello-ec2",
            dependencies: [
                .product(name: "AWSEC2", package: "aws-sdk-swift"),
                .product(name: "ArgumentParser", package: "swift-argument-parser")
            ],
            path: "Sources")

    ]
)
```
The `entry.swift` file.  

```
// An example that shows how to use the AWS SDK for Swift to perform a simple
// operation using Amazon Elastic Compute Cloud (EC2).
//

import ArgumentParser
import Foundation

import AWSEC2

struct ExampleCommand: ParsableCommand {
    @Option(help: "The AWS Region to run AWS API calls in.")
    var awsRegion = "us-east-1"

    @Option(
        help: ArgumentHelp("The level of logging for the Swift SDK to perform."),
        completion: .list([
            "critical",
            "debug",
            "error",
            "info",
            "notice",
            "trace",
            "warning"
        ])
    )
    var logLevel: String = "error"

    static var configuration = CommandConfiguration(
        commandName: "hello-ec2",
        abstract: """
        Demonstrates a simple operation using Amazon EC2.
        """,
        discussion: """
        An example showing how to make a call to Amazon EC2 using the AWS SDK for Swift.
        """
    )

    /// Return an array of strings giving the names of every security group
    /// the user is a member of.
    ///
    /// - Parameter ec2Client: The `EC2Client` to use when calling
    ///   `describeSecurityGroupsPaginated()`.
    ///
    /// - Returns: An array of strings giving the names of every security
    ///   group the user is a member of.
    func getSecurityGroupNames(ec2Client: EC2Client) async -> [String] {
        let pages = ec2Client.describeSecurityGroupsPaginated(
            input: DescribeSecurityGroupsInput()
        )

        var groupNames: [String] = []

        do {
            for try await page in pages {
                guard let groups = page.securityGroups else {
                    print("*** Error: No groups returned.")
                    continue
                }

                for group in groups {
                    groupNames.append(group.groupName ?? "<unknown>")
                }
            }
        } catch {
            print("*** Error: \(error.localizedDescription)")
        }

        return groupNames
    }

    /// Called by ``main()`` to run the bulk of the example.
    func runAsync() async throws {
        let ec2Config = try await EC2Client.EC2ClientConfiguration(region: awsRegion)
        let ec2Client = EC2Client(config: ec2Config)

        let groupNames = await getSecurityGroupNames(ec2Client: ec2Client)

        print("Found \(groupNames.count) security group(s):")

        for group in groupNames {
            print("    \(group)")
        }
    }
}

/// The program's asynchronous entry point.
@main
struct Main {
    static func main() async {
        let args = Array(CommandLine.arguments.dropFirst())

        do {
            let command = try ExampleCommand.parse(args)
            try await command.runAsync()
        } catch {
            ExampleCommand.exit(withError: error)
        }
    }    
}
```
+  For API details, see [DescribeSecurityGroups](https://sdk.amazonaws.com/swift/api/awsec2/latest/documentation/awsec2/ec2client/describesecuritygroups(input:)) in *Amazon SDK for Swift API reference*. 

------

For a complete list of Amazon SDK developer guides and code examples, see [Create Amazon EC2 resources using an Amazon SDK](sdk-general-information-section.md). This topic also includes information about getting started and details about previous SDK versions.