[SOLVED] Program to downloading a file from S3 to remote EC2 Instance of Windows

Issue

I am writing a program in C# (dotnet 6/Mac) which will issue a PowerShell command to a remote EC2 instance running Windows (2012/PowerShell version 5.x) to download a file from S3.

I am on a Mac and I am able to connect to the EC2 Instance with PowerShell for Mac.

Here is the C# program:

public void DownloadS3FileToRemoteMachine(string host,
                                          string user,
                                          string password,
                                          string bucket,
                                          string s3path,
                                          string localPath)
{

    string s3DownloadCommand =
        $"aws s3 cp s3://{bucket}{s3path} {localPath}";

    var securePass = new SecureString();
    foreach (char p in password)
    {
        securePass.AppendChar(p);
    }

    var credential = new PSCredential(user, securePass);

    var connectionInfo = new WSManConnectionInfo
    {
        ComputerName = host,
        Credential = credential,
        NoEncryption = true,
        Scheme = WSManConnectionInfo.HttpScheme

    };

    using Runspace rs = RunspaceFactory.CreateRunspace(connectionInfo);
    using PowerShell? ps = PowerShell.Create(rs).AddScript(s3DownloadCommand);


    Collection<PSObject>? results;
    try
    {
        rs.Open();
        results = ps.Invoke();
        if (ps.HadErrors)
        {
            string errors = string.Join(Environment.NewLine, ps.Streams
                                                               .Error
                                                               .ReadAll()
                                                               .Select(err => err.ErrorDetails.Message));

            _logger.LogError("Error while downloading the file from S3 to local path {LocalPath}, " +
                             "error {ErrorMsg}", localPath, errors);
        }
    }
    catch (Exception e)
    {
        _logger.LogError(e, "Error copying the file from S3 to remote machine");
        throw;
    }

    string enumerable = string.Join("\n", results.Select(r => r.ToString()));
    _logger.LogInformation(enumerable);
}

With this, I get the error:

Connecting to remote server 10.62.166.198 failed with the following error message : Authorization failed For more information, see the about_Remote_Troubleshooting Help topic.

However, I know that the code works because I have access to another Windows machine running Window 10 on my local network and I am able to successfully download the file on that machine.

If I remove the line NoEncryption = true from the configuration then I get a different message:

Connecting to remote server 10.62.166.198 failed with the following error message : MI_RESULT_FAILED For more information, see the about_Remote_Troubleshooting Help topic.

Any help will be tremendously appreciated.

Solution

Thanks to the amazing people on the PowerShell Discord channel (access via https://www.reddit.com/r/PowerShell) I learnt that the current functionality of PowerShell to remote from Linux to Windows is very limited.

I had to choose OpenSSH option i.e. install OpenSSH on Windows machine, thereafter, I was able to access the service via C# like so:

var info = new ConnectionInfo(host, user, new PasswordAuthenticationMethod(user, password));         

using var client = new SshClient(info);
client.HostKeyReceived += (_, e) => e.CanTrust = true;
client.Connect();

string s3DownloadCommand = $"aws s3 cp s3://{bucket}/{source} {destination}";
using SshCommand? cmd = client.CreateCommand(s3DownloadCommand);
string? output = cmd.Execute();

Answered By - Vinay Pandey

Answer Checked By - Mary Flores (WPSolving Volunteer)