Program.cs

using Newtonsoft.Json;
using Renci.SshNet;
using Renci.SshNet.Sftp;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace SSHBot
{
	sealed class Config
	{
		public class Host
		{
			public string Hostname { get; set; }
			public string Username { get; set; }
			public string Password { get; set; }
			public string PrivateKeyFile { get; set; }
			public FileTransfer[] UploadFiles { get; set; }
			public string[] RunCommands { get; set; }
			public FileTransfer[] DownloadFiles { get; set; }
		}

		public class FileTransfer
		{
			public string RemoteFile { get; set; }
			public string LocalFile { get; set; }
		}

		[JsonProperty(Required = Required.Always)]
		public Host[] Hosts { get; set; }
	}

	static class Program
	{
		static Config config;

		static void Main(string[] args)
		{
			var exePath = System.Reflection.Assembly.GetEntryAssembly().Location;
			var configPath = args.Length >= 1 ? args[0] : Path.Combine(Path.GetDirectoryName(exePath), "config.json");
			config = JsonConvert.DeserializeObject<Config>(File.ReadAllText(configPath));

			Console.WriteLine($"SSH Bot");

			foreach (var host in config.Hosts)
			{
				try
				{
					Console.WriteLine($"Connecting to '{host.Hostname}' as '{host.Username}'.");

					var connectionInfo = new ConnectionInfo(host.Hostname, host.Username, host.PrivateKeyFile != null ?
						(AuthenticationMethod)new PrivateKeyAuthenticationMethod(host.Username, new PrivateKeyFile(host.PrivateKeyFile)) :
						(AuthenticationMethod)new PasswordAuthenticationMethod(host.Username, host.Password));

					// Disable ECDSA on platforms that don't support it.
					try { using (var ecdsa = new System.Security.Cryptography.ECDsaCng()) ; }
					catch (NotImplementedException)
					{
						var algsToRemove = connectionInfo.HostKeyAlgorithms.Keys.Where(algName => algName.StartsWith("ecdsa")).ToArray();
						foreach (var algName in algsToRemove) connectionInfo.HostKeyAlgorithms.Remove(algName);
					}

					if (host.UploadFiles != null)
					{
						using (var sftp = new SftpClient(connectionInfo))
						{
							sftp.Connect();

							Console.WriteLine($"Connected for uploading files.");

							foreach (var fileTransfer in host.UploadFiles)
							{
								Console.WriteLine($"Uploading '{fileTransfer.LocalFile}' to '{fileTransfer.RemoteFile}'.");

								using (var file = new FileStream(fileTransfer.LocalFile, FileMode.Open, FileAccess.Read))
									sftp.UploadFile(file, fileTransfer.RemoteFile, true);
							}
						}
					}

					if (host.RunCommands != null)
					{
						using (var ssh = new SshClient(connectionInfo))
						{
							ssh.Connect();

							Console.WriteLine($"Connected for running commands.");

							foreach (var command in host.RunCommands)
							{
								Console.WriteLine($"Running '{command}'.");

								var result = ssh.RunCommand(command);

								Console.Write(result.Result);
								Console.WriteLine($"Exit status = {result.ExitStatus}");
							}
						}
					}

					if (host.DownloadFiles != null)
					{
						using (var sftp = new SftpClient(connectionInfo))
						{
							sftp.Connect();

							Console.WriteLine($"Connected for downloading files.");

							foreach (var fileTransfer in host.DownloadFiles)
							{
								Console.WriteLine($"Downloading '{fileTransfer.RemoteFile}' to '{fileTransfer.LocalFile}'.");

								using (var file = new FileStream(fileTransfer.LocalFile, FileMode.Create, FileAccess.Write))
									sftp.DownloadFile(fileTransfer.RemoteFile, file);
							}
						}
					}
				}
				catch (Exception e) { Console.WriteLine($"Error communicating with '{host.Hostname}'. {e.ToString()}"); }
			}
		}
	}
}