Add revision command

src/Tgstation.Server.Host/Components/Chat/Commands/CommandFactory.cs

@@ -77,6 +77,7 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 			{
 				new VersionCommand(application),
 				new ByondCommand(byondManager),
+				new RevisionCommand(watchdog, repositoryManager, instance),
 				new PullRequestsCommand(watchdog, repositoryManager, databaseContextFactory, instance),
 				new KekCommand()
 			};

src/Tgstation.Server.Host/Components/Chat/Commands/RevisionCommand.cs

@@ -0,0 +1,75 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Tgstation.Server.Host.Components.Repository;
+using Tgstation.Server.Host.Components.Watchdog;
+
+namespace Tgstation.Server.Host.Components.Chat.Commands
+{
+	/// <summary>
+	/// For displaying <see cref="Api.Models.Internal.RevisionInformation"/>
+	/// </summary>
+	sealed class RevisionCommand : ICommand
+	{
+		/// <inheritdoc />
+		public string Name => "revision";
+
+		/// <inheritdoc />
+		public string HelpText => "Display live commit sha. Add --repo to view repository revision";
+
+		/// <inheritdoc />
+		public bool AdminOnly => false;
+
+		/// <summary>
+		/// The <see cref="IWatchdog"/> for the <see cref="PullRequestsCommand"/>
+		/// </summary>
+		readonly IWatchdog watchdog;
+
+		/// <summary>
+		/// The <see cref="IRepositoryManager"/> for the <see cref="PullRequestsCommand"/>
+		/// </summary>
+		readonly IRepositoryManager repositoryManager;
+
+		/// <summary>
+		/// The <see cref="Models.Instance"/> for the <see cref="PullRequestsCommand"/>
+		/// </summary>
+		readonly Models.Instance instance;
+
+		/// <summary>
+		/// Construct a <see cref="RevisionCommand"/>
+		/// </summary>
+		/// <param name="watchdog">The value of <see cref="watchdog"/></param>
+		/// <param name="repositoryManager">The value of <see cref="repositoryManager"/></param>
+		/// <param name="instance">The value of <see cref="instance"/></param>
+		public RevisionCommand(IWatchdog watchdog, IRepositoryManager repositoryManager, Models.Instance instance)
+		{
+			this.watchdog = watchdog ?? throw new ArgumentNullException(nameof(watchdog));
+			this.repositoryManager = repositoryManager ?? throw new ArgumentNullException(nameof(repositoryManager));
+			this.instance = instance ?? throw new ArgumentNullException(nameof(instance));
+		}
+
+		/// <inheritdoc />
+		public async Task<string> Invoke(string arguments, User user, CancellationToken cancellationToken)
+		{
+			string result;
+			if (arguments.Split(' ').Any(x => x.ToUpperInvariant() == "--REPO"))
+				using (var repo = await repositoryManager.LoadRepository(cancellationToken).ConfigureAwait(false))
+				{
+					if (repo == null)
+						return "Repository unavailable!";
+					result = repo.Head;
+				}
+			else
+			{
+				if (!watchdog.Running)
+					return "Server offline!";
+				result = watchdog.ActiveCompileJob?.RevisionInformation.CommitSha;
+			}
+
+			return String.Format(CultureInfo.InvariantCulture, "^{0}", result);
+		}
+	}
+}