Display more human-friendly help message.

Author: mayuki

sandbox/MultiContainedApp/Program.cs

@@ -17,7 +17,8 @@ await BatchHost.CreateDefaultBuilder()
 
     public class Foo : BatchBase
     {
-        public void Echo(string msg)
+        [Command("Echo", "Echo message to the logger")]
+        public void Echo([Option("msg", "Message to send.")]string msg)
         {
             this.Context.Logger.LogInformation(msg);
         }

src/MicroBatchFramework/BatchEngine.cs

@@ -102,7 +102,7 @@ public async Task RunAsync(Type type, string[] args)
                 }
                 else
                 {
-                    Console.WriteLine(BatchEngine.BuildHelpParameter(methods));
+                    Console.Write(new CommandHelpBuilder().BuildHelpMessage(methods, null));
                     return;
                 }
             }
@@ -370,74 +370,6 @@ struct OptionParameter
             public bool BooleanSwitch;
         }
 
-        internal static string BuildHelpParameter(MethodInfo[] methods)
-        {
-            var sb = new StringBuilder();
-            foreach (var method in methods.OrderBy(x => x, new CustomSorter()))
-            {
-                var command = method.GetCustomAttribute<CommandAttribute>();
-                if (command != null)
-                {
-                    sb.AppendLine(string.Join(", ", command.CommandNames) + ": " + command.Description);
-                }
-                else
-                {
-                    sb.AppendLine("argument list:");
-                }
-
-                var parameters = method.GetParameters();
-                if (parameters.Length == 0)
-                {
-                    sb.AppendLine("()");
-                }
-
-                foreach (var item in parameters)
-                {
-                    // -i, -input | [default=foo]...
-
-                    var option = item.GetCustomAttribute<OptionAttribute>();
-
-                    if (option != null)
-                    {
-                        if (option.Index != -1)
-                        {
-                            sb.Append("[" + option.Index + "]");
-                            goto WRITE_DESCRIPTION;
-                        }
-                        else
-                        {
-                            // If Index is -1, ShortName is initialized at Constractor.
-                            sb.Append("-" + option.ShortName!.Trim('-') + ", ");
-                        }
-                    }
-
-                    sb.Append("-" + item.Name);
-
-                    WRITE_DESCRIPTION:
-                    sb.Append(": ");
-
-                    if (item.HasDefaultValue)
-                    {
-                        sb.Append("[default=" + (item.DefaultValue?.ToString() ?? "null") + "]");
-                    }
-
-                    if (option != null && !string.IsNullOrEmpty(option.Description))
-                    {
-                        sb.Append(option.Description);
-                    }
-                    else
-                    {
-                        sb.Append(item.ParameterType.Name);
-                    }
-                    sb.AppendLine();
-                }
-
-                sb.AppendLine();
-            }
-
-            return sb.ToString();
-        }
-
         class CustomSorter : IComparer<MethodInfo>
         {
             public int Compare(MethodInfo x, MethodInfo y)

src/MicroBatchFramework/BatchEngineHostBuilderExtensions.cs

@@ -30,11 +30,11 @@ public static IHostBuilder UseBatchEngine(this IHostBuilder hostBuilder, string[
                 var (t, mi) = GetTypeFromAssemblies(args[1]);
                 if (mi != null)
                 {
-                    Console.WriteLine(BatchEngine.BuildHelpParameter(new[] { mi }));
+                    Console.Write(new CommandHelpBuilder().BuildHelpMessage(mi, showCommandName: true));
                 }
                 else
                 {
-                    Console.WriteLine("Method not found , please check \"list\" command.");
+                    Console.Error.WriteLine("Method not found , please check \"list\" command.");
                 }
                 hostBuilder.ConfigureServices(services =>
                 {
@@ -96,7 +96,8 @@ public static IHostBuilder UseBatchEngine<T>(this IHostBuilder hostBuilder, stri
                 {
                     if (!hasHelp)
                     {
-                        Console.WriteLine(BatchEngine.BuildHelpParameter(method));
+                        Console.Write(new CommandHelpBuilder().BuildHelpMessage(method, defaultMethod));
+
                         hostBuilder.ConfigureServices(services =>
                         {
                             services.AddOptions<ConsoleLifetimeOptions>().Configure(x => x.SuppressStatusMessages = true);
@@ -125,7 +126,8 @@ public static IHostBuilder UseBatchEngine<T>(this IHostBuilder hostBuilder, stri
 
             if (!hasHelp && args.Length == 1 && args[0].Equals(HelpCommand, StringComparison.OrdinalIgnoreCase))
             {
-                Console.WriteLine(BatchEngine.BuildHelpParameter(method));
+                Console.Write(new CommandHelpBuilder().BuildHelpMessage(method, defaultMethod));
+
                 hostBuilder.ConfigureServices(services =>
                 {
                     services.AddOptions<ConsoleLifetimeOptions>().Configure(x => x.SuppressStatusMessages = true);
@@ -155,15 +157,7 @@ public static Task RunBatchEngineAsync<T>(this IHostBuilder hostBuilder, string[
 
         static void ShowMethodList()
         {
-            Console.WriteLine("list of methods:");
-            var list = GetBatchTypes();
-            foreach (var item in list)
-            {
-                foreach (var item2 in item.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly))
-                {
-                    Console.WriteLine(item.Name + "." + item2.Name);
-                }
-            }
+            Console.Write(new CommandHelpBuilder().BuildHelpMessage(GetBatchTypes()));
         }
 
         static List<Type> GetBatchTypes()