Skip to content

Command Logger#

TLDR, How to enable#

  1. Enable the feature with appRunner.UseCommandLogger()

Command logging#

This feature logs information about the command just before the command method is executed.

The default behavior registers a [cmdlog] directive that outputs to the console using CommandContext.Console.Out.

Default Behavior#

Given a program with default configuration

public class Program
{
    static int Main(string[] args) => AppRunner.Run(args);

    public static AppRunner AppRunner =>
        new AppRunner<Program>().UseCommandLogger();

    public void Add(IConsole console, int x, int y) => console.WriteLine(x + y);
}
snippet source | anchor

When the [cmdlog] directive is specified, the command logger middleware will output

  • original input from the command line
  • target command
  • parsed arguments with source of value
  • some basic system information

$ example.exe [cmdlog] Add 1 1

***************************************
Original input:
  [cmdlog] Add 1 1

command: Add

arguments:

  x <Number>
    value: 1
    inputs: 1
    default:

  y <Number>
    value: 1
    inputs: 1
    default:

Tool version  = doc-examples.dll 1.1.1.1
.Net version  = .NET 5.0.13
OS version    = Microsoft Windows 10.0.12345
***************************************
2
snippet source | anchor

Configuration#

Here are the available parameters for configuration:

/// <summary>Enable the command logger middleware</summary>
/// <param name="appRunner">The <see cref="AppRunner"/></param>
/// <param name="writerFactory">
/// Provide an action to capture the command logger output.
/// When the action is null,
/// the command will not be logged
/// When the parameter is null,
/// the `[cmdlog]` directive is enabled with Console.Out as the target
/// </param>
/// <param name="excludeSystemInfo">Exclude OS, .net version and tool version</param>
/// <param name="includeAppConfig">Prints the entire app configuration</param>
/// <param name="includeMachineAndUser">Include machine name, username</param>
/// <param name="additionalInfoCallback">Additional information to include.</param>
public static AppRunner UseCommandLogger(this AppRunner appRunner,
    Func<CommandContext, Action<string?>?>? writerFactory = null,
    bool excludeSystemInfo = false,
    bool includeAppConfig = false,
    bool includeMachineAndUser = false,
    Func<CommandContext, IEnumerable<(string key, string value)>?>? additionalInfoCallback = null)
snippet source | anchor

Include Machine and User#

.UseCommandLogger(
    excludeSystemInfo: true,
    includeMachineAndUser: true);
snippet source | anchor

$ example.exe [cmdlog] Add 1 1

***************************************
Original input:
  [cmdlog] Add 1 1

command: Add

arguments:

  x <Number>
    value: 1
    inputs: 1
    default:

  y <Number>
    value: 1
    inputs: 1
    default:

Machine   = my-machine
Username  = \my-machine\username
***************************************
2
snippet source | anchor

Additional information can be provided by setting the additionalInfoCallback parameter with a Func<CommandContext, IEnumerable<(string key, string value)>>. Any CommandContext state can be included.

Include AppConfig#

.UseCommandLogger(includeAppConfig: true);
snippet source | anchor

$ example.exe [cmdlog] Add 1 1

***************************************
Original input:
  [cmdlog] Add 1 1

command: Add

arguments:

  x <Number>
    value: 1
    inputs: 1
    default:

  y <Number>
    value: 1
    inputs: 1
    default:

Tool version  = doc-examples.dll 1.1.1.1
.Net version  = .NET 5.0.13
OS version    = Microsoft Windows 10.0.12345

AppConfig:
          AppSettings:
      Arguments:         ArgumentAppSettings:
        BooleanMode: Implicit
        DefaultArgumentMode: Operand
        DefaultOptionSplit: 
        DefaultPipeTargetSymbol: ^
        SkipArityValidation: False
      ArgumentTypeDescriptors: ArgumentTypeDescriptors:
        ErrorReportingDescriptor > CommandDotNet.TypeDescriptors.BoolTypeDescriptor
        ErrorReportingDescriptor > CommandDotNet.TypeDescriptors.EnumTypeDescriptor
        ErrorReportingDescriptor > DelegatedTypeDescriptor<String>: 'Text'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<Password>: 'Text'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<Char>: 'Character'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<Int64>: 'Number'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<Int32>: 'Number'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<Int16>: 'Number'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<UInt64>: 'Number'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<UInt32>: 'Number'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<UInt16>: 'Number'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<Decimal>: 'Decimal'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<Double>: 'Decimal'
        ErrorReportingDescriptor > DelegatedTypeDescriptor<Single>: 'Decimal'
        ErrorReportingDescriptor > CommandDotNet.TypeDescriptors.ComponentModelTypeDescriptor
        ErrorReportingDescriptor > CommandDotNet.TypeDescriptors.StringCtorTypeDescriptor
      Commands:         CommandAppSettings:
        InheritCommandsFromBaseClasses: False
      DisableDirectives: False
      Help:         AppHelpSettings:
        ExpandArgumentsInUsage: True
        PrintHelpOption: False
        TextStyle: Detailed
        UsageAppName: example.exe
        UsageAppNameStyle: Adaptive
      Localize: 
      Parser:         ParseAppSettings:
        AllowBackslashOptionPrefix: False
        AllowSingleHyphenForLongNames: False
        DefaultArgumentSeparatorStrategy: EndOfOptions
        IgnoreUnexpectedOperands: False
    DependencyResolver: 
    HelpProvider: CommandDotNet.Help.HelpTextProvider
    TokenTransformations:

    MiddlewarePipeline:
      <>c__DisplayClass4_1.<RunInMem>g__CaptureCommandContext|4
      AppRunner.OnRunCompleted
      HelpMiddleware.PrintHelp
      TokenizerPipeline.TokenizeInputMiddleware
      ClassModelingMiddleware.CreateRootCommand
      CommandParser.ParseInputMiddleware
      ClassModelingMiddleware.AssembleInvocationPipelineMiddleware
      HelpMiddleware.CheckIfShouldShowHelp
      PipedInputMiddleware.InjectPipedInputToOperandList
      BindValuesMiddleware.BindValues
      ResolveCommandClassesMiddleware.ResolveCommandClassInstances
      ValidateArityMiddleware.ValidateArity
      CommandLoggerMiddleware.CommandLogger
      ClassModelingMiddleware.InvokeInvocationPipelineMiddleware
    ParameterResolvers:
      CommandDotNet.CommandContext
      CommandDotNet.IConsole
      CommandDotNet.IEnvironment
      System.Threading.CancellationToken
***************************************
2
snippet source | anchor

Recipes for writerFactory#

Use writerFactory parameter to conditionally provide a target for the log.

If the factory returns null, the command will not be logged.

How to use:

Change the target output#

writerFactory: ctx => Log.Info

Logs every command to logging framework. See Enable via directive for an example of how to selectively log commands.

Note

This disables [cmdlog] directive enabled. See Enable via directive for an example of how to enable it again.

Enable via attribute#

public class Program
{
    static int Main(string[] args) => AppRunner.Run(args);

    public static AppRunner AppRunner => new AppRunner<Program>()
        .UseCommandLogger(ctx =>
            ctx.ParseResult!.TargetCommand.HasAttribute<LogCommandAttribute>()
                ? ctx.Console.Out.Write
                : null);

    [LogCommand]
    public void Add(IConsole console, int x, int y) => console.WriteLine(x + y);

    public void Subtract(IConsole console, int x, int y) => console.WriteLine(x - y);
}

public class LogCommandAttribute : Attribute { }
snippet source | anchor

Notice Add will always log for the command and Subtract never will.

This can be useful when you have some commands you always want logged.

$ example.exe Add 1 1

***************************************
Original input:
  Add 1 1

command: Add

arguments:

  x <Number>
    value: 1
    inputs: 1
    default:

  y <Number>
    value: 1
    inputs: 1
    default:

Tool version  = doc-examples.dll 1.1.1.1
.Net version  = .NET 5.0.13
OS version    = Microsoft Windows 10.0.12345
***************************************
2
snippet source | anchor

$ example.exe Subtract 1 1
0
snippet source | anchor

Enable via directive#

Allow user to enable as a directive

return ctx.Tokens.TryGetDirective("cmdlog", out _) 
    ? s => ctx.Console.Out.Write(s)
    : null;
snippet source | anchor

Note

this is the default behavior.

Enable via root option#

Add an intercepor method to your root command with a --logcmd option. This also makes the option visible to users via help.

public class Program
{
    static int Main(string[] args) => AppRunner.Run(args);

    public static AppRunner AppRunner => new AppRunner<Program>();

    public Task<int> Interceptor(InterceptorExecutionDelegate next, CommandContext ctx,
        [Option(
            Description = "Output the command with arguments and system info", 
            BooleanMode = BooleanMode.Implicit)] bool logcmd)
    {
        if (logcmd)
        {
            CommandLogger.Log(ctx);
        }
        return next();
    }

    public void Add(IConsole console, int x, int y) => console.WriteLine(x + y);

    public void Subtract(IConsole console, int x, int y) => console.WriteLine(x - y);
}
snippet source | anchor

$ example.exe --logcmd Add 1 1

***************************************
Original input:
  --logcmd Add 1 1

command: Add

arguments:

  x <Number>
    value: 1
    inputs: 1
    default:

  y <Number>
    value: 1
    inputs: 1
    default:

options:

  logcmd <flag>
    value: True
    inputs: true (from: --logcmd)
    default:

Tool version  = doc-examples.dll 1.1.1.1
.Net version  = .NET 5.0.13
OS version    = Microsoft Windows 10.0.12345
***************************************
2
snippet source | anchor

Back to top