ConsoleAppFramework.DryRun 0.0.1

ConsoleAppFramework.DryRun

ConsoleAppFramework.DryRun is a library that allows developers to include a "dry run" mode in their applications that uses ConsoleAppFramework. It provides a unified interface for checking whether the application is running in dry run mode based on command line arguments and/or environment variables.

Features

• Supports command line arguments and environment variables.
• Provides a set of extension methods for conditional service registration based on the dry run flag.
• Includes an interface IDryRunFlag that you can implement to add support for custom dry run flag sources.

How to use

This library provides the UseDryRunFlag() method. You can use it in your console application to enable the dry run mode.

For example:

var consoleApp = ConsoleApp.CreateBuilder(args)
    .UseDryRunFlag(args)
    ...
    .Build();

This method checks if any of the command line arguments match the --dry-run, --dry, or -d patterns, ignoring case. Additionally, it checks if the DOTNET_DRY_RUN environment variable's value is 1 or true, ignoring case. If either condition is met, the application runs in dry run mode.

You can also use the AddWithDryRunFlag<TInterface, TImpl, TDryRunImpl>() and TryAddWithDryRunFlag<TInterface, TImpl, TDryRunImpl>() methods to register services that behave differently in dry run mode.

For example:

var consoleApp = ConsoleApp.CreateBuilder(args)
    .UseDryRunFlag(args)
    .ConfigureServices(services =>
    {
        services.AddTransientWithDryRunFlag<IMyService, MyService, MyDryRunService>();
    })
    .Build();

In this case, MyService is used when the dry run flag is false, and MyDryRunService is used when the dry run flag is true.

Installation

You can install the library via NuGet package manager:

dotnet add package ConsoleAppFramework.DryRun

Creating a Custom IDryRunFlag

You can implement your own IDryRunFlag if you want to check the dry run condition from a different source. The IDryRunFlag interface has a single Boolean property, Value, that should return true if the dry run condition is met.

Here's an example of a custom IDryRunFlag that uses a configuration value:

public class ConfigDryRunFlag : IDryRunFlag
{
    private readonly IConfiguration _config;

    public ConfigDryRunFlag(IConfiguration config)
    {
        _config = config;
    }

    public bool Value => bool.TryParse(_config["DryRun"], out var result) && result;
}

In this example, the Value property will return true if the "DryRun" configuration value is set to "true".

You can use UseDryRunFlag() overload to specify your own IDryRunFlag implementation. This allows you to extend or customize the conditions under which the application will enter dry-run mode.

var consoleApp = ConsoleApp.CreateBuilder(args)
    .UseDryRunFlag(args, new ConfigDryRunFlag(config))
    .Build()

Combining IDryRunFlag Instances

You can use the static methods And(), Or(), and Not() to combine multiple IDryRunFlag instances. These methods are provided in the DryRunFlagOperators static class.

Here's an example of how to use these methods:

var commandLineFlag = CommandLineDryRunFlag.CreateDefault(args);
var environmentFlag = EnvironmentVariableDryRunFlag.Default;
var configFlag = new ConfigDryRunFlag(config);

var combinedFlag = commandLineFlag.Or(environmentFlag).And(configFlag.Not());

// Now, combinedFlag.Value will be true if either commandLineFlag.Value or environmentFlag.Value is true,
// and configFlag.Value is not true.

This can be useful if you want to check the dry run condition from multiple sources and combine them in complex ways.

License

This library is licensed under the MIT License.