NuGetFlow

a smooth and continuous process of downloading and integrating NuGet packages into an application

What does it solve?

You have a dotnet application. You want this application to be able to download and install NuGet packages at runtime without having to restart the application. You also want a mechanism by which you can trigger the installation fo new packages, and be alerted when new packages have been downloaded, so you can process filed from within them - for example to load plugins or extract contents etc.

Show me

NuGetFlow is a small opionated library that allows you to do this.

1. In your dotnet application startup, register the services

       services.AddNuGetPackageUpdater();

2. Configure the NuGetPackageInstallerOptions using the options pattern. NuGetFlow montitors changes to these options, so if you bind this to configuration for example, and then the configuration is changed, NuGetFlow will ensure the latest packages specified are installed. Your application also registers a callback here: OnPackagesInstalledAsync so it can be notified whenever new packages have been installed.

              

               // configure the NuGetPackageInstallerOptions - this is
               var config = ctx.Configuration;
               var section = config.GetSection("NuGetFlow");
               services.Configure<NuGetPackageInstallerOptions>(section); // bind to config, 
               services.Configure<NuGetPackageInstallerOptions>((a) =>
               {
                   // add another package that should always be downloaed perhaps.
                   a.Packages.Add(new PackageOptions(){ Package="Foo", Version="1.0.0" });

                   a.OnPackagesInstalledAsync(async (ct) =>
                   {
                       Console.WriteLine("Packages Installation Complete - Initialising WebHost");

                       // trigger whatever processing you need to do now that packages are installed.
                       await ProcessMyPackagesAsync(ct);
                   });

               });
               

Here is an example config section:

{
  "NuGetFlow": {
    "DotNetRuntimeVersion": "net6.0",
    "Sources": [
      {
        "Source": "..\\.packages"
      },
      {
        "Source": "https://api.nuget.org/v3/index.json"
      }
    ],
    "Packages": [
      {
        "Package": "DotNet.Glob",
        "Version": "3.2.0-alpha.36",
        "PreRelease": true
      },
      {
        "Package": "Plugin",
        "Version": "1.0.6", 
        "PreRelease": true  
      }
    ]
  }
}

Notice that we can configure nuget package sources (including local directories), as well as the list of packages that should be installed.

Once installation has completed - you can get information about the package locations and various folders that you may need to process:

 var packagesOptionsMonitor = host.Services.GetRequiredService<IOptionsMonitor<NuGetPackageInstallerOptions>>();                           
 var packageDirectories = packagesOptionsMonitor.CurrentValue.GetPackageDirectories();
 var contentDirectories = packageDirectories.Select(a => a.ContentDirectoryAbsolutePath) // you can select other folder paths here that you mgiht be interested in, like the assemblies folder for example.

To test this process, whilst your application is running, update the config file and add a nuget package. You should see NuGetFlow kick into action, download the package, and then notify your application via the callback.