Category: .NET Core

Templating Roslyn Source Code Generators

I want that , when I generate code with Roslyn, to have a template that I can easy modify to generate code . Also, I want to let the user ( the programmer , in this case) modify this template  – maybe he has better ideas than me.

For reading from the RSCG, is pretty simple: Make as an embedded resource and read with

internal class EmbedReader
{
     static Assembly assembly;
     static EmbedReader()
     {
         assembly = Assembly.GetExecutingAssembly();

    }
     public static string ContentFile(string name)
     {
         var resourceName = name;

        using (Stream stream = assembly.GetManifestResourceStream(resourceName))
         using (StreamReader reader = new StreamReader(stream))
         {
             string result = reader.ReadToEnd();
             //this is the content
         }
     }
}

For let the programmer user put his template, put as as additional file in the csproj

<ItemGroup>
         <AdditionalFiles Include=”context.txt”  />

</ItemGroup>

and read with

var file = context.AdditionalFiles.Where(it => it.Path.EndsWith($”{val}.txt”))
                     .Select(it => it.GetText())
                     .FirstOrDefault();

            if (file != null)
             {
                 content = string.Join(Environment.NewLine, file.Lines.Select(it => it.ToString()));
             }

To do both,if the result of the first is empty, read the second (or opposite ? )

[NuGet]: Transplator

This is a Nuget that it is what Razor should have been. It is a Roslyn Source Code Generator that transforms template into code.

Link: https://www.nuget.org/packages/Transplator 

Site: https://github.com/atifaziz/Transplator

What it does:  Takes a template and generates source code for outputting anything inside.

Usage:

Somewhere in the csproj:

<ItemGroup>
   <CompilerVisibleProperty Include=”DebugTransplator” />
   <CompilerVisibleItemMetadata Include=”AdditionalFiles” MetadataName=”SourceItemType” />
   <CompilerVisibleItemMetadata Include=”AdditionalFiles” MetadataName=”Name” />
   <AdditionalFiles Include=”ASM.txt” SourceItemType=”Transplate” KeepMetadata=”Name” />

</ItemGroup>

Somewhere in a .cs file

var response = new ASMTemplate().Render();

And the template

partial class ASMTemplate
{
     StringBuilder sb = new StringBuilder();
     public void WriteText(string text)
     {
         sb.AppendLine(text);
     }
     public void WriteValue(int text)
     {
         sb.AppendLine(“”+text);
     }  
     public void WriteValue(int? text)
     {
         if(text != null)
             sb.AppendLine(“” + text);
     }
     public void WriteValue(DateTime text)
     {
         sb.AppendLine(text.ToString(“yyyy MMMM dd HH:mm:ss”));
     }
     public void WriteValue(string text)
     {
         sb.AppendLine(text);
     }
     public string Render()
     {        
         this.RenderCore();
         return sb.ToString();
     }
}

[RSCG]–About My Software

I have made a new improvement to my Roslyn Source Code Generator, AMS . Until now it just said the time and the commit date in a CI scenario  ( Git ( GitLab, GitHub), Azure …)

Now –  what if it can list all the merge requests between 2 dates  , so you can see what is new ? 

Now you can have – see this:

What you need to do  ?

Just add the following codes

using AMS_Base;
[assembly:VersionReleased(Name=”PreviousReleases”,ISODateTime =”2022-03-31″,recordData = RecordData.Merges)]
[assembly: VersionReleased(Name = “WithVersioning”, ISODateTime = “2022-04-02”, recordData = RecordData.Merges)]
[assembly: AMS_Base.VersionReleased(Name = “FutureRelease”, ISODateTime = “9999-04-16”, recordData = AMS_Base.RecordData.Merges)]

( Of course , you should read first how to add the NuGet package – see https://github.com/ignatandrei/RSCG_AMS/blob/main/README.md )

How it is made  ?

First, we should find Git –  start a process with

Where git.exe

or

which git

to find the location.

Second, start a process with the location of the git find below

log –merges –pretty=””%an|%cs|%H|%s

to see the merges . Then merge with the dates

assembly:VersionReleased 

that are registered before – and this is all !

EventId in logging

Finally I have realized why it is necessary to have EventId logged and it is not the same life without him – especially in the microservices context.

So why it is not enough

public static void LogError (this Microsoft.Extensions.Logging.ILogger logger, Exception? exception, string? message, params object?[] args);

and I strongly recommend

public static void LogError (this Microsoft.Extensions.Logging.ILogger logger, Microsoft.Extensions.Logging.EventId eventId, string? message, params object?[] args);

?

  Let’s assume that you have something like a log aggregator , such as ElasticSearch

You want to see from the error message , at a glace the details of the problem – like the root cause , some additional data – without going into details of the object. Something like “Drive C:  too full to write”  or “Drive D:  too full to write”  .

Also, you want to see how many error of this kind occurs – how many “ too full to write “ have occured ?

You ca put the message like “ Drive too full to write – look into details ” – and count those – but the investigators will have to click on more time to find what drive it is.

Welcome to EventID – https://docs.microsoft.com/en-us/dotnet/api/microsoft.extensions.logging.eventid?view=dotnet-plat-ext-6.0 .

You can have a

var evt = new EventId(7000,”DriveTooFull” );

logger.LogError(evt, “Drive C: too full to write” )

Now you have the message detaisl and you can count how many 7000 ( or DriveTooFull ) errors you have

[NuGet]: HealthCheck

This is a Nuget that I use in all projects when I am making any ASP.NET Core prohect

Link: https://www.nuget.org/packages/AspNetCore.HealthChecks.UI/

Site: https://github.com/Xabaril/AspNetCore.Diagnostics.HealthChecks 

What it does:  Implements health checks for your site and/or dependencies

Usage:

public void ConfigureServices(IServiceCollection services)
{

//code
     services.AddHealthChecks()
         .AddSqlServer(myConnectionString)
  }

[NuGet]: Polly

This is a Nuget that I use in all projects when I am making HTTP calls..

Link: https://www.nuget.org/packages/polly

Site: https://github.com/App-vNext/Polly

What it does:  Implements all kind of policies for retrying – see https://github.com/App-vNext/Polly/wiki/Transient-fault-handling-and-proactive-resilience-engineering

Usage: – copied from https://docs.microsoft.com/en-us/dotnet/architecture/microservices/implement-resilient-applications/implement-http-call-retries-exponential-backoff-polly

static IAsyncPolicy<HttpResponseMessage> GetRetryPolicy()
{
     return HttpPolicyExtensions
         .HandleTransientHttpError()
         .OrResult(msg => msg.StatusCode == System.Net.HttpStatusCode.NotFound)
         .WaitAndRetryAsync(6, retryAttempt => TimeSpan.FromSeconds(Math.Pow(2,
                                                                     retryAttempt)));
}

Dependent Framework Versioning

There are multiple ways to version a software . I have used SemanticVersioning ( https://semver.org/ ) and Calendar Versioning (  https://calver.org/ )

Of course , there are others  – please read https://en.wikipedia.org/wiki/Software_versioning   – interesting versioning based on e or PI .

However , I want to propose a new standard :

Dependent Framework Versioning

The major version of a  package is the same of the major version of the framework that is installed on . For the others , can be calver or semver or any other – depending on your choice.

For example , I have made a BlocklyAutomation  package for .NET Core 3 – and it is versioned like

For .NET Core 3  –  https://www.nuget.org/packages/NetCore2Blockly/3.2022.224.16

For .NET Core 5– https://www.nuget.org/packages/NetCore2Blockly/5.2022.210.2007

Why is this ? To be easy identified by the users of the package. If I have one user that have an app  on .NET Core 3 and other on .NET Core 5, how can they identify easy what is the latest version for this package  ? With this approach , this can be done just looking on the major version corresponding with the framework version (and yes, I use calver versioning for the rest – yyyy.Md.Hm)

[NuGet]:Scriban

This is a Nuget that I use in almost every .NET Core project to get the error details ( 500)

Link: https://www.nuget.org/packages/Scriban/

Site: https://github.com/scriban/scriban

What it does:  Like Razor –  a template intepreter

Usage:

var template = Template.Parse(@"
<ul id='products'>
  {{ for product in products }}
    <li>
      <h2>{{ product.name }}</h2>
           Price: {{ product.price }}
           {{ product.description | string.truncate 15 }}
    </li>
  {{ end }}
</ul>
");
var result = template.Render(new { Products = this.ProductList });

Using files in a ASP.NET Core nuget package

To use static (html) files in a NUGET ASP.NET Core package to be displayed I have used the following solution

1. Put the files in a folder ( in my case , blocklyAutomation )

2. Put in the .csproj to embed the files

<ItemGroup>
   <EmbeddedResource Include=”BlocklyAutomation\**\*”>
     <CopyToOutputDirectory>Never</CopyToOutputDirectory>
   </EmbeddedResource>
</ItemGroup>

3.  Create an extension to use it

;

public static void UseBlocklyUI(this IApplicationBuilder appBuilder)
{
    var manifestEmbeddedProvider =
            new ManifestEmbeddedFileProvider(Assembly.GetExecutingAssembly());
    var service = appBuilder.ApplicationServices;
    mapFile("blocklyAutomation", manifestEmbeddedProvider, appBuilder);


}

private static void mapFile(string dirName, IFileProvider provider, IApplicationBuilder appBuilder)
{
    var folder = provider.GetDirectoryContents(dirName);
    foreach (var item in folder)
    {
        if (item.IsDirectory)
        {
            mapFile(dirName + "/" + item.Name, provider, appBuilder);
            continue;
        }
        string map = (dirName + "/" + item.Name).Substring(dirName.Length);
        appBuilder.Map(map, app =>
        {
            var f = item;

            app.Run(async cnt =>
            {
                //TODO: find from extension
                //cnt.Response.ContentType = "text/html";
                using var stream = new MemoryStream();
                using var cs = f.CreateReadStream();
                byte[] buffer = new byte[2048]; // read in chunks of 2KB
                int bytesRead;
                while ((bytesRead = cs.Read(buffer, 0, buffer.Length)) > 0)
                {
                    stream.Write(buffer, 0, bytesRead);
                }
                byte[] result = stream.ToArray();
                var m = new Memory<byte>(result);
                await cnt.Response.BodyWriter.WriteAsync(m);
            });
        });
    }

}

4. That is all

Windows terminal + Powershell to run IDE, Angular, .NET Core

I work at http://github.com/ignatandrei/BlocklyAutomation – and every time I need to run Angular , Visual Studio Code IDE and .NET Core run ( and Visual Studio  sometimes  – it is more web based)

Also, sometimes I need to run in a container – to install globally something that I do not want to have in my PC.

So  I have 1 windows terminal command to run those :

First one

wt new-tab   –title RootSource –suppressApplicationTitle -p “Windows PowerShell” -d . cmd /k “cd src && code . && powershell” ;split-pane  –title Angular –suppressApplicationTitle -V -p “Windows PowerShell” -d . cmd /k “cd src &&  npm run start –watch && powershell” ;split-pane  –title LocalAPI_NetCore –suppressApplicationTitle -V -p “Windows PowerShell” -d . cmd /k “cd src/Local/LocalAPI/LocalAPI && dotnet watch run”

As you see , I have

code .

to run VSCode,

npm run start –watch

to run Angular and

dotnet watch run

to run dotnet.

Second one:

wt new-tab -p “Windows PowerShell” -d . ;split-pane -p “Windows PowerShell” -d . cmd /k “cd src && devcontainer open .”

The second it just works with devcontainer  – if you are interested in sources, see https://github.com/ignatandrei/BlocklyAutomation/tree/main/src/.devcontainer 

With those, I can start my developer environment fast ( how fast, that depends on my PC)

Andrei Ignat weekly software news(mostly .NET)

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