Allow Bootstrapping with WebApplicationBuilder

[Puchaczov]

Is your feature request related to a problem? Please describe. .NET Core team has done some significant changes in the lastest 6 release of dotnet. Right now, there is brand new way of bootstrapping application so we doesn't use startup.cs file anymore and instead of IApplicationBuilder, they have introduced WebApplicationBuilder to configure the framework'

Describe the solution you'd like Extend ApmMiddlewareExtension.UseElasticApm that would make use of newer WebApplicationBuilder

[gregkalapos]

Thanks for reporting, we'll definitely look at this.

[z1c0]

Hi @Puchaczov,

As I'm currently looking into this, may I ask you to elaborate on your use case, please?

Bootstrapping a fresh .NET 6 application results in the following code for Program.cs:

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddRazorPages();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Error");
    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();

app.UseRouting();

app.UseAuthorization();

app.MapRazorPages();

app.Run();

Using the Elastic agent is still possible by adding this line after var app = builder.Build();

var app = builder.Build();
app.UseElasticApm();

or

var app = builder.Build();
app.UseAllElasticApm();

Please let me know if this already covers your use case.

FYI @gregkalapos

[z1c0]

Hi @Puchaczov,

I'm closing this issue based on my above comment. Feel free to reopen it though, should I have missed something.

[gregkalapos]

I was working on something totally different, but then I ran into this.

The suggestion above works, but that ends up in this method which is an extension method for IApplicationBuilder, and it ends up in the following line:

https://github.com/elastic/apm-agent-dotnet/blob/2959306e7e0fcb4651fcc19b04b5e94ebd425752/src/Elastic.Apm.AspNetCore/ApmMiddlewareExtension.cs#L45

That was our original code to capture incoming HTTP calls and that registers an ASP.NET Core middleware. This all works and that code is still maintained.

However... we also offer a UseAllElasticApm extension method for IHostBuilder, which is here which calls into https://github.com/elastic/apm-agent-dotnet/blob/2959306e7e0fcb4651fcc19b04b5e94ebd425752/src/Elastic.Apm.Extensions.Hosting/HostBuilderExtensions.cs#L44

That does not rely on an ASP.NET Core middleware, but it registers a diagnostic listener to start/stop transactions for incoming HTTP calls. The AspNetCoreDiagnosticSubscriber (and listener) was born because of the zero code change agent injection... we can easily register these listeners during startup, but it was way more difficult to register a middleware.

But there are other advantages as well:

• The second approach registers an ITracer in DI, so in user code you can just do public HomeController(ITracer tracer) and the tracer is already injected
• We also register our ApmErrorLoggingProvider (which is an ILoggerProvider) to turn error log lines into APM errors (side note: I was debugging around this and that's how I ended up here).

From what I understand Microsoft moved away from IHostBuilder in .NET 6. It's not there in the default setup discussed above (you can still use it, but it's not in the default project template anymore) and here comes the problem. In .NET 5 users were able to call into our IHostBuilder based UseAllElasticApm extension method and have the features mentioned above, but that does not exist anymore for .NET6 in the default template.

There is now a WebApplicationBuilder, so we could implement something like this:

public static WebApplicationBuilder UseAllElasticApm(this WebApplicationBuilder builder)

and then on the WebApplicationBuilder we can still register everything which we registered on the IHostBuilder.

I reopen this since direct support for WebApplicationBuilder sounds important to me.

I'd suggest we do the following:

• [ ] Let's discuss if we want to do this. I'll bring this to the weekly
• [ ] If we decide to do it, let's implement the extension method for WebApplicationBuilder
• [ ] There is this known but in the IHostBuilder based implementation: https://github.com/elastic/apm-agent-dotnet/issues/1607 If we decide to have a similar one for WebApplicationBuilder let's try to avoid that bug.