[bug] AspNetCore instrumentation Query redaction does not respect the environment variable set in runtime

[jundayin]

Package

OpenTelemetry

Package Version

Package Name	Version
OpenTelemetry.Api	1.10.0
OpenTelemetry	1.10.0
OpenTelemetry.Instrumentation.AspNetCore	1.10.0
OpenTelemetry.Exporter.Console	1.10.0
OpenTelemetry.Extensions.Hosting	1.10.0

Runtime Version

net8.0

Description

The query attributes redaction does not respect the environment variable set in runtime.

Steps to Reproduce

using OpenTelemetry.Trace;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

Environment.SetEnvironmentVariable("OTEL_DOTNET_EXPERIMENTAL_ASPNETCORE_DISABLE_URL_QUERY_REDACTION", "true"); // This does not work
            
var envVar = Environment.GetEnvironmentVariable(
    "OTEL_DOTNET_EXPERIMENTAL_ASPNETCORE_DISABLE_URL_QUERY_REDACTION"); // This is true

var envVars = Environment.GetEnvironmentVariables(); // Contains the env var

builder.Services
    .AddOpenTelemetry()
    .WithTracing(builder =>
    {
        builder.AddAspNetCoreInstrumentation();
        builder.AddConsoleExporter();
    });

var app = builder.Build();
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.MapGet("/search", (string query) =>
{
    return $"You searched for: {query}";
})
.WithName("Search")
.WithOpenApi();

app.Run();

Expected Result

When the environment variable is successfully set during runtime before OpenTelemetry is registered, the Query redaction should be disabled

Actual Result

The query redaction is still being enabled

Additional Context

Please refer this repo https://github.com/jundayin/OpenTelemetryEnvRepro

[rajkumar-rangaraj]

In ASP.NET Core, the recommended way to configure environment variables is by using builder.Configuration.AddEnvironmentVariables(). This ensures that environment variables are properly loaded into the application's configuration during startup.

Did you try using this approach to set the environment variable?

Reference: ASP.NET Core Configuration - Environment Variables

OpenTelemetry .NET relies on IConfiguration to load environment variables, making it more adaptable to the ASP.NET Core configuration model.

[jundayin]

Thanks, that explains why it does not work in my repro since the host configuration is already built. If I move the SetEnvironmentVariable before CreateBuilder it works.

I guess I have to inform my SDK consumer to add the env var or appSetting explicitly. Is it possible to expose these kinds of configuration through code so that we don't need such hard-coded value everywhere

[CEbbinghaus]

I would like to point out that this is not possible for non ASP.Net Core apps...

The application I am having the problem with is a command-line...