Why is the parentId of the called service not the one of the caller service?

[snake-L]

Question

How did Service A call Service B, Service B call Service C, and the parentIDs of Service B and C get?

[martinjt]

There's not a huge amount of information to go on there, but I suspect that the ParentIds are from the HTTP outbound span (HTTP Client), not the inbound AspNet core span, which is what you're showing there.

I'm not sure why ServiceC would be in a new Trace, but perhaps you've not enabled the HTTPClient instrumentation in Service B?

[snake-L]

There's not a huge amount of information to go on there, but I suspect that the ParentIds are from the HTTP outbound span (HTTP Client), not the inbound AspNet core span, which is what you're showing there.

I'm not sure why ServiceC would be in a new Trace, but perhaps you've not enabled the HTTPClient instrumentation in Service B?

@martinjt hi, this is the sample code. I have checked the source code but cannot find the reason

serviceA

	var builder = WebApplication.CreateBuilder(args);
	builder.WebHost.ConfigureKestrel(b =>
{
	b.ListenAnyIP(5000);
});
	builder.Services.AddHttpClient();
	builder.Services.AddOpenTelemetry()
	.ConfigureResource(resource => resource
		.AddService("ServiceA"))
	.WithTracing(tracing => tracing
		.AddAspNetCoreInstrumentation()
		.AddConsoleExporter()
		.AddZipkinExporter()
		);

	var app = builder.Build();
	app.MapGet("/serviceA", async Task<string> (HttpContext context, IHttpClientFactory factory) =>
	{
		using var httpClient = factory.CreateClient("client");
		httpClient.BaseAddress = new Uri("Http://localhost:5001");
		
		var response = await httpClient.GetAsync("/serviceB");
		response.EnsureSuccessStatusCode();
		return await response.Content.ReadAsStringAsync();
	});
	await app.RunAsync();

serviceB

  var builder = WebApplication.CreateBuilder(args);
	builder.WebHost.ConfigureKestrel(b =>
{
	b.ListenAnyIP(5001);
});
	builder.Services.AddHttpClient();
	builder.Services.AddOpenTelemetry()
	.ConfigureResource(resource => resource
		.AddService("ServiceB"))
	.WithTracing(tracing => tracing
		.AddAspNetCoreInstrumentation()
		.AddConsoleExporter().AddZipkinExporter()
		);
	var app = builder.Build();
	app.MapGet("/serviceB", async Task<string> (HttpContext context, IHttpClientFactory factory) =>
	{
		using var httpClient = factory.CreateClient("serviceC");
		httpClient.BaseAddress = new Uri("Http://localhost:5002");

		var response = await httpClient.GetAsync("/serviceC");
		response.EnsureSuccessStatusCode();
		var result =  await response.Content.ReadAsStringAsync();


	    response = await httpClient.GetAsync("/serviceC");
		response.EnsureSuccessStatusCode();
        return await response.Content.ReadAsStringAsync();
	});
	await app.RunAsync();

ServiceC

	var builder = WebApplication.CreateBuilder(args);
	builder.WebHost.ConfigureKestrel(b =>
{
	b.ListenAnyIP(5002);
});
	builder.Services.AddHttpClient();
	builder.Services.AddOpenTelemetry()
	.ConfigureResource(resource => resource
		.AddService("ServiceC"))
	.WithTracing(tracing => tracing
		.AddAspNetCoreInstrumentation()
				.AddConsoleExporter().AddZipkinExporter()
		);

	var app = builder.Build();
	app.MapGet("/serviceC", ValueTask<string> (HttpContext context) =>
{
	return new ValueTask<string>($"DateTime Now：{DateTime.Now},GUid:{Guid.NewGuid().ToString("N")}");
});
	await app.RunAsync();