HelloWorld scope app for OpenTelemetry logging

[Sebosek]

Hi,

I'm trying to run OpenTelemetry logging "HelloWorld" scope application exporting logs into the Debug exporter, but still without any luck. I'm on Windows and here are my steps to reproduce it:

1. Create OTLP configuration

# This is a configuration file for the OpenTelemetry Collector intended to be
# used in conjunction with the OTLP Exporter example (see ../TestOtlpExporter.cs)
#
# For more information about the OpenTelemetry Collector see:
#   https://github.com/open-telemetry/opentelemetry-collector
#
receivers:
  otlp:
    protocols:
      grpc:
      http:

exporters:
  debug:
    verbosity: detailed

service:
  pipelines:
    traces:
      receivers: [otlp]
      exporters: [debug]
    metrics:
      receivers: [otlp]
      exporters: [debug]
    logs:
      receivers: [otlp]
      exporters: [debug]

2. Run the docker image pointing to the configuration

docker run --rm -it -p 4317:4317 -p 4318:4318 -v /c/Projects/opentelemetry/otlp/:/cfg otel/opentelemetry-collector:latest --config=/cfg/otlp-collector-example/config.yaml

I get the following output

2024-08-21T13:24:51.148Z        info    service@v0.107.0/service.go:116 Setting up own telemetry...
2024-08-21T13:24:51.149Z        info    service@v0.107.0/telemetry.go:96        Serving metrics {"address": ":8888", "metrics level": "Normal"}
2024-08-21T13:24:51.149Z        info    exporter@v0.107.0/builder.go:85 Development component. May change in the future.        {"kind": "exporter", "data_type": "metrics", "name": "debug"}
2024-08-21T13:24:51.150Z        info    exporter@v0.107.0/builder.go:85 Development component. May change in the future.        {"kind": "exporter", "data_type": "traces", "name": "debug"}
2024-08-21T13:24:51.150Z        info    exporter@v0.107.0/builder.go:85 Development component. May change in the future.        {"kind": "exporter", "data_type": "logs", "name": "debug"}
2024-08-21T13:24:51.152Z        info    service@v0.107.0/service.go:195 Starting otelcol...     {"Version": "0.107.0", "NumCPU": 20}
2024-08-21T13:24:51.152Z        info    extensions/extensions.go:36     Starting extensions...
2024-08-21T13:24:51.153Z        info    otlpreceiver@v0.107.0/otlp.go:102       Starting GRPC server    {"kind": "receiver", "name": "otlp", "data_type": "traces", "endpoint": "localhost:4317"}
2024-08-21T13:24:51.155Z        info    otlpreceiver@v0.107.0/otlp.go:152       Starting HTTP server    {"kind": "receiver", "name": "otlp", "data_type": "traces", "endpoint": "localhost:4318"}
2024-08-21T13:24:51.157Z        info    service@v0.107.0/service.go:221 Everything is ready. Begin running and processing data.
2024-08-21T13:24:51.157Z        info    localhostgate/featuregate.go:63 The default endpoints for all servers in components have changed to use localhost instead of 0.0.0.0. Disable the feature gate to temporarily revert to the previous default.   {"feature gate ID": "component.UseLocalHostAsDefaultHost"}

3. Create a sample aspnetweb app

using OpenTelemetry.Logs;
using OpenTelemetry.Resources;

var builder = WebApplication.CreateBuilder(args);
builder.Logging.ClearProviders();
builder.Services
    .AddOpenTelemetry()
    .ConfigureResource(r => r
        .AddService(
            serviceName: builder.Configuration.GetValue("ServiceName", defaultValue: "otel-test")!,
            serviceVersion: typeof(Program).Assembly.GetName().Version?.ToString() ?? "unknown",
            serviceInstanceId: Environment.MachineName))
    .WithLogging(builder =>
    {
        builder.AddOtlpExporter(otlpOptions =>
        {
            otlpOptions.Endpoint = new Uri("http://localhost:4317");
        });
        builder.AddConsoleExporter();
    });

var app = builder.Build();
app.MapGet("/", (ILogger<Program> logger) =>
{
    logger.FoodPriceChanged("artichoke", 9.99);

    return "Hello from OpenTelemetry Logs!";
});
app.Run();

internal static partial class LoggerExtensions
{
    [LoggerMessage(LogLevel.Information, "Starting the app...")]
    public static partial void StartingApp(this ILogger logger);

    [LoggerMessage(LogLevel.Information, "Food `{name}` price changed to `{price}`.")]
    public static partial void FoodPriceChanged(this ILogger logger, string name, double price);
}

With the following packages

<ItemGroup>
  <PackageReference Include="OpenTelemetry.Exporter.Console" Version="1.9.0" />
  <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.9.0" />
  <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.9.0" />
  <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.9.0" />
  <PackageReference Include="OpenTelemetry.Instrumentation.Http" Version="1.9.0" />
  <PackageReference Include="OpenTelemetry.Instrumentation.Runtime" Version="1.9.0" />
</ItemGroup>

After hitting the main endpoint, I would expect to see logs in the OTPL collector. Is my expectation incorrect?

[cijothomas]

Yes, your expectation is correct. Are you able to see logs in Console?

OTLP Collector is not working due to recent change to Collector I think, which is mentioed in its logs. You can explicitly set endpoint as shown below and that should fix the issue.

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318

[Sebosek]

Thanks, that was the trick. Knowing the context, the message in the log makes much more sense.

[xiang17]

Submitted a PR to fix the config example: #5811.