Add support for Open Telemetry

[tommasodotNET]

Why make this change?

Initial implementation to add open-telemetry support (reference #2397)

What is this change?

The user can add the open-telemetry configuration in the dab-config.json file as follows:

{
  "runtime": {
    ...
    "telemetry": {
      "open-telemetry": {
        "enabled": true,
        "service-name": "dab", // has a default value
        "endpoint": "OTEL_ENDPOINT",
        "headers": "x-otlp-api-key=OTEL_API_KEY" // if needed
      }
    }
    ...
  }
}

This configuration can be used alongside the current Application Insights instrumentation, to send logs, traces and metrics to both.

Currently, metrics and traces sent to OTEL comes from AspNetCore and the HttpClients.

The OpenTelemetry implementation only supports dotnet 8.

How was this tested?

• Unit Tests

[abhishekkumams]

Thanks @tommasodotNET for taking up this feature.

Added few comments.

Also,

1. Would it possible to add some integration tests that validate the complete workflow.
   and having some assertions to check that traces are created for specific operations or that metrics have the expected values?

2. For actual testing where were you checking the exported data? Can you add some information on that as well?

[abhishekkumams]

The unit tests were failing due to how the CommandLine library handles parameters in immutable option types. For reference, you can review the details in the following links:

• [CommandLine Issue #188](Immutable constructor argument order issues result in NullReferenceException commandlineparser/commandline#188)
• [Immutable Options Type Documentation](https://github.com/commandlineparser/commandline/wiki/Immutable-Options-Type)

I’ve updated your PR to address the issue and applied the necessary fix. Let me know if you have any questions or need further clarification.

[abhishekkumams]

/azp run

[abhishekkumams]

/azp run

[tommasodotNET]

As a demo for how this configuration work, I have started a .NET Aspire Dashboard to start a local SQL Database and OpenTelemetry endpoint with relative dashbaords.
Having that we can start with a configuration like this

{
    "data-source": {
      "database-type": "mssql",
      "connection-string": "Server=127.0.0.1,60632;User ID=sa;Password=tVA035aCbQ{7MDkt!MB5PW;TrustServerCertificate=true;Database=WarehouseDB"
    },
    "runtime": {
      "rest": {
        "path": "/api"
      },
      "graphql": {
        "path": "/graphql"
      },
      "host": {
        "cors": {
          "origins": [],
          "allow-credentials": false
        },
        "authentication": {
            "provider": "StaticWebApps"
        },
        "mode": "development"
      },
      "telemetry": {
        "open-telemetry": {
            "enabled": true,
            "endpoint": "https://localhost:21048",
            "headers": "x-otlp-api-key=ffcae508e4b8085b992df2d2027c6000",
            "exporter-protocol": "grpc",
            "service-name": "dab"
          }
        }
    },
...

By running a few queries on the DAB instance, we can see the traces and metrics in .NET Aspire Dashbaord. Here are some screenshots:

Please note that .NET Aspire IS NOT the only way to instrument DAB with OTEL. I've used it for this demo only because it was a handy way to start a DB and have and OTEL endpoint available with the dashboards.

[abhishekkumams]

LGTM

[abhishekkumams]

/azp run

[RubenCerna2079]

/azp run

[RubenCerna2079]

LGTM