DiagnosKit.Core 2.2.2

DiagnosKit.Core

A lightweight diagnostics toolkit for .NET 8+ that provides:

• Structured logging with Serilog
• Elasticsearch sink support
• Easy integration for both Web APIs and Worker Services
• Unified global exception handling (middleware)
• OpenTelemetry tracing, metrics & logging integration
• Automatic request meters (requests per endpoint, duration, failures)
• Log enrichment with CorrelationId and UserId

📦 Installation

Install from NuGet:

dotnet add package DiagnosKit.Core

🚀 Usage

1. Web API (Program.cs)

using DiagnosKit.Core;

// For pre-bootstrap logging
SerilogBootstrapper.UseBootstrapLogger();

var builder = WebApplication.CreateBuilder(args);

// Configure Serilog + Elasticsearch
builder.Host.ConfigureSerilogESSink();

// Add DiagnosKit logger abstraction
builder.Services.AddLoggerManager();

// Add OpenTelemetry (traces + metrics + logging)
builder.Services.AddDiagnosKitObservability(
    serviceName: "MyWebApi",
    serviceVersion: "1.0.0"
);

// Optional: OTel logging
builder.Logging.AddDiagnosKitOpenTelemetryLogging();

builder.Services.AddControllers();

var app = builder.Build();

// Global exception handler
app.UseUnifiedErrorHandler();

// Log & metrics enrichment (CorrelationId + UserId + meters)
app.UseDiagnosKitLogEnricher();

app.MapControllers();

// Expose /metrics for Prometheus
app.MapPrometheusScrapingEndpoint();
// Enables Prometheus metrics collection for the application
app.UseDiagnosKitPrometheus();

app.Run();

2. Worker Service (Program.cs)

using DiagnosKit.Core;

// Pre-bootstrap logging
SerilogBootstrapper.UseBootstrapLogger();

var builder = Host.CreateApplicationBuilder(args);

// Configure Serilog + Elasticsearch
builder.ConfigureSerilogESSink();

// Add DiagnosKit logger abstraction
builder.Services.AddLoggerManager();

// Add OpenTelemetry (traces + metrics)
builder.Services.AddDiagnosKitObservability(
    serviceName: "MyWorker",
    serviceVersion: "1.0.0"
);

// Optional: OTel logging
builder.Logging.AddDiagnosKitOpenTelemetryLogging();

// Register worker
builder.Services.AddHostedService<MyWorker>();

var host = builder.Build();
host.Run();

Example Worker:

public class MyWorker : BackgroundService
{
    private readonly ILoggerManager _logger;

    public MyWorker(ILoggerManager logger)
    {
        _logger = logger;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        _logger.LogInfo("Worker started");

        while (!stoppingToken.IsCancellationRequested)
        {
            _logger.LogDebug("Heartbeat at: {time}", DateTimeOffset.Now);
            await Task.Delay(1000, stoppingToken);
        }
    }
}

⚙️ Configuration

IndexFormat will default to this format: application-name-{0:yyyy.MM}, if no format is specified

In your appsettings.json:

{
  "Serilog": {
    "MinimumLevel": {
      "Default": "Information",
      "Override": {
        "Microsoft.AspNetCore": "Information",
        "System": "Warning"
      }
    }
  },
  "ElasticSearch": {
    "Url": "http://localhost:9200",
    "IndexFormat": "myapp-{0:yyyy.MM}"
  },
}

📝 Features

✅ Web API support (app.UseDiagnosKitErrorHandler()) ✅ Worker Service support with ILoggerManager abstraction ✅ Serilog + Elasticsearch integration ✅ OpenTelemetry-ready (Tracing, Metrics, Logging) ✅ Request meters (per endpoint: total requests, failures, duration) ✅ Automatic log enrichment with

• CorrelationId
• UserId (when available)
• Environment
• Service

📊 Kibana Filtering

Because logs are enriched with structured properties (like Environment, Service, CorrelationId, and Exception),
you can filter/search logs in Kibana by:

• Environment: "Production"
• Service: "UserService"
• Exception exists
• UserId: 12345

📊 Kibana + Grafana

Kibana → filter structured logs by:

• Environment: "Production"
• Service: "UserService"
• CorrelationId: "abc123"
• UserId: 12345
• Exception exists

Grafana → visualize Prometheus metrics:

• http_requests_total{endpoint="/api/users"}
• http_requests_failed_total
• http_request_duration_seconds

Prometheus Setup

By default, app.MapPrometheusScrapingEndpoint() in your ASP.NET Core app exposes metrics at /metrics. In your Prometheus config (prometheus.yml), the metrics_path tells Prometheus where to scrape from. If you don’t set it, Prometheus automatically defaults to /metrics.

✅ Example (explicit):

scrape_configs:
  - job_name: 'diagnoskit-api'
    scrape_interval: 5s
    metrics_path: /metrics
    static_configs:
      - targets: ['host.docker.internal:5000']

✅ Example (simpler, same result):

scrape_configs:
  - job_name: 'diagnoskit-api'
    scrape_interval: 5s
    static_configs:
      - targets: ['host.docker.internal:5000']

Run Prometheus with this config, and you’ll see metrics like:

• http_server_requests_duration_seconds (per endpoint latency histograms)
• http_server_requests_count (per endpoint request count)
• .NET runtime metrics (GC, memory, threads, exceptions)

Grafana Dashboard Example

Here’s a minimal Grafana dashboard JSON you can import to visualize key metrics:

{
  "id": null,
  "title": "DiagnosKit API Dashboard",
  "timezone": "browser",
  "panels": [
    {
      "type": "graph",
      "title": "Request Count per Endpoint",
      "targets": [
        {
          "expr": "sum by (method, route) (http_server_requests_count)",
          "legendFormat": "{{method}} {{route}}"
        }
      ]
    },
    {
      "type": "graph",
      "title": "Request Duration (p95)",
      "targets": [
        {
          "expr": "histogram_quantile(0.95, sum(rate(http_server_requests_duration_seconds_bucket[5m])) by (le, route))",
          "legendFormat": "{{route}}"
        }
      ]
    },
    {
      "type": "graph",
      "title": ".NET GC Collections",
      "targets": [
        {
          "expr": "dotnet_gc_collections_count_total",
          "legendFormat": "Gen {{generation}}"
        }
      ]
    },
    {
      "type": "graph",
      "title": "Memory Usage",
      "targets": [
        {
          "expr": "process_private_memory_bytes",
          "legendFormat": "Private Memory"
        }
      ]
    }
  ],
  "schemaVersion": 30,
  "version": 1
}

👉 In Grafana:

• Go to Dashboards > Import
• Paste the JSON above
• Select your Prometheus datasource

⚖ License

This project is licensed under the MIT License - see the LICENSE file for details.