applogger-2do 2.5.0

AppLogger

Structured logging to Elasticsearch via Serilog. NuGet package: applogger-2do

What it does

• Automatically logs all HTTP requests (method, path, status code, response time)
• Catches unhandled exceptions with full stack trace
• Adds a correlation ID to every request (for tracing the entire flow)
• Enriches all logs with Customer, AppName, Environment and MachineName

Requirements

• .NET 8+ (ASP.NET Core)
• Does not work with .NET Framework

Setup for ASP.NET Core APIs

1. Add the NuGet package

dotnet add package applogger-2do

2. Add the Elasticsearch section to appsettings.json

{
  "Elasticsearch": {
    "Endpoint": "https://your-cluster.es.westeurope.azure.elastic-cloud.com:9243",
    "ApiKeyBase64": "your-base64-api-key",
    "Customer": "",
    "AppName": "",
    "Environment": "prod"
  }
}

3. Update Program.cs (2 lines)

using AppLogger;

var builder = WebApplication.CreateBuilder(args);

builder.UseAppLogger();  // <-- configures Serilog from appsettings.json

// ... rest of your DI setup ...

var app = builder.Build();

app.UseAppLoggerMiddleware();  // <-- request logging, exception handling, correlation IDs

// ... rest of your pipeline ...
app.Run();

That's it. All requests, exceptions and your own log calls are now sent to Elasticsearch.

What is logged automatically

Each HTTP request produces a log entry like:

HTTP GET /api/orders responded 200 in 42ms
HTTP POST /api/items responded 201 in 128ms
HTTP GET /api/missing failed with exception after 3ms. CorrelationId: a3f2-b1c4-...

Logging in code

Use Serilog's static Log class. All fields (Customer, AppName, Environment etc.) are added automatically.

using Serilog;

// Information
Log.Information("Order {OrderId} created for {Customer}", orderId, customerName);

// Warning
Log.Warning("Stock for item {Item} below minimum: {Qty} pcs", itemNo, qty);

// Error with exception
try
{
    await ProcessOrder(order);
}
catch (Exception ex)
{
    Log.Error(ex, "Failed to process order {OrderId}", order.Id);
    throw;  // let middleware handle the HTTP response
}

Structured logging

Always use {Placeholder} — not string interpolation:

// CORRECT — fields become searchable in Kibana:
Log.Information("Order {OrderId} created", orderId);

// WRONG — the value gets embedded in the text:
Log.Information($"Order {orderId} created");

Fields on each log entry

Correlation ID

The middleware adds a correlation ID to every request. All Log.*() calls within the same request automatically share the same correlation ID — regardless of layer (Controller, Service, Repository).

Search CorrelationId : "a3f2-..." in Kibana to see the full flow for a single request.

Kibana

Data Streams

Logs are organized in data streams:

logs-2do-{customer}-{appname}-{environment}

Create a data view in Kibana with pattern logs-2do-* to see all logs.

Useful KQL queries

Recommended columns in Discover

• @timestamp — when
• log.level — level
• Customer — which customer
• Application — which API/plugin
• message — the log message
• RequestPath — endpoint
• CorrelationId — to trace a request
• MachineName — which server

NuGet Dependencies

• Serilog 4.x
• Serilog.Extensions.Logging 8.x
• Serilog.Sinks.Console 6.x
• Serilog.Enrichers.Environment 3.x
• Elastic.Serilog.Sinks 8.x

Changelog