LangMate.Middleware 1.0.3

LangMate.Middleware

Part of the LangMate.Core SDK

📦 NuGet

LangMate.Middleware provides robust, pluggable middleware components for ASP.NET Core applications in the LangMate ecosystem. These middlewares improve resiliency, observability, and error handling—especially in AI-driven apps using local models like Ollama.

📦 Installation

To use LangMate.Middleware, install the required NuGet package, or include the project reference in your solution.

dotnet add package LangMate.Middleware

✨ Middlewares and Features

• Resiliency Middleware with:
  • Retry (Polly-based)
  • Timeout
  • Circuit Breaker
  • Serilog and APM support for observe and write ability for logging all requests and errors
• Exception Handling Middleware
• Request Logging Middleware
• 📉 Graceful degradation with friendly error responses
• 🧩 Plug-and-play into any ASP.NET Core app

🛡️ Resiliency Middleware

The Resiliency Middleware is a centralized, fault-tolerant HTTP request wrapper built using the Polly resilience framework. It enhances the reliability and responsiveness of your ASP.NET Core application by automatically handling transient failures, long-running requests, and service degradation.

This middleware is designed for AI-driven or service-heavy applications, such as LangMate, that depend on local/remote models, file uploads, and dynamic APIs.

🔧 What It Does

Wraps every HTTP request in a resilient policy pipeline:

Blazor SignalR (/_blazor) and WebSocket requests are automatically excluded to avoid interfering with real-time behavior.

⚙️ Behavior at Runtime

• ✅ Automatically retries transient errors (e.g., exceptions from external calls).
• ⏱ Times out long requests and fails gracefully.
• 🔌 Breaks the circuit when failures reach a threshold.
• 📉 Returns user-friendly responses:
  • 503 Service Unavailable (circuit open)
  • 504 Gateway Timeout (timeout triggered)
• 🧠 Logs events like retries, breaks, resets, and errors.

⚙️ Example Resiliency Middleware appsettings.json

{
  "ResiliencyMiddlewareOptions": {
    "RetryCount": 3,
    "TimeoutSeconds": 10,
    "ExceptionsAllowedBeforeCircuitBreaking": 2,
    "CircuitBreakingDurationSeconds": 30
  }
}

Serilog Logger

• Enrich logs with context and exceptions.
• Add correlation IDs for request tracing.
• Load settings from your appsettings.json.

⚙️ Example Serilog appsettings.json

{
  "Serilog": {
    "Using": [ "Serilog.Sinks.Console", "Serilog.Sinks.File", "Serilog.Sinks.Elasticsearch" ],
    "MinimumLevel": {
      "Default": "Information",
      "Override": {
        "Microsoft": "Warning",
        "System": "Warning"
      }
    },
    "Enrich": [ "FromLogContext", "WithExceptionDetails", "WithCorrelationId" ],
    "WriteTo": [
      {
        "Name": "Console",
        "Args": {
          "outputTemplate": "[{Timestamp:HH:mm:ss} {Level:u3}] {CorrelationId} {Message:lj}{NewLine}{Exception}"
        }
      },
      // optional if you want to save the logs into a file
      {
        "Name": "File",
        "Args": {
          "path": "Logs/log-.txt",
          "rollingInterval": "Day",
          "retainedFileCountLimit": 14,
          "shared": true
        }
      },
      // optional if using APM
      {
        "Name": "Elasticsearch",
        "Args": {
          "nodeUris": "http://localhost:9200",
          "indexFormat": "myapp-logs-{0:yyyy.MM}",
          "autoRegisterTemplate": true,
          "autoRegisterTemplateVersion": "ESv7"
        }
      }
    ]
  },
  // optional if using APM
  "ElasticApm": {
    "ServerUrls": "http://localhost:8200",
    "ServiceName": "MyApp.Service",
    "Environment": "Development",
    "SecretToken": "",
    "TransactionSampleRate": 1.0
  }
}

🔧 Service Registration

In your Program.cs or inside a service registration method (already is done in LangMate.Core):

// Setting Serilog logger
var builder = WebApplication.CreateBuilder(args);
Log.Logger = LangMateLoggingExtensions.AddLangMateLogging(builder.Configuration);

...
// Adding Middleware
services.AddLangMateMiddleware(configuration, useApm: useApm);

...
// Hook Into ASP.NET Core Pipeline
var loggerFactory = app.Services.GetRequiredService<ILoggerFactory>();
app.UseLangMateMiddleware(configuration, loggerFactory);

📄 License

MIT License