AppSettings Configuration

Overview

Each service uses appsettings.json for configuration. These settings can be overridden by environment-specific files (appsettings.Development.json, appsettings.Production.json) or environment variables.

Configuration Structure by Service

Catalog API

File: Services/Catalog/Catalog.API/appsettings.json

{
  "ConnectionStrings": {
    "Database": "Server=localhost;Port=5432;Database=CatalogDb;User Id=postgres;Password=postgres;Include Error Detail=true"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*"
}

Configuration Details:

Section	Key	Description	Default Value
ConnectionStrings	Database	PostgreSQL connection string	localhost:5432
Logging	Default	Default log level	Information
Logging	Microsoft.AspNetCore	ASP.NET Core log level	Warning
-	AllowedHosts	CORS allowed hosts	* (all)

Database: Uses Marten with PostgreSQL for document storage.

Basket API

File: Services/Basket/Basket.API/appsettings.json

{
  "ConnectionStrings": {
    "Database": "Server=localhost;Port=5433;Database=BasketDb;User Id=postgres;Password=postgres;Include Error Detail=true",
    "Redis": "localhost:6379"
  },
  "GrpcSettings": {
    "DiscountUrl": "https://localhost:5052"
  },
  "MessageBroker": {
    "Host": "amqp://localhost:5672",
    "UserName": "guest",
    "Password": "guest"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*"
}

Configuration Details:

Section	Key	Description	Default Value
ConnectionStrings	Database	PostgreSQL connection string	localhost:5433
ConnectionStrings	Redis	Redis cache connection	localhost:6379
GrpcSettings	DiscountUrl	Discount gRPC service URL	https://localhost:5052
MessageBroker	Host	RabbitMQ host address	amqp://localhost:5672
MessageBroker	UserName	RabbitMQ username	guest
MessageBroker	Password	RabbitMQ password	guest

Features:

PostgreSQL for cart persistence
Redis for distributed caching
gRPC client for discount service
MassTransit with RabbitMQ for event publishing

Discount gRPC

File: Services/Discount/Discount.Grpc/appsettings.json

{
  "ConnectionStrings": {
    "Database": "Data Source=discountdb"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Information"
    }
  },
  "AllowedHosts": "*",
  "Kestrel": {
    "EndpointDefaults": {
      "Protocols": "Http2"
    }
  }
}

Configuration Details:

Section	Key	Description	Default Value
ConnectionStrings	Database	SQLite database file	discountdb
Kestrel	Protocols	HTTP protocol version	Http2 (gRPC)
Logging	Default	Default log level	Information
Logging	Microsoft.AspNetCore	ASP.NET Core log level	Information

Important: The Kestrel.EndpointDefaults.Protocols is set to Http2 to enable gRPC communication. Database: Uses Entity Framework Core with SQLite for lightweight discount storage.

Ordering API

File: Services/Ordering/Ordering.API/appsettings.json

{
  "ConnectionStrings": {
    "Database": "Server=localhost;Database=OrderDb;User Id=sa;Password=SwN12345678;Encrypt=False;TrustServerCertificate=True"
  },
  "MessageBroker": {
    "Host": "amqp://localhost:5672",
    "UserName": "guest",
    "Password": "guest"
  },
  "FeatureManagement": {
    "OrderFullfilment": false
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*"
}

Configuration Details:

Section	Key	Description	Default Value
ConnectionStrings	Database	SQL Server connection string	localhost:1433
MessageBroker	Host	RabbitMQ host address	amqp://localhost:5672
MessageBroker	UserName	RabbitMQ username	guest
MessageBroker	Password	RabbitMQ password	guest
FeatureManagement	OrderFullfilment	Feature flag for order fulfillment	false

Features:

SQL Server with Entity Framework Core
MassTransit with RabbitMQ for consuming basket checkout events
Feature flags for controlling order fulfillment workflow

Connection String Options:

Encrypt=False: Disables SSL encryption (dev only)
TrustServerCertificate=True: Bypasses certificate validation (dev only)

YARP API Gateway

File: ApiGateways/YarpApiGateway/appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "ReverseProxy": {
    "Routes": {
      "catalog-route": {
        "ClusterId": "catalog-cluster",
        "Match": {
          "Path": "/catalog-service/{**catch-all}"
        },
        "Transforms": [{ "PathPattern": "{**catch-all}" }]
      },
      "basket-route": {
        "ClusterId": "basket-cluster",
        "Match": {
          "Path": "/basket-service/{**catch-all}"
        },
        "Transforms": [{ "PathPattern": "{**catch-all}" }]
      },
      "ordering-route": {
        "ClusterId": "ordering-cluster",
        "RateLimiterPolicy": "fixed",
        "Match": {
          "Path": "/ordering-service/{**catch-all}"
        },
        "Transforms": [{ "PathPattern": "{**catch-all}" }]
      }
    },
    "Clusters": {
      "catalog-cluster": {
        "Destinations": {
          "destination1": {
            "Address": "http://catalog.api:8080"
          }
        }
      },
      "basket-cluster": {
        "Destinations": {
          "destination1": {
            "Address": "http://basket.api:8080"
          }
        }
      },
      "ordering-cluster": {
        "Destinations": {
          "destination1": {
            "Address": "http://ordering.api:8080"
          }
        }
      }
    }
  }
}

Reverse Proxy Routes:

Route	Path Pattern	Backend Service	Rate Limiting
catalog-route	/catalog-service/*	http://catalog.api:8080	No
basket-route	/basket-service/*	http://basket.api:8080	No
ordering-route	/ordering-service/*	http://ordering.api:8080	Yes (fixed window)

Rate Limiting Configuration (in Program.cs):

Policy: Fixed Window
Window: 10 seconds
Permit Limit: 5 requests per window

Path Transforms:

Incoming: /catalog-service/products
Transformed: /products (service receives without prefix)

Local Development (appsettings.Local.json):

"catalog-cluster": {
  "Destinations": {
    "destination1": {
      "Address": "http://localhost:6000/"
    }
  }
}

For local development, clusters point to localhost ports instead of Docker service names.

Shopping Web

File: WebApps/Shopping.Web/appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "ApiSettings": {
    "GatewayAddress": "https://localhost:6064"
  }
}

Configuration Details:

Section	Key	Description	Default Value
ApiSettings	GatewayAddress	YARP Gateway base URL	https://localhost:6064

API Clients:

Uses Refit for HTTP client generation
All services accessed through the gateway
Service endpoints:
- Catalog: {GatewayAddress}/catalog-service
- Basket: {GatewayAddress}/basket-service
- Ordering: {GatewayAddress}/ordering-service

Common Configuration Sections

Logging

All services use standard ASP.NET Core logging configuration:

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  }
}

Log Levels: Trace, Debug, Information, Warning, Error, Critical, None

AllowedHosts

{
  "AllowedHosts": "*"
}

Controls host header filtering. Use specific domains in production.

Environment-Specific Configuration

Development Settings

Minimal overrides in appsettings.Development.json:

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  }
}

Docker Settings

In Docker environments, settings are primarily controlled via environment variables in docker-compose.override.yml rather than separate appsettings files.

Configuration Best Practices

Use User Secrets for Development

Store sensitive data in User Secrets during development:

dotnet user-secrets set "ConnectionStrings:Database" "your-connection-string"

Environment Variables in Production

Override sensitive settings using environment variables:

export ConnectionStrings__Database="production-connection-string"

Note: Use double underscores (__) to represent nested JSON levels.

Azure App Configuration

For production, consider using Azure App Configuration or Azure Key Vault:

builder.Configuration.AddAzureAppConfiguration(options =>
{
    options.Connect(connectionString)
           .ConfigureKeyVault(kv => kv.SetCredential(credential));
});

Feature Flags

Use the FeatureManagement section for feature toggles:

{
  "FeatureManagement": {
    "OrderFullfilment": true,
    "NewCheckoutFlow": false
  }
}

Reading Configuration in Code

Strongly-Typed Configuration

// Configuration class
public class MessageBrokerSettings
{
    public string Host { get; set; }
    public string UserName { get; set; }
    public string Password { get; set; }
}

// Registration
builder.Services.Configure<MessageBrokerSettings>(
    builder.Configuration.GetSection("MessageBroker"));

// Usage
public class MyService
{
    private readonly MessageBrokerSettings _settings;
    
    public MyService(IOptions<MessageBrokerSettings> options)
    {
        _settings = options.Value;
    }
}

Direct Access

var database = builder.Configuration.GetConnectionString("Database");
var discountUrl = builder.Configuration["GrpcSettings:DiscountUrl"];

Connection String Formats

PostgreSQL

Server={host};Port={port};Database={db};User Id={user};Password={pwd};Include Error Detail=true

SQL Server

Server={host};Database={db};User Id={user};Password={pwd};Encrypt=False;TrustServerCertificate=True

SQLite

Data Source={filename}

Redis

{host}:{port}

RabbitMQ

amqp://{host}:{port}

Docker

Configuration

Operations

Overview

Configuration Structure by Service

Catalog API

Basket API

Discount gRPC

Ordering API

YARP API Gateway

Shopping Web

Common Configuration Sections

Logging

AllowedHosts

Environment-Specific Configuration

Development Settings

Docker Settings

Configuration Best Practices

Reading Configuration in Code

Strongly-Typed Configuration

Direct Access

Connection String Formats

PostgreSQL

SQL Server

SQLite

Redis

RabbitMQ

Build docs developers (and LLMs) love

Docker

Configuration

Operations

​Overview

​Configuration Structure by Service

​Catalog API

​Basket API

​Discount gRPC

​Ordering API

​YARP API Gateway

​Shopping Web

​Common Configuration Sections

​Logging

​AllowedHosts

​Environment-Specific Configuration

​Development Settings

​Docker Settings

​Configuration Best Practices

​Reading Configuration in Code

​Strongly-Typed Configuration

​Direct Access

​Connection String Formats

​PostgreSQL

​SQL Server

​SQLite

​Redis

​RabbitMQ

Build docs developers (and LLMs) love

Overview

Configuration Structure by Service

Catalog API

Basket API

Discount gRPC

Ordering API

YARP API Gateway

Shopping Web

Common Configuration Sections

Logging

AllowedHosts

Environment-Specific Configuration

Development Settings

Docker Settings

Configuration Best Practices

Reading Configuration in Code

Strongly-Typed Configuration

Direct Access

Connection String Formats

PostgreSQL

SQL Server

SQLite

Redis

RabbitMQ