.NET Core development actual combat (Lesson 15: Options Framework: Best Practices Services Component Integration configuration) - Study Notes

15 | Options Framework: Best Practices Services Component Integration configuration

This section explains how to use the relationship framework to deal with service options and configuration

Options Framework features:

1, support the single mode to read configuration Example

2, support snapshot

3, supports the configuration change notification

4, modify the option values ​​to support dynamic run-time

When designing the system need to follow two principles:

1, the principle of separation of the interface (the ISP), we should not rely on the configuration class it does not use the

2, separation of concerns (the SoC), arranged between the different components, services, or coupled type not interdependent

Suggest:

1, for our service design XXXOptions

2, IOptions 、IOptionsSnapshot 、IOptionsMonitor As a parameter of service Constructor

This will make all kinds of our ability to achieve faster service configuration

Source link:
https://github.com/witskeeper/geektime/tree/master/samples/OptionsDemo

In the definition of the service, generally define the service interface

namespace OptionsDemo.Services
{
    public interface IOrderService
    {
        int ShowMaxOrderCount();
    }
    
    public class OrderService : IOrderService
    {
        OrderServiceOptions _options;
        
        public OrderService(OrderServiceOptions options)
        {
            _options = options;
        }

        public int ShowMaxOrderCount()
        {
            return _options.MaxOrderCount;
        }
    }

    // 代表从配置中读取的值
    public class OrderServiceOptions
    {
        public int MaxOrderCount { get; set; } = 100;
    }
}

Followed by a service registry

public void ConfigureServices(IServiceCollection services)
{
    services.AddSingleton<OrderServiceOptions>();
    services.AddSingleton<IOrderService, OrderService>();
}

Followed by the definition of the controller

[HttpGet]
public int Get([FromServices]IOrderService orderService)
{
    Console.WriteLine($"orderService.ShowMaxOrderCount:{orderService.ShowMaxOrderCount()}");
    return 1;
}

Start the program, the output is as follows:

orderService.ShowMaxOrderCount:100

If you say that we need to put this value with the configuration bindings, how to do it?

Necessary to introduce the Options Framework

ASP.NET Core default has actually helped us to come in the framework of the introduction of

Namespace is: Microsoft.Extensions.Options

We need to modify the service to the Senate

public class OrderService : IOrderService
{
    //OrderServiceOptions _options;
    IOptionsMonitor<OrderServiceOptions> _options;
    
    //public OrderService(OrderServiceOptions options)
    public OrderService(IOptionsMonitor<OrderServiceOptions> options)
    {
        _options = options;
    }

    public int ShowMaxOrderCount()
    {
        //return _options.MaxOrderCount;
        return _options.Value.MaxOrderCount;
    }
}

Registered when using config method, read from the configuration file

public void ConfigureServices(IServiceCollection services)
{
    //services.AddSingleton<OrderServiceOptions>();
    services.Configure<OrderServiceOptions>(Configuration.GetSection("OrderService"));
    services.AddSingleton<IOrderService, OrderService>();
}

Profiles

{
  "OrderService": {
    "MaxOrderCount": 200
  }
}

Start the program, the output is as follows:

orderService.ShowMaxOrderCount:200

You can see, the output value of 200, indicating that the configuration has been completed and binding options

Service depends only on the OrderServiceOptions, and did not depend on the configuration framework, that is to say only what they value the service configuration is that it does not care about the value configured come from, lifted the dependencies between configuration and service

In addition to all of the service may be separately designed their Options, configure the options between such services also are not dependent on each other

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