如何将依赖项传递给自定义 .NET Core ILoggerProvider [英] How to pass dependencies to a custom .NET Core ILoggerProvider

问题描述

我正在创建一个自定义的 .NET Core ILoggerProvider，它需要将一些依赖项传递到其构造函数中.

我相信我正在使用一种相当常见的模式来初始化我的日志记录实现；它看起来像这样:

var services = new ServiceCollection();//在这里注册一些服务services.AddLogging(builder =>{builder.AddProvider(new DebugLoggerProvider());});var provider = services.BuildServiceProvider();

我想在 AddLogging 块中添加我的新提供程序，与当前添加 DebugLoggerProvider 的方式相同.

我的自定义提供程序需要将一些其他服务传递到其构造函数中，并且由于这些服务已经在 ServiceCollection 中注册，我假设我应该能够引用它们.但是，与诸如 AddSingleton 之类的方法不同，这些方法具有公开 IServiceProvider 的重载，AddLogging 似乎没有提供等效项.>

是否有一种简单的方法可以实现这一点，或者我是否试图做一些与 .NET Core 日志记录的部署方式相矛盾的事情?

更新:

在对@Nkosi 提出的建议进行试验后，我可以确认可以通过绕过 AddLogging 并直接在内部实现它的功能来使其工作，如下所示:

var services = new ServiceCollection();//注册一些服务services.AddSingleton();//初始化日志服务.AddOptions();services.AddSingleton();services.AddSingleton(typeof(ILogger<>), typeof(Logger<>));services.AddSingleton(p => new DebugLoggerProvider());services.AddSingleton(p => new MyLoggerProvider("Constant value", p.GetService()));var provider = services.BuildServiceProvider();

解决方案

现在我不确定是否已经存在一个扩展来做到这一点，但我看到了这里的潜力.

首先是 AddProvider 在源代码仓库中定义.

public static ILoggingBuilder AddProvider(this ILoggingBuilder builder, ILoggerProvider provider) {builder.Services.AddSingleton(provider);返回生成器；}

您可以在此基础上制作自己的通用版本

public static class MyLoggingBuilderExtensions {公共静态 ILoggingBuilder AddProvider(这个 ILoggingBuilder 构建器)其中 T:类，ILoggerProvider{builder.Services.AddSingleton();返回生成器；}}

这应该允许 DI 容器在解析时建立对象图

services.AddLogging(builder =>{builder.AddProvider();});

并且有扩展此功能的空间，例如添加您自己的重载以公开 IServiceProvider 并将其传递给扩展中的 AddSingleton.

public static ILoggingBuilder AddProvider(这个 ILoggingBuilder builder，Func factory)其中 T:类，ILoggerProvider {builder.Services.AddSingleton(工厂)；返回生成器；}

并使用

services.AddLogging(builder => {builder.AddProvider(p => new CustomLoggerProvider(Constant value", p.GetService()));});

I am creating a custom .NET Core ILoggerProvider that requires some dependencies to be passed into its constructor.

I believe I am using a fairly common pattern to initialize my logging implementation; it looks something like this:

var services = new ServiceCollection();

// Register some services here

services.AddLogging(builder =>
{
    builder.AddProvider(new DebugLoggerProvider());
});

var provider = services.BuildServiceProvider();

I want to add my new provider within the AddLogging block, in the same way that the DebugLoggerProvider is currently added.

My custom provider requires some other services to be passed into its constructor and since these are already registered with the ServiceCollection, I assume that I should be able to reference them. However, unlike methods such as AddSingleton, which have an overload that exposes the IServiceProvider, AddLogging doesn't seem to offer an equivalent.

Is there a simple way to achieve this, or am I attempting to do something that contradicts the way .NET Core logging was designed to be deployed?

UPDATE:

After experimenting with the suggestions proposed by @Nkosi, I can confirm that it is possible to get this to work by bypassing AddLogging and directly implementing what it does internally, as follows:

var services = new ServiceCollection();

// Register some services
services.AddSingleton<IMyService, MyService>();

// Initialize logging
services.AddOptions();
services.AddSingleton<ILoggerFactory, LoggerFactory>();
services.AddSingleton(typeof(ILogger<>), typeof(Logger<>));
services.AddSingleton<ILoggerProvider>(p => new DebugLoggerProvider());
services.AddSingleton<ILoggerProvider>(p => new MyLoggerProvider("Constant value", p.GetService<IMyService>()));

var provider = services.BuildServiceProvider();

解决方案

Now I am not sure if an extension already exists to do this but I see potential here.

First this is how AddProvider is defined in the source code repo.

public static ILoggingBuilder AddProvider(this ILoggingBuilder builder, ILoggerProvider provider) {
    builder.Services.AddSingleton(provider);
    return builder;
}

You could build up on that by making your own generic version

public static class MyLoggingBuilderExtensions {
    public static ILoggingBuilder AddProvider<T>(this ILoggingBuilder builder)
        where T: class, ILoggerProvider{
        builder.Services.AddSingleton<ILoggerProvider, T>();
        return builder;
    }
}

which should allow the DI container to build up the object graph when resolved

services.AddLogging(builder =>
{
    builder.AddProvider<CustomLoggerProvider>();
});

And there is room to extend this functionality, like adding your own overload that exposes the IServiceProvider and passing that on to the AddSingleton within the extension.

public static ILoggingBuilder AddProvider<T>(this ILoggingBuilder builder, Func<IServiceProvider, T> factory)
    where T: class, ILoggerProvider {
    builder.Services.AddSingleton<ILoggerProvider, T>(factory);
    return builder;
}

And used

services.AddLogging(builder => {
    builder.AddProvider<CustomLoggerProvider>(p => new CustomLoggerProvider("Constant value", p.GetService<IMyService>()));
});

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