在.NET Core中将应用程序设置与环境变量合并 [英] Merging appsettings with environment variables in .NET Core

问题描述

我正在Docker中(在Kubernetes中)运行.NET Core应用程序，将环境变量传递给Docker容器并在我的应用程序中使用它们.

I am running a .NET Core app in Docker (in Kubernetes), passing environment variables to the Docker container and using them in my app.

在我的.NET Core应用程序中，我具有以下C#类:

In my .NET Core app I have the following C# class:

public class EnvironmentConfiguration
{
    public string EXAMPLE_SETTING { get; set; }
    public string MY_SETTING_2 { get; set; }
}

然后我这样设置appsettings:

config.
    AddJsonFile("appsettings.json").
    AddJsonFile($"appsettings.docker.json", true).
    AddEnvironmentVariables();  

DI设置:

services.Configure<EnvironmentConfiguration>(Configuration);

然后在我的控制器中按如下方式使用它:

And in my Controller I use it as such:

[ApiVersion("1.0")]
[Route("api/v{version:apiVersion}/my")]
public class MyController : Controller
{
    private readonly IOptions<EnvironmentConfiguration> _environmentConfiguration;

    public MyController(IOptions<EnvironmentConfiguration> environmentConfiguration)
    {
        _environmentConfiguration = environmentConfiguration;
    }
}       

我运行docker:

docker run -p 4000:5000 --env-file=myvariables

文件myvariables看起来像这样:

EXAMPLE_SETTING=example!!!
MY_SETTING_2=my-setting-2!!!!

这有效.我可以使用_environmentConfiguration并看到设置了我的变量.

This works. I can use my _environmentConfiguration and see that my variables are set.

但是...我想将环境变量与appsettings合并，以便在未找到环境变量时将appsettings中的值用作备用.以某种方式合并这两行:

However... I would like to merge environment variables with appsettings so that the values from appsettings are used as fallback when environment variables are not found. Somehow merging these two lines:

services.Configure<EnvironmentConfiguration>(settings => Configuration.GetSection("EnvironmentConfiguration").Bind(settings));
services.Configure<EnvironmentConfiguration>(Configuration);

这有可能吗?

我的后备计划是从EnvironmentConfiguration类继承，并使用单独的DI注入两个单独的配置，然后在代码中手动"合并它们，但这是不可取的.

My fallback plan is to inherit from the EnvironmentConfiguration class and use a separate DI to have two separate configurations injected and then merge them "manually" in code but this solution is undesirable.

推荐答案

config.
    AddJsonFile("appsettings.json").
    AddJsonFile("appsettings.docker.json", true).
    AddEnvironmentVariables();

实际上足以使用环境变量覆盖应用设置值.

is actually enough to override appsettings values using environment variables.

假设您的appsettings.json文件中包含以下内容；

Let's say you have the following in your appsettings.json file;

{
  "Logging": {
      "Level": "Debug"
  }
}

您可以通过将名为Logging:Level的环境变量设置为您的首选项值来覆盖Logging.Level的值.

you can override value of Logging.Level by setting the environment variable named Logging:Level to the value of your preference.

请注意，:用于指定环境变量键中的嵌套属性.

Be aware that : is used to specify nested properties in environment variable keys.

也请注意:来自

Also note: from docs;

如果不能在系统的环境变量名称中使用冒号(:)，请用双下划线(__)替换冒号(:).

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