在 Azure Function v3 中獲取連接字符串

Question

我很困擾。 我想在 Azure v3 function （.Net Core 3.1）中獲取連接字符串。

我的本地設置看起來像

{
    "IsEncrypted": false,
    "Values": {
        "AzureWebJobsStorage": "UseDevelopmentStorage=true",
        "AzureWebJobsDashboard": "UseDevelopmentStorage=true"
    },
    "ConnectionStrings": {
      "DefaultConnection": "bla bla"
    }
}

在 function 我做

string defaultConnection = Environment.GetEnvironmentVariable("ConnectionStrings:DefaultConnection");

這在本地工作正常，但在 Azure 上，defaultConnection 是 null。 我在函數的應用程序設置的連接字符串部分下定義了連接。

我的方法對 Azure function v3 是否正確？

Answer 1

您需要指定連接字符串前綴（請參閱文檔）：

Environment.GetEnvironmentVariable("CUSTOMCONNSTR_DefaultConnection");

Answer 2

請注意

如果您使用實體框架，則連接字符串只能與 function 應用程序一起使用。 對於其他情況，請使用應用程序設置。

所以如果你只是想獲取DefaultConnection的值，你可以把它放在Application settings下，你可以這樣獲取

Environment.GetEnvironmentVariable("DefaultConnection");

對於帶有實體框架的 Azure function，請參考這篇文章。

Answer 3

If you're using Microsoft.NET.Sdk.Functions 3.0.11 and Microsoft.Azure.Functions.Extensions 1.1.0 and you're using Azure Functions with Dependency Injection, you can do the following to access the connection string (or any配置）當您啟動應用程序時。

using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Configuration.AzureAppConfiguration;
using System;

[assembly: FunctionsStartup(typeof(YourNamespace.Startup))]

namespace YourNamespace
{
    public class Startup : FunctionsStartup
    {
        public IConfiguration Configuration { get; set;  }

        public override void ConfigureAppConfiguration(IFunctionsConfigurationBuilder builder)
        {
            var config = builder.ConfigurationBuilder.Build();

            // This can be used to get a connection string from local.settings.json and also works when deployed to Azure
            var appConfigConnection = config.GetConnectionString("AppConfig");
            // This is to access the environment variables. 
            var environment = Environment.GetEnvironmentVariable("Environment");

            // This particular example uses the values retrieved to bootstrap Azure App Configuration
            builder.ConfigurationBuilder.AddAzureAppConfiguration(options =>
            {
                options.Connect(appConfigConnection).Select(KeyFilter.Any, environment.ToLowerInvariant());
            });
        }

        public override void Configure(IFunctionsHostBuilder builder)
        {
            // In case you need to access IConfiguration
            Configuration = builder.GetContext().Configuration;
        }
    }
}

示例 local.setting.json

{
  "IsEncrypted": false,
  "Values": {
    "FUNCTIONS_WORKER_RUNTIME": "dotnet",
    "AzureWebJobsStorage": "your connection string",
    "Environment": "Development"
  },  
  "ConnectionStrings": {
    "AppConfig": "your connection string"
  }
}