c# - 我可以获取触发器本身之外的函数名称吗？

Question

我想在运行时获取执行函数的名称。当我将一些数据存储到数据库时，我想添加函数名称，例如“此文档最后由函数'xxx'修改”。我的函数应用程序有多个函数，每个函数都可以修改同一组文档。显而易见的想法是依赖于 ExecutionContext，但是当我在触发器之外时我无法得到它。

The dependency injection container only holds explicitly registered types. The only services available as injectable types are what are setup in the Configure method. As a result, Functions-specific types like BindingContext and ExecutionContext aren't available during setup or as injectable types.

https://learn.microsoft.com/en-us/azure/azure-functions/functions-dotnet-dependency-injection#caveats

我基本上需要 Microsoft.Azure.WebJobs.ExecutionContext.FunctionName 的值。

    public class TriggerFunction
    {
        private readonly MyService myService;

        public TriggerFunction(MyService myService)
        {
            this.myService = myService ?? throw new ArgumentNullException(nameof(myService));
        }

        [FunctionName("TriggerFunction")]
        public void Run([TimerTrigger("0/15 * * * * *")]TimerInfo myTimer, ILogger log)
        {
            log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");
            myService.Foo();
        }
    }

    public class MyService
    {
        public MyService(ILogger<MyService> logger)
        {
            Logger = logger ?? throw new ArgumentNullException(nameof(logger));
            // would be nice to have ExecutionContext here
        }

        public void Foo()
        {
            Logger.LogInformation("Foo");
            // How do I get "TriggerFunction" here without passing it explicitly as a parameter?
        }
        public ILogger<MyService> Logger { get; }
    }

    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddScoped<MyService>();
        }
    }

我们正在使用进程内运行的 .net core 3.1。

Answer 1

您的选择之一是使用Activity 类。 Azure Function 运行时使用它来跟踪操作/检测。您可以使用 Activty.Current.AddBaggage 添加您自己的信息。此外，事件包含的信息通过流程内的异步调用流动，因此也可以安全地在基于任务的场景中使用。

    public class TriggerFunction
    {
        private readonly MyService myService;

        public TriggerFunction(MyService myService)
        {
            this.myService = myService ?? throw new ArgumentNullException(nameof(myService));
        }

        [FunctionName("TriggerFunction")]
        public void Run([TimerTrigger("0/15 * * * * *")]TimerInfo myTimer, ILogger log, ExecutionContext context)
        {
            log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");

            Activity.Current?.AddBaggage("functionName", context.FunctionName); 

            myService.Foo();
        }
    }

    public class MyService
    {
        public MyService(ILogger<MyService> logger)
        {
            Logger = logger ?? throw new ArgumentNullException(nameof(logger));
            // would be nice to have ExecutionContext here
        }

        public void Foo()
        {
            Logger.LogInformation($"Foo calling in Function { Activity.Current?.GetBaggageItem("functionName") }");
            // How do I get "TriggerFunction" here without passing it explicitly as a parameter?
        }
        public ILogger<MyService> Logger { get; }
    }

    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddScoped<MyService>();
        }
    }

要深入了解 Activity 类，请参阅 this blogpost