.Net Core 2.0 Webjob 与作用域依赖 [英] .Net Core 2.0 Webjob with Scoped Dependencies
问题描述
我正在构建一个使用 IJobActivator 设置的 .Net Core 2.0 的网络作业.IServiceScopeFactory.CreateScope 如果 Functions 是作用域的,则在 IJobActivator 中似乎不起作用,如果它是单例,则在 Functions 中也不起作用.
I am building a webjob with .Net Core 2.0 set up using an IJobActivator. IServiceScopeFactory.CreateScope does not seem to work in the IJobActivator if Functions is scoped, nor within Functions if it's a singleton.
即
public static void Main(string[] args)
{
IServiceCollection serviceCollection = new ServiceCollection();
serviceCollection.AddScoped<Functions>(); //Or serviceCollection.AddSingleton<Functions>();
serviceCollection.AddScoped<TelemetryScopeProvider>();
//... Other scoped dependecies e.g. EF context and repositories.
var serviceProvider = serviceCollection.BuildServiceProvider(true);
var jobHostConfiguration = new JobHostConfiguration();
jobHostConfiguration.Queues.MaxPollingInterval = TimeSpan.FromSeconds(10);
jobHostConfiguration.Queues.BatchSize = 1;
jobHostConfiguration.JobActivator = new ProcessorActivator(serviceProvider);
jobHostConfiguration.UseServiceBus();
jobHostConfiguration.NameResolver = new QueueNameResolver()
{
ResultQueueName = ...
};
var config = new JobHostConfiguration();
var host = new JobHost(jobHostConfiguration);
host.RunAndBlock();
}
public class ProcessorActivator : IJobActivator
{
private readonly IServiceProvider _service;
private IServiceScopeFactory _scopeFactory;
public ProcessorActivator(IServiceProvider service, IServiceScopeFactory scopeFactory)
{
_service = service;
_scopeFactory = scopeFactory;
}
public T CreateInstance<T>()
{
using (var scope = _scopeFactory.CreateScope())
{
var service = _service.GetService(typeof(T));
return (T)service;
}
}
public class Functions
{
private IServiceScopeFactory _scopeFactory;
private IServiceProvider _serviceProvider;
public Functions(IServiceProvider serviceProvider, IServiceScopeFactory scopeFactory)
{
_scopeFactory = scopeFactory;
_serviceProvider = serviceProvider;
}
public async Task ProcessValidationResult([ServiceBusTrigger("%Response%")
] string r)
{
var start = DateTime.UtcNow;
using (var scope = _scopeFactory.CreateScope())
{
try
{
//Deserialize the result.
var result = JsonConvert.DeserializeObject...;
var scopeProvider = _serviceProvider.GetService<TelemetryScopeProvider>(); //FAIL HERE
//Some other Logic which we dont get to
}
catch (Exception e)
{
Console.Out.WriteLine($"Error processing: {e.Message}");
}
}
}
如果 Functions 是范围的:将在激活器中抛出异常:无法解析来自根提供程序的范围服务ValidationResultProcessorWebJob.Functions".
If Functions is scoped : The exception will be thrown in the activator: Cannot resolve scoped service 'ValidationResultProcessorWebJob.Functions' from root provider.
如果 Functions 是单例:System.InvalidOperationException:无法从根提供程序解析范围服务ValidationResultProcessorWebJob.TelemetryScopeProvider".
If Functions is a singleton: System.InvalidOperationException: Cannot resolve scoped service 'ValidationResultProcessorWebJob.TelemetryScopeProvider' from root provider.
未应用 _scopeFactory.CreateScope() 吗?为什么不呢?
Is _scopeFactory.CreateScope() not being applied? Why not?
谢谢,
韦恩
推荐答案
我错误地认为 IServiceScopeFactory 提供了比它更多的魔法.据我目前了解,应该使用 IServiceScopeFactory.CreateScope 创建子作用域.IServiceScope 包含一个 ServiceProvider,可用于实例化新的依赖关系图.
I mistakenly thought that IServiceScopeFactory was providing more magic than it does. As I currently understand a child scope should be created with IServiceScopeFactory.CreateScope. IServiceScope contains a ServiceProvider which can then be used to instantiate a new graph of dependencies.
我将逻辑从函数移到新的处理器类并将其配置为作用域.
I moved the logic from the function to a new processor class and configured it as Scoped.
serviceCollection.AddScoped<Functions>();
serviceCollection.AddScoped<ResponseProcesor>();
//... Other scoped dependecies e.g. EF context and repositories.
我将 IServiceScopeFactory 注入 WebJobs 类(Functions)并从中实例化一个新的对象图.
I inject IServiceScopeFactory to the WebJobs class (Functions) and instantiate a new object graph from it.
public class Functions
{
private IServiceScopeFactory _scopeFactory;
public Functions(IServiceScopeFactory scopeFactory)
{
_scopeFactory = scopeFactory;
}
public async Task ProcessValidationResult([ServiceBusTrigger("%Response%")] string r)
{
using (var scope = _scopeFactory.CreateScope())
{
var processor = scope.ServiceProvider.GetService<ResponseProcesor>();
await processor.Process(r);
}
}
}
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