Question

我已阅读并询问有关如何使用WebJob以及特别是Triggered Webjobs使用DI的一些问题。

我仍然试图弄清楚如何在触发的webjobs中优雅地整合DI，并且@Steven问我一个很好的问题：

是否有办法将服务的执行包裹在某个范围内？例如，MVC和Web API具有 IDependencyScope 抽象。这会通知请求的开始和结束。为了能够进行作用域，你需要有这样的拦截点，或者你需要能够将调用包装到JobActivator。

我知道我可以在触发函数中启动一个范围，但我想知道sdk中是否有任何可扩展性点允许我们进行范围设定？

感谢。

Answer 1

我已向Azure Webjob小组打开了请求Add IDependencyScope to handle scoping。

我创建了一个小型库来收集Azure Webjobs和SimpleInjector的类：

对于QueueTrigger和ServiceBustrigger，我遇到了这些解决方案：

ServiceBusTrigger（来自这个回答：https://stackoverflow.com/a/33759649/4167200）：

public sealed class ScopedMessagingProvider : MessagingProvider
{
    private readonly ServiceBusConfiguration _config;
    private readonly Container _container;

    public ScopedMessagingProvider(ServiceBusConfiguration config, Container container)
        : base(config)
    {
        _config = config;
        _container = container;
    }

    public override MessageProcessor CreateMessageProcessor(string entityPath)
    {
        return new ScopedMessageProcessor(_config.MessageOptions, _container);
    }

    private class ScopedMessageProcessor : MessageProcessor
    {
        private readonly Container _container;

        public ScopedMessageProcessor(OnMessageOptions messageOptions, Container container)
            : base(messageOptions)
        {
            _container = container;
        }

        public override Task<bool> BeginProcessingMessageAsync(BrokeredMessage message, CancellationToken cancellationToken)
        {
            _container.BeginExecutionContextScope();
            return base.BeginProcessingMessageAsync(message, cancellationToken);
        }

        public override Task CompleteProcessingMessageAsync(BrokeredMessage message, FunctionResult result, CancellationToken cancellationToken)
        {
            _container.GetCurrentExecutionContextScope()?.Dispose();
            return base.CompleteProcessingMessageAsync(message, result, cancellationToken);
        }
    }
}

您可以在JobHostConfiguration中使用自定义MessagingProvider，例如

var serviceBusConfig = new ServiceBusConfiguration
{ 
    ConnectionString = config.ServiceBusConnectionString
};
serviceBusConfig.MessagingProvider = new ScopedMessagingProvider(serviceBusConfig, container);
jobHostConfig.UseServiceBus(serviceBusConfig);

QueueTrigger：

public sealed class ScopedQueueProcessorFactory : IQueueProcessorFactory
{
    private readonly Container _container;

    public ScopedQueueProcessorFactory(Container container)
    {
        _container = container;
    }

    public QueueProcessor Create(QueueProcessorFactoryContext context)
    {
        return new ScopedQueueProcessor(context, _container);
    }

    private class ScopedQueueProcessor : QueueProcessor
    {
        private readonly Container _container;

        public ScopedQueueProcessor(QueueProcessorFactoryContext context, Container container)
            : base(context)
        {
            _container = container;
        }

        public override Task<bool> BeginProcessingMessageAsync(CloudQueueMessage message, CancellationToken cancellationToken)
        {
            _container.BeginExecutionContextScope();
            return base.BeginProcessingMessageAsync(message, cancellationToken);
        }

        public override Task CompleteProcessingMessageAsync(CloudQueueMessage message, FunctionResult result,
            CancellationToken cancellationToken)
        {
            _container.GetCurrentExecutionContextScope()?.Dispose();
            return base.CompleteProcessingMessageAsync(message, result, cancellationToken);
        }
    }
}

您可以在JobHostConfiguration中使用自定义IQueueProcessorFactory，如下所示：

 var config = new JobHostConfiguration();
 config.Queues.QueueProcessorFactory = new ScopedQueueProcessorFactory(container);

用于依赖注入的Azure触发Webjobs范围

1 个答案: