尝试从 Azure 队列实现消息的消费者/接收者。我正在使用工作人员服务/后台服务项目.Net core 3.1。
以下是 Program.cs
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureServices((hostContext, services) =>
{
services.AddSingleton<IQueueClient>(x => new QueueClient(hostContext.Configuration.GetConnectionString("ServiceBusConnectionString") ?? hostContext.Configuration["ServiceBusConnectionString"], hostContext.Configuration.GetValue<string>("QueueName")));
services.AddHostedService<WorkerService>();
});
以下是工作人员 service.cs
public class WorkerService : BackgroundService
{
private readonly IQueueClient queueClient;
private readonly ILogger<PolCommunicationRequestQueueServiceBusSubscriber> logger;
public WorkerService(IQueueClient queueClient, ILogger<WorkerService> logger)
{
this.queueClient = queueClient;
this.logger = logger;
}
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
try
{
queueClient.RegisterMessageHandler(ProcessMessagesAsync
, new MessageHandlerOptions(ExceptionReceivedHandler)
{
MaxConcurrentCalls = 1,
AutoComplete = false
});
}
catch (Exception ex)
{
logger.LogError(ex.Message);
}
finally
{
await queueClient.CloseAsync();
}
}
public async Task ProcessMessagesAsync(Message message, CancellationToken token)
{
// Process the message
logger.LogInformation($"Received message: SequenceNumber:{message.SystemProperties.SequenceNumber} Body:{Encoding.UTF8.GetString(message.Body)}");
await queueClient.CompleteAsync(message.SystemProperties.LockToken);
}
public Task ExceptionReceivedHandler(ExceptionReceivedEventArgs exceptionReceivedEventArgs)
{
logger.LogError($"Message handler encountered an exception {exceptionReceivedEventArgs.Exception}.");
return Task.CompletedTask;
}
}
}
然而,该方法的一个变体有效,但它抛出了一个错误“消息处理程序已被注册”。
while (!stoppingToken.IsCancellationRequested)
{
queueClient.RegisterMessageHandler((Message message, CancellationToken cancellationToken) =>
{
logger.LogInformation($"Received message: SequenceNumber:{message.SystemProperties.SequenceNumber} Body:{Encoding.UTF8.GetString(message.Body)}");
//Implement DB/other logic here
return queueClient.CompleteAsync(message.SystemProperties.LockToken);
}, new MessageHandlerOptions(ExceptionReceivedHandler)
{
MaxConcurrentCalls = 1,
AutoComplete = false
});
logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
await Task.Delay(1000, stoppingToken);
}
当我在控制台项目中实现它时,它可以工作。不确定这里缺少什么。