.NET 6类库中Service Bus发送方法执行异常排查

将Service Bus消息发送方法提取到.NET 6类库后，调用该方法时，程序执行CreateMessageBatchAsync后无异常退出，后续代码断点无法触发。原代码在控制台应用中可正常运行。

原控制台应用代码 #

var cln= new ServiceBusClient(connectionString);
var sender = cln.CreateSender(topicName);
var body = JsonSerializer.Serialize(obj);
var message = new ServiceBusMessage(body)
{
    ContentType = "application/json"
};
try
{
    var batch = await sender.CreateMessageBatchAsync();

    var test = "123";

    if (!batch.TryAddMessage(message))
    {
        throw new Exception("Error occured while sending object to topic");
    }
    await sender.SendMessagesAsync(batch);
    await sender.DisposeAsync();
    await cln.DisposeAsync();
}
catch (Exception ex)
{
    Console.WriteLine($"Error sending message: {ex.Message}");
    throw;
}

迁移后的.NET 6类库方法代码 #

public async Task SendBatchMessageAsync(string connectionStr, string topic, ServiceBusMessage message, int maxRetries = 3)
{
    int attempt = 0;
    do
    {
        try
        {

            var _client = new ServiceBusClient(connectionString);
            var _sender = _client.CreateSender(topic);
            var serviceBusMessageBatch = await _sender.CreateMessageBatchAsync();
            if (!serviceBusMessageBatch.TryAddMessage(message))
            {
                throw new Exception("Error occured");
            }
            await _sender.SendMessagesAsync(serviceBusMessageBatch);
            await _sender.DisposeAsync();
            await _client.DisposeAsync();
        }
        catch (ServiceBusException ex) when (ex.Reason == ServiceBusFailureReason.MessagingEntityDisabled ||
        ex.Reason == ServiceBusFailureReason.MessagingEntityNotFound ||
        ex.Reason == ServiceBusFailureReason.ServiceTimeout ||
        ex.Reason == ServiceBusFailureReason.ServiceBusy)
        {

            _logger.Error($"Transient exception caught: {ex.Message}");
            attempt++;
            if (attempt >= maxRetries) throw; // Give up after maxRetries
            // Wait for a bit before retrying
            await Task.Delay(ComputeDelay(attempt));
        }
        catch (Exception ex)
        {
            _logger.Error($"Error sending message: {ex.Message}");
            throw;
        }
    } while (attempt < maxRetries);
}

问题排查与修复 #

1. 参数名不匹配 #

类库方法接收的参数是connectionStr，但代码中使用的是未定义的connectionString，这会直接引发未初始化变量的异常。如果调用方未正确等待异步任务，异常会被吞掉，导致程序无提示退出。

修复：将方法内的connectionString替换为connectionStr，确保使用传入的连接字符串。

2. 异步方法未被正确等待 #

如果调用SendBatchMessageAsync时未添加await，或者在非异步上下文（比如控制台Main方法）中未正确处理异步任务，主线程会提前结束，看起来像是执行到CreateMessageBatchAsync后就退出了。

修复：调用方法时必须添加await；如果是控制台应用，将Main方法改为async Task Main，再用await调用发送方法。

3. 资源管理不合理 #

原类库代码每次重试都会创建新的ServiceBusClient和ServiceBusSender，频繁创建销毁会影响性能，且可能因异步释放问题引发隐藏异常。ServiceBusClient是线程安全的，建议作为单例复用。

优化后的示例代码：

// 通过依赖注入注入单例ServiceBusClient和Logger
private readonly ServiceBusClient _client;
private readonly ILogger _logger;

public ServiceBusSenderService(ServiceBusClient client, ILogger logger)
{
    _client = client;
    _logger = logger;
}

public async Task SendBatchMessageAsync(string topic, ServiceBusMessage message, int maxRetries = 3)
{
    int attempt = 0;
    var sender = _client.CreateSender(topic);
    try
    {
        do
        {
            try
            {
                var batch = await sender.CreateMessageBatchAsync();
                if (!batch.TryAddMessage(message))
                {
                    throw new Exception("消息过大无法加入批次");
                }
                await sender.SendMessagesAsync(batch);
                return;
            }
            catch (ServiceBusException ex) when (ex.Reason is ServiceBusFailureReason.MessagingEntityDisabled or 
                ServiceBusFailureReason.MessagingEntityNotFound or 
                ServiceBusFailureReason.ServiceTimeout or 
                ServiceBusFailureReason.ServiceBusy)
            {
                _logger.Error($"捕获到临时异常: {ex.Message}");
                attempt++;
                if (attempt >= maxRetries) throw;
                await Task.Delay(ComputeDelay(attempt));
            }
            catch (Exception ex)
            {
                _logger.Error($"发送消息出错: {ex.Message}");
                throw;
            }
        } while (attempt < maxRetries);
    }
    finally
    {
        await sender.DisposeAsync();
    }
}

内容的提问来源于stack exchange，提问作者katie77