【Azure 服務總線】Azure.Messaging.ServiceBus 多次發送消息報逾時錯誤，是否可以配置重新發送？是否有内置重試機制？

問題描述

使用 Azure Service Bus，提供應用程式之間松耦合的消息交換，但是有時候發送消息多次出現逾時錯誤。

A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

ErrorCode: TimedOut (ServiceCommunicationProblem)

為了預防這類偶發的Timedout異常對應用的影響，需要重新再次發送或接收消息，是否有内置的重試機制呢？

問題解答

有的，Service Bus的SDK有内置的重試機制，通過ServiceBusRetryOptions 配置。其中，預設的MaxRetries 次數為3次，每次重試的間隔時間預設為 60秒。

如在 .NET應用代碼中使用示例：

using Azure.Messaging.ServiceBus;

string connectionString = "<connection_string>";
string queueName = "<queue_name>";

// Because ServiceBusClient implements IAsyncDisposable, we'll create it
// with "await using" so that it is automatically disposed for us.
var options = new ServiceBusClientOptions();
options.RetryOptions = new ServiceBusRetryOptions
{
    Delay = TimeSpan.FromSeconds(10),
    MaxDelay = TimeSpan.FromSeconds(30),
    Mode = ServiceBusRetryMode.Exponential,
    MaxRetries = 3,
};
await using var client = new ServiceBusClient(connectionString, options);      

對于 Timeout 的異常，如果持續一小段（間斷性）發送，可以通過 telnet 或 psping 來檢視端口，網絡穩定性。

# 測試端口，伺服器是否能ping通
telnet <yournamespacename>.servicebus.chinacloudapi.cn 5671


#測試是否存在網絡丢包問題
.\psping.exe -n 25 -i 1 -q <yournamespace>.servicebus.chinacloudapi.cn:5671 -nobanner      

參考資料

Service Bus的重試政策：​​https://learn.microsoft.com/zh-cn/azure/architecture/best-practices/retry-service-specific#retry-mechanism-6​​

Service Bus Timeout 異常 ：​​https://docs.azure.cn/zh-cn/service-bus-messaging/service-bus-troubleshooting-guide#connectivity-certificate-or-timeout-issues​​

Service Bus Socket 異常 ：​​https://learn.microsoft.com/en-us/azure/service-bus-messaging/service-bus-messaging-exceptions#cause-2​​