azure-cognitive-search - 每个套接字地址(协议(protocol)/网络地址/端口)通常只允许使用一次

Question

过去几周，我们在使用 Azure 搜索 SDK (1.1.1 - 1.1.2) 和执行搜索时遇到此错误消息。

我们使用内部 API(部署为 Azure Web 应用程序)的搜索 SDK，这些 API 根据流量向上扩展(因此可能有超过 1 个 API 实例执行搜索)。

我们的 API 查询 5 个不同的索引，并维护一个与每个索引对应的 SearchIndexClient 对象的内存副本，一个非常简单的实现如下所示:

public class AzureSearchService
{
    private readonly SearchServiceClient _serviceClient;

    private Dictionary<string, SearchIndexClient> _clientDictionary;

    public AzureSearchService()
    {
        _serviceClient = new SearchServiceClient("myservicename", new SearchCredentials("myservicekey"));
        _clientDictionary = new Dictionary<string, SearchIndexClient>();
    }

    public SearchIndexClient GetClient(string indexName)
    {
        try
        {
            if (!_clientDictionary.ContainsKey(indexName))
            {
                _clientDictionary.Add(indexName, _serviceClient.Indexes.GetClient(indexName));
            }
            return _clientDictionary[indexName];
        }
        catch
        {
            return null;
        }
    }

    public async Task<SearchResults> SearchIndex(SearchIndexClient client, string text)
    {
        var parameters = new SearchParameters();
        parameters.Top = 10;
        parameters.IncludeTotalResultCount = true;
        var response = await client.Documents.SearchWithHttpMessagesAsync(text, parameters, null, null);
        return response.Body;
    }
}

API 将通过以下方式调用服务:

public class SearchController : ApiController
{
        private readonly AzureSearchService service;

        public SearchController()
        {
            service = new AzureSearchService();
        }


        public async Task<HttpResponseMessage> Post(string indexName, [FromBody] string text)
        {
            var indexClient = service.GetClient(indexName);
            var results = await service.SearchIndex(indexClient, text);
            return Request.CreateResponse(HttpStatusCode.OK, results, Configuration.Formatters.JsonFormatter);              
        }

}

由于需要接收自定义 HTTP header 而不是 SearchAsync 方法，我们正在使用 SearchWithHttpMessagesAsync。

这样我们就可以避免在流量激增的情况下打开/关闭客户端。在使用此内存缓存(并将每个客户端包装在 using 子句中)之前，我们会在 Azure 应用服务上收到端口耗尽警报。

这是一个好的模式吗？由于并行运行多个实例，我们会收到此错误吗？

如果需要，堆栈跟踪显示:

System.Net.Http.HttpRequestException: Only one usage of each socket address (protocol/network address/port) is normally permitted service.ip.address.hidden:443


[SocketException:Only one usage of each socket address (protocol/network address/port)is normally permitted service.ip.address.hidden:443]

at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)

at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure,Socket s4,Socket s6,Socket& socket,IPAddress& address,ConnectSocketState state,IAsyncResult asyncResult,Exception& exception)



[WebException:Unable to connect to the remote server]

at System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult,TransportContext& context)

at System.Net.Http.HttpClientHandler.GetRequestStreamCallback(IAsyncResult ar)

编辑:我们也收到此错误连接尝试失败，因为连接方在一段时间后未正确响应:

System.Net.Http.HttpRequestException: 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 service.ip.address.hidden:443


[SocketException: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 service.ip.address.hidden:443]

at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)

at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure,Socket s4,Socket s6,Socket& socket,IPAddress& address,ConnectSocketState state,IAsyncResult asyncResult,Exception& exception)



[WebException:Unable to connect to the remote server]

at System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult,TransportContext& context)

at System.Net.Http.HttpClientHandler.GetRequestStreamCallback(IAsyncResult ar)

Answer 1

正如您问题中的代码所实现的那样，缓存不会阻止端口耗尽。这是因为您将其实例化为 ApiController 的字段，每个请求创建一次。如果你想避免端口耗尽，缓存必须在所有请求之间共享。要使其并发安全，您应该使用类似 ConcurrentDictionary 的东西而不是 Dictionary。

“连接尝试失败”错误可能无关。