每个套接字地址 (protocol/network address/port) 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 APIs（部署为 Azure Web 应用程序）的搜索 SDK，它根据流量扩展 up-down（因此可能有超过 1 个 API 正在搜索）。

我们的 API 查询 5 个不同的索引并维护一个 in-memory 对应于每个索引的 SearchIndexClient object 副本，一个非常简单的实现如下：

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;
    }
}

并且 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 headers 而不是 SearchAsync 方法，我们正在使用 SearchWithHttpMessagesAsync。

这样我们就可以避免 opening/closing 客户端处于流量突发状态。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。

这个模式好吗？我们是否会因为并行的多个实例运行而收到此错误？

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：我们也收到这个错误A connection attempt failed because the connected party did not properly respond after a period of time：

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，缓存不会防止端口耗尽。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。为了使其并发安全，您应该使用 ConcurrentDictionary 而不是 Dictionary.

"connection attempt failed" 错误可能无关。

每个套接字地址 (protocol/network address/port) 通常只允许使用一次

Only one usage of each socket address (protocol/network address/port) is normally permitted

azure-cognitive-search