通過給 HttpClint請求的日志增加 TraceId,解鎖自定義擴充 HttpClientFacroty 的姿勢
前言
.NetCore2.1新推出HttpClientFactory工廠類, 替代了早期的HttpClient, 并新增了彈性Http調用機制 (內建Policy元件)。
替換的初衷還是簡單說下:
① using(var client= new HttpClient()) 調用Dispose()方法,并不會很快釋放底層Socket連接配接, 同時建立Socket需要時間,這在高并發場景下Socket耗盡。 傳送門
② 由于①很多人會想到用單例或靜态類建構HttpClient執行個體,但是這裡還有一個坑,HttpClient 會忽略DNS的變化。 傳送門
HttpClientFactory 以一種子產品化、可命名、彈性可預期的方式重建了HttpClient的使用方式。
現在的HttpClientFactory以依賴注入的方式內建到.NETCore 架構:
![](https://img.laitimes.com/img/9ZDMuAjOiMmIsIjOiQnIsIiZpdmLrN2bsJEZlR3YhJHdu92Qvw1cy9GdhNWak5WSn5WaulGb0V3TvwVbvNmLzd2bsJmbj5ycldWYtl2Lc9CX6MHc0RHaiojIsJye.gif)
// 截取自Startup.cs檔案服務配置部分
public void ConfigureServices(IServiceCollection services)
{
services.AddHttpClient("bce-request", x =>
x.BaseAddress = new Uri(Configuration.GetSection("BCE").GetValue<string>("BaseUrl")))
.ConfigurePrimaryHttpMessageHandler(_ => new BceAuthClientHandler()
{
AccessKey = Configuration.GetSection("BCE").GetValue<string>("AccessKey"),
SerectAccessKey = Configuration.GetSection("BCE").GetValue<string>("SecretAccessKey"),
AllowAutoRedirect = true,
UseDefaultCredentials = true
})
.SetHandlerLifetime(TimeSpan.FromHours(12))
.AddPolicyHandler(GetRetryPolicy(3));
}
static IAsyncPolicy<HttpResponseMessage> GetRetryPolicy(int retry)
{
var retryPolicy = HttpPolicyExtensions
.HandleTransientHttpError()
.OrResult(msg => msg.StatusCode == System.Net.HttpStatusCode.NotFound)
.WaitAndRetryAsync(retry, retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)));
return retryPolicy;
}
HttpClientFactory典型用法
使用時從 IHttpClientFactory工廠建立所需HttpClient執行個體,發起業務端請求。
以下是利用NLog觀察到的檔案日志:
19/12/04 11:06:46 [Info].[System.Net.Http.HttpClient.bce-request.LogicalHandler].[18}].[]
Start processing HTTP request GET http://localhost:5000/v1/eqid/b827a9400004132a000000065dc26470
19/12/04 11:06:46 [Info].[System.Net.Http.HttpClient.bce-request.ClientHandler].[18}].[]
Sending HTTP request GET http://localhost:5000/v1/eqid/b827a9400004132a000000065dc26470
19/12/04 11:06:46 [Info].[System.Net.Http.HttpClient.bce-request.ClientHandler].[34}].[]
Received HTTP response after 174.5088ms - OK
19/12/04 11:06:46 [Info].[System.Net.Http.HttpClient.bce-request.LogicalHandler].[34}].[]
End processing HTTP request after 211.1478ms - OK
頭腦風暴
觀察上面單次請求的日志,由外層LogicHandler和内層ClientHandler 日志頭組成。 這樣的日志可以想象到有2個問題:
① 在高并發使用HttpClient,日志條數衆多,沒有類似TraceId 這樣的機制定位 某次HttpClient調用的完整日志。
② 若是微服務/ 分布式調用,可能還有 将本次HttpClient調用日志與後置api日志 結合分析的需求, 這個日志也支援不了。
是以本文打算重新自定義HttpClientFactory日志處理器(給請求的全部日志設定TraceId),實際上CustomLoggingHttpMessageHandler隻是一個引子,掌握如何擴充才是關鍵。
結合我給出的典型用法來看IHttpClientFactory元件原理:
示例中System.Net.Http.HttpClient.bce-request.LogicalHandler,System.Net.Http.HttpClient.bce-request.ClientHandler 日志頭即是來自LoggingScopeHttpMessageHandler ,LoggingHttpMessageHandler 兩個處理器,
給出手繪的UML類圖:
本次要擴充的入口便是 IHttpMessageHandlerFilter接口, 核心是自定義DelegatingHandler日志處理器
+ https://github.com/dotnet/extensions/blob/master/src/HttpClientFactory/Http/src/Logging/LoggingHttpMessageHandlerBuilderFilter.cs
程式設計實踐
如以上分析,
P1 實作 IHttpMessageHandlerFilter接口,在接口中移除預設的兩個日志處理器
public class TraceIdLoggingMessageHandlerFilter : IHttpMessageHandlerBuilderFilter
{
private readonly ILoggerFactory _loggerFactory;
public TraceIdLoggingMessageHandlerFilter(ILoggerFactory loggerFactory)
{
_loggerFactory = loggerFactory ?? throw new ArgumentNullException(nameof(loggerFactory));
}
public Action<HttpMessageHandlerBuilder> Configure(Action<HttpMessageHandlerBuilder> next)
{
if (next == null)
{
throw new ArgumentNullException(nameof(next));
}
return (builder) =>
{
// Run other configuration first, we want to decorate.
next(builder);
var outerLogger =_loggerFactory.CreateLogger($"System.Net.Http.HttpClient.{builder.Name}.LogicalHandler");
builder.AdditionalHandlers.Clear();
builder.AdditionalHandlers.Insert(0,new CustomLoggingScopeHttpMessageHandler(outerLogger));
};
}
}
P2 實作帶有TraceId能力的HttpClient 日志處理器, 并加入到 IHttpMessageHandlerFilter接口實作類
public class CustomLoggingScopeHttpMessageHandler : DelegatingHandler
{
private readonly ILogger _logger;
public CustomLoggingScopeHttpMessageHandler(ILogger logger)
{
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
}
protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
CancellationToken cancellationToken)
{
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
using (Log.BeginRequestPipelineScope(_logger, request))
{
Log.RequestPipelineStart(_logger, request);
var response = await base.SendAsync(request, cancellationToken);
Log.RequestPipelineEnd(_logger, response);
return response;
}
}
private static class Log
{
private static class EventIds
{
public static readonly EventId PipelineStart = new EventId(100, "RequestPipelineStart");
public static readonly EventId PipelineEnd = new EventId(101, "RequestPipelineEnd");
}
private static readonly Func<ILogger, HttpMethod, Uri, string, IDisposable> _beginRequestPipelineScope =
LoggerMessage.DefineScope<HttpMethod, Uri, string>(
"HTTP {HttpMethod} {Uri} {CorrelationId}");
private static readonly Action<ILogger, HttpMethod, Uri, string, Exception> _requestPipelineStart =
LoggerMessage.Define<HttpMethod, Uri, string>(
LogLevel.Information,
EventIds.PipelineStart,
"Start processing HTTP request {HttpMethod} {Uri} [Correlation: {CorrelationId}]");
private static readonly Action<ILogger, HttpStatusCode,string,Exception> _requestPipelineEnd =
LoggerMessage.Define<HttpStatusCode,string>(
LogLevel.Information,
EventIds.PipelineEnd,
"End processing HTTP request - {StatusCode}, [Correlation: {CorrelationId}]");
public static IDisposable BeginRequestPipelineScope(ILogger logger, HttpRequestMessage request)
{
var correlationId = GetCorrelationIdFromRequest(request);
return _beginRequestPipelineScope(logger, request.Method, request.RequestUri, correlationId);
}
public static void RequestPipelineStart(ILogger logger, HttpRequestMessage request)
{
var correlationId = GetCorrelationIdFromRequest(request);
_requestPipelineStart(logger, request.Method, request.RequestUri, correlationId, null);
}
public static void RequestPipelineEnd(ILogger logger, HttpResponseMessage response)
{
var correlationId = GetCorrelationIdFromRequest(response.RequestMessage);
_requestPipelineEnd(logger, response.StatusCode, correlationId, null);
}
private static string GetCorrelationIdFromRequest(HttpRequestMessage request)
{
string correlationId;
if (request.Headers.TryGetValues("X-Correlation-ID", out var values))
correlationId = values.First();
else
{correlationId = Guid.NewGuid().ToString(); request.Headers.Add("X-Correlation-ID",correlationId);}
return correlationId; }
}
}
以上TraceId的實作思路,參考了我前一篇博文《被忽略的TraceId,可以用起來了》的思路,為每次HttpClient調用過程設定 全局唯一的GUID标記, 後置api服務可酌情修改以上代碼處理。
其中寫入日志的代碼Copy自HttpClientFactory源代碼。
P3 在DI架構中替換原有的 IHttpMessageHandlerFilter 實作
services.Replace(ServiceDescriptor.Singleton<IHttpMessageHandlerBuilderFilter, TraceIdLoggingMessageHandlerFilter>());
發起兩次HttpClient請求, 輸出的日志如下:
19/12/04 12:59:22 [Info].[System.Net.Http.HttpClient.bce-request.LogicalHandler].[17}].[]
Start processing HTTP request GET http://localhost:5000/v1/eqid/ad78deef00444ed7000000035de704e8 [Correlation: 03de676d-680e-4a92-aef5-749bcc3ba499]
19/12/04 12:59:22 [Info].[System.Net.Http.HttpClient.bce-request.LogicalHandler].[4}].[]
End processing HTTP request - OK, [Correlation: 03de676d-680e-4a92-aef5-749bcc3ba499]
19/12/04 12:59:48 [Info].[System.Net.Http.HttpClient.bce-request.LogicalHandler].[17}].[]
Start processing HTTP request GET http://localhost:5000/v1/eqid/8ea0c3b66b60f0ff100000005de704fb [Correlation: 6f14393a-3a2b-45c4-a9b4-0b4ab874ef1d]
19/12/04 12:59:48 [Info].[System.Net.Http.HttpClient.bce-request.LogicalHandler].[42}].[]
End processing HTTP request - OK, [Correlation: 6f14393a-3a2b-45c4-a9b4-0b4ab874ef1d]
可以看到每次請求的開始和結束都帶上了設定的guid TraceId。
值得提醒的是:
① 這個TraceId 可以使用你業務上獨具一格的标記,這樣在排查時, 能根據上遊業務更好的追蹤日志。
② 現在這個TraceId位于LogMessage,實際上可以為nlog自定義LogoutRenderer,将該TraceId放在顯著位置,便于ETL等日志內建架構過濾。
That's All, 本次為解決HttpClientFactory日志無追蹤機制的探索,思考 + 實踐 + UML制圖。
實作CustomLoggingScopeHttpMessageHandler隻是擴充HttpClientFactory能力的一個引子,如何擴充HttpClientFactory能力才是關鍵,希望能給大家一些啟發。
--------------------------------------------------------------2019.12.06 更新------------------------
實際上HttpClientFactory内原生LoggingHandler是支援LoggingScope, 在Console 輸出如下:
info: System.Net.Http.HttpClient.bce-request.LogicalHandler[100]
=> ConnectionId:0HLRQ6DAF0JKV => RequestId:0HLRQ6DAF0JKV:00000004 RequestPath:/eqid/f53990dc0002adf0000000045de9c421 => EqidManager.Controllers.DebugController.ResolveEqid (EqidManager) => HTTP GET http://localhost:5000/v1/eqid/f53990dc0002adf0000000045de9c421
Start processing HTTP request GET http://localhost:5000/v1/eqid/f53990dc0002adf0000000045de9c421
info: System.Net.Http.HttpClient.bce-request.ClientHandler[100]
=> ConnectionId:0HLRQ6DAF0JKV => RequestId:0HLRQ6DAF0JKV:00000004 RequestPath:/eqid/f53990dc0002adf0000000045de9c421 => EqidManager.Controllers.DebugController.ResolveEqid (EqidManager) => HTTP GET http://localhost:5000/v1/eqid/f53990dc0002adf0000000045de9c421
Sending HTTP request GET http://localhost:5000/v1/eqid/f53990dc0002adf0000000045de9c421
info: System.Net.Http.HttpClient.bce-request.ClientHandler[101]
=> ConnectionId:0HLRQ6DAF0JKV => RequestId:0HLRQ6DAF0JKV:00000004 RequestPath:/eqid/f53990dc0002adf0000000045de9c421 => EqidManager.Controllers.DebugController.ResolveEqid (EqidManager) => HTTP GET http://localhost:5000/v1/eqid/f53990dc0002adf0000000045de9c421
Received HTTP response after 195.1112ms - OK
info: System.Net.Http.HttpClient.bce-request.LogicalHandler[101]
=> ConnectionId:0HLRQ6DAF0JKV => RequestId:0HLRQ6DAF0JKV:00000004 RequestPath:/eqid/f53990dc0002adf0000000045de9c421 => EqidManager.Controllers.DebugController.ResolveEqid (EqidManager) => HTTP GET http://localhost:5000/v1/eqid/f53990dc0002adf0000000045de9c421
End processing HTTP request after 232.4906ms - OK
Scope需要LoggingProvider 支援,而我們使用的NLog不支援scope, 是以最上面的nlog 檔案日志沒有輸出Scope。
這就引出了本文的目的,是以本文通過解構HttpClientFactory的HttpMessageHandler,為請求響應添加TraceId, 當然你也可以根據HttpClient業務加入其它HttpMessageHandler
本文來自部落格園,作者:{有态度的馬甲},轉載請注明原文連結:https://www.cnblogs.com/JulianHuang/p/11982021.html
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