最近做項目，用到goreplay來做流量回放，什么是goreplay？

GoReplay is an open-source network monitoring tool which can record your live traffic, and use it for shadowing, load testing, monitoring and detailed analysis.

本質(zhì)上就是通過監(jiān)控網(wǎng)絡，錄制http請求信息（對應用無入侵），然后再把請求重新播放出來。

這是官方給出來運行原理圖。

關(guān)于goreplay的使用方式，命令用法官方文檔給的很全面了，不作贅述，本篇文章關(guān)注的是除雜（過濾）。官方本來是支持過濾filtering的，但過濾的范圍有限，目前只有Allow?url regexp,Disallow url regexp,Filter based on regexp of header,Filter based on HTTP method，也就是對url,header,method三個方向作了過濾，我的需求是對body過濾，不包括在范圍內(nèi)（也有可能我沒找到對應文檔）

官方找不到對應辦法，只能“曲線救國”了，因為goreplay錄制的內(nèi)容是文本性質(zhì)，所以可以對錄制內(nèi)容下手，把自己認定的雜質(zhì)除掉，然后再播放，這樣就達到效果了。

錄制：

我是在windows下demo的，所以下載goreplay的winodwst版本【https://github.com/buger/goreplay/releases/download/v1.3.2/gor-1.3.2_windows.zip】，同時還需要安裝WinPcap配合【https://www.winpcap.org/install/bin/WinPcap_4_1_3.exe】，這樣就可以通過命令進行錄制了：

gor?--input-raw?:5000?--output-file?request.gor

被錄制的服務是一個api，實現(xiàn)如下

[HttpPost("/order")] public IActionResult Post([FromBody] Order order) {_logger.LogInformation(System.Text.Json.JsonSerializer.Serialize(order));order.Status = 200;return new JsonResult(order); }public class Order {public string Code { get; set; }public?decimal?Amount?{?get;?set;?}public int Status { get; set; } }

gorreplay錄制的內(nèi)容格式如下：

1 c9051388c0a8000437c39d7f 1629555358511143000 0 POST /pay HTTP/1.1 Content-Type: application/json User-Agent: PostmanRuntime/7.28.3 Accept: */* Postman-Token: 3a49aba0-2e9b-4f1d-8fc8-01fb8b15d620 Host: 192.168.0.7:5000 Accept-Encoding: gzip, deflate, br Connection: keep-alive Content-Length: 92{"code":"3a13abfe-d9cb-4e11-ba90-738e93d2cb07","amount":908.59,"status":552 } ???????????? 1 c9051388c0a8000437c39d7f 1629555358813757000 0 POST /pay HTTP/1.1 Content-Type: application/json User-Agent: PostmanRuntime/7.28.3 Accept: */* Postman-Token: 3a49aba0-2e9b-4f1d-8fc8-01fb8b15d620 Host: 192.168.0.7:5000 Accept-Encoding: gzip, deflate, br Connection: keep-alive Content-Length: 92{"code":"3a13abfe-d9cb-4e11-ba90-738e93d2cb07","amount":908.59,"status":552 } ????????????

除雜

文中的json就是我請求的body，就要依據(jù)這個json中的一些數(shù)據(jù)來除雜，所以就得寫段代碼解決這個事情。

其實原理很簡單，因為我知道我請求的都是json，所以就是從錄制的文件中，按段切割，很明細就是三只猴子????????????為分割點，把內(nèi)容中的json查詢出來，然后運用上規(guī)則引擎達到過濾作用，把符合條件的數(shù)據(jù)留下，不符合條件的數(shù)據(jù)就除雜，最后保存成一個新文件，供流量回放時使用。

規(guī)則引擎

桂素偉，公眾號：桂跡一個簡單的規(guī)則引擎例子

步驟確定了，下面是代碼：

using RulesEngine; using RulesEngine.Models; using RulesEngine.Extensions; using System.IO; using System.Text; using System.Text.RegularExpressions; using Newtonsoft.Json.Converters; using Newtonsoft.Json; using System.Dynamic;var path = @"C:\MyFile\Source\Repos\Asp.NetCoreExperiment\Asp.NetCoreExperiment\GoReplay\GoReplayDemo01\request_0.gor"; var expression = "input1.amount >= 900.00"; await ImpurityRemoval(path, expression);/// <summary> /// 除雜方法，會重新生成一個帶有日期時間的新.gor文件 /// </summary> static async Task ImpurityRemoval(string path, string expression) {using var readFile = new StreamReader(path, Encoding.UTF8);using var writeFile = new StreamWriter(@$"{path.Replace(Path.GetFileName(path), Path.GetFileNameWithoutExtension(path) + "_" + DateTime.Now.ToString("yyyyMMddHHmmss") + Path.GetExtension(path))}", true, Encoding.UTF8);var split = "????????????";string? line;var request = new StringBuilder();while ((line = await readFile.ReadLineAsync()) != null){if (line != split){request.Append(line + "\n");}else{request.Append(line + "\n");var list = GetJson(request.ToString());foreach (var item in list){var converter = new ExpandoObjectConverter();var entity = JsonConvert.DeserializeObject<ExpandoObject>(item, converter);if (await Filter(entity, expression)){await writeFile.WriteAsync(request.ToString());}}request.Clear();}} } /// <summary> /// 獲取json，這里沒有完全測試 /// </summary> static List<string> GetJson(string jsonString) {var pattern = @"\{(.|\s)*\}";var list = new List<string>();var matches = Regex.Matches(jsonString, pattern, RegexOptions.IgnoreCase);foreach (Match m in matches){list.Add(m.Value);}return list; } /// <summary> /// 用規(guī)則引擎匹配過濾規(guī)則 /// </summary> static async Task<bool> Filter(dynamic? entity, string expression) {var workRules = new WorkflowRules();workRules.WorkflowName = "ImpurityRemoval";workRules.Rules = new List<Rule>{new Rule{RuleName="ImpurityRemoval01",SuccessEvent= "10",RuleExpressionType= RuleExpressionType.LambdaExpression,Expression= expression, }};var rulesEngine = new RulesEngine.RulesEngine(new WorkflowRules[] { workRules });List<RuleResultTree> resultList = await rulesEngine.ExecuteAllRulesAsync("ImpurityRemoval", entity);var result = false;resultList.OnSuccess((eventName) =>{result = true;});return result; }

回放

gor?--input-file=request_0_20210821234723.gor?--output-http="http://localhost:5000"

注意事項：

在錄制的時候本機請求不進行錄制，需要外部訪問api

在除雜過程中，重新生成gor文件時，換行一定要UNIX(LF)，不要是Windows(CRLF)，說人話就是生成文件的換行用\n，不要\r\n，否則回放時goreplay不起作用

總結(jié)

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