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# 22 | 压测平台：如何解决 GoReplay 动态数据关联？
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你好，我是高楼。
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在第 6 讲，我们说过目前主流的流量回放工具都无法轻易解决 session 的问题，所以从系统安全的角度来说，工具需要做对应的改造。
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这节课，我们来聊一下 GoReplay 如何通过改造解决回放过程中动态数据关联的问题。
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## 关联是什么？
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我们可以把关联简单地理解为把服务端返回的某个值，传递给后续的调用使用。我们可以在很多场景用到它。举个例子，我们常见的“Session ID”就是一个典型的需要关联的数据。它需要在交互过程中标识一个客户端身份，这个身份要在后续的调用中一直存在，否则服务端就不认识这个客户端了。
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对每一个性能测试工具来说，关联是应该具备的基本功能，GoReplay 也不例外。
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但是有很多新手同学对关联的逻辑并不是十分理解，甚至有人觉得关联和参数化（流量数据）是一样的，因为它们用的都是动态的数据，并且关联过来的数据也可以用到参数化（流量数据）中。其实，这二者还是有所不同的，因为关联的数据后续脚本中会用到，但参数化就不会。
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现在有很多全链路压测都是由单接口基准创建的，这样一来，关联就用得比较少。因为接口级的基准场景都是一发一收就结束了，不需要将数据保存下来再发送出去。
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那么正常情况下，什么样的场景需要关联呢？一般情况下， 它们需要满足下面几个条件：
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1. 数据是由服务器端生成的；
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2. 数据在每一次请求时都是动态变化的；
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3. 数据在后续的请求中需要再发送出去。
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你可以通过这张示意图加深一下理解：
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好了，我们知道了关联的基本概念和适用场景，那么在 GoReplay 中又如何改造呢？
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作为一款流量回放工具，我们知道GoReplay的核心原理就是基于流量文件去倍数回放请求。很显然，这个流量文件是个死的东西，是不能动态参数数据的，那么，我们又该怎么办呢？
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这时候，我们就需要搬出 GoReplay 的中间件了。
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## 中间件是什么？
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[中间件](https://github.com/buger/goreplay/wiki/middleware)（ [Middleware](https://github.com/buger/goreplay/wiki/middleware) ）是一个在 STDIN（标准输入） 接收请求、响应 payload （有效请求负载）并在 STDOUT（标准输出） 发出修改请求的程序。你可以在中间件上实现任何自定义逻辑，比如认证、复杂的重写和筛选请求等。
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通过传入 Middleware 参数，我们可以发送命令给 GoReplay，GoReplay 会拉起一个进程执行这个命令。在录制过程中，GoReplay 通过获取进程的 STDIN 和 STDOUT 与输入输出插件进程进行通信，中间件内部逻辑为 STDERR，数据流向大致如下：
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```bash
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Original request +--------------+
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+-------------+----------STDIN---------->+ |
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| Gor input | | Middleware |
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+-------------+----------STDIN---------->+ |
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Original response +------+---+---+
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| ^
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+-------------+ Modified request v |
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| Gor output +<---------STDOUT-----------------+ |
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+-----+-------+ |
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| Replayed response |
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+------------------STDIN----------------->----+
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```
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需要注意的是，如果希望记录原始响应和回放响应，不要忘记添加 **– output-http-track-response** 和 **– input-raw-track-response** 参数。
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GoReplay 支持用任何语言编写中间件的协议，同时中间件程序还需要格外注意一点，就是中间件和 Gor 的所有通信都是异步，因此，我们不能保证原始请求和响应消息会一个接一个地出现。如果业务逻辑依赖于原始响应或回放响应，那么中间件应用程序就应该处理好状态，也就是要做好动态数据的处理动作。
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为了简化中间件的功能实现，官方为 [node.js](https://github.com/buger/goreplay/tree/master/middleware) 和 Go (即将推出)提供了包。
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## 如何使用中间件？
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那么，应该怎样使用中间件呢？
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下面就是一个简单的使用 bash echo 中间件的示例，我们用它来打印对应的 payload 类型：
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```
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#!/usr/bin/env bash
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#
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# `xxd` utility included into vim-common package
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# It allow hex decoding/encoding
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#
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# This example may broke if you request contains `null` string, you may consider using pipes instead.
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# See: https://github.com/buger/gor/issues/309
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#
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function log {
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# Logging to stderr, because stdout/stdin used for data transfer
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# 记录到 stderr，因 为 stdout/stdin 用于数据传输
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>&2 echo "[DEBUG][ECHO] $1"
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}
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while read line; do
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decoded=$(echo -e "$line" | xxd -r -p)
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header=$(echo -e "$decoded" | head -n +1)
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payload=$(echo -e "$decoded" | tail -n +2)
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encoded=$(echo -e "$header\n$payload" | xxd -p | tr -d "\\n")
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log ""
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log "==================================="
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case ${header:0:1} in
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"1")
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log "Request type: Request"
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;;
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"2")
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log "Request type: Original Response"
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;;
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"3")
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log "Request type: Replayed Response"
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;;
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*)
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log "Unknown request type $header"
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esac
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echo "$encoded"
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log "==================================="
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log "Original data: $line"
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log "Decoded request: $decoded"
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log "Encoded data: $encoded"
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done;
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```
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这里我们使用【会员登录接口】来做演示。
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首先，通过指定 Middleware 可执行文件的命令，也就是使用 Middleware 参数在 GoReplay 启用中间件功能：
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```bash
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sudo ./goreplay --input-raw :8081 --middleware "./echo.sh" --output-http "http://staging.server"
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```
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接下来，我们通过 Postman 对【会员登录】接口做一次测试。
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通过控制台我们看到，中间件程序已经成功把经过的流量信息全部打印出来了。
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```bash
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Interface: en0 . BPF Filter: ((tcp dst port 8081) and (dst host fe80::8f6:ee40:ebd1:bec or dst host 192.168.3.58))
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Interface: awdl0 . BPF Filter: ((tcp dst port 8081) and (dst host fe80::50a5:ceff:feeb:47e3))
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Interface: llw0 . BPF Filter: ((tcp dst port 8081) and (dst host fe80::50a5:ceff:feeb:47e3))
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Interface: utun0 . BPF Filter: ((tcp dst port 8081) and (dst host fe80::d9a3:ab1b:f8e4:4de))
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Interface: utun1 . BPF Filter: ((tcp dst port 8081) and (dst host fe80::c2a0:19a0:9d9d:6699))
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Interface: utun2 . BPF Filter: ((tcp dst port 8081) and (dst host fe80::771:4985:8642:7857))
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Interface: utun3 . BPF Filter: ((tcp dst port 8081) and (dst host fe80::4a93:e598:6e37:37b3))
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Interface: lo0 . BPF Filter: ((tcp dst port 8081) and (dst host 127.0.0.1 or dst host ::1 or dst host fe80::1))
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2021/11/14 17:16:34 [PPID 8021 and PID 8022] Version:1.3.0
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[DEBUG][ECHO]
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[DEBUG][ECHO] ===================================
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[DEBUG][ECHO] Request type: Request
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[DEBUG][ECHO] ===================================
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[DEBUG][ECHO] Original data: 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[DEBUG][ECHO] Decoded request: 1 cb9f1f910000000155599937 1636881399760637000 0
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POST /admin/login HTTP/1.1
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Content-Type: application/json
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Authorization: true
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User-Agent: PostmanRuntime/7.28.4
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Accept: */*
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Postman-Token: 4fa25e6b-fd46-4e96-8af6-f6c5ba0f003f
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Host: localhost:8081
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Accept-Encoding: gzip, deflate, br
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Connection: keep-alive
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Content-Length: 52
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{
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"password": "123456",
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"username": "test"
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}
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[DEBUG][ECHO] Encoded data: 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```
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到这里，我们已经了解了中间件的基本功能和使用方法，接下来我们回到这节课的主题，如何实现关联操作？
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## 如何实现回放关联？
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这里我们引入“会员登录”和“查询所有后台资源分类”两个接口为例。
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你可以先看看这张整体的请求交互示意图：
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* 会员登录
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* 查询所有后台资源分类
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我们知道 token 是有时效的，如果失效，那么二次请求服务端校验就会失败。如下图：
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下面我们具体来演示下如何解决token关联的问题。
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第一步，创建一个流量录制的命令：
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```shell
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#!/bin/bash
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PORT="8081"
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OUT_FILE="request.gor"
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sudo ./goreplay --input-raw :$PORT --output-file=$OUT_FILE -output-file-append --input-raw-track-response --prettify-http
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```
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录制下的流量文件如下：
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```shell
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1 d1ae1f9100000001e404ee86 1635588156669182000 0
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POST /admin/login HTTP/1.1
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Content-Type: application/json
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Authorization: true
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User-Agent: PostmanRuntime/7.28.4
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Accept: */*
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Postman-Token: 480f15ca-53df-44fd-8980-5e9118b2107e
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Host: localhost:8081
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Accept-Encoding: gzip, deflate, br
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Connection: keep-alive
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Content-Length: 52
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{
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"password": "123456",
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"username": "test"
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}
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🐵🙈🙉
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2 d1ae1f9100000001e404ee86 1635588156828973000 458000
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HTTP/1.1 200
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Content-Length: 254
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Vary: Origin
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Vary: Access-Control-Request-Method
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Vary: Access-Control-Request-Headers
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X-Content-Type-Options: nosniff
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X-XSS-Protection: 1; mode=block
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Cache-Control: no-cache, no-store, max-age=0, must-revalidate
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Pragma: no-cache
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Expires: 0
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X-Frame-Options: DENY
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Content-Type: application/json
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Date: Sat, 30 Oct 2021 10:02:36 GMT
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Keep-Alive: timeout=60
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Connection: keep-alive
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{"code":200,"message":"操作成功","data":{"tokenHead":"","token":"eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJ0ZXN0IiwiY3JlYXRlZCI6MTYzNTU4ODE1Njc5NCwiZXhwIjoxNjM1NTg4MjE2fQ.-wsZa0gijz2KfCF-eAYK1Tt-pd_vw2_LShShlIDCQOsHjOZZlGl8yX2MncZlO9St_oPj1JdBaERjfEU6iu12qw"}}
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🐵🙈🙉
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1 d1ae1f9100000001e405029a 1635588192031592000 0
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GET /resource/listAll HTTP/1.1
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token: eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJ0ZXN0IiwiY3JlYXRlZCI6MTYzNTU4ODE1Njc5NCwiZXhwIjoxNjM1NTg4MjE2fQ.-wsZa0gijz2KfCF-eAYK1Tt-pd_vw2_LShShlIDCQOsHjOZZlGl8yX2MncZlO9St_oPj1JdBaERjfEU6iu12qw
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User-Agent: PostmanRuntime/7.28.4
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Accept: */*
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Postman-Token: 4bc2152e-dbd4-4b2a-b880-72ed5ee4303a
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Host: localhost:8081
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Accept-Encoding: gzip, deflate, br
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Connection: keep-alive
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🐵🙈🙉
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2 d1ae1f9100000001e405029a 1635588192064563000 1084000
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HTTP/1.1 200
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Content-Length: 3997
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Vary: Origin
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Vary: Access-Control-Request-Method
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Vary: Access-Control-Request-Headers
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X-Content-Type-Options: nosniff
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X-XSS-Protection: 1; mode=block
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Cache-Control: no-cache, no-store, max-age=0, must-revalidate
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Pragma: no-cache
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Expires: 0
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X-Frame-Options: DENY
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Content-Type: application/json
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Date: Sat, 30 Oct 2021 10:03:12 GMT
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Keep-Alive: timeout=60
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Connection: keep-alive
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{"code":200,"message":"操作成功","data":[{"id":1,"createTime":"2020-02-04T09:04:55.000+00:00","name":"商品品牌管理","url":"/brand/**","description":null,"categoryId":1},{"id":2,"createTime":"2020-02-04T09:05:35.000+00:00","name":"商品属性分类管理","url":"/productAttribute/**","description":null,"categoryId":1},{"id":3,"createTime":"2020-02-04T09:06:13.000+00:00","name":"商品属性管理","url":"/productAttribute/**","description":null,"categoryId":1},{"id":4,"createTime":"2020-02-04T09:07:15.000+00:00","name":"商品分类管理","url":"/productCategory/**","description":null,"categoryId":1},{"id":5,"createTime":"2020-02-04T09:09:16.000+00:00","name":"商品管理","url":"/product/**","description":null,"categoryId":1},{"id":6,"createTime":"2020-02-04T09:09:53.000+00:00","name":"商品库存管理","url":"/sku/**","description":null,"categoryId":1},{"id":8,"createTime":"2020-02-05T06:43:37.000+00:00","name":"订单管理","url":"/order/**","description":"","categoryId":2},{"id":9,"createTime":"2020-02-05T06:44:22.000+00:00","name":" 订单退货申请管理","url":"/returnApply/**","description":"","categoryId":2},{"id":10,"createTime":"2020-02-05T06:45:08.000+00:00","name":"退货原因管理","url":"/returnReason/**","description":"","categoryId":2},{"id":11,"createTime":"2020-02-05T06:45:43.000+00:00","name":"订单设置管理","url":"/orderSetting/**","description":"","categoryId":2},{"id":12,"createTime":"2020-02-05T06:46:23.000+00:00","name":"收货地址管理","url":"/companyAddress/**","description":"","categoryId":2},{"id":13,"createTime":"2020-02-07T08:37:22.000+00:00","name":"优惠券管理","url":"/coupon/**","description":"","categoryId":3},{"id":14,"createTime":"2020-02-07T08:37:59.000+00:00","name":"优惠券领取记录管理","url":"/couponHistory/**","description":"","categoryId":3},{"id":15,"createTime":"2020-02-07T08:38:28.000+00:00","name":"限时购活动管理","url":"/flash/**","description":"","categoryId":3},{"id":16,"createTime":"2020-02-07T08:38:59.000+00:00","name":"限时购商品关系管理","url":"/flashProductRelation/**","description":"","categoryId":3},{"id":17,"createTime":"2020-02-07T08:39:22.000+00:00","name":"限时购场次管理","url":"/flashSession/**","description":"","categoryId":3},{"id":18,"createTime":"2020-02-07T08:40:07.000+00:00","name":"首页轮播广告管理","url":"/home/advertise/**","description":"","categoryId":3},{"id":19,"createTime":"2020-02-07T08:40:34.000+00:00","name":"首页品牌管理","url":"/home/brand/**","description":"","categoryId":3},{"id":20,"createTime":"2020-02-07T08:41:06.000+00:00","name":"首页新品管理","url":"/home/newProduct/**","description":"","categoryId":3},{"id":21,"createTime":"2020-02-07T08:42:16.000+00:00","name":"首页人气推荐管理","url":"/home/recommendProduct/**","description":"","categoryId":3},{"id":22,"createTime":"2020-02-07T08:42:48.000+00:00","name":"首页专题推荐管理","url":"/home/recommendSubject/**","description":"","categoryId":3},{"id":23,"createTime":"2020-02-07T08:44:56.000+00:00","name":" 商品优选管理","url":"/prefrenceArea/**","description":"","categoryId":5},{"id":24,"createTime":"2020-02-07T08:45:39.000+00:00","name":"商品专题管理","url":"/subject/**","description":"","categoryId":5},{"id":25,"createTime":"2020-02-07T08:47:34.000+00:00","name":"后台用户管理","url":"/admin/**","description":"","categoryId":4},{"id":26,"createTime":"2020-02-07T08:48:24.000+00:00","name":"后台用户角色管理","url":"/role/**","description":"","categoryId":4},{"id":27,"createTime":"2020-02-07T08:48:48.000+00:00","name":"后台菜单管理","url":"/menu/**","description":"","categoryId":4},{"id":28,"createTime":"2020-02-07T08:49:18.000+00:00","name":"后台资源分类管理","url":"/resourceCategory/**","description":"","categoryId":4},{"id":29,"createTime":"2020-02-07T08:49:45.000+00:00","name":"后台资源管理","url":"/resource/**","description":"","categoryId":4}]}
|
|
|
🐵🙈🙉
|
|
|
|
|
|
```
|
|
|
|
|
|
第二步，创建一个流量回放 Shell 脚本。
|
|
|
|
|
|
```shell
|
|
|
#!/bin/bash
|
|
|
## Usage: ./replay.sh
|
|
|
|
|
|
OUTPUT="http://127.0.0.1:8081"
|
|
|
INPUT_FILE="requests.gor"
|
|
|
|
|
|
sudo ./goreplay --input-file $INPUT_FILE --input-file-loop --output-http=$OUTPUT --prettify-http --output-http-track-response --output-stdout
|
|
|
|
|
|
```
|
|
|
|
|
|
第三步，我们尝试进行一次回放操作。
|
|
|
|
|
|
|
|
|
|
|
|
等待一会，我们看到回放的【查询所有后台资源分类】接口已经失败了，提示 token 失效了。
|
|
|
|
|
|
要怎么解决这个问题呢？
|
|
|
|
|
|
在这种情况下，我们需要实时将来自录制的 token 关联到来自回放响应的 token 上 ，然后使用关联的 token 修改回放的请求。我们使用 GoReplay 存储库中的这个方便的[示例](https://github.com/buger/goreplay/blob/master/examples/middleware/token_modifier.go)进行扩展。
|
|
|
|
|
|
所涉及的基本算法你可以看看下面这张图片。
|
|
|
|
|
|
|
|
|
因为原始服务器没有预定义的token，而回放服务器有自己的token，它不能与原始服务器同步。所以不使用中间件或者中间件只使用请求有效 payload，都会使得token失效。
|
|
|
|
|
|
为了解决这个问题，我们的中间件应该考虑回放和源服务器的响应，存储’ originalToken -> replayedToken '别名，并使用此 token 重写所有请求以使用回放别名。
|
|
|
|
|
|
顺着这个思路，我们看下第四步，创建 token 关联中间件程序。
|
|
|
|
|
|
```go
|
|
|
package main
|
|
|
|
|
|
import (
|
|
|
"bufio"
|
|
|
"bytes"
|
|
|
"encoding/hex"
|
|
|
"fmt"
|
|
|
"github.com/bitly/go-simplejson"
|
|
|
"github.com/buger/goreplay/proto"
|
|
|
"os"
|
|
|
)
|
|
|
|
|
|
// requestID -> originalToken
|
|
|
// 请求 ID -> 原始 Token
|
|
|
var originalTokens map[string][]byte
|
|
|
|
|
|
// originalToken -> replayedToken
|
|
|
// 原始 Token -> 回放 Token
|
|
|
var tokenAliases map[string][]byte
|
|
|
|
|
|
var json_data interface{}
|
|
|
|
|
|
|
|
|
|
|
|
func main() {
|
|
|
originalTokens = make(map[string][]byte)
|
|
|
tokenAliases = make(map[string][]byte)
|
|
|
|
|
|
scanner := bufio.NewScanner(os.Stdin)
|
|
|
|
|
|
for scanner.Scan() {
|
|
|
encoded := scanner.Bytes()
|
|
|
buf := make([]byte, len(encoded)/2)
|
|
|
hex.Decode(buf, encoded)
|
|
|
|
|
|
process(buf)
|
|
|
}
|
|
|
}
|
|
|
|
|
|
func process(buf []byte) {
|
|
|
// First byte indicate payload type, possible values:
|
|
|
// 1 - Request
|
|
|
// 2 - Response
|
|
|
// 3 - ReplayedResponse
|
|
|
// 第一个字节表示有效负载类型，可能的值:
|
|
|
// 1 - 请求
|
|
|
// 2 - 响应
|
|
|
// 3 - 回放响应
|
|
|
payloadType := buf[0]
|
|
|
headerSize := bytes.IndexByte(buf, '\n') + 1
|
|
|
header := buf[:headerSize-1]
|
|
|
|
|
|
// Header contains space separated values of: request type, request id, and request start time (or round-trip time for responses)
|
|
|
// Header 包含空格分隔的值:请求类型，请求 id，请求开始时间(或响应的往返时间)
|
|
|
meta := bytes.Split(header, []byte(" "))
|
|
|
|
|
|
// For each request you should receive 3 payloads (request, response, replayed response) with same request id
|
|
|
// 对于每个请求，你应该收到 3 个有效负载(request, response, replayed response)，具有相同的请求 id
|
|
|
reqID := string(meta[1])
|
|
|
payload := buf[headerSize:]
|
|
|
|
|
|
Debug("Received payload:", string(buf))
|
|
|
|
|
|
switch payloadType {
|
|
|
case '1': // Request
|
|
|
if bytes.Equal(proto.Path(payload), []byte("/admin/login")) {
|
|
|
originalTokens[reqID] = []byte{}
|
|
|
Debug("Found token request:", reqID)
|
|
|
} else {
|
|
|
//token, vs, _ := proto.PathParam(payload, []byte("token")) //取到回放响应的 token 值
|
|
|
token := proto.Header(payload, []byte("token")) //取到原始的 token 值
|
|
|
|
|
|
Debug("Received token:", string(token))
|
|
|
|
|
|
if len(token) != 0 { // If there is GET token param
|
|
|
Debug("If there is GET token param")
|
|
|
Debug("tokenAliases", tokenAliases)
|
|
|
if alias, ok := tokenAliases[string(token)]; ok { //检查要替换的 token 值是否存在
|
|
|
Debug("Received alias")
|
|
|
// Rewrite original token to alias
|
|
|
payload = proto.SetHeader(payload, []byte("token"), alias) //将原始的 token 替换成回放的 token
|
|
|
|
|
|
// Copy modified payload to our buffer
|
|
|
buf = append(buf[:headerSize], payload...)
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
// Emitting data back
|
|
|
os.Stdout.Write(encode(buf)) //重写请求准备发往回放服务
|
|
|
case '2': // Original response
|
|
|
if _, ok := originalTokens[reqID]; ok {
|
|
|
jsonObject, err := simplejson.NewJson([]byte(proto.Body(payload)))
|
|
|
if err != nil {
|
|
|
fmt.Println(err)
|
|
|
}
|
|
|
|
|
|
result := jsonObject.Get("data")
|
|
|
token := result.Get("token")
|
|
|
secureToken:=token
|
|
|
|
|
|
f ,_:=secureToken.Bytes()
|
|
|
|
|
|
originalTokens[reqID] = f
|
|
|
Debug("Remember origial token:", f)
|
|
|
|
|
|
}
|
|
|
case '3': // Replayed response
|
|
|
if originalToken, ok := originalTokens[reqID]; ok {
|
|
|
delete(originalTokens, reqID)
|
|
|
|
|
|
|
|
|
|
|
|
jsonObject, err := simplejson.NewJson([]byte(proto.Body(payload)))
|
|
|
if err != nil {
|
|
|
fmt.Println(err)
|
|
|
}
|
|
|
result := jsonObject.Get("data")
|
|
|
token := result.Get("token")
|
|
|
f ,_:=token.Bytes()
|
|
|
tokenAliases[string(originalToken)] = f //拿到现在的 token 值用来替换掉过去的 token 值
|
|
|
|
|
|
Debug("Create alias for new token token, was:", string(originalToken), "now:", string(f))
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
func encode(buf []byte) []byte {
|
|
|
dst := make([]byte, len(buf)*2+1)
|
|
|
hex.Encode(dst, buf)
|
|
|
dst[len(dst)-1] = '\n'
|
|
|
|
|
|
return dst
|
|
|
}
|
|
|
|
|
|
func Debug(args ...interface{}) {
|
|
|
if os.Getenv("GOR_TEST") == "" { // if we are not testing
|
|
|
fmt.Fprint(os.Stderr, "[DEBUG][TOKEN-MOD] ")
|
|
|
fmt.Fprintln(os.Stderr, args...)
|
|
|
}
|
|
|
|
|
|
}
|
|
|
|
|
|
```
|
|
|
|
|
|
我们可以使用 process 函数异步处理原始请求或回放响应从而重新设置 token。由于 GoReplay 的每个三元组（请求、响应、回放响应）共享一个请求 ID，因此到达中间件的第一个响应可以将它的 token 关联到请求 ID。当第二个响应到达时，我们就可以访问两个 token了。我们可以将原始 token 关联到回放的 token，并能够一一对应（因为第二个响应类型也可用）。
|
|
|
|
|
|
好了，这样中间件就写完了，我们一起来测试一下。
|
|
|
|
|
|
我们先创建一个运行中间件的 Shell 脚本 middleware\_wrapper.sh。
|
|
|
|
|
|
```bash
|
|
|
#!/bin/bash
|
|
|
go run token_modifier.go
|
|
|
|
|
|
```
|
|
|
|
|
|
第二步，修改启动回放的 Shell 脚本 replay.sh。
|
|
|
|
|
|
```bash
|
|
|
#!/bin/bash
|
|
|
## Usage: ./replay.sh
|
|
|
|
|
|
OUTPUT="http://127.0.0.1:8081"
|
|
|
MIDDLEWARE="./middleware_wrapper.sh"
|
|
|
INPUT_FILE="requests.gor"
|
|
|
|
|
|
sudo ./goreplay --input-file $INPUT_FILE --input-file-loop --output-http=$OUTPUT --middleware $MIDDLEWARE --prettify-http --output-http-track-response --output-stdout
|
|
|
|
|
|
```
|
|
|
|
|
|
最后一步，我们就要紧盯运行控制台了。
|
|
|
|
|
|
* 登录接口实时返回的 token。
|
|
|
|
|
|
|
|
|
|
|
|
* 【查询所有后台资源分类】接口，可以看到已经成功替换到回放响应的 token了。
|
|
|
|
|
|
|
|
|
|
|
|
* 【查询所有后台资源分类】接口，回放响应的数据也是正常的。
|
|
|
|
|
|
|
|
|
|
|
|
* 服务端日志显示正常。
|
|
|
|
|
|
|
|
|
|
|
|
好了，到这里，我们的动态数据关联功能就已经实现了。
|
|
|
|
|
|
## 总结
|
|
|
|
|
|
好了，这节课就讲到这里。刚才，我们一起梳理了关联的基本概念、 GoReplay 中间件（ Middleware ）原理、常用的用法。我们还通过例子演示了GoReplay 如何通过扩展 Middleware 做到关联功能。实际上，我们可以在中间件上实现任何自定义逻辑，比如认证、复杂的重写和筛选请求等。
|
|
|
|
|
|
下一节课，我们将进入具体的分布式改造环节，我会通过案例演示如何做分布式平台改造工作。
|
|
|
|
|
|
## 课后题
|
|
|
|
|
|
学完这节课，请你思考两个问题：
|
|
|
|
|
|
1. 你有没有使用过 Middleware，谈谈你对 Middleware 应用的一些心得吧！
|
|
|
2. 相比 JMeter，你觉得 GoReplay 关联的难度在什么地方？
|
|
|
|
|
|
欢迎你在留言区与我交流讨论。当然了，你也可以把这节课分享给你身边的朋友，他们的一些想法或许会让你有更大的收获。我们下节课见！
|
|
|
|