很多数据竞争的网络应用程序

huangapple
go评论115阅读模式
英文:

A lot of data race web application

问题

根据你提供的信息，中间件可能是导致数据竞争的原因之一。数据竞争通常发生在多个goroutine同时访问和修改共享数据时。在你的代码中，不同的中间件在处理请求时可能会同时访问和修改响应的Header。这可能导致数据竞争。

为了解决这个问题，你可以考虑使用互斥锁（Mutex）或其他同步机制来保护共享数据，确保在同一时间只有一个goroutine可以访问和修改它。另外，你还可以检查中间件的实现，确保它们在处理请求时没有产生竞争条件。

此外，你还可以使用Go语言的竞争检测工具（如go run -race或go test -race）来帮助你发现和解决数据竞争问题。这些工具可以在运行时检测到潜在的竞争条件，并提供相关的报告和调试信息。

总之，中间件可能是导致数据竞争的原因之一。你可以通过使用同步机制和竞争检测工具来解决这个问题。

英文:

I am writing a web application. Incoming requests will pass through middlewares first. At the moment, I've added two middlwares session and security.
After walked through middlwares, it will execute the handler for the request.
Session and security middlwares will execute in their own goroutine.

When I am testing I've got a lot of data race, specially in middlware section

  1. WARNING: DATA RACE
  2. Write by goroutine 18:
  3.   runtime.mapassign1()
  4.       c:/go/src/runtime/hashmap.go:383 +0x0
  5.   net/textproto.MIMEHeader.Set()
  6.       c:/go/src/net/textproto/header.go:22 +0xf4
  7.   net/http.Header.Set()
  8.       c:/go/src/net/http/header.go:31 +0x64
  9.   project/middlewares/session.(*ctrl).setHttpHeader()
  10.       D:/gocode/src/project/middlewares/session/ctrl.go:76 +0x9d
  11.   project/middlewares/session.(*ctrl).evaluateJwt()
  12.       D:/gocode/src/project/middlewares/session/ctrl.go:56 +0x31a
  13.   project/middlewares/session.(*ctrl).serveHttp()
  14.       D:/gocode/src/project/middlewares/session/ctrl.go:94 +0x8a
  15.   project/middlewares/session.func┬À006()
  16.       D:/gocode/src/project/middlewares/session/serve_http.go:23 +0x
  18. Previous write by goroutine 17:
  19.   runtime.mapassign1()
  20.       c:/go/src/runtime/hashmap.go:383 +0x0
  21.   net/textproto.MIMEHeader.Add()
  22.       c:/go/src/net/textproto/header.go:15 +0x212
  23.   net/http.Header.Add()
  24.       c:/go/src/net/http/header.go:24 +0x64
  25.   github.com/unrolled/secure.(*Secure).Process()
  26.       D:/gocode/src/github.com/unrolled/secure/secure.go:177 +0xe5b
  27.   project/middlewares/security.func┬À001()
  28.       D:/gocode/src/project/middlewares/security/serve_http.go:33 +0
  30. Goroutine 18 (running) created at:
  31.   project/middlewares/session.ServeHttp()
  32.       D:/gocode/src/project/middlewares/session/serve_http.go:29 +0x
  33.   project/middlewares.New()
  34.       D:/gocode/src/project/middlewares/ctrl.go:12 +0x99
  35.   github.com/codegangsta/negroni.HandlerFunc.ServeHTTP()
  36.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:24 +0x5f
  37.   github.com/codegangsta/negroni.middleware.ServeHTTP()
  38.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x114
  39.   github.com/codegangsta/negroni.middleware.ServeHTTP┬Àfm()
  40.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x84
  41.   github.com/codegangsta/negroni.(*Static).ServeHTTP()
  42.       D:/gocode/src/github.com/codegangsta/negroni/static.go:30 +0xb71
  43.   github.com/codegangsta/negroni.middleware.ServeHTTP()
  44.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x114
  45.   github.com/codegangsta/negroni.middleware.ServeHTTP┬Àfm()
  46.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x84
  47.   github.com/codegangsta/negroni.(*Logger).ServeHTTP()
  48.       D:/gocode/src/github.com/codegangsta/negroni/logger.go:25 +0x249
  49.   github.com/codegangsta/negroni.middleware.ServeHTTP()
  50.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x114
  51.   github.com/codegangsta/negroni.middleware.ServeHTTP┬Àfm()
  52.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x84
  53.   github.com/codegangsta/negroni.(*Recovery).ServeHTTP()
  54.       D:/gocode/src/github.com/codegangsta/negroni/recovery.go:45 +0xd9
  55.   github.com/codegangsta/negroni.middleware.ServeHTTP()
  56.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x114
  57.   github.com/codegangsta/negroni.(*Negroni).ServeHTTP()
  58.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:73 +0x1c7
  59.   net/http/httptest.(*waitGroupHandler).ServeHTTP()
  60.       c:/go/src/net/http/httptest/server.go:200 +0xfe
  61.   net/http.serverHandler.ServeHTTP()
  62.       c:/go/src/net/http/server.go:1703 +0x1fd
  63.   net/http.(*conn).serve()
  64.       c:/go/src/net/http/server.go:1204 +0x108e
  66. Goroutine 17 (finished) created at:
  67.   project/middlewares/security.ServeHttp()
  68.       D:/gocode/src/project/middlewares/security/serve_http.go:37 +0
  69.   project/middlewares.New()
  70.       D:/gocode/src/project/middlewares/ctrl.go:12 +0x64
  71.   github.com/codegangsta/negroni.HandlerFunc.ServeHTTP()
  72.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:24 +0x5f
  73.   github.com/codegangsta/negroni.middleware.ServeHTTP()
  74.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x114
  75.   github.com/codegangsta/negroni.middleware.ServeHTTP┬Àfm()
  76.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x84
  77.   github.com/codegangsta/negroni.(*Static).ServeHTTP()
  78.       D:/gocode/src/github.com/codegangsta/negroni/static.go:30 +0xb71
  79.   github.com/codegangsta/negroni.middleware.ServeHTTP()
  80.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x114
  81.   github.com/codegangsta/negroni.middleware.ServeHTTP┬Àfm()
  82.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x84
  83.   github.com/codegangsta/negroni.(*Logger).ServeHTTP()
  84.       D:/gocode/src/github.com/codegangsta/negroni/logger.go:25 +0x249
  85.   github.com/codegangsta/negroni.middleware.ServeHTTP()
  86.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x114
  87.   github.com/codegangsta/negroni.middleware.ServeHTTP┬Àfm()
  88.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x84
  89.   github.com/codegangsta/negroni.(*Recovery).ServeHTTP()
  90.       D:/gocode/src/github.com/codegangsta/negroni/recovery.go:45 +0xd9
  91.   github.com/codegangsta/negroni.middleware.ServeHTTP()
  92.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:33 +0x114
  93.   github.com/codegangsta/negroni.(*Negroni).ServeHTTP()
  94.       D:/gocode/src/github.com/codegangsta/negroni/negroni.go:73 +0x1c7
  95.   net/http/httptest.(*waitGroupHandler).ServeHTTP()
  96.       c:/go/src/net/http/httptest/server.go:200 +0xfe
  97.   net/http.serverHandler.ServeHTTP()
  98.       c:/go/src/net/http/server.go:1703 +0x1fd
  99.   net/http.(*conn).serve()
  100.       c:/go/src/net/http/server.go:1204 +0x108e
  101. ==================
  102. 2015/02/03 15:05:31 ctrl.go:17: End of process middlewares
  103. 2015/02/03 15:05:31 funcs.go:10: Create new user
  104. 2015/02/03 15:05:31 validate.go:14: Validate email thompson@example.com
  105. 2015/02/03 15:05:31 validate.go:100: Validate password Test!1234
  106. 2015/02/03 15:05:31 validate.go:52: Validate name:  ValidName
  107. 2015/02/03 15:05:31 create.go:120: Done
  108. [negroni] Completed 0  in 197ms
  109. PASS
  110. ok      project/testing/account_test 0.664s
  111. PS D:\gocode\src\project\testing\account_test> go test -race
  112. 2015/02/03 15:08:10 vs.go:50: Connect to neo4j db.
  113. [negroni] Started POST /user
  114. ==================
  115. WARNING: DATA RACE
  116. Write by goroutine 18:
  117.   net/http.(*response).Header()
  118.       c:/go/src/net/http/server.go:615 +0x11a
  119.   github.com/codegangsta/negroni.(*responseWriter).Header()
  120.       <autogenerated>:42 +0x78
  121.   project/middlewares/session.(*ctrl).setHttpHeader()
  122.       D:/gocode/src/project/middlewares/session/ctrl.go:76 +0x68
  123.   project/middlewares/session.(*ctrl).evaluateJwt()
  124.       D:/gocode/src/project/middlewares/session/ctrl.go:56 +0x31a
  125.   project/middlewares/session.(*ctrl).serveHttp()
  126.       D:/gocode/src/project/middlewares/session/ctrl.go:94 +0x8a
  127.   project/middlewares/session.func┬À006()
  128.       D:/gocode/src/project/middlewares/session/serve_http.go:23 +0x
  130. Previous write by goroutine 17:
  131.   net/http.(*response).Header()
  132.       c:/go/src/net/http/server.go:615 +0x11a
  133.   github.com/codegangsta/negroni.(*responseWriter).Header()
  134.       <autogenerated>:42 +0x78
  135.   github.com/unrolled/secure.(*Secure).Process()
  136.       D:/gocode/src/github.com/unrolled/secure/secure.go:177 +0xe24
  137.   project/middlewares/security.func┬À001()
  138.       D:/gocode/src/project/middlewares/security/serve_http.go:33 +0

I use negroni to process middlwares works.

The way, how I process middlwares

  1. func New(res http.ResponseWriter, req *http.Request, next http.HandlerFunc) {
  3. 	if err := process(security.ServeHttp(res, req), session.ServeHttp(res, req)); err != nil {
  4. 		res.WriteHeader(http.StatusInternalServerError)
  5. 		return
  6. 	}
  8. 	log.Println("End of process middlewares")
  9. 	next(res, req)
  11. }
  13. // Process all middlewares
  14. func process(chErrs ...<-chan error) error {
  16. 	for _, chErr := range chErrs {
  18. 		// Will abort the loop, when error occurs
  19. 		if err := <-chErr; err != nil {
  20. 			return err
  21. 		}
  23. 	}
  24. 	return nil
  25. }

As you can see, every middlware have they own channel. The for statement will loop until the error channel is closed or error send.

The server configuration

  1. func Config() *negroni.Negroni {
  2. 	n := negroni.Classic()
  3. 	n.Use(negroni.HandlerFunc(middlewares.New))
  4. 	n.UseHandler(routes.Set())
  5. 	return n
  7. }

My question is, are the middlewares the reason, why I've got the data race?

答案1

得分: 1

你在goroutine中运行中间件是问题的原因。

如果你想并行运行你的中间件，你需要在任何在goroutine中执行的中间件写入的内存周围设置一个互斥锁(mutex)。

在你的特定情况下，你既写入又读取ResponseWriter的Header。

英文:

It's the fact that you're running the middleware within a goroutine that is the problem.

If you want to run your middleware in parallel you will have to set up a mutex around the memory that is written to by any middleware executed within a goroutine.

In your particular case you are both writing and reading from the ResponseWriter's Header

huangapple
  • 本文由 发表于 2015年2月3日 22:32:17
  • 转载请务必保留本文链接：https://go.coder-hub.com/28301402.html
  • concurrency
  • go
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