Golang中我们使用Channel或者sync.Mutex等锁保护数据,有没有一种机制可以检测代码中的数据竞争呢?

背景知识

数据竞争是并发情况下,存在多线程/协程读写相同数据的情况,必须存在至少一方写。另外,全是读的情况下是不存在数据竞争的。

使用race检测数据竞争
go buildrace
➜  awesome git:(master) ✗ go help build
//.... omit
-race
        enable data race detection.
        Supported only on linux/amd64, freebsd/amd64, darwin/amd64 and windows/amd64.

下面举个栗子:

package main

import "fmt"

func main() {
    i := 0

    go func() {
        i++ // write i
    }()

    fmt.Println(i) // read i
}

测试方法:

➜  awesome git:(master) ✗ go build -race hi.go
➜  awesome git:(master) ✗ ./hi
0
==================
WARNING: DATA RACE
Write at 0x00c00009c008 by goroutine 6:
  main.main.func1()
      /Users/mac/go/src/github.com/mac/awesome/hi.go:9 +0x4e

Previous read at 0x00c00009c008 by main goroutine:
  main.main()
      /Users/mac/go/src/github.com/mac/awesome/hi.go:12 +0x88

Goroutine 6 (running) created at:
  main.main()
      /Users/mac/go/src/github.com/mac/awesome/hi.go:8 +0x7a
==================
Found 1 data race(s)
exit status 66

提示示例代码存在1处数据竞争,说明了数据会在第9行写,并且同时会在12行读形成了数据竞争。

go run
➜  awesome git:(master) ✗ go run -race hi.go
0
==================
WARNING: DATA RACE
Write at 0x00c000094008 by goroutine 6:
  main.main.func1()
      /Users/shitaibin/go/src/github.com/shitaibin/awesome/hi.go:9 +0x4e

Previous read at 0x00c000094008 by main goroutine:
  main.main()
      /Users/shitaibin/go/src/github.com/shitaibin/awesome/hi.go:12 +0x88

Goroutine 6 (running) created at:
  main.main()
      /Users/shitaibin/go/src/github.com/shitaibin/awesome/hi.go:8 +0x7a
==================
Found 1 data race(s)
exit status 66
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