golang 故障模拟工具failpoint的使用

r囧r小猫 2023-06-13 09:42 5阅读 0赞

测试是功能上线之前的重要环节。

测试过程中，要尽量覆盖各种场景。故障情况或异常情况下的场景测试，也是必不可少的。

如何模拟故障呢？

在FreeBSD 中, failpoints经常用来模拟故障。

在golang，也有failpoint的实现，就是目前pingcap 公司的开源项目`failpoint`.

下面介绍golang中的failpoint的实现。

# 1.安装failpoint工具 #

cd $GOPATH/src
    
    mkdir -p github.com/pingcap
    
    cd github.com/pingcap
    
    git clone https://github.com/pingcap/failpoint.git
     
    cd failpoint
    
    make
    GO111MODULE=on CGO_ENABLED=0 GO111MODULE=on go build  -ldflags '-X "github.com/pingcap/failpoint/failpoint-ctl/version.releaseVersion=12f4ac2-dev" -X "github.com/pingcap/failpoint/failpoint-ctl/version.buildTS=2019-11-15 09:41:49" -X "github.com/pingcap/failpoint/failpoint-ctl/version.gitHash=12f4ac2fd11dfc6b2f7018b00bb90f61a5b6b692" -X "github.com/pingcap/failpoint/failpoint-ctl/version.gitBranch=master" -X "github.com/pingcap/failpoint/failpoint-ctl/version.goVersion=go version go1.13 darwin/amd64"' -o bin/failpoint-ctl failpoint-ctl/main.go
    failpoint-ctl build successfully :-) !

**注意：仔细确认这些步骤。如果搞错，会出现无法转换代码的情况。**

编译后，生成可执行文件failpoint-ctl：

ll bin
    total 6840
    -rwxr-xr-x  1 lanyang  staff   3.3M 11 15 17:41 failpoint-ctl

# 2. 测试代码 #

代码结构如下：

cd $GOPATH/src
    
    mkdir fp_example
    
    cd fp_example

# tree ./
    ./
    ├── fruit
    │   └── banana.go
    ├── main.go
    └── util
        ├── apple.go
        └── orange.go

其中，main.go文件内容：

package main
    
    import (
            "fmt"
            "fp_example/hot_fruit"
            "fp_example/fruit"
    )
    
    func main() {
    
            hot_fruit.Apple()
            hot_fruit.Orange()
            fruit.Banana()
    
            fmt.Println("main end")
    }

fruit/banana.go：

package fruit
    
    import (
            "fmt"
            "github.com/pingcap/failpoint"
    )
    
    func Banana() {
            fmt.Println("banana....")
    
            failpoint.Inject("bananaPanic", func() {
                    panic("banana failpoint triggerd")
            })
    
    }

注入一个panic。

hot\_fruit/apple.go：

package hot_fruit
    
    import (
            "fmt"
            "github.com/pingcap/failpoint"
    )
    
    func Apple() {
            fmt.Println("apple....")
    
            failpoint.Inject("applePanic", func() {
                    panic("apple failpoint triggerd")
            })
    
    }

再次注入一个panic。

hot\_fruit/orange.go：

package hot_fruit
    
    import (
            "fmt"
            "github.com/pingcap/failpoint"
    
    )
    func Orange() {
            fmt.Println("orange....")
    
            failpoint.Inject("orangePanic", func() {
                    panic("orange failpoint triggerd")
            })
    
    }

再次注入一个panic。

# 3. 使用failpoint转换代码 #

$GOPATH/src/github.com/pingcap/failpoint/bin/failpoint-ctl enable

代码转换之后，看下代码文件结构：

tree ./
    ./
    ├── fruit
    │   ├── banana.go
    │   ├── banana.go__failpoint_stash__
    │   └── binding__failpoint_binding__.go
    ├── hot_fruit
    │   ├── apple.go
    │   ├── apple.go__failpoint_stash__
    │   ├── binding__failpoint_binding__.go
    │   ├── orange.go
    │   └── orange.go__failpoint_stash__
    ├── main.go
    
    2 directories, 10 files

可以看到多了几个文件。

如果执行disable，这些文件又会消失。

$GOPATH/src/github.com/pingcap/failpoint/bin/failpoint-ctl disable

# 4.编译和执行 #

使用装换之后的代码，进行编译：

go build -o simple main.go

生成可执行文件`simple`.

正常执行:

./simple
    apple....
    orange....
    banana....
    main end

触发bananaPanic故障执行：

GO_FAILPOINTS="fp_example/fruit/bananaPanic=return(true)" ./simple
    apple....
    orange....
    banana....
    panic: banana failpoint triggerd
    
    goroutine 1 [running]:
    fp_example/fruit.Banana()
    	/Users/lanyang/workspace/go_projects/src/fp_example/fruit/banana.go:12 +0x10e
    main.main()
    	/Users/lanyang/workspace/go_projects/src/fp_example/main.go:13 +0x2c

其中，`fp_example/fruit` 是package名称, `bananaPanic`是注入的故障名称。

触发applePanic故障执行：

GO_FAILPOINTS="fp_example/hot_fruit/applePanic=return(true)" ./simple
    
    apple....
    panic: apple failpoint triggerd
    
    goroutine 1 [running]:
    fp_example/hot_fruit.Apple()
    	/Users/lanyang/workspace/go_projects/src/fp_example/hot_fruit/apple.go:12 +0x10e
    main.main()
    	/Users/lanyang/workspace/go_projects/src/fp_example/main.go:11 +0x22

触发orangePanic故障执行：

GO_FAILPOINTS="fp_example/hot_fruit/orangePanic=return(true)" ./simple
    apple....
    orange....
    panic: orange failpoint triggerd
    
    goroutine 1 [running]:
    fp_example/hot_fruit.Orange()
    	/Users/lanyang/workspace/go_projects/src/fp_example/hot_fruit/orange.go:12 +0x10e
    main.main()
    	/Users/lanyang/workspace/go_projects/src/fp_example/main.go:12 +0x27

# 5.参考 #

[pingcap/failpoint][pingcap_failpoint]

[Golang Failpoint 的设计与实现][Golang Failpoint]

[pingcap_failpoint]: https://github.com/pingcap/failpoint
[Golang Failpoint]: https://juejin.im/post/5cce7a9c6fb9a03247156d15