Use of golang fault simulation tools failpoint

Testing is an important part of the line before the function.

During the test, to try to cover various scenarios. Fault conditions or scenario testing under unusual circumstances, it is also essential.

How to simulate malfunction?

In FreeBSD, failpoints often used to simulate the failure.

In golang, but also to achieve failpoint, the company is currently pingcap open source project failpoint.

Here achieve golang in failpoint introduction.

1. Install failpoint Tools

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 :-) !

Note: double-check these steps. If wrong, the situation can not be converted code will appear.

After compilation, generate an executable file failpoint-ctl:

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

2. Test the code

Code structure is as follows:

cd $GOPATH/src

mkdir fp_example

cd fp_example

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

Which, main.go contents of the file:

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")
        })

}

Injecting a 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")
        })

} 

Injecting a panic again.

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")
        })

}

Injecting a panic again.

3. Transferable failpoint

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

After transcoding, look at the code file structure:

 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

We can see more than a few files.

If you do disable, those files will disappear.

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

4. compile and execute

Using the code after the change means, to compile:

go build -o simple main.go

Generate an executable file simple.

Normal execution:

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

BananaPanic fault trigger execution:

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

Among them, fp_example/fruitis the package name, bananaPanicis injected fault name.

ApplePanic fault trigger execution:

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

OrangePanic fault trigger execution:

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. Reference

pingcap / failpoint

Design and Implementation of Golang Failpoint