超好用的golang工具分享

// 1. 安装
git clone https://github.com/ofabry/go-callvis.git
cd go-callvis && make install

// 2. 以著名golang开源项目bigcache 的main函数为入口，分析代码调用关系（不打开浏览器 | 忽略标准库的方法）
go-callvis -skipbrowser -nostd ./server/

// 3. 访问http://localhost:7878查看调用关系矢量图

// 一个简单工厂模式代码实现

package simplefactory

import "fmt"

//API is interface
type API interface {
	Say(name string) string
}

//NewAPI return Api instance by type
func NewAPI(t int) API {
	if t == 1 {
		return &hiAPI{}
	} else if t == 2 {
		return &helloAPI{}
	}
	return nil
}

//hiAPI is one of API implement
type hiAPI struct{}

//Say hi to name
func (*hiAPI) Say(name string) string {
	return fmt.Sprintf("Hi, %s", name)
}

//HelloAPI is another API implement
type helloAPI struct{}

//Say hello to name
func (*helloAPI) Say(name string) string {
	return fmt.Sprintf("Hello, %s", name)
}

PS D:\code\golang-design-pattern\00_simple_factory> gotests.exe  -all .\simple.go
Generated TestNewAPI
Generated Test_hiAPI_Say
Generated Test_helloAPI_Say
package simplefactory

import (
        "reflect"
        "testing"
)

func TestNewAPI(t *testing.T) {
        type args struct {
                t int
        }
        tests := []struct {
                name string
                args args
                want API
        }{
                // TODO: Add test cases.
        }
        for _, tt := range tests {
                t.Run(tt.name, func(t *testing.T) {
                        if got := NewAPI(tt.args.t); !reflect.DeepEqual(got, tt.want) {
                                t.Errorf("NewAPI() = %v, want %v", got, tt.want)
                        }
                })
        }
}

func Test_hiAPI_Say(t *testing.T) {
                })
        }
}

func Test_helloAPI_Say(t *testing.T) {
        type args struct {
                name string
        }
        tests := []struct {
                name string
                h    *helloAPI
                args args
                want string
        }{
                // TODO: Add test cases.
        }
        for _, tt := range tests {
                t.Run(tt.name, func(t *testing.T) {
                        h := &helloAPI{}
                        if got := h.Say(tt.args.name); got != tt.want {
                                t.Errorf("helloAPI.Say() = %v, want %v", got, tt.want)
                        }
                })
        }
}
PS D:\code\golang-design-pattern\00_simple_factory>

package main

import (
    "fmt"
    "errors"
    multierror"github.com/hashicorp/go-multierror"
)

func step1() error {
    return errors.New("xhihu")
}

func step2() error {
    return errors.New("yhihu")
}


func main() {
    var result error

    if err := step1(); err != nil {
        result = multierror.Append(result, err)
    }
    if err := step2(); err != nil {
        result = multierror.Append(result, err)
    }

    fmt.Printf(result.Error())

    if merr, ok := result.(*multierror.Error); ok {
        // Use merr.Errors
        // merr.Errors -> []error    
    }

    if errors.Is(result, os.ErrNotExist) {
	// err contains os.ErrNotExist
    }
    return
}

var result *multierror.Error

// ... accumulate errors here, maybe using Append

if result != nil {
	result.ErrorFormat = func([]error) string {
		return "errors!"
	}
}

//demo.go
func leak() error {
    go func() {
        time.Sleep(time.Minute)
    }()

    return nil
}

//demo_test.go
func TestLeakFunction(t *testing.T) {
    defer goleak.VerifyNone(t)

    if err := leak(); err != nil {
        t.Fatal("error not expected")
    }
}

package main

import (
    "fmt"
    "time"
    "log"
    "net/http"
    _ "net/http/pprof"
    "os"
    "runtime"
)

func alloc(outCh chan<- int) {
        buf := make([]byte, 1024)
        outCh <- 0
}

func Leak() {
        outCh := make(chan int)

        go func() {
                if false {
                        <-outCh
                }
                select {}
        }()

        tick := time.Tick(time.Second / 100)
        i := 0
        for range tick {
                i++
                fmt.Println(i)
                //一直分配内存，不释放放
                go alloc(outCh)
}

func main() {
    log.SetFlags(log.Lshortfile | log.LstdFlags)
    log.SetOutput(os.Stdout)

    runtime.GOMAXPROCS(1)
    runtime.SetMutexProfileFraction(1)
    runtime.SetBlockProfileRate(1)

    // 需要性能分析的业务逻辑
    go Leak()

    go func() {
        // 通过http://locahost:6060/debug/pprof进行查看相关的监控信息文件
        if err := http.ListenAndServe(":6060", nil); err != nil {
            log.Fatal(err)
        }
        os.Exit(0)
    }()

    select{}
}


1. go build  prof_demo.go

2. ./prof_demo

3. 手动登陆浏览器，通过http://locahost:6060/debug/pprof进行查看相关的监控信息文件

4. go install github.com/google/pprof@latest

5. yum install graphviz

// 查看火焰图
6. pprof -http=:6061  http://192.168.159.140:6060/debug/pprof/profile

import jsoniter "github.com/json-iterator/go"

var json = jsoniter.ConfigCompatibleWithStandardLibrary
json.Marshal(&data)

json.Unmarshal(input, &data)