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stay Java in , We use it Junit Unit test , use JMH Performance benchmark （benchmark）, use async-profiler analyse cpu performance , use jstack、jmap、arthas Wait to find out the problem . As a relatively new programming language ,golang Are these tools easier to use ？

unit testing

Java Unit testing requires the use of third-party libraries , It's usually Junit, It's complicated to configure . In the use of the golang And then I found out golang The unit test that comes with it is really simple . If we have one cal.go file , Then the corresponding unit test file is cal_test.go, The method must be named TestXxx, This method of unit testing by name is simple and effective , That's what we usually say “ Convention over configuration ”. Let's take a simple example ：

package unit

func add(a int, b int) int {
   return a + b
}

func sub(a int, b int) int {
   return a - b
}

package unit

import (
    "github.com/stretchr/testify/assert"
    "testing"
)

func TestAdd(t *testing.T) {
    assert.Equal(t, 10, add(5, 5))
}

func TestSub(t *testing.T) {
    assert.Equal(t, 0, sub(5, 5))
}

Unit tests only need to be run （ More usage references go help test）

go test --cover cal_test.go cal.go -v

benchmark

It's similar to unit testing ,golang Of benchmark It's also out of the box . stay cal_test.go Add one more BenchmarkAdd Method

package unit

import (
   "github.com/stretchr/testify/assert"
   "testing"
)

func TestAdd(t *testing.T) {
   assert.Equal(t, 10, add(5, 5))
}

func TestSub(t *testing.T) {
   assert.Equal(t, 0, sub(5, 5))
}

func BenchmarkAdd(b *testing.B) {
   for i:= 0; i < b.N; i++ {
      add(5, 5)
   }
}

Execution can be （ More usage references go help test）

go test -bench=. -cpu=4 -count=3

pprof

pprof yes golang It can be used to make cpu、 Memory 、 Tools for lock analysis , Very similar java Of async-profiler. pprof Is very simple to use , You just need to bring in the code net/http/pprof package , Then listen to a port . A simple example is as follows ：

package main

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

func main() {
    go func() {
        //example: visit http://127.0.0.1:6060/debug/pprof in browser.
        err := http.ListenAndServe("0.0.0.0:6060", nil)
        if err != nil {
            fmt.Println("failed to start pprof goroutine:", err)
        }
    }()

    http.HandleFunc("/", handler)
    log.Fatal(http.ListenAndServe("localhost:8000", nil))
}

func handler(w http.ResponseWriter, r *http.Request) {
    time.Sleep(1 * time.Second)
    eat()
    time := time.Now().Unix() * 2 + 1000000
    fmt.Fprintf(w, "URL.Path = %q; time = %d\n", r.URL.Path, time)
}

func eat() {
    loop := 10000000000
    for i := 0; i < loop; i++ {
        // do nothing
    }
}

Enter... On the command line

go tool pprof http://127.0.0.1:6060/debug/pprof/profile

At the same time , Give Way pprof It can collect data , My request here is

curl http://127.0.0.1:8000/hello

wait for 30 Seconds later , At the end of the acquisition, the address of the acquisition file will be displayed

Saved profile in /Users/roshi/pprof/pprof.samples.cpu.003.pb.gz

You can use top Wait for the command to view directly cpu Functions that consume too much , More commands can be used help see .

Or download the file and analyze it with visual interface , have access to

go tool pprof -http=":8080" /User/roshi/pprof/pprof.samples.cpu.003.pb.gz

To open a visual page , see , If an error is reported, it needs to be installed graphviz, The installation documentation can be found here ：https://graphviz.gitlab.io/download/

visit http://localhost:8080/ui/ You can see the following , The block with the largest area represents consumption cpu most

Here's an article right pprof The presentation was very detailed , You can refer to ：https://blog.wolfogre.com/posts/go-ppof-practice/

dlv

pprof useful , But one drawback is that it must be opened in the code in advance , If there is a problem online and it is not turned on pprof, You might need something like that jstack、jmap、arthas And so on . Here is a very good one that has been used recently golang A sharp tool for troubleshooting ——dlv, Please refer to

https://github.com/go-delve/delve

One of its useful features is attach, Sure attach To the running golang Program , see goroutine. This is a good way to check online problems . The installation of each platform is in github It's very clear , What needs to be explained is the installation dlv Of golang Version and process to be checked golang The version needs to be consistent . Write a test program first , Two goroutine, A running , A block

package main

import (
   "fmt"
   "sync"
)

func main()  {
   go count()
   go wait()
   wait()
}

func count()  {
   count := 0
   for {
      count = count + 1
      if count % 1000000000 == 0 {
         fmt.Println("I'm a running routine")
      }
   }
}

func wait()  {
   wg := sync.WaitGroup{}
   wg.Add(1)
   wg.Wait()
}

Run up , And then use dlv Conduct attach, Here's the picture （ The specific order is OK attach After use help see ）

So it's very convenient to see all of them goroutine What are you doing

At the end

As a relatively new programming language ,golang The essence of existing languages is its essence. , Bring necessary tools with you , Lower the threshold further , It's very friendly for beginners to learn .

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