第六章: Go中的大杀器
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简介
介绍了PProf,trace,godebug,gops,metrrics,prometheus等等库来进行性能监控等等的功能
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PProf
- 使用net/http/pprof可以能方便的采集web服务在运行时的数据,直接import十分简单
import ( _ "net/http/pprof" ) // 看看pprof的init发现注入了很多handler func init() { http.HandleFunc("/debug/pprof/", Index) http.HandleFunc("/debug/pprof/cmdline", Cmdline) http.HandleFunc("/debug/pprof/profile", Profile) http.HandleFunc("/debug/pprof/symbol", Symbol) http.HandleFunc("/debug/pprof/trace", Trace) }
可以通过浏览器或是交互式终端进行访问,我选择浏览器。-> IP地址/debug/pprof
浏览器有时效性,真要查问题还是用终端
go tool pprof ip/debug/pprof/profile?seconds=60
不同的路由对应的项,比如cpu/heap/goroutine等等,这就不贴了。
采集生成的profile文件也是可以用web方式查阅的,go tool pprof -http=:6000 profile,如果报graphviz的错说明要装组件。
- 通过Lookup进行采集,这种方式需要写code,支持6种类型,goroutine,threadcreate,heap,block,mutex
这种方式需要写code,支持6种类型,goroutine,threadcreate,heap,block,mutex
package main import ( "io" "net/http" _ "net/http/pprof" "os" "runtime" "runtime/pprof" ) //go tool pprof http://localhost:6060/debug/pprof/profile?seconds=60 func main() { http.HandleFunc("/lookup/heap", func(w http.ResponseWriter, r *http.Request) { _ = pprofLookup(LookupHeap, os.Stdout) }) http.HandleFunc("/lookup/threadcreate", func(w http.ResponseWriter, r *http.Request) { _ = pprofLookup(LookupThreadcreate, os.Stdout) }) http.HandleFunc("/lookup/block", func(w http.ResponseWriter, r *http.Request) { _ = pprofLookup(LookupBlock, os.Stdout) }) http.HandleFunc("/lookup/goroutine", func(w http.ResponseWriter, r *http.Request) { _ = pprofLookup(LookupGoroutine, os.Stdout) }) _ = http.ListenAndServe("0.0.0.0:6060", nil) } type LookupType int8 const ( LookupGoroutine LookupType = iota LookupThreadcreate LookupHeap LookupAllocs LookupBlock LookupMutex ) func pprofLookup(lookupType LookupType, w io.Writer) error { var err error switch lookupType { case LookupGoroutine: p := pprof.Lookup("goroutine") err = p.WriteTo(w, 2) case LookupThreadcreate: p := pprof.Lookup("threadcreate") err = p.WriteTo(w, 2) case LookupHeap: p := pprof.Lookup("heap") err = p.WriteTo(w, 2) case LookupAllocs: p := pprof.Lookup("allocs") err = p.WriteTo(w, 2) case LookupBlock: p := pprof.Lookup("block") err = p.WriteTo(w, 2) case LookupMutex: p := pprof.Lookup("mutex") err = p.WriteTo(w, 2) } return err } func init() { runtime.SetMutexProfileFraction(1) runtime.SetBlockProfileRate(1) }
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trace
详细的使用方式/指标之类还是看书吧,字太多。
package main // --go run .cmd racemain.go 2> trace.out // go build .cmd racemain.go // .main.exe // go tool trace trace.dat import ( "context" "fmt" "os" "runtime" "runtime/trace" "sync" ) func main() { // 为了看协程抢占,这里设置了一个cpu 跑 runtime.GOMAXPROCS(1) f, _ := os.Create("trace.dat") defer f.Close() _ = trace.Start(f) defer trace.Stop() ctx, task := trace.NewTask(context.Background(), "sumTask") defer task.End() var wg sync.WaitGroup wg.Add(10) for i := 0; i < 10; i++ { // 启动10个协程,只是做一个累加运算 go func(region string) { defer wg.Done() // 标记region trace.WithRegion(ctx, region, func() { var sum, k int64 for ; k < 1000000000; k++ { sum += k } fmt.Println(region, sum) }) }(fmt.Sprintf("region_%02d", i)) } wg.Wait() }
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godebug
这个同样太长不写了。环境变量可以通过vscode写入launch.json文件中,比如
"env": { "GODEBUG":"scheddetail=1,schedtrace=1000" }
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进程诊断工具 gops
go get -u github.com/google/gops package main import ( "log" "net/http" "github.com/google/gops/agent" ) func main() { if err := agent.Listen(agent.Options{}); err != nil { log.Fatal("agent listen err : %v", err) } http.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) { _, _ = w.Write([]byte("golang projecct")) }) _ = http.ListenAndServe(":6060", http.DefaultServeMux) }
gops help查看命令,也是有很多,不细写
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metrics 使用expvar标准库
code中自定义了类型,并且封装成了gin中间件,可以和gin联动了
package main import ( "expvar" _ "expvar" "fmt" "net/http" "runtime" "time" "github.com/gin-gonic/gin" ) //http://localhost:6060/debug/vars func main() { router := NewRouter() http.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) { appleCounter.Add(1) _, _ = w.Write([]byte("go project")) }) _ = http.ListenAndServe(":6060", router) } var ( appleCounter *expvar.Int GOMAXPROCSMetrics *expvar.Int upTimeMetrice *upTimeVar ) type upTimeVar struct { value time.Time } func (v *upTimeVar) Set(date time.Time) { v.value = date } func (v *upTimeVar) Add(duration time.Duration) { v.value = v.value.Add(duration) } func (v *upTimeVar) String() string { return v.value.Format(time.UnixDate) } func init() { upTimeMetrice = &upTimeVar{value: time.Now().Local()} expvar.Publish("uptime", upTimeMetrice) appleCounter = expvar.NewInt("apple") GOMAXPROCSMetrics = expvar.NewInt("GOMAXPROCS") GOMAXPROCSMetrics.Set(int64(runtime.NumCPU())) } func Expvar(c *gin.Context) { c.Writer.Header().Set("content-type", "application/json; charset=utf-8") first := true report := func(key string, value interface{}) { if !first { fmt.Fprintf(c.Writer, ", ") } first = false if str, ok := value.(string); ok { fmt.Fprintf(c.Writer, "%q: %q", key, str) } else { fmt.Fprintf(c.Writer, "%q: %v", key, value) } } fmt.Fprintf(c.Writer, "{ ") expvar.Do(func(kv expvar.KeyValue) { report(kv.Key, kv.Value) }) fmt.Fprintf(c.Writer, " } ") } func NewRouter() *gin.Engine { r := gin.New() r.Use(gin.Logger()) r.Use(gin.Recovery()) r.GET("/debug/vars", Expvar) return r }
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Pronmetheus
Pronmetheus还是很出名的。四大指标类型Counter累计指标,Histogram一定时间范围内采样,Gauge可任意变化的指标,Summary也是一定时间内采样,他有仨指标,分位数分布/样本值大小总和/样本总数。
go get -u github.com/prometheus/client_golang package main import ( "net/http" "github.com/prometheus/client_golang/prometheus/promhttp" ) func main() { http.Handle("/metrics", promhttp.Handler()) http.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) { _, _ = w.Write([]byte("go project")) }) _ = http.ListenAndServe(":6060", http.DefaultServeMux) }
启动后访问 :6060/metrics
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其他 包括附录
- 逃逸分析,有很多情况会造成逃逸,这个还是要经验的,初学者的我还是用命令最直接。
// 用-gcflags查看逃逸分析过程 go build -gcflags '-m -l' main.go // 反编译命令查看 go tool compile -S main.go
- Go modules
去年刚开始学时用过gopath,那玩意儿能坑死,还是modules适合老子。
// go get后的模块会缓存在gopath/pkg/mod 和gopath/pkg/sumdb中,如果需要清理可以执行 go clean -modcache
- 为什么defer才能recover
panic结构是一个链表,defer结构中包含了一个对panic结构的引用,在gopanic(interface{})方法中,会触发defer,如果没有defer则会直接跳出,就不会进行接来下的recover了。
还有一些defer了也无法recover的方法,比如fatalthrow,fatalpanic等,比如并发写入map时就会引起fatalthrow。
10种panic方法:数组切片越界,空指针调用,过早关闭HTTP响应体(resp.body.calose()),除零,向关闭的chan发送消息,重复关闭chan,关闭未初始化的的chan,使用未初始化的map,跨goroutine处理panic,sync计数负数。
- 让golang更适应docker
// 这个库可以根据cgroup的挂载信息来修改GOMAXPROCS核数 import _ "go.uber.org/automaxprocs"
完!