instrument.go

import (
        "github.com/gorilla/mux"
        "net/http/pprof"
        "runtime/debug"
        "runtime"
        runtimepprof "runtime/pprof"
)

const (

debugPath = "/debug"

)


func RegisterDebugInfo(router *mux.Router, prefixRoute string) {
        subRoute := router.NewRoute().PathPrefix(prefixRoute + debugPath ).Subrouter()

        subRoute.HandleFunc("/pprof/heap",getHeapProfile)
        subRoute.HandleFunc("/pprof/cmdline",pprof.Cmdline)
        subRoute.HandleFunc("/pprof/profile",pprof.Profile)

        subRoute.HandleFunc("/goroutines",getGoroutinesCountHandler)
        subRoute.HandleFunc("/stacktrace",getStackTraceHandler)
}





// get the count of number of go routines in the system.
func countGoRoutines() int {
        return runtime.NumGoroutine()
}      

func getGoroutinesCountHandler(w http.ResponseWriter, r *http.Request) {
        // Get the count of number of go routines running.
        count := countGoRoutines()
        w.Write([]byte(strconv.Itoa(count)))
}


func getHeapProfile(w http.ResponseWriter, r *http.Request) {
        runtimepprof.WriteHeapProfile(w)
}

func getStackTraceHandler(w http.ResponseWriter, r *http.Request) {
       stack := debug.Stack()
       w.Write(stack)
       runtimepprof.Lookup("goroutine").WriteTo(w, 2)
}