text: package main
  
  import (
  	"github.com/emicklei/go-restful"
  	"io"
  	"log"
  	"os"
  	"runtime/pprof"
  )
  
  // ProfilingService is a WebService that can start/stop a CPU profile and write results to a file
  // 	GET /{rootPath}/start will activate CPU profiling
  //	GET /{rootPath}/stop will stop profiling
  //
  // NewProfileService("/profiler", "ace.prof").AddWebServiceTo(restful.DefaultContainer)
  //
  type ProfilingService struct {
  	rootPath   string   // the base (root) of the service, e.g. /profiler
  	cpuprofile string   // the output filename to write profile results, e.g. myservice.prof
  	cpufile    *os.File // if not nil, then profiling is active
  }
  
  func NewProfileService(rootPath string, outputFilename string) *ProfilingService {
  	ps := new(ProfilingService)
  	ps.rootPath = rootPath
  	ps.cpuprofile = outputFilename
  	return ps
  }
  
  // Add this ProfileService to a restful Container
  func (p ProfilingService) AddWebServiceTo(container *restful.Container) {
  	ws := new(restful.WebService)
  	ws.Path(p.rootPath).Consumes("*/*").Produces(restful.MIME_JSON)
  	ws.Route(ws.GET("/start").To(p.startProfiler))
  	ws.Route(ws.GET("/stop").To(p.stopProfiler))
  	container.Add(ws)
  }
  
  func (p *ProfilingService) startProfiler(req *restful.Request, resp *restful.Response) {
  	if p.cpufile != nil {
  		io.WriteString(resp.ResponseWriter, "[restful] CPU profiling already running")
  		return // error?
  	}
  	cpufile, err := os.Create(p.cpuprofile)
  	if err != nil {
  		log.Fatal(err)
  	}
  	// remember for close
  	p.cpufile = cpufile
  	pprof.StartCPUProfile(cpufile)
  	io.WriteString(resp.ResponseWriter, "[restful] CPU profiling started, writing on:"+p.cpuprofile)
  }
  
  func (p *ProfilingService) stopProfiler(req *restful.Request, resp *restful.Response) {
  	if p.cpufile == nil {
  		io.WriteString(resp.ResponseWriter, "[restful] CPU profiling not active")
  		return // error?
  	}
  	pprof.StopCPUProfile()
  	p.cpufile.Close()
  	p.cpufile = nil
  	io.WriteString(resp.ResponseWriter, "[restful] CPU profiling stopped, closing:"+p.cpuprofile)
  }
  
  func main() {} // exists for example compilation only
  