github.com/letsencrypt/boulder@v0.20251208.0/test/load-generator/latency.go (about)

     1  package main
     2  
     3  import (
     4  	"encoding/json"
     5  	"fmt"
     6  	"os"
     7  	"time"
     8  )
     9  
    10  type point struct {
    11  	Sent     time.Time `json:"sent"`
    12  	Finished time.Time `json:"finished"`
    13  	Took     int64     `json:"took"`
    14  	PType    string    `json:"type"`
    15  	Action   string    `json:"action"`
    16  }
    17  
    18  type latencyWriter interface {
    19  	Add(action string, sent, finished time.Time, pType string)
    20  	Close()
    21  }
    22  
    23  type latencyNoop struct{}
    24  
    25  func (ln *latencyNoop) Add(_ string, _, _ time.Time, _ string) {}
    26  
    27  func (ln *latencyNoop) Close() {}
    28  
    29  type latencyFile struct {
    30  	metrics chan *point
    31  	output  *os.File
    32  	stop    chan struct{}
    33  }
    34  
    35  func newLatencyFile(filename string) (latencyWriter, error) {
    36  	if filename == "" {
    37  		return &latencyNoop{}, nil
    38  	}
    39  	fmt.Printf("[+] Opening results file %s\n", filename)
    40  	file, err := os.OpenFile(filename, os.O_RDWR|os.O_APPEND|os.O_CREATE, os.ModePerm)
    41  	if err != nil {
    42  		return nil, err
    43  	}
    44  	f := &latencyFile{
    45  		metrics: make(chan *point, 2048),
    46  		stop:    make(chan struct{}, 1),
    47  		output:  file,
    48  	}
    49  	go f.write()
    50  	return f, nil
    51  }
    52  
    53  func (f *latencyFile) write() {
    54  	for {
    55  		select {
    56  		case p := <-f.metrics:
    57  			data, err := json.Marshal(p)
    58  			if err != nil {
    59  				panic(err)
    60  			}
    61  			_, err = f.output.Write(append(data, []byte("\n")...))
    62  			if err != nil {
    63  				panic(err)
    64  			}
    65  		case <-f.stop:
    66  			return
    67  		}
    68  	}
    69  }
    70  
    71  // Add writes a point to the file
    72  func (f *latencyFile) Add(action string, sent, finished time.Time, pType string) {
    73  	f.metrics <- &point{
    74  		Sent:     sent,
    75  		Finished: finished,
    76  		Took:     finished.Sub(sent).Nanoseconds(),
    77  		PType:    pType,
    78  		Action:   action,
    79  	}
    80  }
    81  
    82  // Close stops f.write() and closes the file, any remaining metrics will be discarded
    83  func (f *latencyFile) Close() {
    84  	f.stop <- struct{}{}
    85  	_ = f.output.Close()
    86  }