Zero-downtime deployment tester

todo-tester.go

package main

import (
	"fmt"
	"log"
	"os"
	"os/exec"
	"time"

	"golang.org/x/sync/errgroup"
)

const (
	NumConcurrentSenders = 50
	MaxRequestPerSecond  = 500
	Duration             = 2 * time.Minute
	DeploymentName       = "todod"
	Endpoint             = "http://192.168.64.2:32197/todo"
)

func main() {
	var g errgroup.Group
	g.Go(func() error {
		return runFortio(fortioConfig{
			C:   NumConcurrentSenders,
			QPS: MaxRequestPerSecond,
			T:   Duration,
			URL: Endpoint,
		})
	})
	g.Go(func() error {
		return chaosDeployment(chaosConfig{
			Deployment: DeploymentName,
			T:          Duration,
		})
	})
	if err := g.Wait(); err != nil {
		log.Fatal(err)
	}
}

type chaosConfig struct {
	Deployment string
	T          time.Duration
}

func chaosDeployment(cfg chaosConfig) error {
	if _, err := exec.LookPath("kubectl"); err != nil {
		return fmt.Errorf("kubectl executable not found: %v", err)
	}

	tickCh := time.Tick(cfg.T / 5)
	doneCh := time.After(cfg.T)

loop:
	for {
		select {
		case <-tickCh:
			log.Print("chaos: restarting deployment")
			cmd := exec.Command("kubectl",
				"rollout", "restart", "deployment", cfg.Deployment)
			cmd.Stdout = os.Stdout
			cmd.Stderr = os.Stderr
			if err := cmd.Run(); err != nil {
				return fmt.Errorf("command execution failed: %v", err)
			}
		case <-doneCh:
			break loop
		}
	}
	log.Print("chaos: finished")
	return nil
}

type fortioConfig struct {
	C   int
	QPS float64
	T   time.Duration
	URL string
}

func runFortio(cfg fortioConfig) error {
	if _, err := exec.LookPath("fortio"); err != nil {
		return fmt.Errorf("fortio executable not found: %v", err)
	}

	cmd := exec.Command("fortio",
		"load",
		"-c", fmt.Sprintf("%d", cfg.C),
		"-qps", fmt.Sprintf("%f", cfg.QPS),
		"-t", fmt.Sprintf("%s", cfg.T.String()),
		cfg.URL,
	)

	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	if err := cmd.Run(); err != nil {
		return fmt.Errorf("command execution failed: %v", err)
	}
	return nil
}