mysql service wrapper

gistfile1.go

package main

import (
	"bytes"
	"errors"
	"fmt"
	"os/exec"
	"strings"
	"time"
)

const (
	bashPath = `/bin/bash`
)

var (
	ErrStatusUnknown  = errors.New(`Unknown response from command 'service mysql status'`)
	ErrStderrNotEmpty = errors.New(`Expected stderr from mysql service command to be empty`)
)

type StatusVal int

const (
	StatusUnknown StatusVal = iota
	StatusStopped
	StatusRunning
)

func (v StatusVal) String() string {
	switch v {
	case StatusStopped:
		return `Status: Stopped`
	case StatusRunning:
		return `Status: Running`
	}

	return `Status: Unknown`
}

type ServiceStatus struct {
	Status    StatusVal
	CheckedAt time.Time
}

func (s ServiceStatus) IsRunning() bool {
	return s.Status == StatusRunning
}

func ServiceStart() (ServiceStatus, error) {
	return serviceAction(`start`)
}

func ServiceStop() (ServiceStatus, error) {
	return serviceAction(`stop`)
}

func ServiceGetStatus() (ServiceStatus, error) {
	return serviceAction(`status`)
}

func serviceAction(action string) (ServiceStatus, error) {
	stdout, stderr, err := BashExec(`service mysql ` + action)

	fmt.Println(`stdout:`, stdout)
	fmt.Println(`stderr:`, stderr)

	switch {
	case err != nil:
		return ServiceStatus{}, err
	case stderr != ``:
		return ServiceStatus{}, ErrStderrNotEmpty
	}

	return parseServiceStatusMsg(stdout)
}

func parseServiceStatusMsg(msg string) (ServiceStatus, error) {
	switch {
	case strings.HasPrefix(msg, `mysql start/running`):
		return ServiceStatus{StatusRunning, time.Now()}, nil
	case strings.HasPrefix(msg, `mysql stop/waiting`):
		return ServiceStatus{StatusStopped, time.Now()}, nil
	}

	return ServiceStatus{}, ErrStatusUnknown
}

func BashExec(bashCmd string) (string, string, error) {
	cmd := exec.Command(bashPath, `-c`, bashCmd)

	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	if err := cmd.Start(); err != nil {
		return ``, ``, err
	}

	if err := cmd.Wait(); err != nil {
		return ``, ``, err
	}

	return stdout.String(), stderr.String(), nil
}

func main() {
	serviceStatus, err := ServiceGetStatus()
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println(serviceStatus)

	startStatus, err := ServiceStart()
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println(startStatus)

	stopStatus, err := ServiceStop()
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println(stopStatus)
}