runner.go

package exe

import (
	"bytes"
	"context"
	"fmt"
	"os"
	"os/exec"
	"text/template"
)

// Runner combines all run functions into one interface.
type Runner interface {
	Run(cmd *exec.Cmd, name string, settings ...SettingsFunc)
	RunE(cmd *exec.Cmd, name string, settings ...SettingsFunc) (err error)

	RunWithOutput(cmd *exec.Cmd, name string, settings ...SettingsFunc) string
	RunWithOutputE(cmd *exec.Cmd, name string, settings ...SettingsFunc) (out string, err error)

	Execute(s string, obj interface{}, settings ...SettingsFunc) *exec.Cmd
	ExecuteE(s string, obj interface{}, settings ...SettingsFunc) (*exec.Cmd, error)

	SplitCommand(string) []string

	ExecuteWithContext(ctx context.Context, s string, obj interface{}, settings ...SettingsFunc) *exec.Cmd
	ExecuteEWithContext(ctx context.Context, s string, obj interface{}, settings ...SettingsFunc) (*exec.Cmd, error)

	ExecuteWithOutput(s string, obj interface{}, settings ...SettingsFunc) string
	ExecuteWithOutputE(s string, obj interface{}, settings ...SettingsFunc) (out string, err error)
}

// DefaultRunner returns the default Runner implementation.
func DefaultRunner() Runner {
	return &runner{}
}

type runner struct {
}

func (r *runner) Run(cmd *exec.Cmd, name string, settings ...SettingsFunc) {
	if err := r.RunE(cmd, name, settings...); err != nil {
		os.Exit(1)
	}
}

func (r *runner) RunE(cmd *exec.Cmd, name string, settings ...SettingsFunc) (err error) {
	setting := extractSettingsFromSlice(settings)
	applySettings(cmd, setting)

	_, err = runWithSettings(cmd, setting)
	if err != nil {
		fmt.Printf("%s failed: %v\n", name, err)
		return err
	}
	return nil
}

func (r *runner) RunWithOutput(cmd *exec.Cmd, name string, settings ...SettingsFunc) string {
	out, err := r.RunWithOutputE(cmd, name, settings...)
	if err != nil {
		os.Exit(1)
	}
	return out
}

func (r *runner) RunWithOutputE(cmd *exec.Cmd, name string, settings ...SettingsFunc) (out string, err error) {
	setting := extractSettingsFromSlice(append(settings, withOutput))
	applySettings(cmd, setting)

	out, err = runWithSettings(cmd, setting)
	if err != nil {
		fmt.Printf("%s - %v failed with %v\n", name, cmd, err)
		return out, err
	}
	return
}

func (r *runner) Execute(s string, obj interface{}, settings ...SettingsFunc) *exec.Cmd {
	return r.ExecuteWithContext(context.Background(), s, obj, settings...)
}

func (r *runner) ExecuteE(s string, obj interface{}, settings ...SettingsFunc) (*exec.Cmd, error) {
	return r.ExecuteEWithContext(context.Background(), s, obj, settings...)
}

func (r *runner) ExecuteWithContext(ctx context.Context, s string, obj interface{}, settings ...SettingsFunc) *exec.Cmd {
	cmd, _ := r.ExecuteEWithContext(ctx, s, obj, settings...)
	return cmd
}

func (r *runner) ExecuteEWithContext(ctx context.Context, s string, obj interface{}, settings ...SettingsFunc) (*exec.Cmd, error) {
	t := template.Must(template.New("").Parse(s))

	var tpl bytes.Buffer

	if err := t.Execute(&tpl, obj); err != nil {
		panic(err)
	}

	fmt.Println(tpl.String())

	args := r.SplitCommand(os.ExpandEnv(tpl.String()))
	//args := strings.Split(tpl.String(), " ")

	if len(args) == 0 {
		panic("template length was zero.")
	}

	cmd := exec.CommandContext(ctx, args[0], args[1:]...)
	return cmd, r.RunE(cmd, args[0], settings...)
}

func (r *runner) ExecuteWithOutput(s string, obj interface{}, settings ...SettingsFunc) string {
	out, err := r.ExecuteWithOutputE(s, obj, settings...)
	if err != nil {
		fmt.Printf("Command failed with %v\n", err)
		os.Exit(1)
	}
	return out
}

func (r *runner) ExecuteWithOutputE(s string, obj interface{}, settings ...SettingsFunc) (out string, err error) {
	t := template.Must(template.New("").Parse(s))

	var tpl bytes.Buffer

	if err := t.Execute(&tpl, obj); err != nil {
		panic(err)
	}

	fmt.Println(tpl.String())

	args := r.SplitCommand(os.ExpandEnv(tpl.String()))

	if len(args) == 0 {
		panic("template length was zero.")
	}

	cmd := exec.Command(args[0], args[1:]...)
	return r.RunWithOutputE(cmd, args[0], settings...)
}

func extractSettingsFromSlice(settings []SettingsFunc) ExecuteSetting {
	setting := defaultSettings()

	for _, settingsFunc := range settings {
		settingsFunc(&setting)
	}

	return setting
}

func applySettings(cmd *exec.Cmd, setting ExecuteSetting) {
	if setting.dir != "" {
		cmd.Dir = os.ExpandEnv(setting.dir)
	}

	if setting.output {
		cmd.Stderr = os.Stderr
		cmd.Stdin = os.Stdin
	} else {
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr
		cmd.Stdin = os.Stdin
	}
}

func defaultSettings() ExecuteSetting {
	return ExecuteSetting{}
}