gotic.go

package gotic

import (
	"bufio"
	"fmt"
	"io"
	"log"
	"os"
	"os/exec"
	"strings"
)

/*
Gotic package

Provides a proper interface to execute shell command lines.

License: MIT
*/

// the dependencies below are declared as package vars to enable dummies in unit tests
// BuildCommand builds up a exec.Command.CombinedOutput
var (
	BuildCommand = buildCommand
	logFatal     = log.Fatal
	ReadPrompt   = readPrompt
)

func readPrompt(stdin io.Reader) (text string) {
	reader := bufio.NewReader(stdin)
	text, _ = reader.ReadString('\n')
	return text
}

func buildCommand(command string) ([]byte, error) {
	cmd := exec.Command("bash", "-c", command)
	return cmd.CombinedOutput()
}

// ExecBashPipedCommand executes a simple command or a piped bash command
func ExecBashPipedCommand(command string, showOutput bool) (string, error) {
	out, err := BuildCommand(command)

	count := strings.Count(string(out), "\n")

	if count == 1 {
		out = []byte(strings.ReplaceAll(string(out), "\n", ""))
	}

	if out != nil && showOutput {
		log.Printf("Done executing command: %s", command)
		log.Printf("Output:%s", string(out))
	}

	if err != nil {
		s := fmt.Sprintf("ExecBashPipedCommand failed with %s", err)
		logFatal(s)
	}

	return string(out), err
}

// ExecBashPipedCommandIgnoreExitCode executes a simple command or a piped bash command
func ExecBashPipedCommandIgnoreExitCode(command string, showOutput bool) (string, error) {
	out, err := BuildCommand(command)

	count := strings.Count(string(out), "\n")

	if count == 1 {
		out = []byte(strings.ReplaceAll(string(out), "\n", ""))
	}

	if out != nil && showOutput {
		log.Printf("Done executing command: %s", command)
		log.Printf("Output:%s", string(out))
	}

	if err != nil && showOutput {
		log.Printf("ExecBashPipedCommand failed with %v\n", err)
	}

	return string(out), err
}

// ExecShellScript executes a shell script file
func ExecShellScript(shFilePath string, showOutput bool) (string, string) {
	out, err := BuildCommand(shFilePath)

	if err != nil {
		logFatal("ExecShellScript failed with %s\n", err)
	}

	if out != nil {
		fmt.Printf("Done executing shellscript file %s\n", shFilePath)
		fmt.Printf("Out \n%s\n", string(out))
	}
	return string(out), fmt.Sprintf("%s", err)
}

// Prompt asks to execute a commands
func Prompt(question, command string, showOutput bool) bool {
	fmt.Printf("==> %s '%s'? (y/n)\n", question, command)
	text := ReadPrompt(os.Stdin)

	fmt.Println(text)
	// convert CRLF to LF
	text = strings.Replace(text, "\n", "", -1)

	if strings.Compare("Y", text) == 0 || strings.Compare("y", text) == 0 {
		_, _ = ExecBashPipedCommand(command, showOutput)
		log.Printf("Command '%s' finished\n", command)
		return true
	}
	return false
}