prologic-saltyim/utils.go

package saltyim

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"net/http"
	"os"
	"os/exec"
	"syscall"
	"text/template"
	"time"

	log "github.com/sirupsen/logrus"
)

const (
	defaultRequestTimeout = time.Second * 5
)

func MustRenderString(s string, ctx interface{}) string {
	out, err := RenderString(s, ctx)
	if err != nil {
		log.WithError(err).Fatal("error rendering string template")
	}
	return out
}

// DirExists returns true if the  given directory exists
func DirExists(name string) bool {
	stat, err := os.Stat(name)
	if err != nil {
		if os.IsNotExist(err) {
			return false
		}
		return false
	}
	return stat.IsDir()
}

// FileExists returns true if the  given file exists
func FileExists(name string) bool {
	if _, err := os.Stat(name); err != nil {
		if os.IsNotExist(err) {
			return false
		}
	}
	return true
}

// RenderString renders the string `s` as a `text/template` using the provided
// context `ctx` as input into the template.
// Typically used to render the results into a Markdown document.
func RenderString(s string, ctx interface{}) (string, error) {
	t := template.Must(template.New("s").Parse(s))
	buf := bytes.NewBuffer([]byte{})
	err := t.Execute(buf, ctx)
	if err != nil {
		return "", err
	}

	return buf.String(), nil
}

// Request is a generic request handling function for making artbitrary HTPT
// requests to Salty endpoints for looking up Salty Addresses, Configs and
// publishing encrypted messages.
func Request(method, uri string, headers http.Header, body io.Reader) (*http.Response, error) {
	req, err := http.NewRequest(method, uri, body)
	if err != nil {
		return nil, fmt.Errorf("%s: http.NewRequest fail: %s", uri, err)
	}

	if headers == nil {
		headers = make(http.Header)
	}

	// Set a default User-Agent (if none set)
	if headers.Get("User-Agent") == "" {
		headers.Set("User-Agent", fmt.Sprintf("saltyim/%s", FullVersion()))
	}

	req.Header = headers

	client := http.Client{
		Timeout: defaultRequestTimeout,
	}

	res, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("%s: client.Do fail: %s", uri, err)
	}

	if res.StatusCode/100 != 2 {
		return nil, fmt.Errorf("non-2xx response received: %s", res.Status)
	}

	return res, nil
}

// CmdExists ...
func CmdExists(cmd string) bool {
	_, err := exec.LookPath(cmd)
	return err == nil
}

// RunCmd ...
func RunCmd(timeout time.Duration, command string, stdin io.Reader, args ...string) (string, error) {
	var (
		ctx    context.Context
		cancel context.CancelFunc
	)

	if timeout > 0 {
		ctx, cancel = context.WithTimeout(context.Background(), timeout)
	} else {
		ctx, cancel = context.WithCancel(context.Background())
	}
	defer cancel()

	cmd := exec.CommandContext(ctx, command, args...)
	cmd.Stdin = stdin

	out, err := cmd.CombinedOutput()
	if err != nil {
		if exitError, ok := err.(*exec.ExitError); ok {
			if ws, ok := exitError.Sys().(syscall.WaitStatus); ok && ws.Signal() == syscall.SIGKILL {
				err = &ErrCommandKilled{Err: err, Signal: ws.Signal()}
			} else {
				err = &ErrCommandFailed{Err: err, Status: exitError.ExitCode()}
			}
		}

		return "", err
	}

	return string(out), nil
}

// SetTerminalTitle sets the Terminal/Console's title
func SetTerminalTitle(format string, args ...interface{}) {
	fmt.Printf("\033]0;%s\007", fmt.Sprintf(format, args...))
}