helpers.go

package cmd

import (
	"fmt"
	"net/url"
	"os"
	"strings"

	"github.com/golang/glog"
	"github.com/spf13/cobra"
)

const (
	DefaultErrorExitCode = 1

	DefaultWritePermissions = 0760
)

type debugError interface {
	DebugError() (msg string, args []interface{})
}

var fatalErrHandler = fatal

// BehaviorOnFatal allows you to override the default behavior when a fatal
// error occurs, which is to call os.Exit(code). You can pass 'panic' as a function
// here if you prefer the panic() over os.Exit(1).
func BehaviorOnFatal(f func(string, int)) {
	fatalErrHandler = f
}

// DefaultBehaviorOnFatal allows you to undo any previous override.  Useful in
// tests.
func DefaultBehaviorOnFatal() {
	fatalErrHandler = fatal
}

// fatal prints the message (if provided) and then exits. If V(2) or greater,
// glog.Fatal is invoked for extended information.
func fatal(msg string, code int) {
	/*
		if glog.V(2) {
			glog.FatalDepth(2, msg)
		}
	*/
	if len(msg) > 0 {
		// add newline if needed
		if !strings.HasSuffix(msg, "\n") {
			msg += "\n"
		}
		fmt.Fprint(os.Stderr, msg)
	}
	os.Exit(code)
}

// ErrExit may be passed to CheckError to instruct it to output nothing but exit with
// status code 1.
var ErrExit = fmt.Errorf("exit")

// CheckErr prints a user friendly error to STDERR and exits with a non-zero
// exit code. Unrecognized errors will be printed with an "error: " prefix.
//
// This method is generic to the command in use and may be used by non-Kubectl
// commands.
func CheckErr(err error) {
	checkErr("", err, fatalErrHandler)
}

// checkErrWithPrefix works like CheckErr, but adds a caller-defined prefix to non-nil errors
func checkErrWithPrefix(prefix string, err error) {
	checkErr(prefix, err, fatalErrHandler)
}

// checkErr formats a given error as a string and calls the passed handleErr
// func with that string and an kubectl exit code.
func checkErr(prefix string, err error, handleErr func(string, int)) {
	// unwrap aggregates of 1
	/*
		if agg, ok := err.(utilerrors.Aggregate); ok && len(agg.Errors()) == 1 {
			err = agg.Errors()[0]
		}
	*/

	switch {
	case err == nil:
		return
	case err == ErrExit:
		handleErr("", DefaultErrorExitCode)
		return
	/*
		case kerrors.IsInvalid(err):
			details := err.(*kerrors.StatusError).Status().Details
			s := fmt.Sprintf("%sThe %s %q is invalid", prefix, details.Kind, details.Name)
			if len(details.Causes) > 0 {
				errs := statusCausesToAggrError(details.Causes)
				handleErr(MultilineError(s+": ", errs), DefaultErrorExitCode)
			} else {
				handleErr(s, DefaultErrorExitCode)
			}
		case clientcmd.IsConfigurationInvalid(err):
			handleErr(MultilineError(fmt.Sprintf("%sError in configuration: ", prefix), err), DefaultErrorExitCode)
	*/
	default:
		switch err := err.(type) {
		/*
			case *meta.NoResourceMatchError:
				switch {
				case len(err.PartialResource.Group) > 0 && len(err.PartialResource.Version) > 0:
					handleErr(fmt.Sprintf("%sthe server doesn't have a resource type %q in group %q and version %q", prefix, err.PartialResource.Resource, err.PartialResource.Group, err.PartialResource.Version), DefaultErrorExitCode)
				case len(err.PartialResource.Group) > 0:
					handleErr(fmt.Sprintf("%sthe server doesn't have a resource type %q in group %q", prefix, err.PartialResource.Resource, err.PartialResource.Group), DefaultErrorExitCode)
				case len(err.PartialResource.Version) > 0:
					handleErr(fmt.Sprintf("%sthe server doesn't have a resource type %q in version %q", prefix, err.PartialResource.Resource, err.PartialResource.Version), DefaultErrorExitCode)
				default:
					handleErr(fmt.Sprintf("%sthe server doesn't have a resource type %q", prefix, err.PartialResource.Resource), DefaultErrorExitCode)
				}
			case utilerrors.Aggregate:
				handleErr(MultipleErrors(prefix, err.Errors()), DefaultErrorExitCode)
			case utilexec.ExitError:
				// do not print anything, only terminate with given error
				handleErr("", err.ExitStatus())
		*/
		default: // for any other error type
			msg, ok := StandardErrorMessage(err)
			if !ok {
				msg = err.Error()
				if !strings.HasPrefix(msg, "error: ") {
					msg = fmt.Sprintf("error: %s", msg)
				}
			}
			handleErr(msg, DefaultErrorExitCode)
		}
	}
}

// StandardErrorMessage translates common errors into a human readable message, or returns
// false if the error is not one of the recognized types. It may also log extended
// information to glog.
//
// This method is generic to the command in use and may be used by non-Kubectl
// commands.
func StandardErrorMessage(err error) (string, bool) {
	/*
		if debugErr, ok := err.(debugError); ok {
			glog.V(4).Infof(debugErr.DebugError())
		}
		status, isStatus := err.(kerrors.APIStatus)
		switch {
		case isStatus:
			switch s := status.Status(); {
			case s.Reason == unversioned.StatusReasonUnauthorized:
				return fmt.Sprintf("error: You must be logged in to the server (%s)", s.Message), true
			case len(s.Reason) > 0:
				return fmt.Sprintf("Error from server (%s): %s", s.Reason, err.Error()), true
			default:
				return fmt.Sprintf("Error from server: %s", err.Error()), true
			}
		case kerrors.IsUnexpectedObjectError(err):
			return fmt.Sprintf("Server returned an unexpected response: %s", err.Error()), true
		}
	*/
	switch t := err.(type) {
	case *url.Error:
		glog.V(4).Infof("Connection error: %s %s: %v", t.Op, t.URL, t.Err)
		switch {
		case strings.Contains(t.Err.Error(), "connection refused"):
			host := t.URL
			if server, err := url.Parse(t.URL); err == nil {
				host = server.Host
			}
			return fmt.Sprintf("The connection to the server %s was refused - did you specify the right host or port?", host), true
		}
		return fmt.Sprintf("Unable to connect to the server: %v", t.Err), true
	}
	return "", false
}

func UsageError(cmd *cobra.Command, format string, args ...interface{}) error {
	msg := fmt.Sprintf(format, args...)
	return fmt.Errorf("%s\nSee '%s -h' for help and examples.", msg, cmd.CommandPath())
}

func HomeDir() string {
	if h := os.Getenv("HOME"); h != "" {
		return h
	}
	h := os.Getenv("USERPROFILE") // windows
	if h == "" {
		h = "."
	}
	return h
}